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Commit b68d57c310d4d9a5385e7b265b6f93b2fc39857e

Authored by Marek Vasut
Committed by Stefano Babic
1 parent 04fe4273d3

M28: Add doc/README.m28 documentation 

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Detlev Zundel <dzu@denx.de>

Showing 1 changed file with 223 additions and 0 deletions Side-by-side Diff

  1 +DENX M28EVK
  2 +===========
  3 +
  4 +This document describes the DENX M28/M28EVK U-Boot port. This document mostly
  5 +covers topics related to making the module/board bootable.
  6 +
  7 +Terminology
  8 +-----------
  9 +
  10 +The dollar symbol ($) introduces a snipped of shell code. This shall be typed
  11 +into the unix command prompt in U-Boot source code root directory.
  12 +
  13 +The (=>) introduces a snipped of code that should by typed into U-Boot command
  14 +prompt.
  15 +
  16 +Contents
  17 +--------
  18 +
  19 +0) Files of the M28/M28EVK port
  20 +1) Prerequisites
  21 +2) Compiling U-Boot for M28
  22 +3) Installation of U-Boot for M28EVK to SD card
  23 +4) Installation of U-Boot for M28 to NAND flash
  24 +
  25 +0) Files of the M28/M28EVK port
  26 +-------------------------------
  27 +
  28 +arch/arm/cpu/arm926ejs/mx28/ - The CPU support code for the Freescale i.MX28
  29 +arch/arm/include/asm/arch-mx28/ - Header files for the Freescale i.MX28
  30 +board/denx/m28evk/ - M28EVK board specific files
  31 +include/configs/m28evk.h - M28EVK configuration file
  32 +
  33 +1) Prerequisites
  34 +----------------
  35 +
  36 +To make the M28 module or the M28 module or M28EVK board bootable, some tools
  37 +are necessary. The first one is the "elftosb" tool distributed by Freescale
  38 +Semiconductor. The other tool is the "mxsboot" tool found in U-Boot source tree.
  39 +
  40 +Firstly, obtain the elftosb archive from the following location:
  41 +
  42 + http://foss.doredevelopment.dk/mirrors/imx/elftosb-10.12.01.tar.gz
  43 +
  44 +We use a $VER variable here to denote the current version. At the time of
  45 +writing of this document, that is "10.12.01". To obtain the file from command
  46 +line, use:
  47 +
  48 + $ VER="10.12.01"
  49 + $ wget http://foss.doredevelopment.dk/mirrors/imx/elftosb-${VER}.tar.gz
  50 +
  51 +Extract the file:
  52 +
  53 + $ tar xzf elftosb-${VER}.tar.gz
  54 +
  55 +Compile the file. We need to manually tell the linker to use also libm:
  56 +
  57 + $ cd elftosb-${VER}/
  58 + $ make LIBS="-lstdc++ -lm" elftosb
  59 +
  60 +Optionally, remove debugging symbols from elftosb:
  61 +
  62 + $ strip bld/linux/elftosb
  63 +
  64 +Finally, install the