Eric Lee / smarc-uboot

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# Wolfgang Denk, DENX Software Engineering, wd@denx.de.

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# Wolfgang Denk, DENX Software Engineering, wd@denx.de.

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# SPDX-License-Identifier: GPL-2.0+

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# SPDX-License-Identifier: GPL-2.0+

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Summary:

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Summary:

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========

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========

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This directory contains the source code for U-Boot, a boot loader for

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This directory contains the source code for U-Boot, a boot loader for

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Embedded boards based on PowerPC, ARM, MIPS and several other

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Embedded boards based on PowerPC, ARM, MIPS and several other

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processors, which can be installed in a boot ROM and used to

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processors, which can be installed in a boot ROM and used to

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initialize and test the hardware or to download and run application

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initialize and test the hardware or to download and run application

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code.

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code.

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The development of U-Boot is closely related to Linux: some parts of

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The development of U-Boot is closely related to Linux: some parts of

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the source code originate in the Linux source tree, we have some

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the source code originate in the Linux source tree, we have some

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header files in common, and special provision has been made to

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header files in common, and special provision has been made to

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support booting of Linux images.

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support booting of Linux images.

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Some attention has been paid to make this software easily

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Some attention has been paid to make this software easily

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configurable and extendable. For instance, all monitor commands are

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configurable and extendable. For instance, all monitor commands are

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implemented with the same call interface, so that it's very easy to

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implemented with the same call interface, so that it's very easy to

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add new commands. Also, instead of permanently adding rarely used

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add new commands. Also, instead of permanently adding rarely used

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code (for instance hardware test utilities) to the monitor, you can

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code (for instance hardware test utilities) to the monitor, you can

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load and run it dynamically.

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load and run it dynamically.

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Status:

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Status:

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=======

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=======

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In general, all boards for which a configuration option exists in the

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In general, all boards for which a configuration option exists in the

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Makefile have been tested to some extent and can be considered

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Makefile have been tested to some extent and can be considered

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"working". In fact, many of them are used in production systems.

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"working". In fact, many of them are used in production systems.

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In case of problems see the CHANGELOG file to find out who contributed

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In case of problems see the CHANGELOG file to find out who contributed

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the specific port. In addition, there are various MAINTAINERS files

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the specific port. In addition, there are various MAINTAINERS files

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scattered throughout the U-Boot source identifying the people or

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scattered throughout the U-Boot source identifying the people or

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companies responsible for various boards and subsystems.

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companies responsible for various boards and subsystems.

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Note: As of August, 2010, there is no longer a CHANGELOG file in the

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Note: As of August, 2010, there is no longer a CHANGELOG file in the

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actual U-Boot source tree; however, it can be created dynamically

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actual U-Boot source tree; however, it can be created dynamically

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from the Git log using:

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from the Git log using:

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make CHANGELOG

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make CHANGELOG

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Where to get help:

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Where to get help:

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==================

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==================

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In case you have questions about, problems with or contributions for

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In case you have questions about, problems with or contributions for

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U-Boot, you should send a message to the U-Boot mailing list at

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U-Boot, you should send a message to the U-Boot mailing list at

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<u-boot@lists.denx.de>. There is also an archive of previous traffic

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<u-boot@lists.denx.de>. There is also an archive of previous traffic

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on the mailing list - please search the archive before asking FAQ's.

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on the mailing list - please search the archive before asking FAQ's.

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Please see http://lists.denx.de/pipermail/u-boot and

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Please see http://lists.denx.de/pipermail/u-boot and

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http://dir.gmane.org/gmane.comp.boot-loaders.u-boot

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http://dir.gmane.org/gmane.comp.boot-loaders.u-boot

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Where to get source code:

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Where to get source code:

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=========================

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=========================

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The U-Boot source code is maintained in the Git repository at

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The U-Boot source code is maintained in the Git repository at

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git://www.denx.de/git/u-boot.git ; you can browse it online at

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git://www.denx.de/git/u-boot.git ; you can browse it online at

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http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary

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http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary

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The "snapshot" links on this page allow you to download tarballs of

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The "snapshot" links on this page allow you to download tarballs of

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any version you might be interested in. Official releases are also

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any version you might be interested in. Official releases are also

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available for FTP download from the ftp://ftp.denx.de/pub/u-boot/

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available for FTP download from the ftp://ftp.denx.de/pub/u-boot/

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directory.

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directory.

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Pre-built (and tested) images are available from

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Pre-built (and tested) images are available from

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ftp://ftp.denx.de/pub/u-boot/images/

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ftp://ftp.denx.de/pub/u-boot/images/

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Where we come from:

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Where we come from:

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===================

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===================

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- start from 8xxrom sources

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- start from 8xxrom sources

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- create PPCBoot project (http://sourceforge.net/projects/ppcboot)

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- create PPCBoot project (http://sourceforge.net/projects/ppcboot)

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- clean up code

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- clean up code

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- make it easier to add custom boards

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- make it easier to add custom boards

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- make it possible to add other [PowerPC] CPUs

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- make it possible to add other [PowerPC] CPUs

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- extend functions, especially:

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- extend functions, especially:

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* Provide extended interface to Linux boot loader

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* Provide extended interface to Linux boot loader

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* S-Record download

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* S-Record download

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* network boot

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* network boot

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* PCMCIA / CompactFlash / ATA disk / SCSI ... boot

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* PCMCIA / CompactFlash / ATA disk / SCSI ... boot

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- create ARMBoot project (http://sourceforge.net/projects/armboot)

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- create ARMBoot project (http://sourceforge.net/projects/armboot)

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- add other CPU families (starting with ARM)

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- add other CPU families (starting with ARM)

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- create U-Boot project (http://sourceforge.net/projects/u-boot)

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- create U-Boot project (http://sourceforge.net/projects/u-boot)

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- current project page: see http://www.denx.de/wiki/U-Boot

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- current project page: see http://www.denx.de/wiki/U-Boot

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Names and Spelling:

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Names and Spelling:

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===================

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===================

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The "official" name of this project is "Das U-Boot". The spelling

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The "official" name of this project is "Das U-Boot". The spelling

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"U-Boot" shall be used in all written text (documentation, comments

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"U-Boot" shall be used in all written text (documentation, comments

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in source files etc.). Example:

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in source files etc.). Example:

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This is the README file for the U-Boot project.

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This is the README file for the U-Boot project.

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File names etc. shall be based on the string "u-boot". Examples:

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File names etc. shall be based on the string "u-boot". Examples:

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include/asm-ppc/u-boot.h

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include/asm-ppc/u-boot.h

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#include <asm/u-boot.h>

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#include <asm/u-boot.h>

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Variable names, preprocessor constants etc. shall be either based on

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Variable names, preprocessor constants etc. shall be either based on

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the string "u_boot" or on "U_BOOT". Example:

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the string "u_boot" or on "U_BOOT". Example:

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U_BOOT_VERSION u_boot_logo

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U_BOOT_VERSION u_boot_logo

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IH_OS_U_BOOT u_boot_hush_start

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IH_OS_U_BOOT u_boot_hush_start

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Versioning:

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Versioning:

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===========

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===========

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Starting with the release in October 2008, the names of the releases

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Starting with the release in October 2008, the names of the releases

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were changed from numerical release numbers without deeper meaning

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were changed from numerical release numbers without deeper meaning

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into a time stamp based numbering. Regular releases are identified by

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into a time stamp based numbering. Regular releases are identified by

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names consisting of the calendar year and month of the release date.

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names consisting of the calendar year and month of the release date.

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Additional fields (if present) indicate release candidates or bug fix

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Additional fields (if present) indicate release candidates or bug fix

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releases in "stable" maintenance trees.

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releases in "stable" maintenance trees.

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Examples:

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Examples:

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U-Boot v2009.11 - Release November 2009

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U-Boot v2009.11 - Release November 2009

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U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree

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U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree

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U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release

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U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release

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Directory Hierarchy:

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Directory Hierarchy:

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====================

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====================

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/arch Architecture specific files

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/arch Architecture specific files

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/arc Files generic to ARC architecture

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/arc Files generic to ARC architecture

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/arm Files generic to ARM architecture

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/arm Files generic to ARM architecture

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/m68k Files generic to m68k architecture

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/m68k Files generic to m68k architecture

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/microblaze Files generic to microblaze architecture

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/microblaze Files generic to microblaze architecture

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/mips Files generic to MIPS architecture

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/mips Files generic to MIPS architecture

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/nds32 Files generic to NDS32 architecture

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/nds32 Files generic to NDS32 architecture

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/nios2 Files generic to Altera NIOS2 architecture

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/nios2 Files generic to Altera NIOS2 architecture

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/openrisc Files generic to OpenRISC architecture

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/openrisc Files generic to OpenRISC architecture

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/powerpc Files generic to PowerPC architecture

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/powerpc Files generic to PowerPC architecture

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/sandbox Files generic to HW-independent "sandbox"

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/sandbox Files generic to HW-independent "sandbox"

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/sh Files generic to SH architecture

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/sh Files generic to SH architecture

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/x86 Files generic to x86 architecture

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/x86 Files generic to x86 architecture

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/api Machine/arch independent API for external apps

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/api Machine/arch independent API for external apps

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/board Board dependent files

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/board Board dependent files

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/cmd U-Boot commands functions

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/cmd U-Boot commands functions

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/common Misc architecture independent functions

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/common Misc architecture independent functions

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/configs Board default configuration files

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/configs Board default configuration files

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/disk Code for disk drive partition handling

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/disk Code for disk drive partition handling

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/doc Documentation (don't expect too much)

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/doc Documentation (don't expect too much)

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/drivers Commonly used device drivers

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/drivers Commonly used device drivers

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/dts Contains Makefile for building internal U-Boot fdt.

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/dts Contains Makefile for building internal U-Boot fdt.

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/examples Example code for standalone applications, etc.

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/examples Example code for standalone applications, etc.

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/fs Filesystem code (cramfs, ext2, jffs2, etc.)

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/fs Filesystem code (cramfs, ext2, jffs2, etc.)

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/include Header Files

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/include Header Files

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/lib Library routines generic to all architectures

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/lib Library routines generic to all architectures

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/Licenses Various license files

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/Licenses Various license files

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/net Networking code

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/net Networking code

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/post Power On Self Test

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/post Power On Self Test

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/scripts Various build scripts and Makefiles

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/scripts Various build scripts and Makefiles

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/test Various unit test files

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/test Various unit test files

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/tools Tools to build S-Record or U-Boot images, etc.

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/tools Tools to build S-Record or U-Boot images, etc.

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Software Configuration:

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Software Configuration:

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=======================

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=======================

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Configuration is usually done using C preprocessor defines; the

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Configuration is usually done using C preprocessor defines; the

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rationale behind that is to avoid dead code whenever possible.

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rationale behind that is to avoid dead code whenever possible.

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There are two classes of configuration variables:

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There are two classes of configuration variables:

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* Configuration _OPTIONS_:

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* Configuration _OPTIONS_:

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These are selectable by the user and have names beginning with

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These are selectable by the user and have names beginning with

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"CONFIG_".

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"CONFIG_".

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* Configuration _SETTINGS_:

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* Configuration _SETTINGS_:

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These depend on the hardware etc. and should not be meddled with if

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These depend on the hardware etc. and should not be meddled with if

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you don't know what you're doing; they have names beginning with

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you don't know what you're doing; they have names beginning with

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"CONFIG_SYS_".

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"CONFIG_SYS_".

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Previously, all configuration was done by hand, which involved creating

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Previously, all configuration was done by hand, which involved creating

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symbolic links and editing configuration files manually. More recently,

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symbolic links and editing configuration files manually. More recently,

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U-Boot has added the Kbuild infrastructure used by the Linux kernel,

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U-Boot has added the Kbuild infrastructure used by the Linux kernel,

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allowing you to use the "make menuconfig" command to configure your

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allowing you to use the "make menuconfig" command to configure your

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build.

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build.

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Selection of Processor Architecture and Board Type:

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Selection of Processor Architecture and Board Type:

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---------------------------------------------------

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---------------------------------------------------

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For all supported boards there are ready-to-use default

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For all supported boards there are ready-to-use default

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configurations available; just type "make <board_name>_defconfig".

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configurations available; just type "make <board_name>_defconfig".

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Example: For a TQM823L module type:

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Example: For a TQM823L module type:

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cd u-boot

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cd u-boot

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make TQM823L_defconfig

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make TQM823L_defconfig

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Note: If you're looking for the default configuration file for a board

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Note: If you're looking for the default configuration file for a board

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you're sure used to be there but is now missing, check the file

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you're sure used to be there but is now missing, check the file

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doc/README.scrapyard for a list of no longer supported boards.

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doc/README.scrapyard for a list of no longer supported boards.

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Sandbox Environment:

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Sandbox Environment:

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--------------------

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--------------------

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U-Boot can be built natively to run on a Linux host using the 'sandbox'

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U-Boot can be built natively to run on a Linux host using the 'sandbox'

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board. This allows feature development which is not board- or architecture-

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board. This allows feature development which is not board- or architecture-

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specific to be undertaken on a native platform. The sandbox is also used to

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specific to be undertaken on a native platform. The sandbox is also used to

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run some of U-Boot's tests.

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run some of U-Boot's tests.

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See board/sandbox/README.sandbox for more details.

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See board/sandbox/README.sandbox for more details.

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Board Initialisation Flow:

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Board Initialisation Flow:

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--------------------------

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--------------------------

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This is the intended start-up flow for boards. This should apply for both

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This is the intended start-up flow for boards. This should apply for both

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SPL and U-Boot proper (i.e. they both follow the same rules).

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SPL and U-Boot proper (i.e. they both follow the same rules).

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Note: "SPL" stands for "Secondary Program Loader," which is explained in

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Note: "SPL" stands for "Secondary Program Loader," which is explained in

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more detail later in this file.

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more detail later in this file.

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At present, SPL mostly uses a separate code path, but the function names

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At present, SPL mostly uses a separate code path, but the function names

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and roles of each function are the same. Some boards or architectures

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and roles of each function are the same. Some boards or architectures

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may not conform to this. At least most ARM boards which use

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may not conform to this. At least most ARM boards which use

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CONFIG_SPL_FRAMEWORK conform to this.

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CONFIG_SPL_FRAMEWORK conform to this.

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Execution typically starts with an architecture-specific (and possibly

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Execution typically starts with an architecture-specific (and possibly

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CPU-specific) start.S file, such as:

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CPU-specific) start.S file, such as:

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- arch/arm/cpu/armv7/start.S

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- arch/arm/cpu/armv7/start.S

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- arch/powerpc/cpu/mpc83xx/start.S

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- arch/powerpc/cpu/mpc83xx/start.S

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- arch/mips/cpu/start.S

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- arch/mips/cpu/start.S

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and so on. From there, three functions are called; the purpose and

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and so on. From there, three functions are called; the purpose and

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limitations of each of these functions are described below.

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limitations of each of these functions are described below.

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lowlevel_init():

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lowlevel_init():

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- purpose: essential init to permit execution to reach board_init_f()

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- purpose: essential init to permit execution to reach board_init_f()

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- no global_data or BSS

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- no global_data or BSS

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- there is no stack (ARMv7 may have one but it will soon be removed)

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- there is no stack (ARMv7 may have one but it will soon be removed)

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- must not set up SDRAM or use console

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- must not set up SDRAM or use console

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- must only do the bare minimum to allow execution to continue to

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- must only do the bare minimum to allow execution to continue to

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board_init_f()

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board_init_f()

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- this is almost never needed

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- this is almost never needed

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- return normally from this function

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- return normally from this function

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board_init_f():

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board_init_f():

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- purpose: set up the machine ready for running board_init_r():

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- purpose: set up the machine ready for running board_init_r():

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i.e. SDRAM and serial UART

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i.e. SDRAM and serial UART

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- global_data is available

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- global_data is available

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- stack is in SRAM

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- stack is in SRAM

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- BSS is not available, so you cannot use global/static variables,

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- BSS is not available, so you cannot use global/static variables,

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only stack variables and global_data

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only stack variables and global_data

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Non-SPL-specific notes:

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Non-SPL-specific notes:

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- dram_init() is called to set up DRAM. If already done in SPL this

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- dram_init() is called to set up DRAM. If already done in SPL this

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can do nothing

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can do nothing

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SPL-specific notes:

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SPL-specific notes:

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- you can override the entire board_init_f() function with your own

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- you can override the entire board_init_f() function with your own

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version as needed.

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version as needed.

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- preloader_console_init() can be called here in extremis

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- preloader_console_init() can be called here in extremis

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- should set up SDRAM, and anything needed to make the UART work

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- should set up SDRAM, and anything needed to make the UART work

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- these is no need to clear BSS, it will be done by crt0.S

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- these is no need to clear BSS, it will be done by crt0.S

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- must return normally from this function (don't call board_init_r()

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- must return normally from this function (don't call board_init_r()

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directly)

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directly)

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Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at

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Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at

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this point the stack and global_data are relocated to below

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this point the stack and global_data are relocated to below

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CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of

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CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of

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memory.

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memory.

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board_init_r():

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board_init_r():

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- purpose: main execution, common code

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- purpose: main execution, common code

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- global_data is available

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- global_data is available

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- SDRAM is available

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- SDRAM is available

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- BSS is available, all static/global variables can be used

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- BSS is available, all static/global variables can be used

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- execution eventually continues to main_loop()

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- execution eventually continues to main_loop()

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Non-SPL-specific notes:

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Non-SPL-specific notes:

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- U-Boot is relocated to the top of memory and is now running from

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- U-Boot is relocated to the top of memory and is now running from

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there.

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there.

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SPL-specific notes:

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SPL-specific notes:

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- stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and

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- stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and

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CONFIG_SPL_STACK_R_ADDR points into SDRAM

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CONFIG_SPL_STACK_R_ADDR points into SDRAM

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- preloader_console_init() can be called here - typically this is

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- preloader_console_init() can be called here - typically this is

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done by selecting CONFIG_SPL_BOARD_INIT and then supplying a

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done by selecting CONFIG_SPL_BOARD_INIT and then supplying a

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spl_board_init() function containing this call

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spl_board_init() function containing this call

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- loads U-Boot or (in falcon mode) Linux

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- loads U-Boot or (in falcon mode) Linux

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Configuration Options:

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Configuration Options:

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----------------------

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----------------------

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Configuration depends on the combination of board and CPU type; all

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Configuration depends on the combination of board and CPU type; all

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such information is kept in a configuration file

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such information is kept in a configuration file

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"include/configs/<board_name>.h".

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"include/configs/<board_name>.h".

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Example: For a TQM823L module, all configuration settings are in

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Example: For a TQM823L module, all configuration settings are in

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"include/configs/TQM823L.h".

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"include/configs/TQM823L.h".

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Many of the options are named exactly as the corresponding Linux

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Many of the options are named exactly as the corresponding Linux

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kernel configuration options. The intention is to make it easier to

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kernel configuration options. The intention is to make it easier to

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build a config tool - later.

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build a config tool - later.

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The following options need to be configured:

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The following options need to be configured:

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- CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.

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- CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.

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- Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.

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- Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.

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- Marvell Family Member

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- Marvell Family Member

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CONFIG_SYS_MVFS - define it if you want to enable

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CONFIG_SYS_MVFS - define it if you want to enable

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multiple fs option at one time

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multiple fs option at one time

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for marvell soc family

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for marvell soc family

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- 85xx CPU Options:

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- 85xx CPU Options:

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CONFIG_SYS_PPC64

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CONFIG_SYS_PPC64

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Specifies that the core is a 64-bit PowerPC implementation (implements

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Specifies that the core is a 64-bit PowerPC implementation (implements

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the "64" category of the Power ISA). This is necessary for ePAPR

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the "64" category of the Power ISA). This is necessary for ePAPR

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compliance, among other possible reasons.

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compliance, among other possible reasons.

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CONFIG_SYS_FSL_TBCLK_DIV

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CONFIG_SYS_FSL_TBCLK_DIV

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Defines the core time base clock divider ratio compared to the

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Defines the core time base clock divider ratio compared to the

337

system clock. On most PQ3 devices this is 8, on newer QorIQ

337

system clock. On most PQ3 devices this is 8, on newer QorIQ

338

devices it can be 16 or 32. The ratio varies from SoC to Soc.

338

devices it can be 16 or 32. The ratio varies from SoC to Soc.

339

340

CONFIG_SYS_FSL_PCIE_COMPAT

340

CONFIG_SYS_FSL_PCIE_COMPAT

341

342

Defines the string to utilize when trying to match PCIe device

342

Defines the string to utilize when trying to match PCIe device

343

tree nodes for the given platform.

343

tree nodes for the given platform.

344

345

CONFIG_SYS_FSL_ERRATUM_A004510

345

CONFIG_SYS_FSL_ERRATUM_A004510

346

347

Enables a workaround for erratum A004510. If set,

347

Enables a workaround for erratum A004510. If set,

348

then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and

348

then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and

349

CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.

349

CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.

350

351

CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV

351

CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV

352

CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)

352

CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)

353

354

Defines one or two SoC revisions (low 8 bits of SVR)

354

Defines one or two SoC revisions (low 8 bits of SVR)

355

for which the A004510 workaround should be applied.

355

for which the A004510 workaround should be applied.

356

357

The rest of SVR is either not relevant to the decision

357

The rest of SVR is either not relevant to the decision

358

of whether the erratum is present (e.g. p2040 versus

358

of whether the erratum is present (e.g. p2040 versus

359

p2041) or is implied by the build target, which controls

359

p2041) or is implied by the build target, which controls

360

whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.

360

whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.

361

362

See Freescale App Note 4493 for more information about

362

See Freescale App Note 4493 for more information about

363

this erratum.

363

this erratum.

364

365

CONFIG_A003399_NOR_WORKAROUND

365

CONFIG_A003399_NOR_WORKAROUND

366

Enables a workaround for IFC erratum A003399. It is only

366

Enables a workaround for IFC erratum A003399. It is only

367

required during NOR boot.

367

required during NOR boot.

368

369

CONFIG_A008044_WORKAROUND

369

CONFIG_A008044_WORKAROUND

370

Enables a workaround for T1040/T1042 erratum A008044. It is only

370

Enables a workaround for T1040/T1042 erratum A008044. It is only

371

required during NAND boot and valid for Rev 1.0 SoC revision

371

required during NAND boot and valid for Rev 1.0 SoC revision

372

373

CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY

373

CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY

374

375

This is the value to write into CCSR offset 0x18600

375

This is the value to write into CCSR offset 0x18600

376

according to the A004510 workaround.

376

according to the A004510 workaround.

377

378

CONFIG_SYS_FSL_DSP_DDR_ADDR

378

CONFIG_SYS_FSL_DSP_DDR_ADDR

379

This value denotes start offset of DDR memory which is

379

This value denotes start offset of DDR memory which is

380

connected exclusively to the DSP cores.

380

connected exclusively to the DSP cores.

381

382

CONFIG_SYS_FSL_DSP_M2_RAM_ADDR

382

CONFIG_SYS_FSL_DSP_M2_RAM_ADDR

383

This value denotes start offset of M2 memory

383

This value denotes start offset of M2 memory

384

which is directly connected to the DSP core.

384

which is directly connected to the DSP core.

385

386

CONFIG_SYS_FSL_DSP_M3_RAM_ADDR

386

CONFIG_SYS_FSL_DSP_M3_RAM_ADDR

387

This value denotes start offset of M3 memory which is directly

387

This value denotes start offset of M3 memory which is directly

388

connected to the DSP core.

388

connected to the DSP core.

389

390

CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT

390

CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT

391

This value denotes start offset of DSP CCSR space.

391

This value denotes start offset of DSP CCSR space.

392

393

CONFIG_SYS_FSL_SINGLE_SOURCE_CLK

393

CONFIG_SYS_FSL_SINGLE_SOURCE_CLK

394

Single Source Clock is clocking mode present in some of FSL SoC's.

394

Single Source Clock is clocking mode present in some of FSL SoC's.

395

In this mode, a single differential clock is used to supply

395

In this mode, a single differential clock is used to supply

396

clocks to the sysclock, ddrclock and usbclock.

396

clocks to the sysclock, ddrclock and usbclock.

397

398

CONFIG_SYS_CPC_REINIT_F

398

CONFIG_SYS_CPC_REINIT_F

399

This CONFIG is defined when the CPC is configured as SRAM at the

399

This CONFIG is defined when the CPC is configured as SRAM at the

400

time of U-Boot entry and is required to be re-initialized.

400

time of U-Boot entry and is required to be re-initialized.

401

402

CONFIG_DEEP_SLEEP

402

CONFIG_DEEP_SLEEP

403

Indicates this SoC supports deep sleep feature. If deep sleep is

403

Indicates this SoC supports deep sleep feature. If deep sleep is

404

supported, core will start to execute uboot when wakes up.

404

supported, core will start to execute uboot when wakes up.

405

406

- Generic CPU options:

406

- Generic CPU options:

407

CONFIG_SYS_GENERIC_GLOBAL_DATA

407

CONFIG_SYS_GENERIC_GLOBAL_DATA

408

Defines global data is initialized in generic board board_init_f().

408

Defines global data is initialized in generic board board_init_f().

409

If this macro is defined, global data is created and cleared in

409

If this macro is defined, global data is created and cleared in

410

generic board board_init_f(). Without this macro, architecture/board

410

generic board board_init_f(). Without this macro, architecture/board

411

should initialize global data before calling board_init_f().

411

should initialize global data before calling board_init_f().

412

413

CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN

413

CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN

414

415

Defines the endianess of the CPU. Implementation of those

415

Defines the endianess of the CPU. Implementation of those

416

values is arch specific.

416

values is arch specific.

417

418

CONFIG_SYS_FSL_DDR

418

CONFIG_SYS_FSL_DDR

419

Freescale DDR driver in use. This type of DDR controller is

419

Freescale DDR driver in use. This type of DDR controller is

420

found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core

420

found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core

421

SoCs.

421

SoCs.

422

423

CONFIG_SYS_FSL_DDR_ADDR

423

CONFIG_SYS_FSL_DDR_ADDR

424

Freescale DDR memory-mapped register base.

424

Freescale DDR memory-mapped register base.

425

426

CONFIG_SYS_FSL_DDR_EMU

426

CONFIG_SYS_FSL_DDR_EMU

427

Specify emulator support for DDR. Some DDR features such as

427

Specify emulator support for DDR. Some DDR features such as

428

deskew training are not available.

428

deskew training are not available.

429

430

CONFIG_SYS_FSL_DDRC_GEN1

430

CONFIG_SYS_FSL_DDRC_GEN1

431

Freescale DDR1 controller.

431

Freescale DDR1 controller.

432

433

CONFIG_SYS_FSL_DDRC_GEN2

433

CONFIG_SYS_FSL_DDRC_GEN2

434

Freescale DDR2 controller.

434

Freescale DDR2 controller.

435

436

CONFIG_SYS_FSL_DDRC_GEN3

436

CONFIG_SYS_FSL_DDRC_GEN3

437

Freescale DDR3 controller.

437

Freescale DDR3 controller.

438

439

CONFIG_SYS_FSL_DDRC_GEN4

439

CONFIG_SYS_FSL_DDRC_GEN4

440

Freescale DDR4 controller.

440

Freescale DDR4 controller.

441

442

CONFIG_SYS_FSL_DDRC_ARM_GEN3

442

CONFIG_SYS_FSL_DDRC_ARM_GEN3

443

Freescale DDR3 controller for ARM-based SoCs.

443

Freescale DDR3 controller for ARM-based SoCs.

444

445

CONFIG_SYS_FSL_DDR1

445

CONFIG_SYS_FSL_DDR1

446

Board config to use DDR1. It can be enabled for SoCs with

446

Board config to use DDR1. It can be enabled for SoCs with

447

Freescale DDR1 or DDR2 controllers, depending on the board

447

Freescale DDR1 or DDR2 controllers, depending on the board

448

implemetation.

448

implemetation.

449

450

CONFIG_SYS_FSL_DDR2

450

CONFIG_SYS_FSL_DDR2

451

Board config to use DDR2. It can be enabled for SoCs with

451

Board config to use DDR2. It can be enabled for SoCs with

452

Freescale DDR2 or DDR3 controllers, depending on the board

452

Freescale DDR2 or DDR3 controllers, depending on the board

453

implementation.

453

implementation.

454

455

CONFIG_SYS_FSL_DDR3

455

CONFIG_SYS_FSL_DDR3

456

Board config to use DDR3. It can be enabled for SoCs with

456

Board config to use DDR3. It can be enabled for SoCs with

457

Freescale DDR3 or DDR3L controllers.

457

Freescale DDR3 or DDR3L controllers.

458

459

CONFIG_SYS_FSL_DDR3L

459

CONFIG_SYS_FSL_DDR3L

460

Board config to use DDR3L. It can be enabled for SoCs with

460

Board config to use DDR3L. It can be enabled for SoCs with

461

DDR3L controllers.

461

DDR3L controllers.

462

463

CONFIG_SYS_FSL_DDR4

463

CONFIG_SYS_FSL_DDR4

464

Board config to use DDR4. It can be enabled for SoCs with

464

Board config to use DDR4. It can be enabled for SoCs with

465

DDR4 controllers.

465

DDR4 controllers.

466

467

CONFIG_SYS_FSL_IFC_BE

467

CONFIG_SYS_FSL_IFC_BE

468

Defines the IFC controller register space as Big Endian

468

Defines the IFC controller register space as Big Endian

469

470

CONFIG_SYS_FSL_IFC_LE

470

CONFIG_SYS_FSL_IFC_LE

471

Defines the IFC controller register space as Little Endian

471

Defines the IFC controller register space as Little Endian

472

473

CONFIG_SYS_FSL_IFC_CLK_DIV

473

CONFIG_SYS_FSL_IFC_CLK_DIV

474

Defines divider of platform clock(clock input to IFC controller).

474

Defines divider of platform clock(clock input to IFC controller).

475

476

CONFIG_SYS_FSL_LBC_CLK_DIV

476

CONFIG_SYS_FSL_LBC_CLK_DIV

477

Defines divider of platform clock(clock input to eLBC controller).

477

Defines divider of platform clock(clock input to eLBC controller).

478

479

CONFIG_SYS_FSL_PBL_PBI

479

CONFIG_SYS_FSL_PBL_PBI

480

It enables addition of RCW (Power on reset configuration) in built image.

480

It enables addition of RCW (Power on reset configuration) in built image.

481

Please refer doc/README.pblimage for more details

481

Please refer doc/README.pblimage for more details

482

483

CONFIG_SYS_FSL_PBL_RCW

483

CONFIG_SYS_FSL_PBL_RCW

484

It adds PBI(pre-boot instructions) commands in u-boot build image.

484

It adds PBI(pre-boot instructions) commands in u-boot build image.

485

PBI commands can be used to configure SoC before it starts the execution.

485

PBI commands can be used to configure SoC before it starts the execution.

486

Please refer doc/README.pblimage for more details

486

Please refer doc/README.pblimage for more details

487

488

CONFIG_SPL_FSL_PBL

488

CONFIG_SPL_FSL_PBL

489

It adds a target to create boot binary having SPL binary in PBI format

489

It adds a target to create boot binary having SPL binary in PBI format

490

concatenated with u-boot binary.

490

concatenated with u-boot binary.

491

492

CONFIG_SYS_FSL_DDR_BE

492

CONFIG_SYS_FSL_DDR_BE

493

Defines the DDR controller register space as Big Endian

493

Defines the DDR controller register space as Big Endian

494

495

CONFIG_SYS_FSL_DDR_LE

495

CONFIG_SYS_FSL_DDR_LE

496

Defines the DDR controller register space as Little Endian

496

Defines the DDR controller register space as Little Endian

497

498

CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY

498

CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY

499

Physical address from the view of DDR controllers. It is the

499

Physical address from the view of DDR controllers. It is the

500

same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But

500

same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But

501

it could be different for ARM SoCs.

501

it could be different for ARM SoCs.

502

503

CONFIG_SYS_FSL_DDR_INTLV_256B

503

CONFIG_SYS_FSL_DDR_INTLV_256B

504

DDR controller interleaving on 256-byte. This is a special

504

DDR controller interleaving on 256-byte. This is a special

505

interleaving mode, handled by Dickens for Freescale layerscape

505

interleaving mode, handled by Dickens for Freescale layerscape

506

SoCs with ARM core.

506

SoCs with ARM core.

507

508

CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS

508

CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS

509

Number of controllers used as main memory.

509

Number of controllers used as main memory.

510

511

CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS

511

CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS

512

Number of controllers used for other than main memory.

512

Number of controllers used for other than main memory.

513

514

CONFIG_SYS_FSL_HAS_DP_DDR

514

CONFIG_SYS_FSL_HAS_DP_DDR

515

Defines the SoC has DP-DDR used for DPAA.

515

Defines the SoC has DP-DDR used for DPAA.

516

517

CONFIG_SYS_FSL_SEC_BE

517

CONFIG_SYS_FSL_SEC_BE

518

Defines the SEC controller register space as Big Endian

518

Defines the SEC controller register space as Big Endian

519

520

CONFIG_SYS_FSL_SEC_LE

520

CONFIG_SYS_FSL_SEC_LE

521

Defines the SEC controller register space as Little Endian

521

Defines the SEC controller register space as Little Endian

522

523

- MIPS CPU options:

523

- MIPS CPU options:

524

CONFIG_SYS_INIT_SP_OFFSET

524

CONFIG_SYS_INIT_SP_OFFSET

525

526

Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack

526

Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack

527

pointer. This is needed for the temporary stack before

527

pointer. This is needed for the temporary stack before

528

relocation.

528

relocation.

529

530

CONFIG_SYS_MIPS_CACHE_MODE

530

CONFIG_SYS_MIPS_CACHE_MODE

531

532

Cache operation mode for the MIPS CPU.

532

Cache operation mode for the MIPS CPU.

533

See also arch/mips/include/asm/mipsregs.h.

533

See also arch/mips/include/asm/mipsregs.h.

534

Possible values are:

534

Possible values are:

535

CONF_CM_CACHABLE_NO_WA

535

CONF_CM_CACHABLE_NO_WA

536

CONF_CM_CACHABLE_WA

536

CONF_CM_CACHABLE_WA

537

CONF_CM_UNCACHED

537

CONF_CM_UNCACHED

538

CONF_CM_CACHABLE_NONCOHERENT

538

CONF_CM_CACHABLE_NONCOHERENT

539

CONF_CM_CACHABLE_CE

539

CONF_CM_CACHABLE_CE

540

CONF_CM_CACHABLE_COW

540

CONF_CM_CACHABLE_COW

541

CONF_CM_CACHABLE_CUW

541

CONF_CM_CACHABLE_CUW

542

CONF_CM_CACHABLE_ACCELERATED

542

CONF_CM_CACHABLE_ACCELERATED

543

544

CONFIG_SYS_XWAY_EBU_BOOTCFG

544

CONFIG_SYS_XWAY_EBU_BOOTCFG

545

546

Special option for Lantiq XWAY SoCs for booting from NOR flash.

546

Special option for Lantiq XWAY SoCs for booting from NOR flash.

547

1	/*		File was deleted
2	* Copyright 2007 Freescale Semiconductor, Inc.
3	*
4	* This file is licensed under the terms of the GNU General Public
5	* License Version 2. This file is licensed "as is" without any
6	* warranty of any kind, whether express or implied.
7	*/
8
9	#ifndef _CONFIG_CMD_ALL_H
10	#define _CONFIG_CMD_ALL_H
11
12	/*
13	* Alphabetical list of all possible commands.
14	*/
15
16	#endif /* _CONFIG_CMD_ALL_H */
17		1	/*

GITLAB

Drop config_cmd_all.h

 #
 # (C) Copyright 2000 - 2013
 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 #
 # SPDX-License-Identifier:	GPL-2.0+
 #
 Summary:
 ========
 This directory contains the source code for U-Boot, a boot loader for
 Embedded boards based on PowerPC, ARM, MIPS and several other
 processors, which can be installed in a boot ROM and used to
 initialize and test the hardware or to download and run application
 code.
 The development of U-Boot is closely related to Linux: some parts of
 the source code originate in the Linux source tree, we have some
 header files in common, and special provision has been made to
 support booting of Linux images.
 Some attention has been paid to make this software easily
 configurable and extendable. For instance, all monitor commands are
 implemented with the same call interface, so that it's very easy to
 add new commands. Also, instead of permanently adding rarely used
 code (for instance hardware test utilities) to the monitor, you can
 load and run it dynamically.
 Status:
 =======
 In general, all boards for which a configuration option exists in the
 Makefile have been tested to some extent and can be considered
 "working". In fact, many of them are used in production systems.
 In case of problems see the CHANGELOG file to find out who contributed
 the specific port. In addition, there are various MAINTAINERS files
 scattered throughout the U-Boot source identifying the people or
 companies responsible for various boards and subsystems.
 Note: As of August, 2010, there is no longer a CHANGELOG file in the
 actual U-Boot source tree; however, it can be created dynamically
 from the Git log using:
 	make CHANGELOG
 Where to get help:
 ==================
 In case you have questions about, problems with or contributions for
 U-Boot, you should send a message to the U-Boot mailing list at
 <u-boot@lists.denx.de>. There is also an archive of previous traffic
 on the mailing list - please search the archive before asking FAQ's.
 Please see http://lists.denx.de/pipermail/u-boot and
 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
 Where to get source code:
 =========================
 The U-Boot source code is maintained in the Git repository at
 git://www.denx.de/git/u-boot.git ; you can browse it online at
 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
 The "snapshot" links on this page allow you to download tarballs of
 any version you might be interested in. Official releases are also
 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
 directory.
 Pre-built (and tested) images are available from
 ftp://ftp.denx.de/pub/u-boot/images/
 Where we come from:
 ===================
 - start from 8xxrom sources
 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
 - clean up code
 - make it easier to add custom boards
 - make it possible to add other [PowerPC] CPUs
 - extend functions, especially:
   * Provide extended interface to Linux boot loader
   * S-Record download
   * network boot
   * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
 - create ARMBoot project (http://sourceforge.net/projects/armboot)
 - add other CPU families (starting with ARM)
 - create U-Boot project (http://sourceforge.net/projects/u-boot)
 - current project page: see http://www.denx.de/wiki/U-Boot
 Names and Spelling:
 ===================
 The "official" name of this project is "Das U-Boot". The spelling
 "U-Boot" shall be used in all written text (documentation, comments
 in source files etc.). Example:
 	This is the README file for the U-Boot project.
 File names etc. shall be based on the string "u-boot". Examples:
 	include/asm-ppc/u-boot.h
 	#include <asm/u-boot.h>
 Variable names, preprocessor constants etc. shall be either based on
 the string "u_boot" or on "U_BOOT". Example:
 	U_BOOT_VERSION		u_boot_logo
 	IH_OS_U_BOOT		u_boot_hush_start
 Versioning:
 ===========
 Starting with the release in October 2008, the names of the releases
 were changed from numerical release numbers without deeper meaning
 into a time stamp based numbering. Regular releases are identified by
 names consisting of the calendar year and month of the release date.
 Additional fields (if present) indicate release candidates or bug fix
 releases in "stable" maintenance trees.
 Examples:
 	U-Boot v2009.11	    - Release November 2009
 	U-Boot v2009.11.1   - Release 1 in version November 2009 stable tree
 	U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release
 Directory Hierarchy:
 ====================
 /arch			Architecture specific files
   /arc			Files generic to ARC architecture
   /arm			Files generic to ARM architecture
   /m68k			Files generic to m68k architecture
   /microblaze		Files generic to microblaze architecture
   /mips			Files generic to MIPS architecture
   /nds32		Files generic to NDS32 architecture
   /nios2		Files generic to Altera NIOS2 architecture
   /openrisc		Files generic to OpenRISC architecture
   /powerpc		Files generic to PowerPC architecture
   /sandbox		Files generic to HW-independent "sandbox"
   /sh			Files generic to SH architecture
   /x86			Files generic to x86 architecture
 /api			Machine/arch independent API for external apps
 /board			Board dependent files
 /cmd			U-Boot commands functions
 /common			Misc architecture independent functions
 /configs		Board default configuration files
 /disk			Code for disk drive partition handling
 /doc			Documentation (don't expect too much)
 /drivers		Commonly used device drivers
 /dts			Contains Makefile for building internal U-Boot fdt.
 /examples		Example code for standalone applications, etc.
 /fs			Filesystem code (cramfs, ext2, jffs2, etc.)
 /include		Header Files
 /lib			Library routines generic to all architectures
 /Licenses		Various license files
 /net			Networking code
 /post			Power On Self Test
 /scripts		Various build scripts and Makefiles
 /test			Various unit test files
 /tools			Tools to build S-Record or U-Boot images, etc.
 Software Configuration:
 =======================
 Configuration is usually done using C preprocessor defines; the
 rationale behind that is to avoid dead code whenever possible.
 There are two classes of configuration variables:
 * Configuration _OPTIONS_:
   These are selectable by the user and have names beginning with
   "CONFIG_".
 * Configuration _SETTINGS_:
   These depend on the hardware etc. and should not be meddled with if
   you don't know what you're doing; they have names beginning with
   "CONFIG_SYS_".
 Previously, all configuration was done by hand, which involved creating
 symbolic links and editing configuration files manually. More recently,
 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
 allowing you to use the "make menuconfig" command to configure your
 build.
 Selection of Processor Architecture and Board Type:
 ---------------------------------------------------
 For all supported boards there are ready-to-use default
 configurations available; just type "make <board_name>_defconfig".
 Example: For a TQM823L module type:
 	cd u-boot
 	make TQM823L_defconfig
 Note: If you're looking for the default configuration file for a board
 you're sure used to be there but is now missing, check the file
 doc/README.scrapyard for a list of no longer supported boards.
 Sandbox Environment:
 --------------------
 U-Boot can be built natively to run on a Linux host using the 'sandbox'
 board. This allows feature development which is not board- or architecture-
 specific to be undertaken on a native platform. The sandbox is also used to
 run some of U-Boot's tests.
 See board/sandbox/README.sandbox for more details.
 Board Initialisation Flow:
 --------------------------
 This is the intended start-up flow for boards. This should apply for both
 SPL and U-Boot proper (i.e. they both follow the same rules).
 Note: "SPL" stands for "Secondary Program Loader," which is explained in
 more detail later in this file.
 At present, SPL mostly uses a separate code path, but the function names
 and roles of each function are the same. Some boards or architectures
 may not conform to this.  At least most ARM boards which use
 CONFIG_SPL_FRAMEWORK conform to this.
 Execution typically starts with an architecture-specific (and possibly
 CPU-specific) start.S file, such as:
 	- arch/arm/cpu/armv7/start.S
 	- arch/powerpc/cpu/mpc83xx/start.S
 	- arch/mips/cpu/start.S
 and so on. From there, three functions are called; the purpose and
 limitations of each of these functions are described below.
 lowlevel_init():
 	- purpose: essential init to permit execution to reach board_init_f()
 	- no global_data or BSS
 	- there is no stack (ARMv7 may have one but it will soon be removed)
 	- must not set up SDRAM or use console
 	- must only do the bare minimum to allow execution to continue to
 		board_init_f()
 	- this is almost never needed
 	- return normally from this function
 board_init_f():
 	- purpose: set up the machine ready for running board_init_r():
 		i.e. SDRAM and serial UART
 	- global_data is available
 	- stack is in SRAM
 	- BSS is not available, so you cannot use global/static variables,
 		only stack variables and global_data
 	Non-SPL-specific notes:
 	- dram_init() is called to set up DRAM. If already done in SPL this
 		can do nothing
 	SPL-specific notes:
 	- you can override the entire board_init_f() function with your own
 		version as needed.
 	- preloader_console_init() can be called here in extremis
 	- should set up SDRAM, and anything needed to make the UART work
 	- these is no need to clear BSS, it will be done by crt0.S
 	- must return normally from this function (don't call board_init_r()
 		directly)
 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
 this point the stack and global_data are relocated to below
 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
 memory.
 board_init_r():
 	- purpose: main execution, common code
 	- global_data is available
 	- SDRAM is available
 	- BSS is available, all static/global variables can be used
 	- execution eventually continues to main_loop()
 	Non-SPL-specific notes:
 	- U-Boot is relocated to the top of memory and is now running from
 		there.
 	SPL-specific notes:
 	- stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
 		CONFIG_SPL_STACK_R_ADDR points into SDRAM
 	- preloader_console_init() can be called here - typically this is
 		done by selecting CONFIG_SPL_BOARD_INIT and then supplying a
 		spl_board_init() function containing this call
 	- loads U-Boot or (in falcon mode) Linux
 Configuration Options:
 ----------------------
 Configuration depends on the combination of board and CPU type; all
 such information is kept in a configuration file
 "include/configs/<board_name>.h".
 Example: For a TQM823L module, all configuration settings are in
 "include/configs/TQM823L.h".
 Many of the options are named exactly as the corresponding Linux
 kernel configuration options. The intention is to make it easier to
 build a config tool - later.
 The following options need to be configured:
 - CPU Type:	Define exactly one, e.g. CONFIG_MPC85XX.
 - Board Type:	Define exactly one, e.g. CONFIG_MPC8540ADS.
 - Marvell Family Member
 		CONFIG_SYS_MVFS		- define it if you want to enable
 					  multiple fs option at one time
 					  for marvell soc family
 - 85xx CPU Options:
 		CONFIG_SYS_PPC64
 		Specifies that the core is a 64-bit PowerPC implementation (implements
 		the "64" category of the Power ISA). This is necessary for ePAPR
 		compliance, among other possible reasons.
 		CONFIG_SYS_FSL_TBCLK_DIV
 		Defines the core time base clock divider ratio compared to the
 		system clock.  On most PQ3 devices this is 8, on newer QorIQ
 		devices it can be 16 or 32.  The ratio varies from SoC to Soc.
 		CONFIG_SYS_FSL_PCIE_COMPAT
 		Defines the string to utilize when trying to match PCIe device
 		tree nodes for the given platform.
 		CONFIG_SYS_FSL_ERRATUM_A004510
 		Enables a workaround for erratum A004510.  If set,
 		then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
 		CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
 		CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
 		CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
 		Defines one or two SoC revisions (low 8 bits of SVR)
 		for which the A004510 workaround should be applied.
 		The rest of SVR is either not relevant to the decision
 		of whether the erratum is present (e.g. p2040 versus
 		p2041) or is implied by the build target, which controls
 		whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
 		See Freescale App Note 4493 for more information about
 		this erratum.
 		CONFIG_A003399_NOR_WORKAROUND
 		Enables a workaround for IFC erratum A003399. It is only
 		required during NOR boot.
 		CONFIG_A008044_WORKAROUND
 		Enables a workaround for T1040/T1042 erratum A008044. It is only
 		required during NAND boot and valid for Rev 1.0 SoC revision
 		CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
 		This is the value to write into CCSR offset 0x18600
 		according to the A004510 workaround.
 		CONFIG_SYS_FSL_DSP_DDR_ADDR
 		This value denotes start offset of DDR memory which is
 		connected exclusively to the DSP cores.
 		CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
 		This value denotes start offset of M2 memory
 		which is directly connected to the DSP core.
 		CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
 		This value denotes start offset of M3 memory which is directly
 		connected to the DSP core.
 		CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
 		This value denotes start offset of DSP CCSR space.
 		CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
 		Single Source Clock is clocking mode present in some of FSL SoC's.
 		In this mode, a single differential clock is used to supply
 		clocks to the sysclock, ddrclock and usbclock.
 		CONFIG_SYS_CPC_REINIT_F
 		This CONFIG is defined when the CPC is configured as SRAM at the
 		time of U-Boot entry and is required to be re-initialized.
 		CONFIG_DEEP_SLEEP
 		Indicates this SoC supports deep sleep feature. If deep sleep is
 		supported, core will start to execute uboot when wakes up.
 - Generic CPU options:
 		CONFIG_SYS_GENERIC_GLOBAL_DATA
 		Defines global data is initialized in generic board board_init_f().
 		If this macro is defined, global data is created and cleared in
 		generic board board_init_f(). Without this macro, architecture/board
 		should initialize global data before calling board_init_f().
 		CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
 		Defines the endianess of the CPU. Implementation of those
 		values is arch specific.
 		CONFIG_SYS_FSL_DDR
 		Freescale DDR driver in use. This type of DDR controller is
 		found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
 		SoCs.
 		CONFIG_SYS_FSL_DDR_ADDR
 		Freescale DDR memory-mapped register base.
 		CONFIG_SYS_FSL_DDR_EMU
 		Specify emulator support for DDR. Some DDR features such as
 		deskew training are not available.
 		CONFIG_SYS_FSL_DDRC_GEN1
 		Freescale DDR1 controller.
 		CONFIG_SYS_FSL_DDRC_GEN2
 		Freescale DDR2 controller.
 		CONFIG_SYS_FSL_DDRC_GEN3
 		Freescale DDR3 controller.
 		CONFIG_SYS_FSL_DDRC_GEN4
 		Freescale DDR4 controller.
 		CONFIG_SYS_FSL_DDRC_ARM_GEN3
 		Freescale DDR3 controller for ARM-based SoCs.
 		CONFIG_SYS_FSL_DDR1
 		Board config to use DDR1. It can be enabled for SoCs with
 		Freescale DDR1 or DDR2 controllers, depending on the board
 		implemetation.
 		CONFIG_SYS_FSL_DDR2
 		Board config to use DDR2. It can be enabled for SoCs with
 		Freescale DDR2 or DDR3 controllers, depending on the board
 		implementation.
 		CONFIG_SYS_FSL_DDR3
 		Board config to use DDR3. It can be enabled for SoCs with
 		Freescale DDR3 or DDR3L controllers.
 		CONFIG_SYS_FSL_DDR3L
 		Board config to use DDR3L. It can be enabled for SoCs with
 		DDR3L controllers.
 		CONFIG_SYS_FSL_DDR4
 		Board config to use DDR4. It can be enabled for SoCs with
 		DDR4 controllers.
 		CONFIG_SYS_FSL_IFC_BE
 		Defines the IFC controller register space as Big Endian
 		CONFIG_SYS_FSL_IFC_LE
 		Defines the IFC controller register space as Little Endian
 		CONFIG_SYS_FSL_IFC_CLK_DIV
 		Defines divider of platform clock(clock input to IFC controller).
 		CONFIG_SYS_FSL_LBC_CLK_DIV
 		Defines divider of platform clock(clock input to eLBC controller).
 		CONFIG_SYS_FSL_PBL_PBI
 		It enables addition of RCW (Power on reset configuration) in built image.
 		Please refer doc/README.pblimage for more details
 		CONFIG_SYS_FSL_PBL_RCW
 		It adds PBI(pre-boot instructions) commands in u-boot build image.
 		PBI commands can be used to configure SoC before it starts the execution.
 		Please refer doc/README.pblimage for more details
 		CONFIG_SPL_FSL_PBL
 		It adds a target to create boot binary having SPL binary in PBI format
 		concatenated with u-boot binary.
 		CONFIG_SYS_FSL_DDR_BE
 		Defines the DDR controller register space as Big Endian
 		CONFIG_SYS_FSL_DDR_LE
 		Defines the DDR controller register space as Little Endian
 		CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
 		Physical address from the view of DDR controllers. It is the
 		same as CONFIG_SYS_DDR_SDRAM_BASE for  all Power SoCs. But
 		it could be different for ARM SoCs.
 		CONFIG_SYS_FSL_DDR_INTLV_256B
 		DDR controller interleaving on 256-byte. This is a special
 		interleaving mode, handled by Dickens for Freescale layerscape
 		SoCs with ARM core.
 		CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
 		Number of controllers used as main memory.
 		CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
 		Number of controllers used for other than main memory.
 		CONFIG_SYS_FSL_HAS_DP_DDR
 		Defines the SoC has DP-DDR used for DPAA.
 		CONFIG_SYS_FSL_SEC_BE
 		Defines the SEC controller register space as Big Endian
 		CONFIG_SYS_FSL_SEC_LE
 		Defines the SEC controller register space as Little Endian
 - MIPS CPU options:
 		CONFIG_SYS_INIT_SP_OFFSET
 		Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
 		pointer. This is needed for the temporary stack before
 		relocation.
 		CONFIG_SYS_MIPS_CACHE_MODE
 		Cache operation mode for the MIPS CPU.
 		See also arch/mips/include/asm/mipsregs.h.
 		Possible values are:
 			CONF_CM_CACHABLE_NO_WA
 			CONF_CM_CACHABLE_WA
 			CONF_CM_UNCACHED
 			CONF_CM_CACHABLE_NONCOHERENT
 			CONF_CM_CACHABLE_CE
 			CONF_CM_CACHABLE_COW
 			CONF_CM_CACHABLE_CUW
 			CONF_CM_CACHABLE_ACCELERATED
 		CONFIG_SYS_XWAY_EBU_BOOTCFG
 		Special option for Lantiq XWAY SoCs for booting from NOR flash.
 		See also arch/mips/cpu/mips32/start.S.
 		CONFIG_XWAY_SWAP_BYTES
 		Enable compilation of tools/xway-swap-bytes needed for Lantiq
 		XWAY SoCs for booting from NOR flash. The U-Boot image needs to
 		be swapped if a flash programmer is used.
 - ARM options:
 		CONFIG_SYS_EXCEPTION_VECTORS_HIGH
 		Select high exception vectors of the ARM core, e.g., do not
 		clear the V bit of the c1 register of CP15.
 		COUNTER_FREQUENCY
 		Generic timer clock source frequency.
 		COUNTER_FREQUENCY_REAL
 		Generic timer clock source frequency if the real clock is
 		different from COUNTER_FREQUENCY, and can only be determined
 		at run time.
 - Tegra SoC options:
 		CONFIG_TEGRA_SUPPORT_NON_SECURE
 		Support executing U-Boot in non-secure (NS) mode. Certain
 		impossible actions will be skipped if the CPU is in NS mode,
 		such as ARM architectural timer initialization.
 - Linux Kernel Interface:
 		CONFIG_CLOCKS_IN_MHZ
 		U-Boot stores all clock information in Hz
 		internally. For binary compatibility with older Linux
 		kernels (which expect the clocks passed in the
 		bd_info data to be in MHz) the environment variable
 		"clocks_in_mhz" can be defined so that U-Boot
 		converts clock data to MHZ before passing it to the
 		Linux kernel.
 		When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
 		"clocks_in_mhz=1" is automatically included in the
 		default environment.
 		CONFIG_MEMSIZE_IN_BYTES		[relevant for MIPS only]
 		When transferring memsize parameter to Linux, some versions
 		expect it to be in bytes, others in MB.
 		Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
 		CONFIG_OF_LIBFDT
 		New kernel versions are expecting firmware settings to be
 		passed using flattened device trees (based on open firmware
 		concepts).
 		CONFIG_OF_LIBFDT
 		 * New libfdt-based support
 		 * Adds the "fdt" command
 		 * The bootm command automatically updates the fdt
 		OF_TBCLK - The timebase frequency.
 		OF_STDOUT_PATH - The path to the console device
 		boards with QUICC Engines require OF_QE to set UCC MAC
 		addresses
 		CONFIG_OF_BOARD_SETUP
 		Board code has addition modification that it wants to make
 		to the flat device tree before handing it off to the kernel
 		CONFIG_OF_SYSTEM_SETUP
 		Other code has addition modification that it wants to make
 		to the flat device tree before handing it off to the kernel.
 		This causes ft_system_setup() to be called before booting
 		the kernel.
 		CONFIG_OF_IDE_FIXUP
 		U-Boot can detect if an IDE device is present or not.
 		If not, and this new config option is activated, U-Boot
 		removes the ATA node from the DTS before booting Linux,
 		so the Linux IDE driver does not probe the device and
 		crash. This is needed for buggy hardware (uc101) where
 		no pull down resistor is connected to the signal IDE5V_DD7.
 		CONFIG_MACH_TYPE	[relevant for ARM only][mandatory]
 		This setting is mandatory for all boards that have only one
 		machine type and must be used to specify the machine type
 		number as it appears in the ARM machine registry
 		(see http://www.arm.linux.org.uk/developer/machines/).
 		Only boards that have multiple machine types supported
 		in a single configuration file and the machine type is
 		runtime discoverable, do not have to use this setting.
 - vxWorks boot parameters:
 		bootvx constructs a valid bootline using the following
 		environments variables: bootdev, bootfile, ipaddr, netmask,
 		serverip, gatewayip, hostname, othbootargs.
 		It loads the vxWorks image pointed bootfile.
 		Note: If a "bootargs" environment is defined, it will overwride
 		the defaults discussed just above.
 - Cache Configuration:
 		CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
 		CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
 		CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
 - Cache Configuration for ARM:
 		CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
 				      controller
 		CONFIG_SYS_PL310_BASE - Physical base address of PL310
 					controller register space
 - Serial Ports:
 		CONFIG_PL010_SERIAL
 		Define this if you want support for Amba PrimeCell PL010 UARTs.
 		CONFIG_PL011_SERIAL
 		Define this if you want support for Amba PrimeCell PL011 UARTs.
 		CONFIG_PL011_CLOCK
 		If you have Amba PrimeCell PL011 UARTs, set this variable to
 		the clock speed of the UARTs.
 		CONFIG_PL01x_PORTS
 		If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
 		define this to a list of base addresses for each (supported)
 		port. See e.g. include/configs/versatile.h
 		CONFIG_SERIAL_HW_FLOW_CONTROL
 		Define this variable to enable hw flow control in serial driver.
 		Current user of this option is drivers/serial/nsl16550.c driver
 - Console Baudrate:
 		CONFIG_BAUDRATE - in bps
 		Select one of the baudrates listed in
 		CONFIG_SYS_BAUDRATE_TABLE, see below.
 - Autoboot Command:
 		CONFIG_BOOTCOMMAND
 		Only needed when CONFIG_BOOTDELAY is enabled;
 		define a command string that is automatically executed
 		when no character is read on the console interface
 		within "Boot Delay" after reset.
 		CONFIG_BOOTARGS
 		This can be used to pass arguments to the bootm
 		command. The value of CONFIG_BOOTARGS goes into the
 		environment value "bootargs".
 		CONFIG_RAMBOOT and CONFIG_NFSBOOT
 		The value of these goes into the environment as
 		"ramboot" and "nfsboot" respectively, and can be used
 		as a convenience, when switching between booting from
 		RAM and NFS.
 - Bootcount:
 		CONFIG_BOOTCOUNT_LIMIT
 		Implements a mechanism for detecting a repeating reboot
 		cycle, see:
 		http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
 		CONFIG_BOOTCOUNT_ENV
 		If no softreset save registers are found on the hardware
 		"bootcount" is stored in the environment. To prevent a
 		saveenv on all reboots, the environment variable
 		"upgrade_available" is used. If "upgrade_available" is
 		0, "bootcount" is always 0, if "upgrade_available" is
 		1 "bootcount" is incremented in the environment.
 		So the Userspace Applikation must set the "upgrade_available"
 		and "bootcount" variable to 0, if a boot was successfully.
 - Pre-Boot Commands:
 		CONFIG_PREBOOT
 		When this option is #defined, the existence of the
 		environment variable "preboot" will be checked
 		immediately before starting the CONFIG_BOOTDELAY
 		countdown and/or running the auto-boot command resp.
 		entering interactive mode.
 		This feature is especially useful when "preboot" is
 		automatically generated or modified. For an example
 		see the LWMON board specific code: here "preboot" is
 		modified when the user holds down a certain
 		combination of keys on the (special) keyboard when
 		booting the systems
 - Serial Download Echo Mode:
 		CONFIG_LOADS_ECHO
 		If defined to 1, all characters received during a
 		serial download (using the "loads" command) are
 		echoed back. This might be needed by some terminal
 		emulations (like "cu"), but may as well just take
 		time on others. This setting #define's the initial
 		value of the "loads_echo" environment variable.
 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
 		CONFIG_KGDB_BAUDRATE
 		Select one of the baudrates listed in
 		CONFIG_SYS_BAUDRATE_TABLE, see below.
 - Monitor Functions:
-		Monitor commands can be included or excluded
-		from the build by using the #include files
-		<config_cmd_all.h> and #undef'ing unwanted
-		commands, or adding #define's for wanted commands.
 		The default command configuration includes all commands
 		except those marked below with a "*".
 		CONFIG_CMD_AES		  AES 128 CBC encrypt/decrypt
 		CONFIG_CMD_ASKENV	* ask for env variable
 		CONFIG_CMD_BDI		  bdinfo
 		CONFIG_CMD_BOOTD	  bootd
 		CONFIG_CMD_BOOTI	* ARM64 Linux kernel Image support
 		CONFIG_CMD_CACHE	* icache, dcache
 		CONFIG_CMD_CONSOLE	  coninfo
 		CONFIG_CMD_DHCP		* DHCP support
 		CONFIG_CMD_DIAG		* Diagnostics
 		CONFIG_CMD_ECHO		  echo arguments
 		CONFIG_CMD_EDITENV	  edit env variable
 		CONFIG_CMD_ELF		* bootelf, bootvx
 		CONFIG_CMD_ENV_EXISTS	* check existence of env variable
 		CONFIG_CMD_EXPORTENV	* export the environment
 		CONFIG_CMD_EXT2		* ext2 command support
 		CONFIG_CMD_EXT4		* ext4 command support
 		CONFIG_CMD_FS_GENERIC	* filesystem commands (e.g. load, ls)
 					  that work for multiple fs types
 		CONFIG_CMD_FS_UUID	* Look up a filesystem UUID
 		CONFIG_CMD_SAVEENV	  saveenv
 		CONFIG_CMD_FLASH	  flinfo, erase, protect
 		CONFIG_CMD_FPGA		  FPGA device initialization support
 		CONFIG_CMD_GO		* the 'go' command (exec code)
 		CONFIG_CMD_GREPENV	* search environment
 		CONFIG_CMD_I2C		* I2C serial bus support
 		CONFIG_CMD_IMI		  iminfo
 		CONFIG_CMD_IMLS		  List all images found in NOR flash
 		CONFIG_CMD_IMLS_NAND	* List all images found in NAND flash
 		CONFIG_CMD_IMPORTENV	* import an environment
 		CONFIG_CMD_INI		* import data from an ini file into the env
 		CONFIG_CMD_ITEST	  Integer/string test of 2 values
 		CONFIG_CMD_LDRINFO	* ldrinfo (display Blackfin loader)
 		CONFIG_CMD_LINK_LOCAL	* link-local IP address auto-configuration
 					  (169.254.*.*)
 		CONFIG_CMD_LOADB	  loadb
 		CONFIG_CMD_LOADS	  loads
 		CONFIG_CMD_MD5SUM	* print md5 message digest
 					  (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
 		CONFIG_CMD_MEMINFO	* Display detailed memory information
 		CONFIG_CMD_MEMORY	  md, mm, nm, mw, cp, cmp, crc, base,
 					  loop, loopw
 		CONFIG_CMD_MEMTEST	* mtest
 		CONFIG_CMD_MISC		  Misc functions like sleep etc
 		CONFIG_CMD_MMC		* MMC memory mapped support
 		CONFIG_CMD_MII		* MII utility commands
 		CONFIG_CMD_NET		  bootp, tftpboot, rarpboot
 		CONFIG_CMD_NFS		  NFS support
 		CONFIG_CMD_PING		* send ICMP ECHO_REQUEST to network
 					  host
 		CONFIG_CMD_RUN		  run command in env variable
 		CONFIG_CMD_SF		* Read/write/erase SPI NOR flash
 		CONFIG_CMD_SOFTSWITCH	* Soft switch setting command for BF60x
 		CONFIG_CMD_SOURCE	  "source" command Support
 		CONFIG_CMD_SPI		* SPI serial bus support
 		CONFIG_CMD_TFTPSRV	* TFTP transfer in server mode
 		CONFIG_CMD_TFTPPUT	* TFTP put command (upload)
 		CONFIG_CMD_TIME		* run command and report execution time (ARM specific)
 		CONFIG_CMD_TIMER	* access to the system tick timer
 		CONFIG_CMD_USB		* USB support
 		CONFIG_CMD_CDP		* Cisco Discover Protocol support
 		CONFIG_CMD_XIMG		  Load part of Multi Image
 		EXAMPLE: If you want all functions except of network
 		support you can write:
 		#include "config_cmd_all.h"
 		#undef CONFIG_CMD_NET
 	Other Commands:
 		fdt (flattened device tree) command: CONFIG_OF_LIBFDT
 	Note:	Don't enable the "icache" and "dcache" commands
 		(configuration option CONFIG_CMD_CACHE) unless you know
 		what you (and your U-Boot users) are doing. Data
 		cache cannot be enabled on systems like the
 		8xx (where accesses to the IMMR region must be
 		uncached), and it cannot be disabled on all other
 		systems where we (mis-) use the data cache to hold an
 		initial stack and some data.
 		XXX - this list needs to get updated!
 - Removal of commands
 		If no commands are needed to boot, you can disable
 		CONFIG_CMDLINE to remove them. In this case, the command line
 		will not be available, and when U-Boot wants to execute the
 		boot command (on start-up) it will call board_run_command()
 		instead. This can reduce image size significantly for very
 		simple boot procedures.
 - Regular expression support:
 		CONFIG_REGEX
 		If this variable is defined, U-Boot is linked against
 		the SLRE (Super Light Regular Expression) library,
 		which adds regex support to some commands, as for
 		example "env grep" and "setexpr".
 - Device tree:
 		CONFIG_OF_CONTROL
 		If this variable is defined, U-Boot will use a device tree
 		to configure its devices, instead of relying on statically
 		compiled #defines in the board file. This option is
 		experimental and only available on a few boards. The device
 		tree is available in the global data as gd->fdt_blob.
 		U-Boot needs to get its device tree from somewhere. This can
 		be done using one of the three options below:
 		CONFIG_OF_EMBED
 		If this variable is defined, U-Boot will embed a device tree
 		binary in its image. This device tree file should be in the
 		board directory and called <soc>-<board>.dts. The binary file
 		is then picked up in board_init_f() and made available through
 		the global data structure as gd->blob.
 		CONFIG_OF_SEPARATE
 		If this variable is defined, U-Boot will build a device tree
 		binary. It will be called u-boot.dtb. Architecture-specific
 		code will locate it at run-time. Generally this works by:
 			cat u-boot.bin u-boot.dtb >image.bin
 		and in fact, U-Boot does this for you, creating a file called
 		u-boot-dtb.bin which is useful in the common case. You can
 		still use the individual files if you need something more
 		exotic.
 		CONFIG_OF_BOARD
 		If this variable is defined, U-Boot will use the device tree
 		provided by the board at runtime instead of embedding one with
 		the image. Only boards defining board_fdt_blob_setup() support
 		this option (see include/fdtdec.h file).
 - Watchdog:
 		CONFIG_WATCHDOG
 		If this variable is defined, it enables watchdog
 		support for the SoC. There must be support in the SoC
 		specific code for a watchdog. For the 8xx
 		CPUs, the SIU Watchdog feature is enabled in the SYPCR
 		register.  When supported for a specific SoC is
 		available, then no further board specific code should
 		be needed to use it.
 		CONFIG_HW_WATCHDOG
 		When using a watchdog circuitry external to the used
 		SoC, then define this variable and provide board
 		specific code for the "hw_watchdog_reset" function.
 		CONFIG_AT91_HW_WDT_TIMEOUT
 		specify the timeout in seconds. default 2 seconds.
 - U-Boot Version:
 		CONFIG_VERSION_VARIABLE
 		If this variable is defined, an environment variable
 		named "ver" is created by U-Boot showing the U-Boot
 		version as printed by the "version" command.
 		Any change to this variable will be reverted at the
 		next reset.
 - Real-Time Clock:
 		When CONFIG_CMD_DATE is selected, the type of the RTC
 		has to be selected, too. Define exactly one of the
 		following options:
 		CONFIG_RTC_PCF8563	- use Philips PCF8563 RTC
 		CONFIG_RTC_MC13XXX	- use MC13783 or MC13892 RTC
 		CONFIG_RTC_MC146818	- use MC146818 RTC
 		CONFIG_RTC_DS1307	- use Maxim, Inc. DS1307 RTC
 		CONFIG_RTC_DS1337	- use Maxim, Inc. DS1337 RTC
 		CONFIG_RTC_DS1338	- use Maxim, Inc. DS1338 RTC
 		CONFIG_RTC_DS1339	- use Maxim, Inc. DS1339 RTC
 		CONFIG_RTC_DS164x	- use Dallas DS164x RTC
 		CONFIG_RTC_ISL1208	- use Intersil ISL1208 RTC
 		CONFIG_RTC_MAX6900	- use Maxim, Inc. MAX6900 RTC
 		CONFIG_RTC_DS1337_NOOSC	- Turn off the OSC output for DS1337
 		CONFIG_SYS_RV3029_TCR	- enable trickle charger on
 					  RV3029 RTC.
 		Note that if the RTC uses I2C, then the I2C interface
 		must also be configured. See I2C Support, below.
 - GPIO Support:
 		CONFIG_PCA953X		- use NXP's PCA953X series I2C GPIO
 		The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
 		chip-ngpio pairs that tell the PCA953X driver the number of
 		pins supported by a particular chip.
 		Note that if the GPIO device uses I2C, then the I2C interface
 		must also be configured. See I2C Support, below.
 - I/O tracing:
 		When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
 		accesses and can checksum them or write a list of them out
 		to memory. See the 'iotrace' command for details. This is
 		useful for testing device drivers since it can confirm that
 		the driver behaves the same way before and after a code
 		change. Currently this is supported on sandbox and arm. To
 		add support for your architecture, add '#include <iotrace.h>'
 		to the bottom of arch/<arch>/include/asm/io.h and test.
 		Example output from the 'iotrace stats' command is below.
 		Note that if the trace buffer is exhausted, the checksum will
 		still continue to operate.
 			iotrace is enabled
 			Start:  10000000	(buffer start address)
 			Size:   00010000	(buffer size)
 			Offset: 00000120	(current buffer offset)
 			Output: 10000120	(start + offset)
 			Count:  00000018	(number of trace records)
 			CRC32:  9526fb66	(CRC32 of all trace records)
 - Timestamp Support:
 		When CONFIG_TIMESTAMP is selected, the timestamp
 		(date and time) of an image is printed by image
 		commands like bootm or iminfo. This option is
 		automatically enabled when you select CONFIG_CMD_DATE .
 - Partition Labels (disklabels) Supported:
 		Zero or more of the following:
 		CONFIG_MAC_PARTITION   Apple's MacOS partition table.
 		CONFIG_ISO_PARTITION   ISO partition table, used on CDROM etc.
 		CONFIG_EFI_PARTITION   GPT partition table, common when EFI is the
 				       bootloader.  Note 2TB partition limit; see
 				       disk/part_efi.c
 		CONFIG_MTD_PARTITIONS  Memory Technology Device partition table.
 		If IDE or SCSI support is enabled (CONFIG_IDE or
 		CONFIG_SCSI) you must configure support for at
 		least one non-MTD partition type as well.
 - IDE Reset method:
 		CONFIG_IDE_RESET_ROUTINE - this is defined in several
 		board configurations files but used nowhere!
 		CONFIG_IDE_RESET - is this is defined, IDE Reset will
 		be performed by calling the function
 			ide_set_reset(int reset)
 		which has to be defined in a board specific file
 - ATAPI Support:
 		CONFIG_ATAPI
 		Set this to enable ATAPI support.
 - LBA48 Support
 		CONFIG_LBA48
 		Set this to enable support for disks larger than 137GB
 		Also look at CONFIG_SYS_64BIT_LBA.
 		Whithout these , LBA48 support uses 32bit variables and will 'only'
 		support disks up to 2.1TB.
 		CONFIG_SYS_64BIT_LBA:
 			When enabled, makes the IDE subsystem use 64bit sector addresses.
 			Default is 32bit.
 - SCSI Support:
 		CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
 		CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
 		CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
 		maximum numbers of LUNs, SCSI ID's and target
 		devices.
 		The environment variable 'scsidevs' is set to the number of
 		SCSI devices found during the last scan.
 - NETWORK Support (PCI):
 		CONFIG_E1000
 		Support for Intel 8254x/8257x gigabit chips.
 		CONFIG_E1000_SPI
 		Utility code for direct access to the SPI bus on Intel 8257x.
 		This does not do anything useful unless you set at least one
 		of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
 		CONFIG_E1000_SPI_GENERIC
 		Allow generic access to the SPI bus on the Intel 8257x, for
 		example with the "sspi" command.
 		CONFIG_CMD_E1000
 		Management command for E1000 devices.  When used on devices
 		with SPI support you can reprogram the EEPROM from U-Boot.
 		CONFIG_EEPRO100
 		Support for Intel 82557/82559/82559ER chips.
 		Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
 		write routine for first time initialisation.
 		CONFIG_TULIP
 		Support for Digital 2114x chips.
 		Optional CONFIG_TULIP_SELECT_MEDIA for board specific
 		modem chip initialisation (KS8761/QS6611).
 		CONFIG_NATSEMI
 		Support for National dp83815 chips.
 		CONFIG_NS8382X
 		Support for National dp8382[01] gigabit chips.
 - NETWORK Support (other):
 		CONFIG_DRIVER_AT91EMAC
 		Support for AT91RM9200 EMAC.
 			CONFIG_RMII
 			Define this to use reduced MII inteface
 			CONFIG_DRIVER_AT91EMAC_QUIET
 			If this defined, the driver is quiet.
 			The driver doen't show link status messages.
 		CONFIG_CALXEDA_XGMAC
 		Support for the Calxeda XGMAC device
 		CONFIG_LAN91C96
 		Support for SMSC's LAN91C96 chips.
 			CONFIG_LAN91C96_USE_32_BIT
 			Define this to enable 32 bit addressing
 		CONFIG_SMC91111
 		Support for SMSC's LAN91C111 chip
 			CONFIG_SMC91111_BASE
 			Define this to hold the physical address
 			of the device (I/O space)
 			CONFIG_SMC_USE_32_BIT
 			Define this if data bus is 32 bits
 			CONFIG_SMC_USE_IOFUNCS
 			Define this to use i/o functions instead of macros
 			(some hardware wont work with macros)
 		CONFIG_DRIVER_TI_EMAC
 		Support for davinci emac
 			CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
 			Define this if you have more then 3 PHYs.
 		CONFIG_FTGMAC100
 		Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
 			CONFIG_FTGMAC100_EGIGA
 			Define this to use GE link update with gigabit PHY.
 			Define this if FTGMAC100 is connected to gigabit PHY.
 			If your system has 10/100 PHY only, it might not occur
 			wrong behavior. Because PHY usually return timeout or
 			useless data when polling gigabit status and gigabit
 			control registers. This behavior won't affect the
 			correctnessof 10/100 link speed update.
 		CONFIG_SMC911X
 		Support for SMSC's LAN911x and LAN921x chips
 			CONFIG_SMC911X_BASE
 			Define this to hold the physical address
 			of the device (I/O space)
 			CONFIG_SMC911X_32_BIT
 			Define this if data bus is 32 bits
 			CONFIG_SMC911X_16_BIT
 			Define this if data bus is 16 bits. If your processor
 			automatically converts one 32 bit word to two 16 bit
 			words you may also try CONFIG_SMC911X_32_BIT.
 		CONFIG_SH_ETHER
 		Support for Renesas on-chip Ethernet controller
 			CONFIG_SH_ETHER_USE_PORT
 			Define the number of ports to be used
 			CONFIG_SH_ETHER_PHY_ADDR
 			Define the ETH PHY's address
 			CONFIG_SH_ETHER_CACHE_WRITEBACK
 			If this option is set, the driver enables cache flush.
 - PWM Support:
 		CONFIG_PWM_IMX
 		Support for PWM module on the imx6.
 - TPM Support:
 		CONFIG_TPM
 		Support TPM devices.
 		CONFIG_TPM_TIS_INFINEON
 		Support for Infineon i2c bus TPM devices. Only one device
 		per system is supported at this time.
 			CONFIG_TPM_TIS_I2C_BURST_LIMITATION
 			Define the burst count bytes upper limit
 		CONFIG_TPM_ST33ZP24
 		Support for STMicroelectronics TPM devices. Requires DM_TPM support.
 			CONFIG_TPM_ST33ZP24_I2C
 			Support for STMicroelectronics ST33ZP24 I2C devices.
 			Requires TPM_ST33ZP24 and I2C.
 			CONFIG_TPM_ST33ZP24_SPI
 			Support for STMicroelectronics ST33ZP24 SPI devices.
 			Requires TPM_ST33ZP24 and SPI.
 		CONFIG_TPM_ATMEL_TWI
 		Support for Atmel TWI TPM device. Requires I2C support.
 		CONFIG_TPM_TIS_LPC
 		Support for generic parallel port TPM devices. Only one device
 		per system is supported at this time.
 			CONFIG_TPM_TIS_BASE_ADDRESS
 			Base address where the generic TPM device is mapped
 			to. Contemporary x86 systems usually map it at
 			0xfed40000.
 		CONFIG_CMD_TPM
 		Add tpm monitor functions.
 		Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
 		provides monitor access to authorized functions.
 		CONFIG_TPM
 		Define this to enable the TPM support library which provides
 		functional interfaces to some TPM commands.
 		Requires support for a TPM device.
 		CONFIG_TPM_AUTH_SESSIONS
 		Define this to enable authorized functions in the TPM library.
 		Requires CONFIG_TPM and CONFIG_SHA1.
 - USB Support:
 		At the moment only the UHCI host controller is
 		supported (PIP405, MIP405); define
 		CONFIG_USB_UHCI to enable it.
 		define CONFIG_USB_KEYBOARD to enable the USB Keyboard
 		and define CONFIG_USB_STORAGE to enable the USB
 		storage devices.
 		Note:
 		Supported are USB Keyboards and USB Floppy drives
 		(TEAC FD-05PUB).
 		CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
 		txfilltuning field in the EHCI controller on reset.
 		CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
 		HW module registers.
 - USB Device:
 		Define the below if you wish to use the USB console.
 		Once firmware is rebuilt from a serial console issue the
 		command "setenv stdin usbtty; setenv stdout usbtty" and
 		attach your USB cable. The Unix command "dmesg" should print
 		it has found a new device. The environment variable usbtty
 		can be set to gserial or cdc_acm to enable your device to
 		appear to a USB host as a Linux gserial device or a
 		Common Device Class Abstract Control Model serial device.
 		If you select usbtty = gserial you should be able to enumerate
 		a Linux host by
 		# modprobe usbserial vendor=0xVendorID product=0xProductID
 		else if using cdc_acm, simply setting the environment
 		variable usbtty to be cdc_acm should suffice. The following
 		might be defined in YourBoardName.h
 			CONFIG_USB_DEVICE
 			Define this to build a UDC device
 			CONFIG_USB_TTY
 			Define this to have a tty type of device available to
 			talk to the UDC device
 			CONFIG_USBD_HS
 			Define this to enable the high speed support for usb
 			device and usbtty. If this feature is enabled, a routine
 			int is_usbd_high_speed(void)
 			also needs to be defined by the driver to dynamically poll
 			whether the enumeration has succeded at high speed or full
 			speed.
 			CONFIG_SYS_CONSOLE_IS_IN_ENV
 			Define this if you want stdin, stdout &/or stderr to
 			be set to usbtty.
 		If you have a USB-IF assigned VendorID then you may wish to
 		define your own vendor specific values either in BoardName.h
 		or directly in usbd_vendor_info.h. If you don't define
 		CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
 		CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
 		should pretend to be a Linux device to it's target host.
 			CONFIG_USBD_MANUFACTURER
 			Define this string as the name of your company for
 			- CONFIG_USBD_MANUFACTURER "my company"
 			CONFIG_USBD_PRODUCT_NAME
 			Define this string as the name of your product
 			- CONFIG_USBD_PRODUCT_NAME "acme usb device"
 			CONFIG_USBD_VENDORID
 			Define this as your assigned Vendor ID from the USB
 			Implementors Forum. This *must* be a genuine Vendor ID
 			to avoid polluting the USB namespace.
 			- CONFIG_USBD_VENDORID 0xFFFF
 			CONFIG_USBD_PRODUCTID
 			Define this as the unique Product ID
 			for your device
 			- CONFIG_USBD_PRODUCTID 0xFFFF
 - ULPI Layer Support:
 		The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
 		the generic ULPI layer. The generic layer accesses the ULPI PHY
 		via the platform viewport, so you need both the genric layer and
 		the viewport enabled. Currently only Chipidea/ARC based
 		viewport is supported.
 		To enable the ULPI layer support, define CONFIG_USB_ULPI and
 		CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
 		If your ULPI phy needs a different reference clock than the
 		standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
 		the appropriate value in Hz.
 - MMC Support:
 		The MMC controller on the Intel PXA is supported. To
 		enable this define CONFIG_MMC. The MMC can be
 		accessed from the boot prompt by mapping the device
 		to physical memory similar to flash. Command line is
 		enabled with CONFIG_CMD_MMC. The MMC driver also works with
 		the FAT fs. This is enabled with CONFIG_CMD_FAT.
 		CONFIG_SH_MMCIF
 		Support for Renesas on-chip MMCIF controller
 			CONFIG_SH_MMCIF_ADDR
 			Define the base address of MMCIF registers
 			CONFIG_SH_MMCIF_CLK
 			Define the clock frequency for MMCIF
 		CONFIG_SUPPORT_EMMC_BOOT
 		Enable some additional features of the eMMC boot partitions.
 		CONFIG_SUPPORT_EMMC_RPMB
 		Enable the commands for reading, writing and programming the
 		key for the Replay Protection Memory Block partition in eMMC.
 - USB Device Firmware Update (DFU) class support:
 		CONFIG_USB_FUNCTION_DFU
 		This enables the USB portion of the DFU USB class
 		CONFIG_CMD_DFU
 		This enables the command "dfu" which is used to have
 		U-Boot create a DFU class device via USB.  This command
 		requires that the "dfu_alt_info" environment variable be
 		set and define the alt settings to expose to the host.
 		CONFIG_DFU_MMC
 		This enables support for exposing (e)MMC devices via DFU.
 		CONFIG_DFU_NAND
 		This enables support for exposing NAND devices via DFU.
 		CONFIG_DFU_RAM
 		This enables support for exposing RAM via DFU.
 		Note: DFU spec refer to non-volatile memory usage, but
 		allow usages beyond the scope of spec - here RAM usage,
 		one that would help mostly the developer.
 		CONFIG_SYS_DFU_DATA_BUF_SIZE
 		Dfu transfer uses a buffer before writing data to the
 		raw storage device. Make the size (in bytes) of this buffer
 		configurable. The size of this buffer is also configurable
 		through the "dfu_bufsiz" environment variable.
 		CONFIG_SYS_DFU_MAX_FILE_SIZE
 		When updating files rather than the raw storage device,
 		we use a static buffer to copy the file into and then write
 		the buffer once we've been given the whole file.  Define
 		this to the maximum filesize (in bytes) for the buffer.
 		Default is 4 MiB if undefined.
 		DFU_DEFAULT_POLL_TIMEOUT
 		Poll timeout [ms], is the timeout a device can send to the
 		host. The host must wait for this timeout before sending
 		a subsequent DFU_GET_STATUS request to the device.
 		DFU_MANIFEST_POLL_TIMEOUT
 		Poll timeout [ms], which the device sends to the host when
 		entering dfuMANIFEST state. Host waits this timeout, before
 		sending again an USB request to the device.
 - USB Device Android Fastboot support:
 		CONFIG_USB_FUNCTION_FASTBOOT
 		This enables the USB part of the fastboot gadget
 		CONFIG_CMD_FASTBOOT
 		This enables the command "fastboot" which enables the Android
 		fastboot mode for the platform's USB device. Fastboot is a USB
 		protocol for downloading images, flashing and device control
 		used on Android devices.
 		See doc/README.android-fastboot for more information.
 		CONFIG_ANDROID_BOOT_IMAGE
 		This enables support for booting images which use the Android
 		image format header.
 		CONFIG_FASTBOOT_BUF_ADDR
 		The fastboot protocol requires a large memory buffer for
 		downloads. Define this to the starting RAM address to use for
 		downloaded images.
 		CONFIG_FASTBOOT_BUF_SIZE
 		The fastboot protocol requires a large memory buffer for
 		downloads. This buffer should be as large as possible for a
 		platform. Define this to the size available RAM for fastboot.
 		CONFIG_FASTBOOT_FLASH
 		The fastboot protocol includes a "flash" command for writing
 		the downloaded image to a non-volatile storage device. Define
 		this to enable the "fastboot flash" command.
 		CONFIG_FASTBOOT_FLASH_MMC_DEV
 		The fastboot "flash" command requires additional information
 		regarding the non-volatile storage device. Define this to
 		the eMMC device that fastboot should use to store the image.
 		CONFIG_FASTBOOT_GPT_NAME
 		The fastboot "flash" command supports writing the downloaded
 		image to the Protective MBR and the Primary GUID Partition
 		Table. (Additionally, this downloaded image is post-processed
 		to generate and write the Backup GUID Partition Table.)
 		This occurs when the specified "partition name" on the
 		"fastboot flash" command line matches this value.
 		The default is "gpt" if undefined.
 		CONFIG_FASTBOOT_MBR_NAME
 		The fastboot "flash" command supports writing the downloaded
 		image to DOS MBR.
 		This occurs when the "partition name" specified on the
 		"fastboot flash" command line matches this value.
 		If not defined the default value "mbr" is used.
 - Journaling Flash filesystem support:
 		CONFIG_JFFS2_NAND
 		Define these for a default partition on a NAND device
 		CONFIG_SYS_JFFS2_FIRST_SECTOR,
 		CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
 		Define these for a default partition on a NOR device
 - Keyboard Support:
 		See Kconfig help for available keyboard drivers.
 		CONFIG_KEYBOARD
 		Define this to enable a custom keyboard support.
 		This simply calls drv_keyboard_init() which must be
 		defined in your board-specific files. This option is deprecated
 		and is only used by novena. For new boards, use driver model
 		instead.
 - Video support:
 		CONFIG_FSL_DIU_FB
 		Enable the Freescale DIU video driver.	Reference boards for
 		SOCs that have a DIU should define this macro to enable DIU
 		support, and should also define these other macros:
 			CONFIG_SYS_DIU_ADDR
 			CONFIG_VIDEO
 			CONFIG_CFB_CONSOLE
 			CONFIG_VIDEO_SW_CURSOR
 			CONFIG_VGA_AS_SINGLE_DEVICE
 			CONFIG_VIDEO_LOGO
 			CONFIG_VIDEO_BMP_LOGO
 		The DIU driver will look for the 'video-mode' environment
 		variable, and if defined, enable the DIU as a console during
 		boot.  See the documentation file doc/README.video for a
 		description of this variable.
 - LCD Support:	CONFIG_LCD
 		Define this to enable LCD support (for output to LCD
 		display); also select one of the supported displays
 		by defining one of these:
 		CONFIG_ATMEL_LCD:
 			HITACHI TX09D70VM1CCA, 3.5", 240x320.
 		CONFIG_NEC_NL6448AC33:
 			NEC NL6448AC33-18. Active, color, single scan.
 		CONFIG_NEC_NL6448BC20
 			NEC NL6448BC20-08. 6.5", 640x480.
 			Active, color, single scan.
 		CONFIG_NEC_NL6448BC33_54
 			NEC NL6448BC33-54. 10.4", 640x480.
 			Active, color, single scan.
 		CONFIG_SHARP_16x9
 			Sharp 320x240. Active, color, single scan.
 			It isn't 16x9, and I am not sure what it is.
 		CONFIG_SHARP_LQ64D341
 			Sharp LQ64D341 display, 640x480.
 			Active, color, single scan.
 		CONFIG_HLD1045
 			HLD1045 display, 640x480.
 			Active, color, single scan.
 		CONFIG_OPTREX_BW
 			Optrex	 CBL50840-2 NF-FW 99 22 M5
 			or
 			Hitachi	 LMG6912RPFC-00T
 			or
 			Hitachi	 SP14Q002
 			320x240. Black & white.
 		CONFIG_LCD_ALIGNMENT
 		Normally the LCD is page-aligned (typically 4KB). If this is
 		defined then the LCD will be aligned to this value instead.
 		For ARM it is sometimes useful to use MMU_SECTION_SIZE
 		here, since it is cheaper to change data cache settings on
 		a per-section basis.
 		CONFIG_LCD_ROTATION
 		Sometimes, for example if the display is mounted in portrait
 		mode or even if it's mounted landscape but rotated by 180degree,
 		we need to rotate our content of the display relative to the
 		framebuffer, so that user can read the messages which are
 		printed out.
 		Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
 		initialized with a given rotation from "vl_rot" out of
 		"vidinfo_t" which is provided by the board specific code.
 		The value for vl_rot is coded as following (matching to
 		fbcon=rotate:<n> linux-kernel commandline):
 		0 = no rotation respectively 0 degree
 		1 = 90 degree rotation
 		2 = 180 degree rotation
 		3 = 270 degree rotation
 		If CONFIG_LCD_ROTATION is not defined, the console will be
 		initialized with 0degree rotation.
 		CONFIG_LCD_BMP_RLE8
 		Support drawing of RLE8-compressed bitmaps on the LCD.
 		CONFIG_I2C_EDID
 		Enables an 'i2c edid' command which can read EDID
 		information over I2C from an attached LCD display.
 - Splash Screen Support: CONFIG_SPLASH_SCREEN
 		If this option is set, the environment is checked for
 		a variable "splashimage". If found, the usual display
 		of logo, copyright and system information on the LCD
 		is suppressed and the BMP image at the address
 		specified in "splashimage" is loaded instead. The
 		console is redirected to the "nulldev", too. This
 		allows for a "silent" boot where a splash screen is
 		loaded very quickly after power-on.
 		CONFIG_SPLASHIMAGE_GUARD
 		If this option is set, then U-Boot will prevent the environment
 		variable "splashimage" from being set to a problematic address
 		(see doc/README.displaying-bmps).
 		This option is useful for targets where, due to alignment
 		restrictions, an improperly aligned BMP image will cause a data
 		abort. If you think you will not have problems with unaligned
 		accesses (for example because your toolchain prevents them)
 		there is no need to set this option.
 		CONFIG_SPLASH_SCREEN_ALIGN
 		If this option is set the splash image can be freely positioned
 		on the screen. Environment variable "splashpos" specifies the
 		position as "x,y". If a positive number is given it is used as
 		number of pixel from left/top. If a negative number is given it
 		is used as number of pixel from right/bottom. You can also
 		specify 'm' for centering the image.
 		Example:
 		setenv splashpos m,m
 			=> image at center of screen
 		setenv splashpos 30,20
 			=> image at x = 30 and y = 20
 		setenv splashpos -10,m
 			=> vertically centered image
 			   at x = dspWidth - bmpWidth - 9
 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
 		If this option is set, additionally to standard BMP
 		images, gzipped BMP images can be displayed via the
 		splashscreen support or the bmp command.
 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
 		If this option is set, 8-bit RLE compressed BMP images
 		can be displayed via the splashscreen support or the
 		bmp command.
 - Compression support:
 		CONFIG_GZIP
 		Enabled by default to support gzip compressed images.
 		CONFIG_BZIP2
 		If this option is set, support for bzip2 compressed
 		images is included. If not, only uncompressed and gzip
 		compressed images are supported.
 		NOTE: the bzip2 algorithm requires a lot of RAM, so
 		the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
 		be at least 4MB.
 - MII/PHY support:
 		CONFIG_PHY_ADDR
 		The address of PHY on MII bus.
 		CONFIG_PHY_CLOCK_FREQ (ppc4xx)
 		The clock frequency of the MII bus
 		CONFIG_PHY_RESET_DELAY
 		Some PHY like Intel LXT971A need extra delay after
 		reset before any MII register access is possible.
 		For such PHY, set this option to the usec delay
 		required. (minimum 300usec for LXT971A)
 		CONFIG_PHY_CMD_DELAY (ppc4xx)
 		Some PHY like Intel LXT971A need extra delay after
 		command issued before MII status register can be read
 - IP address:
 		CONFIG_IPADDR
 		Define a default value for the IP address to use for
 		the default Ethernet interface, in case this is not
 		determined through e.g. bootp.
 		(Environment variable "ipaddr")
 - Server IP address:
 		CONFIG_SERVERIP
 		Defines a default value for the IP address of a TFTP
 		server to contact when using the "tftboot" command.
 		(Environment variable "serverip")
 		CONFIG_KEEP_SERVERADDR
 		Keeps the server's MAC address, in the env 'serveraddr'
 		for passing to bootargs (like Linux's netconsole option)
 - Gateway IP address:
 		CONFIG_GATEWAYIP
 		Defines a default value for the IP address of the
 		default router where packets to other networks are
 		sent to.
 		(Environment variable "gatewayip")
 - Subnet mask:
 		CONFIG_NETMASK
 		Defines a default value for the subnet mask (or
 		routing prefix) which is used to determine if an IP
 		address belongs to the local subnet or needs to be
 		forwarded through a router.
 		(Environment variable "netmask")
 - Multicast TFTP Mode:
 		CONFIG_MCAST_TFTP
 		Defines whether you want to support multicast TFTP as per
 		rfc-2090; for example to work with atftp.  Lets lots of targets
 		tftp down the same boot image concurrently.  Note: the Ethernet
 		driver in use must provide a function: mcast() to join/leave a
 		multicast group.
 - BOOTP Recovery Mode:
 		CONFIG_BOOTP_RANDOM_DELAY
 		If you have many targets in a network that try to
 		boot using BOOTP, you may want to avoid that all
 		systems send out BOOTP requests at precisely the same
 		moment (which would happen for instance at recovery
 		from a power failure, when all systems will try to
 		boot, thus flooding the BOOTP server. Defining
 		CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
 		inserted before sending out BOOTP requests. The
 		following delays are inserted then:
 		1st BOOTP request:	delay 0 ... 1 sec
 		2nd BOOTP request:	delay 0 ... 2 sec
 		3rd BOOTP request:	delay 0 ... 4 sec
 		4th and following
 		BOOTP requests:		delay 0 ... 8 sec
 		CONFIG_BOOTP_ID_CACHE_SIZE
 		BOOTP packets are uniquely identified using a 32-bit ID. The
 		server will copy the ID from client requests to responses and
 		U-Boot will use this to determine if it is the destination of
 		an incoming response. Some servers will check that addresses
 		aren't in use before handing them out (usually using an ARP
 		ping) and therefore take up to a few hundred milliseconds to
 		respond. Network congestion may also influence the time it
 		takes for a response to make it back to the client. If that
 		time is too long, U-Boot will retransmit requests. In order
 		to allow earlier responses to still be accepted after these
 		retransmissions, U-Boot's BOOTP client keeps a small cache of
 		IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
 		cache. The default is to keep IDs for up to four outstanding
 		requests. Increasing this will allow U-Boot to accept offers
 		from a BOOTP client in networks with unusually high latency.
 - DHCP Advanced Options:
 		You can fine tune the DHCP functionality by defining
 		CONFIG_BOOTP_* symbols:
 		CONFIG_BOOTP_SUBNETMASK
 		CONFIG_BOOTP_GATEWAY
 		CONFIG_BOOTP_HOSTNAME
 		CONFIG_BOOTP_NISDOMAIN
 		CONFIG_BOOTP_BOOTPATH
 		CONFIG_BOOTP_BOOTFILESIZE
 		CONFIG_BOOTP_DNS
 		CONFIG_BOOTP_DNS2
 		CONFIG_BOOTP_SEND_HOSTNAME
 		CONFIG_BOOTP_NTPSERVER
 		CONFIG_BOOTP_TIMEOFFSET
 		CONFIG_BOOTP_VENDOREX
 		CONFIG_BOOTP_MAY_FAIL
 		CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
 		environment variable, not the BOOTP server.
 		CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
 		after the configured retry count, the call will fail
 		instead of starting over.  This can be used to fail over
 		to Link-local IP address configuration if the DHCP server
 		is not available.
 		CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
 		serverip from a DHCP server, it is possible that more
 		than one DNS serverip is offered to the client.
 		If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
 		serverip will be stored in the additional environment
 		variable "dnsip2". The first DNS serverip is always
 		stored in the variable "dnsip", when CONFIG_BOOTP_DNS
 		is defined.
 		CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
 		to do a dynamic update of a DNS server. To do this, they
 		need the hostname of the DHCP requester.
 		If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
 		of the "hostname" environment variable is passed as
 		option 12 to the DHCP server.
 		CONFIG_BOOTP_DHCP_REQUEST_DELAY
 		A 32bit value in microseconds for a delay between
 		receiving a "DHCP Offer" and sending the "DHCP Request".
 		This fixes a problem with certain DHCP servers that don't
 		respond 100% of the time to a "DHCP request". E.g. On an
 		AT91RM9200 processor running at 180MHz, this delay needed
 		to be *at least* 15,000 usec before a Windows Server 2003
 		DHCP server would reply 100% of the time. I recommend at
 		least 50,000 usec to be safe. The alternative is to hope
 		that one of the retries will be successful but note that
 		the DHCP timeout and retry process takes a longer than
 		this delay.
  - Link-local IP address negotiation:
 		Negotiate with other link-local clients on the local network
 		for an address that doesn't require explicit configuration.
 		This is especially useful if a DHCP server cannot be guaranteed
 		to exist in all environments that the device must operate.
 		See doc/README.link-local for more information.
  - CDP Options:
 		CONFIG_CDP_DEVICE_ID
 		The device id used in CDP trigger frames.
 		CONFIG_CDP_DEVICE_ID_PREFIX
 		A two character string which is prefixed to the MAC address
 		of the device.
 		CONFIG_CDP_PORT_ID
 		A printf format string which contains the ascii name of
 		the port. Normally is set to "eth%d" which sets
 		eth0 for the first Ethernet, eth1 for the second etc.
 		CONFIG_CDP_CAPABILITIES
 		A 32bit integer which indicates the device capabilities;
 		0x00000010 for a normal host which does not forwards.
 		CONFIG_CDP_VERSION
 		An ascii string containing the version of the software.
 		CONFIG_CDP_PLATFORM
 		An ascii string containing the name of the platform.
 		CONFIG_CDP_TRIGGER
 		A 32bit integer sent on the trigger.
 		CONFIG_CDP_POWER_CONSUMPTION
 		A 16bit integer containing the power consumption of the
 		device in .1 of milliwatts.
 		CONFIG_CDP_APPLIANCE_VLAN_TYPE
 		A byte containing the id of the VLAN.
 - Status LED:	CONFIG_LED_STATUS
 		Several configurations allow to display the current
 		status using a LED. For instance, the LED will blink
 		fast while running U-Boot code, stop blinking as
 		soon as a reply to a BOOTP request was received, and
 		start blinking slow once the Linux kernel is running
 		(supported by a status LED driver in the Linux
 		kernel). Defining CONFIG_LED_STATUS enables this
 		feature in U-Boot.
 		Additional options:
 		CONFIG_LED_STATUS_GPIO
 		The status LED can be connected to a GPIO pin.
 		In such cases, the gpio_led driver can be used as a
 		status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
 		to include the gpio_led driver in the U-Boot binary.
 		CONFIG_GPIO_LED_INVERTED_TABLE
 		Some GPIO connected LEDs may have inverted polarity in which
 		case the GPIO high value corresponds to LED off state and
 		GPIO low value corresponds to LED on state.
 		In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
 		with a list of GPIO LEDs that have inverted polarity.
 - I2C Support:	CONFIG_SYS_I2C
 		This enable the NEW i2c subsystem, and will allow you to use
 		i2c commands at the u-boot command line (as long as you set
 		CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
 		based realtime clock chips or other i2c devices. See
 		common/cmd_i2c.c for a description of the command line
 		interface.
 		ported i2c driver to the new framework:
 		- drivers/i2c/soft_i2c.c:
 		  - activate first bus with CONFIG_SYS_I2C_SOFT define
 		    CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
 		    for defining speed and slave address
 		  - activate second bus with I2C_SOFT_DECLARATIONS2 define
 		    CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
 		    for defining speed and slave address
 		  - activate third bus with I2C_SOFT_DECLARATIONS3 define
 		    CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
 		    for defining speed and slave address
 		  - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
 		    CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
 		    for defining speed and slave address
 		- drivers/i2c/fsl_i2c.c:
 		  - activate i2c driver with CONFIG_SYS_I2C_FSL
 		    define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
 		    offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
 		    CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
 		    bus.
 		  - If your board supports a second fsl i2c bus, define
 		    CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
 		    CONFIG_SYS_FSL_I2C2_SPEED for the speed and
 		    CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
 		    second bus.
 		- drivers/i2c/tegra_i2c.c:
 		  - activate this driver with CONFIG_SYS_I2C_TEGRA
 		  - This driver adds 4 i2c buses with a fix speed from
 		    100000 and the slave addr 0!
 		- drivers/i2c/ppc4xx_i2c.c
 		  - activate this driver with CONFIG_SYS_I2C_PPC4XX
 		  - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
 		  - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
 		- drivers/i2c/i2c_mxc.c
 		  - activate this driver with CONFIG_SYS_I2C_MXC
 		  - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
 		  - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
 		  - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
 		  - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
 		  - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
 		  - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
 		  - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
 		  - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
 		  - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
 		  - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
 		  - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
 		  - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
 		If those defines are not set, default value is 100000
 		for speed, and 0 for slave.
 		- drivers/i2c/rcar_i2c.c:
 		  - activate this driver with CONFIG_SYS_I2C_RCAR
 		  - This driver adds 4 i2c buses
 		  - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
 		  - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
 		  - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
 		  - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
 		  - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
 		  - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
 		  - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
 		  - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
 		  - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
 		- drivers/i2c/sh_i2c.c:
 		  - activate this driver with CONFIG_SYS_I2C_SH
 		  - This driver adds from 2 to 5 i2c buses
 		  - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
 		  - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
 		  - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
 		  - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
 		  - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
 		  - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
 		  - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
 		  - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
 		  - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
 		  - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
 		  - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
 		- drivers/i2c/omap24xx_i2c.c
 		  - activate this driver with CONFIG_SYS_I2C_OMAP24XX
 		  - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
 		  - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
 		  - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
 		  - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
 		  - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
 		  - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
 		  - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
 		  - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
 		  - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
 		  - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
 		- drivers/i2c/zynq_i2c.c
 		  - activate this driver with CONFIG_SYS_I2C_ZYNQ
 		  - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
 		  - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
 		- drivers/i2c/s3c24x0_i2c.c:
 		  - activate this driver with CONFIG_SYS_I2C_S3C24X0
 		  - This driver adds i2c buses (11 for Exynos5250, Exynos5420
 		    9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
 		    with a fix speed from 100000 and the slave addr 0!
 		- drivers/i2c/ihs_i2c.c
 		  - activate this driver with CONFIG_SYS_I2C_IHS
 		  - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
 		  - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
 		  - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
 		  - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
 		  - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
 		  - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
 		  - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
 		  - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
 		  - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
 		  - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
 		  - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
 		  - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
 		  - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
 		  - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
 		  - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
 		  - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
 		  - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
 		  - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
 		  - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
 		  - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
 		  - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
 		additional defines:
 		CONFIG_SYS_NUM_I2C_BUSES
 		Hold the number of i2c buses you want to use.
 		CONFIG_SYS_I2C_DIRECT_BUS
 		define this, if you don't use i2c muxes on your hardware.
 		if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
 		omit this define.
 		CONFIG_SYS_I2C_MAX_HOPS
 		define how many muxes are maximal consecutively connected
 		on one i2c bus. If you not use i2c muxes, omit this
 		define.
 		CONFIG_SYS_I2C_BUSES
 		hold a list of buses you want to use, only used if
 		CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
 		a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
 		CONFIG_SYS_NUM_I2C_BUSES = 9:
 		 CONFIG_SYS_I2C_BUSES	{{0, {I2C_NULL_HOP}}, \
 					{0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
 					{0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
 					{0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
 					{0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
 					{0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
 					{1, {I2C_NULL_HOP}}, \
 					{1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
 					{1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
 					}
 		which defines
 			bus 0 on adapter 0 without a mux
 			bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
 			bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
 			bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
 			bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
 			bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
 			bus 6 on adapter 1 without a mux
 			bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
 			bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
 		If you do not have i2c muxes on your board, omit this define.
 - Legacy I2C Support:
 		If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
 		then the following macros need to be defined (examples are
 		from include/configs/lwmon.h):
 		I2C_INIT
 		(Optional). Any commands necessary to enable the I2C
 		controller or configure ports.
 		eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |=	PB_SCL)
 		I2C_ACTIVE
 		The code necessary to make the I2C data line active
 		(driven).  If the data line is open collector, this
 		define can be null.
 		eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |=  PB_SDA)
 		I2C_TRISTATE
 		The code necessary to make the I2C data line tri-stated
 		(inactive).  If the data line is open collector, this
 		define can be null.
 		eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
 		I2C_READ
 		Code that returns true if the I2C data line is high,
 		false if it is low.
 		eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
 		I2C_SDA(bit)
 		If <bit> is true, sets the I2C data line high. If it
 		is false, it clears it (low).
 		eg: #define I2C_SDA(bit) \
 			if(bit) immr->im_cpm.cp_pbdat |=  PB_SDA; \
 			else	immr->im_cpm.cp_pbdat &= ~PB_SDA
 		I2C_SCL(bit)
 		If <bit> is true, sets the I2C clock line high. If it
 		is false, it clears it (low).
 		eg: #define I2C_SCL(bit) \
 			if(bit) immr->im_cpm.cp_pbdat |=  PB_SCL; \
 			else	immr->im_cpm.cp_pbdat &= ~PB_SCL
 		I2C_DELAY
 		This delay is invoked four times per clock cycle so this
 		controls the rate of data transfer.  The data rate thus
 		is 1 / (I2C_DELAY * 4). Often defined to be something
 		like:
 		#define I2C_DELAY  udelay(2)
 		CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
 		If your arch supports the generic GPIO framework (asm/gpio.h),
 		then you may alternatively define the two GPIOs that are to be
 		used as SCL / SDA.  Any of the previous I2C_xxx macros will
 		have GPIO-based defaults assigned to them as appropriate.
 		You should define these to the GPIO value as given directly to
 		the generic GPIO functions.
 		CONFIG_SYS_I2C_INIT_BOARD
 		When a board is reset during an i2c bus transfer
 		chips might think that the current transfer is still
 		in progress. On some boards it is possible to access
 		the i2c SCLK line directly, either by using the
 		processor pin as a GPIO or by having a second pin
 		connected to the bus. If this option is defined a
 		custom i2c_init_board() routine in boards/xxx/board.c
 		is run early in the boot sequence.
 		CONFIG_I2C_MULTI_BUS
 		This option allows the use of multiple I2C buses, each of which
 		must have a controller.	 At any point in time, only one bus is
 		active.	 To switch to a different bus, use the 'i2c dev' command.
 		Note that bus numbering is zero-based.
 		CONFIG_SYS_I2C_NOPROBES
 		This option specifies a list of I2C devices that will be skipped
 		when the 'i2c probe' command is issued.	 If CONFIG_I2C_MULTI_BUS
 		is set, specify a list of bus-device pairs.  Otherwise, specify
 		a 1D array of device addresses
 		e.g.
 			#undef	CONFIG_I2C_MULTI_BUS
 			#define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
 		will skip addresses 0x50 and 0x68 on a board with one I2C bus
 			#define CONFIG_I2C_MULTI_BUS
 			#define CONFIG_SYS_I2C_NOPROBES	{{0,0x50},{0,0x68},{1,0x54}}
 		will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
 		CONFIG_SYS_SPD_BUS_NUM
 		If defined, then this indicates the I2C bus number for DDR SPD.
 		If not defined, then U-Boot assumes that SPD is on I2C bus 0.
 		CONFIG_SYS_RTC_BUS_NUM
 		If defined, then this indicates the I2C bus number for the RTC.
 		If not defined, then U-Boot assumes that RTC is on I2C bus 0.
 		CONFIG_SOFT_I2C_READ_REPEATED_START
 		defining this will force the i2c_read() function in
 		the soft_i2c driver to perform an I2C repeated start
 		between writing the address pointer and reading the
 		data.  If this define is omitted the default behaviour
 		of doing a stop-start sequence will be used.  Most I2C
 		devices can use either method, but some require one or
 		the other.
 - SPI Support:	CONFIG_SPI
 		Enables SPI driver (so far only tested with
 		SPI EEPROM, also an instance works with Crystal A/D and
 		D/As on the SACSng board)
 		CONFIG_SH_SPI
 		Enables the driver for SPI controller on SuperH. Currently
 		only SH7757 is supported.
 		CONFIG_SOFT_SPI
 		Enables a software (bit-bang) SPI driver rather than
 		using hardware support. This is a general purpose
 		driver that only requires three general I/O port pins
 		(two outputs, one input) to function. If this is
 		defined, the board configuration must define several
 		SPI configuration items (port pins to use, etc). For
 		an example, see include/configs/sacsng.h.
 		CONFIG_HARD_SPI
 		Enables a hardware SPI driver for general-purpose reads
 		and writes.  As with CONFIG_SOFT_SPI, the board configuration
 		must define a list of chip-select function pointers.
 		Currently supported on some MPC8xxx processors.	 For an
 		example, see include/configs/mpc8349emds.h.
 		CONFIG_MXC_SPI
 		Enables the driver for the SPI controllers on i.MX and MXC
 		SoCs. Currently i.MX31/35/51 are supported.
 		CONFIG_SYS_SPI_MXC_WAIT
 		Timeout for waiting until spi transfer completed.
 		default: (CONFIG_SYS_HZ/100)     /* 10 ms */
 - FPGA Support: CONFIG_FPGA
 		Enables FPGA subsystem.
 		CONFIG_FPGA_<vendor>
 		Enables support for specific chip vendors.
 		(ALTERA, XILINX)
 		CONFIG_FPGA_<family>
 		Enables support for FPGA family.
 		(SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
 		CONFIG_FPGA_COUNT
 		Specify the number of FPGA devices to support.
 		CONFIG_SYS_FPGA_PROG_FEEDBACK
 		Enable printing of hash marks during FPGA configuration.
 		CONFIG_SYS_FPGA_CHECK_BUSY
 		Enable checks on FPGA configuration interface busy
 		status by the configuration function. This option
 		will require a board or device specific function to
 		be written.
 		CONFIG_FPGA_DELAY
 		If defined, a function that provides delays in the FPGA
 		configuration driver.
 		CONFIG_SYS_FPGA_CHECK_CTRLC
 		Allow Control-C to interrupt FPGA configuration
 		CONFIG_SYS_FPGA_CHECK_ERROR
 		Check for configuration errors during FPGA bitfile
 		loading. For example, abort during Virtex II
 		configuration if the INIT_B line goes low (which
 		indicated a CRC error).
 		CONFIG_SYS_FPGA_WAIT_INIT
 		Maximum time to wait for the INIT_B line to de-assert
 		after PROB_B has been de-asserted during a Virtex II
 		FPGA configuration sequence. The default time is 500
 		ms.
 		CONFIG_SYS_FPGA_WAIT_BUSY
 		Maximum time to wait for BUSY to de-assert during
 		Virtex II FPGA configuration. The default is 5 ms.
 		CONFIG_SYS_FPGA_WAIT_CONFIG
 		Time to wait after FPGA configuration. The default is
 		200 ms.
 - Configuration Management:
 		CONFIG_BUILD_TARGET
 		Some SoCs need special image types (e.g. U-Boot binary
 		with a special header) as build targets. By defining
 		CONFIG_BUILD_TARGET in the SoC / board header, this
 		special image will be automatically built upon calling
 		make / buildman.
 		CONFIG_IDENT_STRING
 		If defined, this string will be added to the U-Boot
 		version information (U_BOOT_VERSION)
 - Vendor Parameter Protection:
 		U-Boot considers the values of the environment
 		variables "serial#" (Board Serial Number) and
 		"ethaddr" (Ethernet Address) to be parameters that
 		are set once by the board vendor / manufacturer, and
 		protects these variables from casual modification by
 		the user. Once set, these variables are read-only,
 		and write or delete attempts are rejected. You can
 		change this behaviour:
 		If CONFIG_ENV_OVERWRITE is #defined in your config
 		file, the write protection for vendor parameters is
 		completely disabled. Anybody can change or delete
 		these parameters.
 		Alternatively, if you define _both_ an ethaddr in the
 		default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
 		Ethernet address is installed in the environment,
 		which can be changed exactly ONCE by the user. [The
 		serial# is unaffected by this, i. e. it remains
 		read-only.]
 		The same can be accomplished in a more flexible way
 		for any variable by configuring the type of access
 		to allow for those variables in the ".flags" variable
 		or define CONFIG_ENV_FLAGS_LIST_STATIC.
 - Protected RAM:
 		CONFIG_PRAM
 		Define this variable to enable the reservation of
 		"protected RAM", i. e. RAM which is not overwritten
 		by U-Boot. Define CONFIG_PRAM to hold the number of
 		kB you want to reserve for pRAM. You can overwrite
 		this default value by defining an environment
 		variable "pram" to the number of kB you want to
 		reserve. Note that the board info structure will
 		still show the full amount of RAM. If pRAM is
 		reserved, a new environment variable "mem" will
 		automatically be defined to hold the amount of
 		remaining RAM in a form that can be passed as boot
 		argument to Linux, for instance like that:
 			setenv bootargs ... mem=\${mem}
 			saveenv
 		This way you can tell Linux not to use this memory,
 		either, which results in a memory region that will
 		not be affected by reboots.
 		*WARNING* If your board configuration uses automatic
 		detection of the RAM size, you must make sure that
 		this memory test is non-destructive. So far, the
 		following board configurations are known to be
 		"pRAM-clean":
 			IVMS8, IVML24, SPD8xx,
 			HERMES, IP860, RPXlite, LWMON,
 			FLAGADM
 - Access to physical memory region (> 4GB)
 		Some basic support is provided for operations on memory not
 		normally accessible to U-Boot - e.g. some architectures
 		support access to more than 4GB of memory on 32-bit
 		machines using physical address extension or similar.
 		Define CONFIG_PHYSMEM to access this basic support, which
 		currently only supports clearing the memory.
 - Error Recovery:
 		CONFIG_PANIC_HANG
 		Define this variable to stop the system in case of a
 		fatal error, so that you have to reset it manually.
 		This is probably NOT a good idea for an embedded
 		system where you want the system to reboot
 		automatically as fast as possible, but it may be
 		useful during development since you can try to debug
 		the conditions that lead to the situation.
 		CONFIG_NET_RETRY_COUNT
 		This variable defines the number of retries for
 		network operations like ARP, RARP, TFTP, or BOOTP
 		before giving up the operation. If not defined, a
 		default value of 5 is used.
 		CONFIG_ARP_TIMEOUT
 		Timeout waiting for an ARP reply in milliseconds.
 		CONFIG_NFS_TIMEOUT
 		Timeout in milliseconds used in NFS protocol.
 		If you encounter "ERROR: Cannot umount" in nfs command,
 		try longer timeout such as
 		#define CONFIG_NFS_TIMEOUT 10000UL
 - Command Interpreter:
 		CONFIG_AUTO_COMPLETE
 		Enable auto completion of commands using TAB.
 		CONFIG_SYS_PROMPT_HUSH_PS2
 		This defines the secondary prompt string, which is
 		printed when the command interpreter needs more input
 		to complete a command. Usually "> ".
 	Note:
 		In the current implementation, the local variables
 		space and global environment variables space are
 		separated. Local variables are those you define by
 		simply typing `name=value'. To access a local
 		variable later on, you have write `$name' or
 		`${name}'; to execute the contents of a variable
 		directly type `$name' at the command prompt.
 		Global environment variables are those you use
 		setenv/printenv to work with. To run a command stored
 		in such a variable, you need to use the run command,
 		and you must not use the '$' sign to access them.
 		To store commands and special characters in a
 		variable, please use double quotation marks
 		surrounding the whole text of the variable, instead
 		of the backslashes before semicolons and special
 		symbols.
 - Command Line Editing and History:
 		CONFIG_CMDLINE_EDITING
 		Enable editing and History functions for interactive
 		command line input operations
 - Command Line PS1/PS2 support:
 		CONFIG_CMDLINE_PS_SUPPORT
 		Enable support for changing the command prompt string
 		at run-time. Only static string is supported so far.
 		The string is obtained from environment variables PS1
 		and PS2.
 - Default Environment:
 		CONFIG_EXTRA_ENV_SETTINGS
 		Define this to contain any number of null terminated
 		strings (variable = value pairs) that will be part of
 		the default environment compiled into the boot image.
 		For example, place something like this in your
 		board's config file:
 		#define CONFIG_EXTRA_ENV_SETTINGS \
 			"myvar1=value1\0" \
 			"myvar2=value2\0"
 		Warning: This method is based on knowledge about the
 		internal format how the environment is stored by the
 		U-Boot code. This is NOT an official, exported
 		interface! Although it is unlikely that this format
 		will change soon, there is no guarantee either.
 		You better know what you are doing here.
 		Note: overly (ab)use of the default environment is
 		discouraged. Make sure to check other ways to preset
 		the environment like the "source" command or the
 		boot command first.
 		CONFIG_ENV_VARS_UBOOT_CONFIG
 		Define this in order to add variables describing the
 		U-Boot build configuration to the default environment.
 		These will be named arch, cpu, board, vendor, and soc.
 		Enabling this option will cause the following to be defined:
 		- CONFIG_SYS_ARCH
 		- CONFIG_SYS_CPU
 		- CONFIG_SYS_BOARD
 		- CONFIG_SYS_VENDOR
 		- CONFIG_SYS_SOC
 		CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
 		Define this in order to add variables describing certain
 		run-time determined information about the hardware to the
 		environment.  These will be named board_name, board_rev.
 		CONFIG_DELAY_ENVIRONMENT
 		Normally the environment is loaded when the board is
 		initialised so that it is available to U-Boot. This inhibits
 		that so that the environment is not available until
 		explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
 		this is instead controlled by the value of
 		/config/load-environment.
 - DataFlash Support:
 		CONFIG_HAS_DATAFLASH
 		Defining this option enables DataFlash features and
 		allows to read/write in Dataflash via the standard
 		commands cp, md...
 - Serial Flash support
 		CONFIG_CMD_SF
 		Defining this option enables SPI flash commands
 		'sf probe/read/write/erase/update'.
 		Usage requires an initial 'probe' to define the serial
 		flash parameters, followed by read/write/erase/update
 		commands.
 		The following defaults may be provided by the platform
 		to handle the common case when only a single serial
 		flash is present on the system.
 		CONFIG_SF_DEFAULT_BUS		Bus identifier
 		CONFIG_SF_DEFAULT_CS		Chip-select
 		CONFIG_SF_DEFAULT_MODE 		(see include/spi.h)
 		CONFIG_SF_DEFAULT_SPEED		in Hz
 		CONFIG_SYSTEMACE
 		Adding this option adds support for Xilinx SystemACE
 		chips attached via some sort of local bus. The address
 		of the chip must also be defined in the
 		CONFIG_SYS_SYSTEMACE_BASE macro. For example:
 		#define CONFIG_SYSTEMACE
 		#define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
 		When SystemACE support is added, the "ace" device type
 		becomes available to the fat commands, i.e. fatls.
 - TFTP Fixed UDP Port:
 		CONFIG_TFTP_PORT
 		If this is defined, the environment variable tftpsrcp
 		is used to supply the TFTP UDP source port value.
 		If tftpsrcp isn't defined, the normal pseudo-random port
 		number generator is used.
 		Also, the environment variable tftpdstp is used to supply
 		the TFTP UDP destination port value.  If tftpdstp isn't
 		defined, the normal port 69 is used.
 		The purpose for tftpsrcp is to allow a TFTP server to
 		blindly start the TFTP transfer using the pre-configured
 		target IP address and UDP port. This has the effect of
 		"punching through" the (Windows XP) firewall, allowing
 		the remainder of the TFTP transfer to proceed normally.
 		A better solution is to properly configure the firewall,
 		but sometimes that is not allowed.
 - bootcount support:
 		CONFIG_BOOTCOUNT_LIMIT
 		This enables the bootcounter support, see:
 		http://www.denx.de/wiki/DULG/UBootBootCountLimit
 		CONFIG_AT91SAM9XE
 		enable special bootcounter support on at91sam9xe based boards.
 		CONFIG_SOC_DA8XX
 		enable special bootcounter support on da850 based boards.
 		CONFIG_BOOTCOUNT_RAM
 		enable support for the bootcounter in RAM
 		CONFIG_BOOTCOUNT_I2C
 		enable support for the bootcounter on an i2c (like RTC) device.
 			CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
 			CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
 						    the bootcounter.
 			CONFIG_BOOTCOUNT_ALEN = address len
 - Show boot progress:
 		CONFIG_SHOW_BOOT_PROGRESS
 		Defining this option allows to add some board-
 		specific code (calling a user-provided function
 		"show_boot_progress(int)") that enables you to show
 		the system's boot progress on some display (for
 		example, some LED's) on your board. At the moment,
 		the following checkpoints are implemented:
 Legacy uImage format:
   Arg	Where			When
     1	common/cmd_bootm.c	before attempting to boot an image
    -1	common/cmd_bootm.c	Image header has bad	 magic number
     2	common/cmd_bootm.c	Image header has correct magic number
    -2	common/cmd_bootm.c	Image header has bad	 checksum
     3	common/cmd_bootm.c	Image header has correct checksum
    -3	common/cmd_bootm.c	Image data   has bad	 checksum
     4	common/cmd_bootm.c	Image data   has correct checksum
    -4	common/cmd_bootm.c	Image is for unsupported architecture
     5	common/cmd_bootm.c	Architecture check OK
    -5	common/cmd_bootm.c	Wrong Image Type (not kernel, multi)
     6	common/cmd_bootm.c	Image Type check OK
    -6	common/cmd_bootm.c	gunzip uncompression error
    -7	common/cmd_bootm.c	Unimplemented compression type
     7	common/cmd_bootm.c	Uncompression OK
     8	common/cmd_bootm.c	No uncompress/copy overwrite error
    -9	common/cmd_bootm.c	Unsupported OS (not Linux, BSD, VxWorks, QNX)
     9	common/image.c		Start initial ramdisk verification
   -10	common/image.c		Ramdisk header has bad	   magic number
   -11	common/image.c		Ramdisk header has bad	   checksum
    10	common/image.c		Ramdisk header is OK
   -12	common/image.c		Ramdisk data   has bad	   checksum
    11	common/image.c		Ramdisk data   has correct checksum
    12	common/image.c		Ramdisk verification complete, start loading
   -13	common/image.c		Wrong Image Type (not PPC Linux ramdisk)
    13	common/image.c		Start multifile image verification
    14	common/image.c		No initial ramdisk, no multifile, continue.
    15	arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
   -30	arch/powerpc/lib/board.c	Fatal error, hang the system
   -31	post/post.c		POST test failed, detected by post_output_backlog()
   -32	post/post.c		POST test failed, detected by post_run_single()
    34	common/cmd_doc.c	before loading a Image from a DOC device
   -35	common/cmd_doc.c	Bad usage of "doc" command
    35	common/cmd_doc.c	correct usage of "doc" command
   -36	common/cmd_doc.c	No boot device
    36	common/cmd_doc.c	correct boot device
   -37	common/cmd_doc.c	Unknown Chip ID on boot device
    37	common/cmd_doc.c	correct chip ID found, device available
   -38	common/cmd_doc.c	Read Error on boot device
    38	common/cmd_doc.c	reading Image header from DOC device OK
   -39	common/cmd_doc.c	Image header has bad magic number
    39	common/cmd_doc.c	Image header has correct magic number
   -40	common/cmd_doc.c	Error reading Image from DOC device
    40	common/cmd_doc.c	Image header has correct magic number
    41	common/cmd_ide.c	before loading a Image from a IDE device
   -42	common/cmd_ide.c	Bad usage of "ide" command
    42	common/cmd_ide.c	correct usage of "ide" command
   -43	common/cmd_ide.c	No boot device
    43	common/cmd_ide.c	boot device found
   -44	common/cmd_ide.c	Device not available
    44	common/cmd_ide.c	Device available
   -45	common/cmd_ide.c	wrong partition selected
    45	common/cmd_ide.c	partition selected
   -46	common/cmd_ide.c	Unknown partition table
    46	common/cmd_ide.c	valid partition table found
   -47	common/cmd_ide.c	Invalid partition type
    47	common/cmd_ide.c	correct partition type
   -48	common/cmd_ide.c	Error reading Image Header on boot device
    48	common/cmd_ide.c	reading Image Header from IDE device OK
   -49	common/cmd_ide.c	Image header has bad magic number
    49	common/cmd_ide.c	Image header has correct magic number
   -50	common/cmd_ide.c	Image header has bad	 checksum
    50	common/cmd_ide.c	Image header has correct checksum
   -51	common/cmd_ide.c	Error reading Image from IDE device
    51	common/cmd_ide.c	reading Image from IDE device OK
    52	common/cmd_nand.c	before loading a Image from a NAND device
   -53	common/cmd_nand.c	Bad usage of "nand" command
    53	common/cmd_nand.c	correct usage of "nand" command
   -54	common/cmd_nand.c	No boot device
    54	common/cmd_nand.c	boot device found
   -55	common/cmd_nand.c	Unknown Chip ID on boot device
    55	common/cmd_nand.c	correct chip ID found, device available
   -56	common/cmd_nand.c	Error reading Image Header on boot device
    56	common/cmd_nand.c	reading Image Header from NAND device OK
   -57	common/cmd_nand.c	Image header has bad magic number
    57	common/cmd_nand.c	Image header has correct magic number
   -58	common/cmd_nand.c	Error reading Image from NAND device
    58	common/cmd_nand.c	reading Image from NAND device OK
   -60	common/env_common.c	Environment has a bad CRC, using default
    64	net/eth.c		starting with Ethernet configuration.
   -64	net/eth.c		no Ethernet found.
    65	net/eth.c		Ethernet found.
   -80	common/cmd_net.c	usage wrong
    80	common/cmd_net.c	before calling net_loop()
   -81	common/cmd_net.c	some error in net_loop() occurred
    81	common/cmd_net.c	net_loop() back without error
   -82	common/cmd_net.c	size == 0 (File with size 0 loaded)
    82	common/cmd_net.c	trying automatic boot
    83	common/cmd_net.c	running "source" command
   -83	common/cmd_net.c	some error in automatic boot or "source" command
    84	common/cmd_net.c	end without errors
 FIT uImage format:
   Arg	Where			When
   100	common/cmd_bootm.c	Kernel FIT Image has correct format
  -100	common/cmd_bootm.c	Kernel FIT Image has incorrect format
   101	common/cmd_bootm.c	No Kernel subimage unit name, using configuration
  -101	common/cmd_bootm.c	Can't get configuration for kernel subimage
   102	common/cmd_bootm.c	Kernel unit name specified
  -103	common/cmd_bootm.c	Can't get kernel subimage node offset
   103	common/cmd_bootm.c	Found configuration node
   104	common/cmd_bootm.c	Got kernel subimage node offset
  -104	common/cmd_bootm.c	Kernel subimage hash verification failed
   105	common/cmd_bootm.c	Kernel subimage hash verification OK
  -105	common/cmd_bootm.c	Kernel subimage is for unsupported architecture
   106	common/cmd_bootm.c	Architecture check OK
  -106	common/cmd_bootm.c	Kernel subimage has wrong type
   107	common/cmd_bootm.c	Kernel subimage type OK
  -107	common/cmd_bootm.c	Can't get kernel subimage data/size
   108	common/cmd_bootm.c	Got kernel subimage data/size
  -108	common/cmd_bootm.c	Wrong image type (not legacy, FIT)
  -109	common/cmd_bootm.c	Can't get kernel subimage type
  -110	common/cmd_bootm.c	Can't get kernel subimage comp
  -111	common/cmd_bootm.c	Can't get kernel subimage os
  -112	common/cmd_bootm.c	Can't get kernel subimage load address
  -113	common/cmd_bootm.c	Image uncompress/copy overwrite error
   120	common/image.c		Start initial ramdisk verification
  -120	common/image.c		Ramdisk FIT image has incorrect format
   121	common/image.c		Ramdisk FIT image has correct format
   122	common/image.c		No ramdisk subimage unit name, using configuration
  -122	common/image.c		Can't get configuration for ramdisk subimage
   123	common/image.c		Ramdisk unit name specified
  -124	common/image.c		Can't get ramdisk subimage node offset
   125	common/image.c		Got ramdisk subimage node offset
  -125	common/image.c		Ramdisk subimage hash verification failed
   126	common/image.c		Ramdisk subimage hash verification OK
  -126	common/image.c		Ramdisk subimage for unsupported architecture
   127	common/image.c		Architecture check OK
  -127	common/image.c		Can't get ramdisk subimage data/size
   128	common/image.c		Got ramdisk subimage data/size
   129	common/image.c		Can't get ramdisk load address
  -129	common/image.c		Got ramdisk load address
  -130	common/cmd_doc.c	Incorrect FIT image format
   131	common/cmd_doc.c	FIT image format OK
  -140	common/cmd_ide.c	Incorrect FIT image format
   141	common/cmd_ide.c	FIT image format OK
  -150	common/cmd_nand.c	Incorrect FIT image format
   151	common/cmd_nand.c	FIT image format OK
 - legacy image format:
 		CONFIG_IMAGE_FORMAT_LEGACY
 		enables the legacy image format support in U-Boot.
 		Default:
 		enabled if CONFIG_FIT_SIGNATURE is not defined.
 		CONFIG_DISABLE_IMAGE_LEGACY
 		disable the legacy image format
 		This define is introduced, as the legacy image format is
 		enabled per default for backward compatibility.
 - Standalone program support:
 		CONFIG_STANDALONE_LOAD_ADDR
 		This option defines a board specific value for the
 		address where standalone program gets loaded, thus
 		overwriting the architecture dependent default
 		settings.
 - Frame Buffer Address:
 		CONFIG_FB_ADDR
 		Define CONFIG_FB_ADDR if you want to use specific
 		address for frame buffer.  This is typically the case
 		when using a graphics controller has separate video
 		memory.  U-Boot will then place the frame buffer at
 		the given address instead of dynamically reserving it
 		in system RAM by calling lcd_setmem(), which grabs
 		the memory for the frame buffer depending on the
 		configured panel size.
 		Please see board_init_f function.
 - Automatic software updates via TFTP server
 		CONFIG_UPDATE_TFTP
 		CONFIG_UPDATE_TFTP_CNT_MAX
 		CONFIG_UPDATE_TFTP_MSEC_MAX
 		These options enable and control the auto-update feature;
 		for a more detailed description refer to doc/README.update.
 - MTD Support (mtdparts command, UBI support)
 		CONFIG_MTD_DEVICE
 		Adds the MTD device infrastructure from the Linux kernel.
 		Needed for mtdparts command support.
 		CONFIG_MTD_PARTITIONS
 		Adds the MTD partitioning infrastructure from the Linux
 		kernel. Needed for UBI support.
 - UBI support
 		CONFIG_UBI_SILENCE_MSG
 		Make the verbose messages from UBI stop printing.  This leaves
 		warnings and errors enabled.
 		CONFIG_MTD_UBI_WL_THRESHOLD
 		This parameter defines the maximum difference between the highest
 		erase counter value and the lowest erase counter value of eraseblocks
 		of UBI devices. When this threshold is exceeded, UBI starts performing
 		wear leveling by means of moving data from eraseblock with low erase
 		counter to eraseblocks with high erase counter.
 		The default value should be OK for SLC NAND flashes, NOR flashes and
 		other flashes which have eraseblock life-cycle 100000 or more.
 		However, in case of MLC NAND flashes which typically have eraseblock
 		life-cycle less than 10000, the threshold should be lessened (e.g.,
 		to 128 or 256, although it does not have to be power of 2).
 		default: 4096
 		CONFIG_MTD_UBI_BEB_LIMIT
 		This option specifies the maximum bad physical eraseblocks UBI
 		expects on the MTD device (per 1024 eraseblocks). If the
 		underlying flash does not admit of bad eraseblocks (e.g. NOR
 		flash), this value is ignored.
 		NAND datasheets often specify the minimum and maximum NVM
 		(Number of Valid Blocks) for the flashes' endurance lifetime.
 		The maximum expected bad eraseblocks per 1024 eraseblocks
 		then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
 		which gives 20 for most NANDs (MaxNVB is basically the total
 		count of eraseblocks on the chip).
 		To put it differently, if this value is 20, UBI will try to
 		reserve about 1.9% of physical eraseblocks for bad blocks
 		handling. And that will be 1.9% of eraseblocks on the entire
 		NAND chip, not just the MTD partition UBI attaches. This means
 		that if you have, say, a NAND flash chip admits maximum 40 bad
 		eraseblocks, and it is split on two MTD partitions of the same
 		size, UBI will reserve 40 eraseblocks when attaching a
 		partition.
 		default: 20
 		CONFIG_MTD_UBI_FASTMAP
 		Fastmap is a mechanism which allows attaching an UBI device
 		in nearly constant time. Instead of scanning the whole MTD device it
 		only has to locate a checkpoint (called fastmap) on the device.
 		The on-flash fastmap contains all information needed to attach
 		the device. Using fastmap makes only sense on large devices where
 		attaching by scanning takes long. UBI will not automatically install
 		a fastmap on old images, but you can set the UBI parameter
 		CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
 		that fastmap-enabled images are still usable with UBI implementations
 		without	fastmap support. On typical flash devices the whole fastmap
 		fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
 		CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
 		Set this parameter to enable fastmap automatically on images
 		without a fastmap.
 		default: 0
 		CONFIG_MTD_UBI_FM_DEBUG
 		Enable UBI fastmap debug
 		default: 0
 - UBIFS support
 		CONFIG_UBIFS_SILENCE_MSG
 		Make the verbose messages from UBIFS stop printing.  This leaves
 		warnings and errors enabled.
 - SPL framework
 		CONFIG_SPL
 		Enable building of SPL globally.
 		CONFIG_SPL_LDSCRIPT
 		LDSCRIPT for linking the SPL binary.
 		CONFIG_SPL_MAX_FOOTPRINT
 		Maximum size in memory allocated to the SPL, BSS included.
 		When defined, the linker checks that the actual memory
 		used by SPL from _start to __bss_end does not exceed it.
 		CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
 		must not be both defined at the same time.
 		CONFIG_SPL_MAX_SIZE
 		Maximum size of the SPL image (text, data, rodata, and
 		linker lists sections), BSS excluded.
 		When defined, the linker checks that the actual size does
 		not exceed it.
 		CONFIG_SPL_TEXT_BASE
 		TEXT_BASE for linking the SPL binary.
 		CONFIG_SPL_RELOC_TEXT_BASE
 		Address to relocate to.  If unspecified, this is equal to
 		CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
 		CONFIG_SPL_BSS_START_ADDR
 		Link address for the BSS within the SPL binary.
 		CONFIG_SPL_BSS_MAX_SIZE
 		Maximum size in memory allocated to the SPL BSS.
 		When defined, the linker checks that the actual memory used
 		by SPL from __bss_start to __bss_end does not exceed it.
 		CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
 		must not be both defined at the same time.
 		CONFIG_SPL_STACK
 		Adress of the start of the stack SPL will use
 		CONFIG_SPL_PANIC_ON_RAW_IMAGE
 		When defined, SPL will panic() if the image it has
 		loaded does not have a signature.
 		Defining this is useful when code which loads images
 		in SPL cannot guarantee that absolutely all read errors
 		will be caught.
 		An example is the LPC32XX MLC NAND driver, which will
 		consider that a completely unreadable NAND block is bad,
 		and thus should be skipped silently.
 		CONFIG_SPL_RELOC_STACK
 		Adress of the start of the stack SPL will use after
 		relocation.  If unspecified, this is equal to
 		CONFIG_SPL_STACK.
 		CONFIG_SYS_SPL_MALLOC_START
 		Starting address of the malloc pool used in SPL.
 		When this option is set the full malloc is used in SPL and
 		it is set up by spl_init() and before that, the simple malloc()
 		can be used if CONFIG_SYS_MALLOC_F is defined.
 		CONFIG_SYS_SPL_MALLOC_SIZE
 		The size of the malloc pool used in SPL.
 		CONFIG_SPL_FRAMEWORK
 		Enable the SPL framework under common/.  This framework
 		supports MMC, NAND and YMODEM loading of U-Boot and NAND
 		NAND loading of the Linux Kernel.
 		CONFIG_SPL_OS_BOOT
 		Enable booting directly to an OS from SPL.
 		See also: doc/README.falcon
 		CONFIG_SPL_DISPLAY_PRINT
 		For ARM, enable an optional function to print more information
 		about the running system.
 		CONFIG_SPL_INIT_MINIMAL
 		Arch init code should be built for a very small image
 		CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
 		Partition on the MMC to load U-Boot from when the MMC is being
 		used in raw mode
 		CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
 		Sector to load kernel uImage from when MMC is being
 		used in raw mode (for Falcon mode)
 		CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
 		CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
 		Sector and number of sectors to load kernel argument
 		parameters from when MMC is being used in raw mode
 		(for falcon mode)
 		CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
 		Partition on the MMC to load U-Boot from when the MMC is being
 		used in fs mode
 		CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
 		Filename to read to load U-Boot when reading from filesystem
 		CONFIG_SPL_FS_LOAD_KERNEL_NAME
 		Filename to read to load kernel uImage when reading
 		from filesystem (for Falcon mode)
 		CONFIG_SPL_FS_LOAD_ARGS_NAME
 		Filename to read to load kernel argument parameters
 		when reading from filesystem (for Falcon mode)
 		CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
 		Set this for NAND SPL on PPC mpc83xx targets, so that
 		start.S waits for the rest of the SPL to load before
 		continuing (the hardware starts execution after just
 		loading the first page rather than the full 4K).
 		CONFIG_SPL_SKIP_RELOCATE
 		Avoid SPL relocation
 		CONFIG_SPL_NAND_BASE
 		Include nand_base.c in the SPL.  Requires
 		CONFIG_SPL_NAND_DRIVERS.
 		CONFIG_SPL_NAND_DRIVERS
 		SPL uses normal NAND drivers, not minimal drivers.
 		CONFIG_SPL_NAND_ECC
 		Include standard software ECC in the SPL
 		CONFIG_SPL_NAND_SIMPLE
 		Support for NAND boot using simple NAND drivers that
 		expose the cmd_ctrl() interface.
 		CONFIG_SPL_UBI
 		Support for a lightweight UBI (fastmap) scanner and
 		loader
 		CONFIG_SPL_NAND_RAW_ONLY
 		Support to boot only raw u-boot.bin images. Use this only
 		if you need to save space.
 		CONFIG_SPL_COMMON_INIT_DDR
 		Set for common ddr init with serial presence detect in
 		SPL binary.
 		CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
 		CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
 		CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
 		CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
 		CONFIG_SYS_NAND_ECCBYTES
 		Defines the size and behavior of the NAND that SPL uses
 		to read U-Boot
 		CONFIG_SPL_NAND_BOOT
 		Add support NAND boot
 		CONFIG_SYS_NAND_U_BOOT_OFFS
 		Location in NAND to read U-Boot from
 		CONFIG_SYS_NAND_U_BOOT_DST
 		Location in memory to load U-Boot to
 		CONFIG_SYS_NAND_U_BOOT_SIZE
 		Size of image to load
 		CONFIG_SYS_NAND_U_BOOT_START
 		Entry point in loaded image to jump to
 		CONFIG_SYS_NAND_HW_ECC_OOBFIRST
 		Define this if you need to first read the OOB and then the
 		data. This is used, for example, on davinci platforms.
 		CONFIG_SPL_OMAP3_ID_NAND
 		Support for an OMAP3-specific set of functions to return the
 		ID and MFR of the first attached NAND chip, if present.
 		CONFIG_SPL_RAM_DEVICE
 		Support for running image already present in ram, in SPL binary
 		CONFIG_SPL_PAD_TO
 		Image offset to which the SPL should be padded before appending
 		the SPL payload. By default, this is defined as
 		CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
 		CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
 		payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
 		CONFIG_SPL_TARGET
 		Final target image containing SPL and payload.  Some SPLs
 		use an arch-specific makefile fragment instead, for
 		example if more than one image needs to be produced.
 		CONFIG_FIT_SPL_PRINT
 		Printing information about a FIT image adds quite a bit of
 		code to SPL. So this is normally disabled in SPL. Use this
 		option to re-enable it. This will affect the output of the
 		bootm command when booting a FIT image.
 - TPL framework
 		CONFIG_TPL
 		Enable building of TPL globally.
 		CONFIG_TPL_PAD_TO
 		Image offset to which the TPL should be padded before appending
 		the TPL payload. By default, this is defined as
 		CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
 		CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
 		payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
 - Interrupt support (PPC):
 		There are common interrupt_init() and timer_interrupt()
 		for all PPC archs. interrupt_init() calls interrupt_init_cpu()
 		for CPU specific initialization. interrupt_init_cpu()
 		should set decrementer_count to appropriate value. If
 		CPU resets decrementer automatically after interrupt
 		(ppc4xx) it should set decrementer_count to zero.
 		timer_interrupt() calls timer_interrupt_cpu() for CPU
 		specific handling. If board has watchdog / status_led
 		/ other_activity_monitor it works automatically from
 		general timer_interrupt().
 Board initialization settings:
 ------------------------------
 During Initialization u-boot calls a number of board specific functions
 to allow the preparation of board specific prerequisites, e.g. pin setup
 before drivers are initialized. To enable these callbacks the
 following configuration macros have to be defined. Currently this is
 architecture specific, so please check arch/your_architecture/lib/board.c
 typically in board_init_f() and board_init_r().
 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
 Configuration Settings:
 -----------------------
 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
 		Optionally it can be defined to support 64-bit memory commands.
 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
 		undefine this when you're short of memory.
 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
 		width of the commands listed in the 'help' command output.
 - CONFIG_SYS_PROMPT:	This is what U-Boot prints on the console to
 		prompt for user input.
 - CONFIG_SYS_CBSIZE:	Buffer size for input from the Console
 - CONFIG_SYS_PBSIZE:	Buffer size for Console output
 - CONFIG_SYS_MAXARGS:	max. Number of arguments accepted for monitor commands
 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
 		the application (usually a Linux kernel) when it is
 		booted
 - CONFIG_SYS_BAUDRATE_TABLE:
 		List of legal baudrate settings for this board.
 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
 		Begin and End addresses of the area used by the
 		simple memory test.
 - CONFIG_SYS_ALT_MEMTEST:
 		Enable an alternate, more extensive memory test.
 - CONFIG_SYS_MEMTEST_SCRATCH:
 		Scratch address used by the alternate memory test
 		You only need to set this if address zero isn't writeable
 - CONFIG_SYS_MEM_RESERVE_SECURE
 		Only implemented for ARMv8 for now.
 		If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
 		is substracted from total RAM and won't be reported to OS.
 		This memory can be used as secure memory. A variable
 		gd->arch.secure_ram is used to track the location. In systems
 		the RAM base is not zero, or RAM is divided into banks,
 		this variable needs to be recalcuated to get the address.
 - CONFIG_SYS_MEM_TOP_HIDE:
 		If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
 		this specified memory area will get subtracted from the top
 		(end) of RAM and won't get "touched" at all by U-Boot. By
 		fixing up gd->ram_size the Linux kernel should gets passed
 		the now "corrected" memory size and won't touch it either.
 		This should work for arch/ppc and arch/powerpc. Only Linux
 		board ports in arch/powerpc with bootwrapper support that
 		recalculate the memory size from the SDRAM controller setup
 		will have to get fixed in Linux additionally.
 		This option can be used as a workaround for the 440EPx/GRx
 		CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
 		be touched.
 		WARNING: Please make sure that this value is a multiple of
 		the Linux page size (normally 4k). If this is not the case,
 		then the end address of the Linux memory will be located at a
 		non page size aligned address and this could cause major
 		problems.
 - CONFIG_SYS_LOADS_BAUD_CHANGE:
 		Enable temporary baudrate change while serial download
 - CONFIG_SYS_SDRAM_BASE:
 		Physical start address of SDRAM. _Must_ be 0 here.
 - CONFIG_SYS_FLASH_BASE:
 		Physical start address of Flash memory.
 - CONFIG_SYS_MONITOR_BASE:
 		Physical start address of boot monitor code (set by
 		make config files to be same as the text base address
 		(CONFIG_SYS_TEXT_BASE) used when linking) - same as
 		CONFIG_SYS_FLASH_BASE when booting from flash.
 - CONFIG_SYS_MONITOR_LEN:
 		Size of memory reserved for monitor code, used to
 		determine _at_compile_time_ (!) if the environment is
 		embedded within the U-Boot image, or in a separate
 		flash sector.
 - CONFIG_SYS_MALLOC_LEN:
 		Size of DRAM reserved for malloc() use.
 - CONFIG_SYS_MALLOC_F_LEN
 		Size of the malloc() pool for use before relocation. If
 		this is defined, then a very simple malloc() implementation
 		will become available before relocation. The address is just
 		below the global data, and the stack is moved down to make
 		space.
 		This feature allocates regions with increasing addresses
 		within the region. calloc() is supported, but realloc()
 		is not available. free() is supported but does nothing.
 		The memory will be freed (or in fact just forgotten) when
 		U-Boot relocates itself.
 - CONFIG_SYS_MALLOC_SIMPLE
 		Provides a simple and small malloc() and calloc() for those
 		boards which do not use the full malloc in SPL (which is
 		enabled with CONFIG_SYS_SPL_MALLOC_START).
 - CONFIG_SYS_NONCACHED_MEMORY:
 		Size of non-cached memory area. This area of memory will be
 		typically located right below the malloc() area and mapped
 		uncached in the MMU. This is useful for drivers that would
 		otherwise require a lot of explicit cache maintenance. For
 		some drivers it's also impossible to properly maintain the
 		cache. For example if the regions that need to be flushed
 		are not a multiple of the cache-line size, *and* padding
 		cannot be allocated between the regions to align them (i.e.
 		if the HW requires a contiguous array of regions, and the
 		size of each region is not cache-aligned), then a flush of
 		one region may result in overwriting data that hardware has
 		written to another region in the same cache-line. This can
 		happen for example in network drivers where descriptors for
 		buffers are typically smaller than the CPU cache-line (e.g.
 		16 bytes vs. 32 or 64 bytes).
 		Non-cached memory is only supported on 32-bit ARM at present.
 - CONFIG_SYS_BOOTM_LEN:
 		Normally compressed uImages are limited to an
 		uncompressed size of 8 MBytes. If this is not enough,
 		you can define CONFIG_SYS_BOOTM_LEN in your board config file
 		to adjust this setting to your needs.
 - CONFIG_SYS_BOOTMAPSZ:
 		Maximum size of memory mapped by the startup code of
 		the Linux kernel; all data that must be processed by
 		the Linux kernel (bd_info, boot arguments, FDT blob if
 		used) must be put below this limit, unless "bootm_low"
 		environment variable is defined and non-zero. In such case
 		all data for the Linux kernel must be between "bootm_low"
 		and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.	 The environment
 		variable "bootm_mapsize" will override the value of
 		CONFIG_SYS_BOOTMAPSZ.  If CONFIG_SYS_BOOTMAPSZ is undefined,
 		then the value in "bootm_size" will be used instead.
 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
 		Enable initrd_high functionality.  If defined then the
 		initrd_high feature is enabled and the bootm ramdisk subcommand
 		is enabled.
 - CONFIG_SYS_BOOT_GET_CMDLINE:
 		Enables allocating and saving kernel cmdline in space between
 		"bootm_low" and "bootm_low" + BOOTMAPSZ.
 - CONFIG_SYS_BOOT_GET_KBD:
 		Enables allocating and saving a kernel copy of the bd_info in
 		space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
 - CONFIG_SYS_MAX_FLASH_BANKS:
 		Max number of Flash memory banks
 - CONFIG_SYS_MAX_FLASH_SECT:
 		Max number of sectors on a Flash chip
 - CONFIG_SYS_FLASH_ERASE_TOUT:
 		Timeout for Flash erase operations (in ms)
 - CONFIG_SYS_FLASH_WRITE_TOUT:
 		Timeout for Flash write operations (in ms)
 - CONFIG_SYS_FLASH_LOCK_TOUT
 		Timeout for Flash set sector lock bit operation (in ms)
 - CONFIG_SYS_FLASH_UNLOCK_TOUT
 		Timeout for Flash clear lock bits operation (in ms)
 - CONFIG_SYS_FLASH_PROTECTION
 		If defined, hardware flash sectors protection is used
 		instead of U-Boot software protection.
 - CONFIG_SYS_DIRECT_FLASH_TFTP:
 		Enable TFTP transfers directly to flash memory;
 		without this option such a download has to be
 		performed in two steps: (1) download to RAM, and (2)
 		copy from RAM to flash.
 		The two-step approach is usually more reliable, since
 		you can check if the download worked before you erase
 		the flash, but in some situations (when system RAM is
 		too limited to allow for a temporary copy of the
 		downloaded image) this option may be very useful.
 - CONFIG_SYS_FLASH_CFI:
 		Define if the flash driver uses extra elements in the
 		common flash structure for storing flash geometry.
 - CONFIG_FLASH_CFI_DRIVER
 		This option also enables the building of the cfi_flash driver
 		in the drivers directory
 - CONFIG_FLASH_CFI_MTD
 		This option enables the building of the cfi_mtd driver
 		in the drivers directory. The driver exports CFI flash
 		to the MTD layer.
 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
 		Use buffered writes to flash.
 - CONFIG_FLASH_SPANSION_S29WS_N
 		s29ws-n MirrorBit flash has non-standard addresses for buffered
 		write commands.
 - CONFIG_SYS_FLASH_QUIET_TEST
 		If this option is defined, the common CFI flash doesn't
 		print it's warning upon not recognized FLASH banks. This
 		is useful, if some of the configured banks are only
 		optionally available.
 - CONFIG_FLASH_SHOW_PROGRESS
 		If defined (must be an integer), print out countdown
 		digits and dots.  Recommended value: 45 (9..1) for 80
 		column displays, 15 (3..1) for 40 column displays.
 - CONFIG_FLASH_VERIFY
 		If defined, the content of the flash (destination) is compared
 		against the source after the write operation. An error message
 		will be printed when the contents are not identical.
 		Please note that this option is useless in nearly all cases,
 		since such flash programming errors usually are detected earlier
 		while unprotecting/erasing/programming. Please only enable
 		this option if you really know what you are doing.
 - CONFIG_SYS_RX_ETH_BUFFER:
 		Defines the number of Ethernet receive buffers. On some
 		Ethernet controllers it is recommended to set this value
 		to 8 or even higher (EEPRO100 or 405 EMAC), since all
 		buffers can be full shortly after enabling the interface
 		on high Ethernet traffic.
 		Defaults to 4 if not defined.
 - CONFIG_ENV_MAX_ENTRIES
 	Maximum number of entries in the hash table that is used
 	internally to store the environment settings. The default
 	setting is supposed to be generous and should work in most
 	cases. This setting can be used to tune behaviour; see
 	lib/hashtable.c for details.
 - CONFIG_ENV_FLAGS_LIST_DEFAULT
 - CONFIG_ENV_FLAGS_LIST_STATIC
 	Enable validation of the values given to environment variables when
 	calling env set.  Variables can be restricted to only decimal,
 	hexadecimal, or boolean.  If CONFIG_CMD_NET is also defined,
 	the variables can also be restricted to IP address or MAC address.
 	The format of the list is:
 		type_attribute = [s|d|x|b|i|m]
 		access_attribute = [a|r|o|c]
 		attributes = type_attribute[access_attribute]
 		entry = variable_name[:attributes]
 		list = entry[,list]
 	The type attributes are:
 		s - String (default)
 		d - Decimal
 		x - Hexadecimal
 		b - Boolean ([1yYtT|0nNfF])
 		i - IP address
 		m - MAC address
 	The access attributes are:
 		a - Any (default)
 		r - Read-only
 		o - Write-once
 		c - Change-default
 	- CONFIG_ENV_FLAGS_LIST_DEFAULT
 		Define this to a list (string) to define the ".flags"
 		environment variable in the default or embedded environment.
 	- CONFIG_ENV_FLAGS_LIST_STATIC
 		Define this to a list (string) to define validation that
 		should be done if an entry is not found in the ".flags"
 		environment variable.  To override a setting in the static
 		list, simply add an entry for the same variable name to the
 		".flags" variable.
 	If CONFIG_REGEX is defined, the variable_name above is evaluated as a
 	regular expression. This allows multiple variables to define the same
 	flags without explicitly listing them for each variable.
 - CONFIG_ENV_ACCESS_IGNORE_FORCE
 	If defined, don't allow the -f switch to env set override variable
 	access flags.
 - CONFIG_USE_STDINT
 	If stdint.h is available with your toolchain you can define this
 	option to enable it. You can provide option 'USE_STDINT=1' when
 	building U-Boot to enable this.
 The following definitions that deal with the placement and management
 of environment data (variable area); in general, we support the
 following configurations:
 - CONFIG_BUILD_ENVCRC:
 	Builds up envcrc with the target environment so that external utils
 	may easily extract it and embed it in final U-Boot images.
 BE CAREFUL! The first access to the environment happens quite early
 in U-Boot initialization (when we try to get the setting of for the
 console baudrate). You *MUST* have mapped your NVRAM area then, or
 U-Boot will hang.
 Please note that even with NVRAM we still use a copy of the
 environment in RAM: we could work on NVRAM directly, but we want to
 keep settings there always unmodified except somebody uses "saveenv"
 to save the current settings.
 BE CAREFUL! For some special cases, the local device can not use
 "saveenv" command. For example, the local device will get the
 environment stored in a remote NOR flash by SRIO or PCIE link,
 but it can not erase, write this NOR flash by SRIO or PCIE interface.
 - CONFIG_NAND_ENV_DST
 	Defines address in RAM to which the nand_spl code should copy the
 	environment. If redundant environment is used, it will be copied to
 	CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
 Please note that the environment is read-only until the monitor
 has been relocated to RAM and a RAM copy of the environment has been
 created; also, when using EEPROM you will have to use getenv_f()
 until then to read environment variables.
 The environment is protected by a CRC32 checksum. Before the monitor
 is relocated into RAM, as a result of a bad CRC you will be working
 with the compiled-in default environment - *silently*!!! [This is
 necessary, because the first environment variable we need is the
 "baudrate" setting for the console - if we have a bad CRC, we don't
 have any device yet where we could complain.]
 Note: once the monitor has been relocated, then it will complain if
 the default environment is used; a new CRC is computed as soon as you
 use the "saveenv" command to store a valid environment.
 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
 		Echo the inverted Ethernet link state to the fault LED.
 		Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
 		      also needs to be defined.
 - CONFIG_SYS_FAULT_MII_ADDR:
 		MII address of the PHY to check for the Ethernet link state.
 - CONFIG_NS16550_MIN_FUNCTIONS:
 		Define this if you desire to only have use of the NS16550_init
 		and NS16550_putc functions for the serial driver located at
 		drivers/serial/ns16550.c.  This option is useful for saving
 		space for already greatly restricted images, including but not
 		limited to NAND_SPL configurations.
 - CONFIG_DISPLAY_BOARDINFO
 		Display information about the board that U-Boot is running on
 		when U-Boot starts up. The board function checkboard() is called
 		to do this.
 - CONFIG_DISPLAY_BOARDINFO_LATE
 		Similar to the previous option, but display this information
 		later, once stdio is running and output goes to the LCD, if
 		present.
 - CONFIG_BOARD_SIZE_LIMIT:
 		Maximum size of the U-Boot image. When defined, the
 		build system checks that the actual size does not
 		exceed it.
 Low Level (hardware related) configuration options:
 ---------------------------------------------------
 - CONFIG_SYS_CACHELINE_SIZE:
 		Cache Line Size of the CPU.
 - CONFIG_SYS_CCSRBAR_DEFAULT:
 		Default (power-on reset) physical address of CCSR on Freescale
 		PowerPC SOCs.
 - CONFIG_SYS_CCSRBAR:
 		Virtual address of CCSR.  On a 32-bit build, this is typically
 		the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
 - CONFIG_SYS_CCSRBAR_PHYS:
 		Physical address of CCSR.  CCSR can be relocated to a new
 		physical address, if desired.  In this case, this macro should
 		be set to that address.	 Otherwise, it should be set to the
 		same value as CONFIG_SYS_CCSRBAR_DEFAULT.  For example, CCSR
 		is typically relocated on 36-bit builds.  It is recommended
 		that this macro be defined via the _HIGH and _LOW macros:
 		#define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
 			* 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
 		Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS.	This value is typically
 		either 0 (32-bit build) or 0xF (36-bit build).	This macro is
 		used in assembly code, so it must not contain typecasts or
 		integer size suffixes (e.g. "ULL").
 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
 		Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS.  This macro is
 		used in assembly code, so it must not contain typecasts or
 		integer size suffixes (e.g. "ULL").
 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
 		If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
 		forced to a value that ensures that CCSR is not relocated.
 - Floppy Disk Support:
 		CONFIG_SYS_FDC_DRIVE_NUMBER
 		the default drive number (default value 0)
 		CONFIG_SYS_ISA_IO_STRIDE
 		defines the spacing between FDC chipset registers
 		(default value 1)
 		CONFIG_SYS_ISA_IO_OFFSET
 		defines the offset of register from address. It
 		depends on which part of the data bus is connected to
 		the FDC chipset. (default value 0)
 		If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
 		CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
 		default value.
 		if CONFIG_SYS_FDC_HW_INIT is defined, then the function
 		fdc_hw_init() is called at the beginning of the FDC
 		setup. fdc_hw_init() must be provided by the board
 		source code. It is used to make hardware-dependent
 		initializations.
 - CONFIG_IDE_AHB:
 		Most IDE controllers were designed to be connected with PCI
 		interface. Only few of them were designed for AHB interface.
 		When software is doing ATA command and data transfer to
 		IDE devices through IDE-AHB controller, some additional
 		registers accessing to these kind of IDE-AHB controller
 		is required.
 - CONFIG_SYS_IMMR:	Physical address of the Internal Memory.
 		DO NOT CHANGE unless you know exactly what you're
 		doing! (11-4) [MPC8xx systems only]
 - CONFIG_SYS_INIT_RAM_ADDR:
 		Start address of memory area that can be used for
 		initial data and stack; please note that this must be
 		writable memory that is working WITHOUT special
 		initialization, i. e. you CANNOT use normal RAM which
 		will become available only after programming the
 		memory controller and running certain initialization
 		sequences.
 		U-Boot uses the following memory types:
 		- MPC8xx: IMMR (internal memory of the CPU)
 - CONFIG_SYS_GBL_DATA_OFFSET:
 		Offset of the initial data structure in the memory
 		area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
 		CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
 		data is located at the end of the available space
 		(sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
 		GENERATED_GBL_DATA_SIZE), and the initial stack is just
 		below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
 		CONFIG_SYS_GBL_DATA_OFFSET) downward.
 	Note:
 		On the MPC824X (or other systems that use the data
 		cache for initial memory) the address chosen for
 		CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
 		point to an otherwise UNUSED address space between
 		the top of RAM and the start of the PCI space.
 - CONFIG_SYS_SCCR:	System Clock and reset Control Register (15-27)
 - CONFIG_SYS_OR_TIMING_SDRAM:
 		SDRAM timing
 - CONFIG_SYS_MAMR_PTA:
 		periodic timer for refresh
 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
   CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
   CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
   CONFIG_SYS_BR1_PRELIM:
 		Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
   CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
   CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
 		Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
 - CONFIG_PCI_ENUM_ONLY
 		Only scan through and get the devices on the buses.
 		Don't do any setup work, presumably because someone or
 		something has already done it, and we don't need to do it
 		a second time.	Useful for platforms that are pre-booted
 		by coreboot or similar.
 - CONFIG_PCI_INDIRECT_BRIDGE:
 		Enable support for indirect PCI bridges.
 - CONFIG_SYS_SRIO:
 		Chip has SRIO or not
 - CONFIG_SRIO1:
 		Board has SRIO 1 port available
 - CONFIG_SRIO2:
 		Board has SRIO 2 port available
 - CONFIG_SRIO_PCIE_BOOT_MASTER
 		Board can support master function for Boot from SRIO and PCIE
 - CONFIG_SYS_SRIOn_MEM_VIRT:
 		Virtual Address of SRIO port 'n' memory region
 - CONFIG_SYS_SRIOn_MEM_PHYS:
 		Physical Address of SRIO port 'n' memory region
 - CONFIG_SYS_SRIOn_MEM_SIZE:
 		Size of SRIO port 'n' memory region
 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
 		Defined to tell the NAND controller that the NAND chip is using
 		a 16 bit bus.
 		Not all NAND drivers use this symbol.
 		Example of drivers that use it:
 		- drivers/mtd/nand/ndfc.c
 		- drivers/mtd/nand/mxc_nand.c
 - CONFIG_SYS_NDFC_EBC0_CFG
 		Sets the EBC0_CFG register for the NDFC. If not defined
 		a default value will be used.
 - CONFIG_SPD_EEPROM
 		Get DDR timing information from an I2C EEPROM. Common
 		with pluggable memory modules such as SODIMMs
   SPD_EEPROM_ADDRESS
 		I2C address of the SPD EEPROM
 - CONFIG_SYS_SPD_BUS_NUM
 		If SPD EEPROM is on an I2C bus other than the first
 		one, specify here. Note that the value must resolve
 		to something your driver can deal with.
 - CONFIG_SYS_DDR_RAW_TIMING
 		Get DDR timing information from other than SPD. Common with
 		soldered DDR chips onboard without SPD. DDR raw timing
 		parameters are extracted from datasheet and hard-coded into
 		header files or board specific files.
 - CONFIG_FSL_DDR_INTERACTIVE
 		Enable interactive DDR debugging. See doc/README.fsl-ddr.
 - CONFIG_FSL_DDR_SYNC_REFRESH
 		Enable sync of refresh for multiple controllers.
 - CONFIG_FSL_DDR_BIST
 		Enable built-in memory test for Freescale DDR controllers.
 - CONFIG_SYS_83XX_DDR_USES_CS0
 		Only for 83xx systems. If specified, then DDR should
 		be configured using CS0 and CS1 instead of CS2 and CS3.
 - CONFIG_RMII
 		Enable RMII mode for all FECs.
 		Note that this is a global option, we can't
 		have one FEC in standard MII mode and another in RMII mode.
 - CONFIG_CRC32_VERIFY
 		Add a verify option to the crc32 command.
 		The syntax is:
 		=> crc32 -v <address> <count> <crc32>
 		Where address/count indicate a memory area
 		and crc32 is the correct crc32 which the
 		area should have.
 - CONFIG_LOOPW
 		Add the "loopw" memory command. This only takes effect if
 		the memory commands are activated globally (CONFIG_CMD_MEMORY).
 - CONFIG_MX_CYCLIC
 		Add the "mdc" and "mwc" memory commands. These are cyclic
 		"md/mw" commands.
 		Examples:
 		=> mdc.b 10 4 500
 		This command will print 4 bytes (10,11,12,13) each 500 ms.
 		=> mwc.l 100 12345678 10
 		This command will write 12345678 to address 100 all 10 ms.
 		This only takes effect if the memory commands are activated
 		globally (CONFIG_CMD_MEMORY).
 - CONFIG_SKIP_LOWLEVEL_INIT
 		[ARM, NDS32, MIPS only] If this variable is defined, then certain
 		low level initializations (like setting up the memory
 		controller) are omitted and/or U-Boot does not
 		relocate itself into RAM.
 		Normally this variable MUST NOT be defined. The only
 		exception is when U-Boot is loaded (to RAM) by some
 		other boot loader or by a debugger which performs
 		these initializations itself.
 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
 		[ARM926EJ-S only] This allows just the call to lowlevel_init()
 		to be skipped. The normal CP15 init (such as enabling the
 		instruction cache) is still performed.
 - CONFIG_SPL_BUILD
 		Modifies the behaviour of start.S when compiling a loader
 		that is executed before the actual U-Boot. E.g. when
 		compiling a NAND SPL.
 - CONFIG_TPL_BUILD
 		Modifies the behaviour of start.S  when compiling a loader
 		that is executed after the SPL and before the actual U-Boot.
 		It is loaded by the SPL.
 - CONFIG_SYS_MPC85XX_NO_RESETVEC
 		Only for 85xx systems. If this variable is specified, the section
 		.resetvec is not kept and the section .bootpg is placed in the
 		previous 4k of the .text section.
 - CONFIG_ARCH_MAP_SYSMEM
 		Generally U-Boot (and in particular the md command) uses
 		effective address. It is therefore not necessary to regard
 		U-Boot address as virtual addresses that need to be translated
 		to physical addresses. However, sandbox requires this, since
 		it maintains its own little RAM buffer which contains all
 		addressable memory. This option causes some memory accesses
 		to be mapped through map_sysmem() / unmap_sysmem().
 - CONFIG_X86_RESET_VECTOR
 		If defined, the x86 reset vector code is included. This is not
 		needed when U-Boot is running from Coreboot.
 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
 		Enables the RTC32K OSC on AM33xx based plattforms
 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
 		Option to disable subpage write in NAND driver
 		driver that uses this:
 		drivers/mtd/nand/davinci_nand.c
 Freescale QE/FMAN Firmware Support:
 -----------------------------------
 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
 loading of "firmware", which is encoded in the QE firmware binary format.
 This firmware often needs to be loaded during U-Boot booting, so macros
 are used to identify the storage device (NOR flash, SPI, etc) and the address
 within that device.
 - CONFIG_SYS_FMAN_FW_ADDR
 	The address in the storage device where the FMAN microcode is located.  The
 	meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
 	is also specified.
 - CONFIG_SYS_QE_FW_ADDR
 	The address in the storage device where the QE microcode is located.  The
 	meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
 	is also specified.
 - CONFIG_SYS_QE_FMAN_FW_LENGTH
 	The maximum possible size of the firmware.  The firmware binary format
 	has a field that specifies the actual size of the firmware, but it
 	might not be possible to read any part of the firmware unless some
 	local storage is allocated to hold the entire firmware first.
 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
 	Specifies that QE/FMAN firmware is located in NOR flash, mapped as
 	normal addressable memory via the LBC.  CONFIG_SYS_FMAN_FW_ADDR is the
 	virtual address in NOR flash.
 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
 	Specifies that QE/FMAN firmware is located in NAND flash.
 	CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
 	Specifies that QE/FMAN firmware is located on the primary SD/MMC
 	device.  CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
 	Specifies that QE/FMAN firmware is located in the remote (master)
 	memory space.	CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
 	can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
 	window->master inbound window->master LAW->the ucode address in
 	master's memory space.
 Freescale Layerscape Management Complex Firmware Support:
 ---------------------------------------------------------
 The Freescale Layerscape Management Complex (MC) supports the loading of
 "firmware".
 This firmware often needs to be loaded during U-Boot booting, so macros
 are used to identify the storage device (NOR flash, SPI, etc) and the address
 within that device.
 - CONFIG_FSL_MC_ENET
 	Enable the MC driver for Layerscape SoCs.
 Freescale Layerscape Debug Server Support:
 -------------------------------------------
 The Freescale Layerscape Debug Server Support supports the loading of
 "Debug Server firmware" and triggering SP boot-rom.
 This firmware often needs to be loaded during U-Boot booting.
 - CONFIG_SYS_MC_RSV_MEM_ALIGN
 	Define alignment of reserved memory MC requires
 Reproducible builds
 -------------------
 In order to achieve reproducible builds, timestamps used in the U-Boot build
 process have to be set to a fixed value.
 This is done using the SOURCE_DATE_EPOCH environment variable.
 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
 option for U-Boot or an environment variable in U-Boot.
 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
 Building the Software:
 ======================
 Building U-Boot has been tested in several native build environments
 and in many different cross environments. Of course we cannot support
 all possibly existing versions of cross development tools in all
 (potentially obsolete) versions. In case of tool chain problems we
 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
 which is extensively used to build and test U-Boot.
 If you are not using a native environment, it is assumed that you
 have GNU cross compiling tools available in your path. In this case,
 you must set the environment variable CROSS_COMPILE in your shell.
 Note that no changes to the Makefile or any other source files are
 necessary. For example using the ELDK on a 4xx CPU, please enter:
 	$ CROSS_COMPILE=ppc_4xx-
 	$ export CROSS_COMPILE
 Note: If you wish to generate Windows versions of the utilities in
       the tools directory you can use the MinGW toolchain
       (http://www.mingw.org).  Set your HOST tools to the MinGW
       toolchain and execute 'make tools'.  For example:
        $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
       Binaries such as tools/mkimage.exe will be created which can
       be executed on computers running Windows.
 U-Boot is intended to be simple to build. After installing the
 sources you must configure U-Boot for one specific board type. This
 is done by typing:
 	make NAME_defconfig
 where "NAME_defconfig" is the name of one of the existing configu-
 rations; see boards.cfg for supported names.
 Note: for some board special configuration names may exist; check if
       additional information is available from the board vendor; for
       instance, the TQM823L systems are available without (standard)
       or with LCD support. You can select such additional "features"
       when choosing the configuration, i. e.
       make TQM823L_defconfig
 	- will configure for a plain TQM823L, i. e. no LCD support
       make TQM823L_LCD_defconfig
 	- will configure for a TQM823L with U-Boot console on LCD
       etc.
 Finally, type "make all", and you should get some working U-Boot
 images ready for download to / installation on your system:
 - "u-boot.bin" is a raw binary image
 - "u-boot" is an image in ELF binary format
 - "u-boot.srec" is in Motorola S-Record format
 By default the build is performed locally and the objects are saved
 in the source directory. One of the two methods can be used to change
 this behavior and build U-Boot to some external directory:
 1. Add O= to the make command line invocations:
 	make O=/tmp/build distclean
 	make O=/tmp/build NAME_defconfig
 	make O=/tmp/build all
 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
 	export KBUILD_OUTPUT=/tmp/build
 	make distclean
 	make NAME_defconfig
 	make all
 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
 variable.
 Please be aware that the Makefiles assume you are using GNU make, so
 for instance on NetBSD you might need to use "gmake" instead of
 native "make".
 If the system board that you have is not listed, then you will need
 to port U-Boot to your hardware platform. To do this, follow these
 steps:
 1.  Create a new directory to hold your board specific code. Add any
     files you need. In your board directory, you will need at least
     the "Makefile" and a "<board>.c".
 2.  Create a new configuration file "include/configs/<board>.h" for
     your board.
 3.  If you're porting U-Boot to a new CPU, then also create a new
     directory to hold your CPU specific code. Add any files you need.
 4.  Run "make <board>_defconfig" with your new name.
 5.  Type "make", and you should get a working "u-boot.srec" file
     to be installed on your target system.
 6.  Debug and solve any problems that might arise.
     [Of course, this last step is much harder than it sounds.]
 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
 ==============================================================
 If you have modified U-Boot sources (for instance added a new board
 or support for new devices, a new CPU, etc.) you are expected to
 provide feedback to the other developers. The feedback normally takes
 the form of a "patch", i. e. a context diff against a certain (latest
 official or latest in the git repository) version of U-Boot sources.
 But before you submit such a patch, please verify that your modifi-
 cation did not break existing code. At least make sure that *ALL* of
 the supported boards compile WITHOUT ANY compiler warnings. To do so,
 just run the buildman script (tools/buildman/buildman), which will
 configure and build U-Boot for ALL supported system. Be warned, this
 will take a while. Please see the buildman README, or run 'buildman -H'
 for documentation.
 See also "U-Boot Porting Guide" below.
 Monitor Commands - Overview:
 ============================
 go	- start application at address 'addr'
 run	- run commands in an environment variable
 bootm	- boot application image from memory
 bootp	- boot image via network using BootP/TFTP protocol
 bootz   - boot zImage from memory
 tftpboot- boot image via network using TFTP protocol
 	       and env variables "ipaddr" and "serverip"
 	       (and eventually "gatewayip")
 tftpput - upload a file via network using TFTP protocol
 rarpboot- boot image via network using RARP/TFTP protocol
 diskboot- boot from IDE devicebootd   - boot default, i.e., run 'bootcmd'
 loads	- load S-Record file over serial line
 loadb	- load binary file over serial line (kermit mode)
 md	- memory display
 mm	- memory modify (auto-incrementing)
 nm	- memory modify (constant address)
 mw	- memory write (fill)
 cp	- memory copy
 cmp	- memory compare
 crc32	- checksum calculation
 i2c	- I2C sub-system
 sspi	- SPI utility commands
 base	- print or set address offset
 printenv- print environment variables
 setenv	- set environment variables
 saveenv - save environment variables to persistent storage
 protect - enable or disable FLASH write protection
 erase	- erase FLASH memory
 flinfo	- print FLASH memory information
 nand	- NAND memory operations (see doc/README.nand)
 bdinfo	- print Board Info structure
 iminfo	- print header information for application image
 coninfo - print console devices and informations
 ide	- IDE sub-system
 loop	- infinite loop on address range
 loopw	- infinite write loop on address range
 mtest	- simple RAM test
 icache	- enable or disable instruction cache
 dcache	- enable or disable data cache
 reset	- Perform RESET of the CPU
 echo	- echo args to console
 version - print monitor version
 help	- print online help
 ?	- alias for 'help'
 Monitor Commands - Detailed Description:
 ========================================
 TODO.
 For now: just type "help <command>".
 Environment Variables:
 ======================
 U-Boot supports user configuration using Environment Variables which
 can be made persistent by saving to Flash memory.
 Environment Variables are set using "setenv", printed using
 "printenv", and saved to Flash using "saveenv". Using "setenv"
 without a value can be used to delete a variable from the
 environment. As long as you don't save the environment you are
 working with an in-memory copy. In case the Flash area containing the
 environment is erased by accident, a default environment is provided.
 Some configuration options can be set using Environment Variables.
 List of environment variables (most likely not complete):
   baudrate	- see CONFIG_BAUDRATE
   bootdelay	- see CONFIG_BOOTDELAY
   bootcmd	- see CONFIG_BOOTCOMMAND
   bootargs	- Boot arguments when booting an RTOS image
   bootfile	- Name of the image to load with TFTP
   bootm_low	- Memory range available for image processing in the bootm
 		  command can be restricted. This variable is given as
 		  a hexadecimal number and defines lowest address allowed
 		  for use by the bootm command. See also "bootm_size"
 		  environment variable. Address defined by "bootm_low" is
 		  also the base of the initial memory mapping for the Linux
 		  kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
 		  bootm_mapsize.
   bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
 		  This variable is given as a hexadecimal number and it
 		  defines the size of the memory region starting at base
 		  address bootm_low that is accessible by the Linux kernel
 		  during early boot.  If unset, CONFIG_SYS_BOOTMAPSZ is used
 		  as the default value if it is defined, and bootm_size is
 		  used otherwise.
   bootm_size	- Memory range available for image processing in the bootm
 		  command can be restricted. This variable is given as
 		  a hexadecimal number and defines the size of the region
 		  allowed for use by the bootm command. See also "bootm_low"
 		  environment variable.
   updatefile	- Location of the software update file on a TFTP server, used
 		  by the automatic software update feature. Please refer to
 		  documentation in doc/README.update for more details.
   autoload	- if set to "no" (any string beginning with 'n'),
 		  "bootp" will just load perform a lookup of the
 		  configuration from the BOOTP server, but not try to
 		  load any image using TFTP
   autostart	- if set to "yes", an image loaded using the "bootp",
 		  "rarpboot", "tftpboot" or "diskboot" commands will
 		  be automatically started (by internally calling
 		  "bootm")
 		  If set to "no", a standalone image passed to the
 		  "bootm" command will be copied to the load address
 		  (and eventually uncompressed), but NOT be started.
 		  This can be used to load and uncompress arbitrary
 		  data.
   fdt_high	- if set this restricts the maximum address that the
 		  flattened device tree will be copied into upon boot.
 		  For example, if you have a system with 1 GB memory
 		  at physical address 0x10000000, while Linux kernel
 		  only recognizes the first 704 MB as low memory, you
 		  may need to set fdt_high as 0x3C000000 to have the
 		  device tree blob be copied to the maximum address
 		  of the 704 MB low memory, so that Linux kernel can
 		  access it during the boot procedure.
 		  If this is set to the special value 0xFFFFFFFF then
 		  the fdt will not be copied at all on boot.  For this
 		  to work it must reside in writable memory, have
 		  sufficient padding on the end of it for u-boot to
 		  add the information it needs into it, and the memory
 		  must be accessible by the kernel.
   fdtcontroladdr- if set this is the address of the control flattened
 		  device tree used by U-Boot when CONFIG_OF_CONTROL is
 		  defined.
   i2cfast	- (PPC405GP|PPC405EP only)
 		  if set to 'y' configures Linux I2C driver for fast
 		  mode (400kHZ). This environment variable is used in
 		  initialization code. So, for changes to be effective
 		  it must be saved and board must be reset.
   initrd_high	- restrict positioning of initrd images:
 		  If this variable is not set, initrd images will be
 		  copied to the highest possible address in RAM; this
 		  is usually what you want since it allows for
 		  maximum initrd size. If for some reason you want to
 		  make sure that the initrd image is loaded below the
 		  CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
 		  variable to a value of "no" or "off" or "0".
 		  Alternatively, you can set it to a maximum upper
 		  address to use (U-Boot will still check that it
 		  does not overwrite the U-Boot stack and data).
 		  For instance, when you have a system with 16 MB
 		  RAM, and want to reserve 4 MB from use by Linux,
 		  you can do this by adding "mem=12M" to the value of
 		  the "bootargs" variable. However, now you must make
 		  sure that the initrd image is placed in the first
 		  12 MB as well - this can be done with
 		  setenv initrd_high 00c00000
 		  If you set initrd_high to 0xFFFFFFFF, this is an
 		  indication to U-Boot that all addresses are legal
 		  for the Linux kernel, including addresses in flash
 		  memory. In this case U-Boot will NOT COPY the
 		  ramdisk at all. This may be useful to reduce the
 		  boot time on your system, but requires that this
 		  feature is supported by your Linux kernel.
   ipaddr	- IP address; needed for tftpboot command
   loadaddr	- Default load address for commands like "bootp",
 		  "rarpboot", "tftpboot", "loadb" or "diskboot"
   loads_echo	- see CONFIG_LOADS_ECHO
   serverip	- TFTP server IP address; needed for tftpboot command
   bootretry	- see CONFIG_BOOT_RETRY_TIME
   bootdelaykey	- see CONFIG_AUTOBOOT_DELAY_STR
   bootstopkey	- see CONFIG_AUTOBOOT_STOP_STR
   ethprime	- controls which interface is used first.
   ethact	- controls which interface is currently active.
 		  For example you can do the following
 		  => setenv ethact FEC
 		  => ping 192.168.0.1 # traffic sent on FEC
 		  => setenv ethact SCC
 		  => ping 10.0.0.1 # traffic sent on SCC
   ethrotate	- When set to "no" U-Boot does not go through all
 		  available network interfaces.
 		  It just stays at the currently selected interface.
   netretry	- When set to "no" each network operation will
 		  either succeed or fail without retrying.
 		  When set to "once" the network operation will
 		  fail when all the available network interfaces
 		  are tried once without success.
 		  Useful on scripts which control the retry operation
 		  themselves.
   npe_ucode	- set load address for the NPE microcode
   silent_linux  - If set then Linux will be told to boot silently, by
 		  changing the console to be empty. If "yes" it will be
 		  made silent. If "no" it will not be made silent. If
 		  unset, then it will be made silent if the U-Boot console
 		  is silent.
   tftpsrcp	- If this is set, the value is used for TFTP's
 		  UDP source port.
   tftpdstp	- If this is set, the value is used for TFTP's UDP
 		  destination port instead of the Well Know Port 69.
   tftpblocksize - Block size to use for TFTP transfers; if not set,
 		  we use the TFTP server's default block size
   tftptimeout	- Retransmission timeout for TFTP packets (in milli-
 		  seconds, minimum value is 1000 = 1 second). Defines
 		  when a packet is considered to be lost so it has to
 		  be retransmitted. The default is 5000 = 5 seconds.
 		  Lowering this value may make downloads succeed
 		  faster in networks with high packet loss rates or
 		  with unreliable TFTP servers.
   tftptimeoutcountmax	- maximum count of TFTP timeouts (no
 		  unit, minimum value = 0). Defines how many timeouts
 		  can happen during a single file transfer before that
 		  transfer is aborted. The default is 10, and 0 means
 		  'no timeouts allowed'. Increasing this value may help
 		  downloads succeed with high packet loss rates, or with
 		  unreliable TFTP servers or client hardware.
   vlan		- When set to a value < 4095 the traffic over
 		  Ethernet is encapsulated/received over 802.1q
 		  VLAN tagged frames.
   bootpretryperiod	- Period during which BOOTP/DHCP sends retries.
 		  Unsigned value, in milliseconds. If not set, the period will
 		  be either the default (28000), or a value based on
 		  CONFIG_NET_RETRY_COUNT, if defined. This value has
 		  precedence over the valu based on CONFIG_NET_RETRY_COUNT.
 The following image location variables contain the location of images
 used in booting. The "Image" column gives the role of the image and is
 not an environment variable name. The other columns are environment
 variable names. "File Name" gives the name of the file on a TFTP
 server, "RAM Address" gives the location in RAM the image will be
 loaded to, and "Flash Location" gives the image's address in NOR
 flash or offset in NAND flash.
 *Note* - these variables don't have to be defined for all boards, some
 boards currently use other variables for these purposes, and some
 boards use these variables for other purposes.
 Image		    File Name	     RAM Address       Flash Location
 -----		    ---------	     -----------       --------------
 u-boot		    u-boot	     u-boot_addr_r     u-boot_addr
 Linux kernel	    bootfile	     kernel_addr_r     kernel_addr
 device tree blob    fdtfile	     fdt_addr_r	       fdt_addr
 ramdisk		    ramdiskfile	     ramdisk_addr_r    ramdisk_addr
 The following environment variables may be used and automatically
 updated by the network boot commands ("bootp" and "rarpboot"),
 depending the information provided by your boot server:
   bootfile	- see above
   dnsip		- IP address of your Domain Name Server
   dnsip2	- IP address of your secondary Domain Name Server
   gatewayip	- IP address of the Gateway (Router) to use
   hostname	- Target hostname
   ipaddr	- see above
   netmask	- Subnet Mask
   rootpath	- Pathname of the root filesystem on the NFS server
   serverip	- see above
 There are two special Environment Variables:
   serial#	- contains hardware identification information such
 		  as type string and/or serial number
   ethaddr	- Ethernet address
 These variables can be set only once (usually during manufacturing of
 the board). U-Boot refuses to delete or overwrite these variables
 once they have been set once.
 Further special Environment Variables:
   ver		- Contains the U-Boot version string as printed
 		  with the "version" command. This variable is
 		  readonly (see CONFIG_VERSION_VARIABLE).
 Please note that changes to some configuration parameters may take
 only effect after the next boot (yes, that's just like Windoze :-).
 Callback functions for environment variables:
 ---------------------------------------------
 For some environment variables, the behavior of u-boot needs to change
 when their values are changed.  This functionality allows functions to
 be associated with arbitrary variables.  On creation, overwrite, or
 deletion, the callback will provide the opportunity for some side
 effect to happen or for the change to be rejected.
 The callbacks are named and associated with a function using the
 U_BOOT_ENV_CALLBACK macro in your board or driver code.
 These callbacks are associated with variables in one of two ways.  The
 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
 in the board configuration to a string that defines a list of
 associations.  The list must be in the following format:
 	entry = variable_name[:callback_name]
 	list = entry[,list]
 If the callback name is not specified, then the callback is deleted.
 Spaces are also allowed anywhere in the list.
 Callbacks can also be associated by defining the ".callbacks" variable
 with the same list format above.  Any association in ".callbacks" will
 override any association in the static list. You can define
 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
 ".callbacks" environment variable in the default or embedded environment.
 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
 regular expression. This allows multiple variables to be connected to
 the same callback without explicitly listing them all out.
 Command Line Parsing:
 =====================
 There are two different command line parsers available with U-Boot:
 the old "simple" one, and the much more powerful "hush" shell:
 Old, simple command line parser:
 --------------------------------
 - supports environment variables (through setenv / saveenv commands)
 - several commands on one line, separated by ';'
 - variable substitution using "... ${name} ..." syntax
 - special characters ('$', ';') can be escaped by prefixing with '\',
   for example:
 	setenv bootcmd bootm \${address}
 - You can also escape text by enclosing in single apostrophes, for example:
 	setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
 Hush shell:
 -----------
 - similar to Bourne shell, with control structures like
   if...then...else...fi, for...do...done; while...do...done,
   until...do...done, ...
 - supports environment ("global") variables (through setenv / saveenv
   commands) and local shell variables (through standard shell syntax
   "name=value"); only environment variables can be used with "run"
   command
 General rules:
 --------------
 (1) If a command line (or an environment variable executed by a "run"
     command) contains several commands separated by semicolon, and
     one of these commands fails, then the remaining commands will be
     executed anyway.
 (2) If you execute several variables with one call to run (i. e.
     calling run with a list of variables as arguments), any failing
     command will cause "run" to terminate, i. e. the remaining
     variables are not executed.
 Note for Redundant Ethernet Interfaces:
 =======================================
 Some boards come with redundant Ethernet interfaces; U-Boot supports
 such configurations and is capable of automatic selection of a
 "working" interface when needed. MAC assignment works as follows:
 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
 "eth1addr" (=>eth1), "eth2addr", ...
 If the network interface stores some valid MAC address (for instance
 in SROM), this is used as default address if there is NO correspon-
 ding setting in the environment; if the corresponding environment
 variable is set, this overrides the settings in the card; that means:
 o If the SROM has a valid MAC address, and there is no address in the
   environment, the SROM's address is used.
 o If there is no valid address in the SROM, and a definition in the
   environment exists, then the value from the environment variable is
   used.
 o If both the SROM and the environment contain a MAC address, and
   both addresses are the same, this MAC address is used.
 o If both the SROM and the environment contain a MAC address, and the
   addresses differ, the value from the environment is used and a
   warning is printed.
 o If neither SROM nor the environment contain a MAC address, an error
   is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
   a random, locally-assigned MAC is used.
 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
 will be programmed into hardware as part of the initialization process.	 This
 may be skipped by setting the appropriate 'ethmacskip' environment variable.
 The naming convention is as follows:
 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
 Image Formats:
 ==============
 U-Boot is capable of booting (and performing other auxiliary operations on)
 images in two formats:
 New uImage format (FIT)
 -----------------------
 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
 to Flattened Device Tree). It allows the use of images with multiple
 components (several kernels, ramdisks, etc.), with contents protected by
 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
 Old uImage format
 -----------------
 Old image format is based on binary files which can be basically anything,
 preceded by a special header; see the definitions in include/image.h for
 details; basically, the header defines the following image properties:
 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
   4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
   LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
   Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
   INTEGRITY).
 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
   IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
   Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
 * Compression Type (uncompressed, gzip, bzip2)
 * Load Address
 * Entry Point
 * Image Name
 * Image Timestamp
 The header is marked by a special Magic Number, and both the header
 and the data portions of the image are secured against corruption by
 CRC32 checksums.
 Linux Support:
 ==============
 Although U-Boot should support any OS or standalone application
 easily, the main focus has always been on Linux during the design of
 U-Boot.
 U-Boot includes many features that so far have been part of some
 special "boot loader" code within the Linux kernel. Also, any
 "initrd" images to be used are no longer part of one big Linux image;
 instead, kernel and "initrd" are separate images. This implementation
 serves several purposes:
 - the same features can be used for other OS or standalone
   applications (for instance: using compressed images to reduce the
   Flash memory footprint)
 - it becomes much easier to port new Linux kernel versions because
   lots of low-level, hardware dependent stuff are done by U-Boot
 - the same Linux kernel image can now be used with different "initrd"
   images; of course this also means that different kernel images can
   be run with the same "initrd". This makes testing easier (you don't
   have to build a new "zImage.initrd" Linux image when you just
   change a file in your "initrd"). Also, a field-upgrade of the
   software is easier now.
 Linux HOWTO:
 ============
 Porting Linux to U-Boot based systems:
 ---------------------------------------
 U-Boot cannot save you from doing all the necessary modifications to
 configure the Linux device drivers for use with your target hardware
 (no, we don't intend to provide a full virtual machine interface to
 Linux :-).
 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
 Just make sure your machine specific header file (for instance
 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
 Information structure as we define in include/asm-<arch>/u-boot.h,
 and make sure that your definition of IMAP_ADDR uses the same value
 as your U-Boot configuration in CONFIG_SYS_IMMR.
 Note that U-Boot now has a driver model, a unified model for drivers.
 If you are adding a new driver, plumb it into driver model. If there
 is no uclass available, you are encouraged to create one. See
 doc/driver-model.
 Configuring the Linux kernel:
 -----------------------------
 No specific requirements for U-Boot. Make sure you have some root
 device (initial ramdisk, NFS) for your target system.
 Building a Linux Image:
 -----------------------
 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
 not used. If you use recent kernel source, a new build target
 "uImage" will exist which automatically builds an image usable by
 U-Boot. Most older kernels also have support for a "pImage" target,
 which was introduced for our predecessor project PPCBoot and uses a
 100% compatible format.
 Example:
 	make TQM850L_defconfig
 	make oldconfig
 	make dep
 	make uImage
 The "uImage" build target uses a special tool (in 'tools/mkimage') to
 encapsulate a compressed Linux kernel image with header	 information,
 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
 * build a standard "vmlinux" kernel image (in ELF binary format):
 * convert the kernel into a raw binary image:
 	${CROSS_COMPILE}-objcopy -O binary \
 				 -R .note -R .comment \
 				 -S vmlinux linux.bin
 * compress the binary image:
 	gzip -9 linux.bin
 * package compressed binary image for U-Boot:
 	mkimage -A ppc -O linux -T kernel -C gzip \
 		-a 0 -e 0 -n "Linux Kernel Image" \
 		-d linux.bin.gz uImage
 The "mkimage" tool can also be used to create ramdisk images for use
 with U-Boot, either separated from the Linux kernel image, or
 combined into one file. "mkimage" encapsulates the images with a 64
 byte header containing information about target architecture,
 operating system, image type, compression method, entry points, time
 stamp, CRC32 checksums, etc.
 "mkimage" can be called in two ways: to verify existing images and
 print the header information, or to build new images.
 In the first form (with "-l" option) mkimage lists the information
 contained in the header of an existing U-Boot image; this includes
 checksum verification:
 	tools/mkimage -l image
 	  -l ==> list image header information
 The second form (with "-d" option) is used to build a U-Boot image
 from a "data file" which is used as image payload:
 	tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
 		      -n name -d data_file image
 	  -A ==> set architecture to 'arch'
 	  -O ==> set operating system to 'os'
 	  -T ==> set image type to 'type'
 	  -C ==> set compression type 'comp'
 	  -a ==> set load address to 'addr' (hex)
 	  -e ==> set entry point to 'ep' (hex)
 	  -n ==> set image name to 'name'
 	  -d ==> use image data from 'datafile'
 Right now, all Linux kernels for PowerPC systems use the same load
 address (0x00000000), but the entry point address depends on the
 kernel version:
 - 2.2.x kernels have the entry point at 0x0000000C,
 - 2.3.x and later kernels have the entry point at 0x00000000.
 So a typical call to build a U-Boot image would read:
 	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \
 	> -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
 	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
 	> examples/uImage.TQM850L
 	Image Name:   2.4.4 kernel for TQM850L
 	Created:      Wed Jul 19 02:34:59 2000
 	Image Type:   PowerPC Linux Kernel Image (gzip compressed)
 	Data Size:    335725 Bytes = 327.86 kB = 0.32 MB
 	Load Address: 0x00000000
 	Entry Point:  0x00000000
 To verify the contents of the image (or check for corruption):
 	-> tools/mkimage -l examples/uImage.TQM850L
 	Image Name:   2.4.4 kernel for TQM850L
 	Created:      Wed Jul 19 02:34:59 2000
 	Image Type:   PowerPC Linux Kernel Image (gzip compressed)
 	Data Size:    335725 Bytes = 327.86 kB = 0.32 MB
 	Load Address: 0x00000000
 	Entry Point:  0x00000000
 NOTE: for embedded systems where boot time is critical you can trade
 speed for memory and install an UNCOMPRESSED image instead: this
 needs more space in Flash, but boots much faster since it does not
 need to be uncompressed:
 	-> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
 	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \
 	> -A ppc -O linux -T kernel -C none -a 0 -e 0 \
 	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
 	> examples/uImage.TQM850L-uncompressed
 	Image Name:   2.4.4 kernel for TQM850L
 	Created:      Wed Jul 19 02:34:59 2000
 	Image Type:   PowerPC Linux Kernel Image (uncompressed)
 	Data Size:    792160 Bytes = 773.59 kB = 0.76 MB
 	Load Address: 0x00000000
 	Entry Point:  0x00000000
 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
 when your kernel is intended to use an initial ramdisk:
 	-> tools/mkimage -n 'Simple Ramdisk Image' \
 	> -A ppc -O linux -T ramdisk -C gzip \
 	> -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
 	Image Name:   Simple Ramdisk Image
 	Created:      Wed Jan 12 14:01:50 2000
 	Image Type:   PowerPC Linux RAMDisk Image (gzip compressed)
 	Data Size:    566530 Bytes = 553.25 kB = 0.54 MB
 	Load Address: 0x00000000
 	Entry Point:  0x00000000
 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
 option performs the converse operation of the mkimage's second form (the "-d"
 option). Given an image built by mkimage, the dumpimage extracts a "data file"
 from the image:
 	tools/dumpimage -i image -T type -p position data_file
 	  -i ==> extract from the 'image' a specific 'data_file'
 	  -T ==> set image type to 'type'
 	  -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
 Installing a Linux Image:
 -------------------------
 To downloading a U-Boot image over the serial (console) interface,
 you must convert the image to S-Record format:
 	objcopy -I binary -O srec examples/image examples/image.srec
 The 'objcopy' does not understand the information in the U-Boot
 image header, so the resulting S-Record file will be relative to
 address 0x00000000. To load it to a given address, you need to
 specify the target address as 'offset' parameter with the 'loads'
 command.
 Example: install the image to address 0x40100000 (which on the
 TQM8xxL is in the first Flash bank):
 	=> erase 40100000 401FFFFF
 	.......... done
 	Erased 8 sectors
 	=> loads 40100000
 	## Ready for S-Record download ...
 	~>examples/image.srec
 	1 2 3 4 5 6 7 8 9 10 11 12 13 ...
 	...
 	15989 15990 15991 15992
 	[file transfer complete]
 	[connected]
 	## Start Addr = 0x00000000
 You can check the success of the download using the 'iminfo' command;
 this includes a checksum verification so you can be sure no data
 corruption happened:
 	=> imi 40100000
 	## Checking Image at 40100000 ...
 	   Image Name:	 2.2.13 for initrd on TQM850L
 	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
 	   Data Size:	 335725 Bytes = 327 kB = 0 MB
 	   Load Address: 00000000
 	   Entry Point:	 0000000c
 	   Verifying Checksum ... OK
 Boot Linux:
 -----------
 The "bootm" command is used to boot an application that is stored in
 memory (RAM or Flash). In case of a Linux kernel image, the contents
 of the "bootargs" environment variable is passed to the kernel as
 parameters. You can check and modify this variable using the
 "printenv" and "setenv" commands:
 	=> printenv bootargs
 	bootargs=root=/dev/ram
 	=> setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
 	=> printenv bootargs
 	bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
 	=> bootm 40020000
 	## Booting Linux kernel at 40020000 ...
 	   Image Name:	 2.2.13 for NFS on TQM850L
 	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
 	   Data Size:	 381681 Bytes = 372 kB = 0 MB
 	   Load Address: 00000000
 	   Entry Point:	 0000000c
 	   Verifying Checksum ... OK
 	   Uncompressing Kernel Image ... OK
 	Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
 	Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
 	time_init: decrementer frequency = 187500000/60
 	Calibrating delay loop... 49.77 BogoMIPS
 	Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
 	...
 If you want to boot a Linux kernel with initial RAM disk, you pass
 the memory addresses of both the kernel and the initrd image (PPBCOOT
 format!) to the "bootm" command:
 	=> imi 40100000 40200000
 	## Checking Image at 40100000 ...
 	   Image Name:	 2.2.13 for initrd on TQM850L
 	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
 	   Data Size:	 335725 Bytes = 327 kB = 0 MB
 	   Load Address: 00000000
 	   Entry Point:	 0000000c
 	   Verifying Checksum ... OK
 	## Checking Image at 40200000 ...
 	   Image Name:	 Simple Ramdisk Image
 	   Image Type:	 PowerPC Linux RAMDisk Image (gzip compressed)
 	   Data Size:	 566530 Bytes = 553 kB = 0 MB
 	   Load Address: 00000000
 	   Entry Point:	 00000000
 	   Verifying Checksum ... OK
 	=> bootm 40100000 40200000
 	## Booting Linux kernel at 40100000 ...
 	   Image Name:	 2.2.13 for initrd on TQM850L
 	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
 	   Data Size:	 335725 Bytes = 327 kB = 0 MB
 	   Load Address: 00000000
 	   Entry Point:	 0000000c
 	   Verifying Checksum ... OK
 	   Uncompressing Kernel Image ... OK
 	## Loading RAMDisk Image at 40200000 ...
 	   Image Name:	 Simple Ramdisk Image
 	   Image Type:	 PowerPC Linux RAMDisk Image (gzip compressed)
 	   Data Size:	 566530 Bytes = 553 kB = 0 MB
 	   Load Address: 00000000
 	   Entry Point:	 00000000
 	   Verifying Checksum ... OK
 	   Loading Ramdisk ... OK
 	Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
 	Boot arguments: root=/dev/ram
 	time_init: decrementer frequency = 187500000/60
 	Calibrating delay loop... 49.77 BogoMIPS
 	...
 	RAMDISK: Compressed image found at block 0
 	VFS: Mounted root (ext2 filesystem).
 	bash#
 Boot Linux and pass a flat device tree:
 -----------
 First, U-Boot must be compiled with the appropriate defines. See the section
 titled "Linux Kernel Interface" above for a more in depth explanation. The
 following is an example of how to start a kernel and pass an updated
 flat device tree:
 => print oftaddr
 oftaddr=0x300000
 => print oft
 oft=oftrees/mpc8540ads.dtb
 => tftp $oftaddr $oft
 Speed: 1000, full duplex
 Using TSEC0 device
 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
 Filename 'oftrees/mpc8540ads.dtb'.
 Load address: 0x300000
 Loading: #
 done
 Bytes transferred = 4106 (100a hex)
 => tftp $loadaddr $bootfile
 Speed: 1000, full duplex
 Using TSEC0 device
 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
 Filename 'uImage'.
 Load address: 0x200000
 Loading:############
 done
 Bytes transferred = 1029407 (fb51f hex)
 => print loadaddr
 loadaddr=200000
 => print oftaddr
 oftaddr=0x300000
 => bootm $loadaddr - $oftaddr
 ## Booting image at 00200000 ...
    Image Name:	 Linux-2.6.17-dirty
    Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
    Data Size:	 1029343 Bytes = 1005.2 kB
    Load Address: 00000000
    Entry Point:	 00000000
    Verifying Checksum ... OK
    Uncompressing Kernel Image ... OK
 Booting using flat device tree at 0x300000
 Using MPC85xx ADS machine description
 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
 [snip]
 More About U-Boot Image Types:
 ------------------------------
 U-Boot supports the following image types:
    "Standalone Programs" are directly runnable in the environment
 	provided by U-Boot; it is expected that (if they behave
 	well) you can continue to work in U-Boot after return from
 	the Standalone Program.
    "OS Kernel Images" are usually images of some Embedded OS which
 	will take over control completely. Usually these programs
 	will install their own set of exception handlers, device
 	drivers, set up the MMU, etc. - this means, that you cannot
 	expect to re-enter U-Boot except by resetting the CPU.
    "RAMDisk Images" are more or less just data blocks, and their
 	parameters (address, size) are passed to an OS kernel that is
 	being started.
    "Multi-File Images" contain several images, typically an OS
 	(Linux) kernel image and one or more data images like
 	RAMDisks. This construct is useful for instance when you want
 	to boot over the network using BOOTP etc., where the boot
 	server provides just a single image file, but you want to get
 	for instance an OS kernel and a RAMDisk image.
 	"Multi-File Images" start with a list of image sizes, each
 	image size (in bytes) specified by an "uint32_t" in network
 	byte order. This list is terminated by an "(uint32_t)0".
 	Immediately after the terminating 0 follow the images, one by
 	one, all aligned on "uint32_t" boundaries (size rounded up to
 	a multiple of 4 bytes).
    "Firmware Images" are binary images containing firmware (like
 	U-Boot or FPGA images) which usually will be programmed to
 	flash memory.
    "Script files" are command sequences that will be executed by
 	U-Boot's command interpreter; this feature is especially
 	useful when you configure U-Boot to use a real shell (hush)
 	as command interpreter.
 Booting the Linux zImage:
 -------------------------
 On some platforms, it's possible to boot Linux zImage. This is done
 using the "bootz" command. The syntax of "bootz" command is the same
 as the syntax of "bootm" command.
 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
 kernel with raw initrd images. The syntax is slightly different, the
 address of the initrd must be augmented by it's size, in the following
 format: "<initrd addres>:<initrd size>".
 Standalone HOWTO:
 =================
 One of the features of U-Boot is that you can dynamically load and
 run "standalone" applications, which can use some resources of
 U-Boot like console I/O functions or interrupt services.
 Two simple examples are included with the sources:
 "Hello World" Demo:
 -------------------
 'examples/hello_world.c' contains a small "Hello World" Demo
 application; it is automatically compiled when you build U-Boot.
 It's configured to run at address 0x00040004, so you can play with it
 like that:
 	=> loads
 	## Ready for S-Record download ...
 	~>examples/hello_world.srec
 	1 2 3 4 5 6 7 8 9 10 11 ...
 	[file transfer complete]
 	[connected]
 	## Start Addr = 0x00040004
 	=> go 40004 Hello World! This is a test.
 	## Starting application at 0x00040004 ...
 	Hello World
 	argc = 7
 	argv[0] = "40004"
 	argv[1] = "Hello"
 	argv[2] = "World!"
 	argv[3] = "This"
 	argv[4] = "is"
 	argv[5] = "a"
 	argv[6] = "test."
 	argv[7] = "<NULL>"
 	Hit any key to exit ...
 	## Application terminated, rc = 0x0
 Another example, which demonstrates how to register a CPM interrupt
 handler with the U-Boot code, can be found in 'examples/timer.c'.
 Here, a CPM timer is set up to generate an interrupt every second.
 The interrupt service routine is trivial, just printing a '.'
 character, but this is just a demo program. The application can be
 controlled by the following keys:
 	? - print current values og the CPM Timer registers
 	b - enable interrupts and start timer
 	e - stop timer and disable interrupts
 	q - quit application
 	=> loads
 	## Ready for S-Record download ...
 	~>examples/timer.srec
 	1 2 3 4 5 6 7 8 9 10 11 ...
 	[file transfer complete]
 	[connected]
 	## Start Addr = 0x00040004
 	=> go 40004
 	## Starting application at 0x00040004 ...
 	TIMERS=0xfff00980
 	Using timer 1
 	  tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
 Hit 'b':
 	[q, b, e, ?] Set interval 1000000 us
 	Enabling timer
 Hit '?':
 	[q, b, e, ?] ........
 	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
 Hit '?':
 	[q, b, e, ?] .
 	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
 Hit '?':
 	[q, b, e, ?] .
 	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
 Hit '?':
 	[q, b, e, ?] .
 	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
 Hit 'e':
 	[q, b, e, ?] ...Stopping timer
 Hit 'q':
 	[q, b, e, ?] ## Application terminated, rc = 0x0
 Minicom warning:
 ================
 Over time, many people have reported problems when trying to use the
 "minicom" terminal emulation program for serial download. I (wd)
 consider minicom to be broken, and recommend not to use it. Under
 Unix, I recommend to use C-Kermit for general purpose use (and
 especially for kermit binary protocol download ("loadb" command), and
 use "cu" for S-Record download ("loads" command).  See
 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
 for help with kermit.
 Nevertheless, if you absolutely want to use it try adding this
 configuration to your "File transfer protocols" section:
 	   Name	   Program			Name U/D FullScr IO-Red. Multi
 	X  kermit  /usr/bin/kermit -i -l %l -s	 Y    U	   Y	   N	  N
 	Y  kermit  /usr/bin/kermit -i -l %l -r	 N    D	   Y	   N	  N
 NetBSD Notes:
 =============
 Starting at version 0.9.2, U-Boot supports NetBSD both as host
 (build U-Boot) and target system (boots NetBSD/mpc8xx).
 Building requires a cross environment; it is known to work on
 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
 need gmake since the Makefiles are not compatible with BSD make).
 Note that the cross-powerpc package does not install include files;
 attempting to build U-Boot will fail because <machine/ansi.h> is
 missing.  This file has to be installed and patched manually:
 	# cd /usr/pkg/cross/powerpc-netbsd/include
 	# mkdir powerpc
 	# ln -s powerpc machine
 	# cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
 	# ${EDIT} powerpc/ansi.h	## must remove __va_list, _BSD_VA_LIST
 Native builds *don't* work due to incompatibilities between native
 and U-Boot include files.
 Booting assumes that (the first part of) the image booted is a
 stage-2 loader which in turn loads and then invokes the kernel
 proper. Loader sources will eventually appear in the NetBSD source
 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
 Implementation Internals:
 =========================
 The following is not intended to be a complete description of every
 implementation detail. However, it should help to understand the
 inner workings of U-Boot and make it easier to port it to custom
 hardware.
 Initial Stack, Global Data:
 ---------------------------
 The implementation of U-Boot is complicated by the fact that U-Boot
 starts running out of ROM (flash memory), usually without access to
 system RAM (because the memory controller is not initialized yet).
 This means that we don't have writable Data or BSS segments, and BSS
 is not initialized as zero. To be able to get a C environment working
 at all, we have to allocate at least a minimal stack. Implementation
 options for this are defined and restricted by the CPU used: Some CPU
 models provide on-chip memory (like the IMMR area on MPC8xx and
 MPC826x processors), on others (parts of) the data cache can be
 locked as (mis-) used as memory, etc.
 	Chris Hallinan posted a good summary of these issues to the
 	U-Boot mailing list:
 	Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
 	From: "Chris Hallinan" <clh@net1plus.com>
 	Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
 	...
 	Correct me if I'm wrong, folks, but the way I understand it
 	is this: Using DCACHE as initial RAM for Stack, etc, does not
 	require any physical RAM backing up the cache. The cleverness
 	is that the cache is being used as a temporary supply of
 	necessary storage before the SDRAM controller is setup. It's
 	beyond the scope of this list to explain the details, but you
 	can see how this works by studying the cache architecture and
 	operation in the architecture and processor-specific manuals.
 	OCM is On Chip Memory, which I believe the 405GP has 4K. It
 	is another option for the system designer to use as an
 	initial stack/RAM area prior to SDRAM being available. Either
 	option should work for you. Using CS 4 should be fine if your
 	board designers haven't used it for something that would
 	cause you grief during the initial boot! It is frequently not
 	used.
 	CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
 	with your processor/board/system design. The default value
 	you will find in any recent u-boot distribution in
 	walnut.h should work for you. I'd set it to a value larger
 	than your SDRAM module. If you have a 64MB SDRAM module, set
 	it above 400_0000. Just make sure your board has no resources
 	that are supposed to respond to that address! That code in
 	start.S has been around a while and should work as is when
 	you get the config right.
 	-Chris Hallinan
 	DS4.COM, Inc.
 It is essential to remember this, since it has some impact on the C
 code for the initialization procedures:
 * Initialized global data (data segment) is read-only. Do not attempt
   to write it.
 * Do not use any uninitialized global data (or implicitly initialized
   as zero data - BSS segment) at all - this is undefined, initiali-
   zation is performed later (when relocating to RAM).
 * Stack space is very limited. Avoid big data buffers or things like
   that.
 Having only the stack as writable memory limits means we cannot use
 normal global data to share information between the code. But it
 turned out that the implementation of U-Boot can be greatly
 simplified by making a global data structure (gd_t) available to all
 functions. We could pass a pointer to this data as argument to _all_
 functions, but this would bloat the code. Instead we use a feature of
 the GCC compiler (Global Register Variables) to share the data: we
 place a pointer (gd) to the global data into a register which we
 reserve for this purpose.
 When choosing a register for such a purpose we are restricted by the
 relevant  (E)ABI  specifications for the current architecture, and by
 GCC's implementation.
 For PowerPC, the following registers have specific use:
 	R1:	stack pointer
 	R2:	reserved for system use
 	R3-R4:	parameter passing and return values
 	R5-R10: parameter passing
 	R13:	small data area pointer
 	R30:	GOT pointer
 	R31:	frame pointer
 	(U-Boot also uses R12 as internal GOT pointer. r12
 	is a volatile register so r12 needs to be reset when
 	going back and forth between asm and C)
     ==> U-Boot will use R2 to hold a pointer to the global data
     Note: on PPC, we could use a static initializer (since the
     address of the global data structure is known at compile time),
     but it turned out that reserving a register results in somewhat
     smaller code - although the code savings are not that big (on
     average for all boards 752 bytes for the whole U-Boot image,
     624 text + 127 data).
 On ARM, the following registers are used:
 	R0:	function argument word/integer result
 	R1-R3:	function argument word
 	R9:	platform specific
 	R10:	stack limit (used only if stack checking is enabled)
 	R11:	argument (frame) pointer
 	R12:	temporary workspace
 	R13:	stack pointer
 	R14:	link register
 	R15:	program counter
     ==> U-Boot will use R9 to hold a pointer to the global data
     Note: on ARM, only R_ARM_RELATIVE relocations are supported.
 On Nios II, the ABI is documented here:
 	http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
     ==> U-Boot will use gp to hold a pointer to the global data
     Note: on Nios II, we give "-G0" option to gcc and don't use gp
     to access small data sections, so gp is free.
 On NDS32, the following registers are used:
 	R0-R1:	argument/return
 	R2-R5:	argument
 	R15:	temporary register for assembler
 	R16:	trampoline register
 	R28:	frame pointer (FP)
 	R29:	global pointer (GP)
 	R30:	link register (LP)
 	R31:	stack pointer (SP)
 	PC:	program counter (PC)
     ==> U-Boot will use R10 to hold a pointer to the global data
 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
 or current versions of GCC may "optimize" the code too much.
 Memory Management:
 ------------------
 U-Boot runs in system state and uses physical addresses, i.e. the
 MMU is not used either for address mapping nor for memory protection.
 The available memory is mapped to fixed addresses using the memory
 controller. In this process, a contiguous block is formed for each
 memory type (Flash, SDRAM, SRAM), even when it consists of several
 physical memory banks.
 U-Boot is installed in the first 128 kB of the first Flash bank (on
 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
 booting and sizing and initializing DRAM, the code relocates itself
 to the upper end of DRAM. Immediately below the U-Boot code some
 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
 configuration setting]. Below that, a structure with global Board
 Info data is placed, followed by the stack (growing downward).
 Additionally, some exception handler code is copied to the low 8 kB
 of DRAM (0x00000000 ... 0x00001FFF).
 So a typical memory configuration with 16 MB of DRAM could look like
 this:
 	0x0000 0000	Exception Vector code
 	      :
 	0x0000 1FFF
 	0x0000 2000	Free for Application Use
 	      :
 	      :
 	      :
 	      :
 	0x00FB FF20	Monitor Stack (Growing downward)
 	0x00FB FFAC	Board Info Data and permanent copy of global data
 	0x00FC 0000	Malloc Arena
 	      :
 	0x00FD FFFF
 	0x00FE 0000	RAM Copy of Monitor Code
 	...		eventually: LCD or video framebuffer
 	...		eventually: pRAM (Protected RAM - unchanged by reset)
 	0x00FF FFFF	[End of RAM]
 System Initialization:
 ----------------------
 In the reset configuration, U-Boot starts at the reset entry point
 (on most PowerPC systems at address 0x00000100). Because of the reset
 configuration for CS0# this is a mirror of the on board Flash memory.
 To be able to re-map memory U-Boot then jumps to its link address.
 To be able to implement the initialization code in C, a (small!)
 initial stack is set up in the internal Dual Ported RAM (in case CPUs
 which provide such a feature like), or in a locked part of the data
 cache. After that, U-Boot initializes the CPU core, the caches and
 the SIU.
 Next, all (potentially) available memory banks are mapped using a
 preliminary mapping. For example, we put them on 512 MB boundaries
 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
 programmed for SDRAM access. Using the temporary configuration, a
 simple memory test is run that determines the size of the SDRAM
 banks.
 When there is more than one SDRAM bank, and the banks are of
 different size, the largest is mapped first. For equal size, the first
 bank (CS2#) is mapped first. The first mapping is always for address
 0x00000000, with any additional banks following immediately to create
 contiguous memory starting from 0.
 Then, the monitor installs itself at the upper end of the SDRAM area
 and allocates memory for use by malloc() and for the global Board
 Info data; also, the exception vector code is copied to the low RAM
 pages, and the final stack is set up.
 Only after this relocation will you have a "normal" C environment;
 until that you are restricted in several ways, mostly because you are
 running from ROM, and because the code will have to be relocated to a
 new address in RAM.
 U-Boot Porting Guide:
 ----------------------
 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
 list, October 2002]
 int main(int argc, char *argv[])
 {
 	sighandler_t no_more_time;
 	signal(SIGALRM, no_more_time);
 	alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
 	if (available_money > available_manpower) {
 		Pay consultant to port U-Boot;
 		return 0;
 	}
 	Download latest U-Boot source;
 	Subscribe to u-boot mailing list;
 	if (clueless)
 		email("Hi, I am new to U-Boot, how do I get started?");
 	while (learning) {
 		Read the README file in the top level directory;
 		Read http://www.denx.de/twiki/bin/view/DULG/Manual;
 		Read applicable doc/*.README;
 		Read the source, Luke;
 		/* find . -name "*.[chS]" | xargs grep -i <keyword> */
 	}
 	if (available_money > toLocalCurrency ($2500))
 		Buy a BDI3000;
 	else
 		Add a lot of aggravation and time;
 	if (a similar board exists) {	/* hopefully... */
 		cp -a board/<similar> board/<myboard>
 		cp include/configs/<similar>.h include/configs/<myboard>.h
 	} else {
 		Create your own board support subdirectory;
 		Create your own board include/configs/<myboard>.h file;
 	}
 	Edit new board/<myboard> files
 	Edit new include/configs/<myboard>.h
 	while (!accepted) {
 		while (!running) {
 			do {
 				Add / modify source code;
 			} until (compiles);
 			Debug;
 			if (clueless)
 				email("Hi, I am having problems...");
 		}
 		Send patch file to the U-Boot email list;
 		if (reasonable critiques)
 			Incorporate improvements from email list code review;
 		else
 			Defend code as written;
 	}
 	return 0;
 }
 void no_more_time (int sig)
 {
       hire_a_guru();
 }
 Coding Standards:
 -----------------
 All contributions to U-Boot should conform to the Linux kernel
 coding style; see the file "Documentation/CodingStyle" and the script
 "scripts/Lindent" in your Linux kernel source directory.
 Source files originating from a different project (for example the
 MTD subsystem) are generally exempt from these guidelines and are not
 reformatted to ease subsequent migration to newer versions of those
 sources.
 Please note that U-Boot is implemented in C (and to some small parts in
 Assembler); no C++ is used, so please do not use C++ style comments (//)
 in your code.
 Please also stick to the following formatting rules:
 - remove any trailing white space
 - use TAB characters for indentation and vertical alignment, not spaces
 - make sure NOT to use DOS '\r\n' line feeds
 - do not add more than 2 consecutive empty lines to source files
 - do not add trailing empty lines to source files
 Submissions which do not conform to the standards may be returned
 with a request to reformat the changes.
 Submitting Patches:
 -------------------
 Since the number of patches for U-Boot is growing, we need to
 establish some rules. Submissions which do not conform to these rules
 may be rejected, even when they contain important and valuable stuff.
 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
 see http://lists.denx.de/mailman/listinfo/u-boot
 When you send a patch, please include the following information with
 it:
 * For bug fixes: a description of the bug and how your patch fixes
   this bug. Please try to include a way of demonstrating that the
   patch actually fixes something.
 * For new features: a description of the feature and your
   implementation.
 * A CHANGELOG entry as plaintext (separate from the patch)
 * For major contributions, add a MAINTAINERS file with your
   information and associated file and directory references.
 * When you add support for a new board, don't forget to add a
   maintainer e-mail address to the boards.cfg file, too.
 * If your patch adds new configuration options, don't forget to
   document these in the README file.
 * The patch itself. If you are using git (which is *strongly*
   recommended) you can easily generate the patch using the
   "git format-patch". If you then use "git send-email" to send it to
   the U-Boot mailing list, you will avoid most of the common problems
   with some other mail clients.
   If you cannot use git, use "diff -purN OLD NEW". If your version of
   diff does not support these options, then get the latest version of
   GNU diff.
   The current directory when running this command shall be the parent
   directory of the U-Boot source tree (i. e. please make sure that
   your patch includes sufficient directory information for the
   affected files).
   We prefer patches as plain text. MIME attachments are discouraged,
   and compressed attachments must not be used.
 * If one logical set of modifications affects or creates several
   files, all these changes shall be submitted in a SINGLE patch file.
 * Changesets that contain different, unrelated modifications shall be
   submitted as SEPARATE patches, one patch per changeset.
 Notes:
 * Before sending the patch, run the buildman script on your patched
   source tree and make sure that no errors or warnings are reported
   for any of the boards.
 * Keep your modifications to the necessary minimum: A patch
   containing several unrelated changes or arbitrary reformats will be
   returned with a request to re-formatting / split it.
 * If you modify existing code, make sure that your new code does not
   add to the memory footprint of the code ;-) Small is beautiful!
   When adding new features, these should compile conditionally only
   (using #ifdef), and the resulting code with the new feature
   disabled must not need more memory than the old code without your
   modification.
 * Remember that there is a size limit of 100 kB per message on the
   u-boot mailing list. Bigger patches will be moderated. If they are
   reasonable and not too big, they will be acknowledged. But patches
   bigger than the size limit should be avoided.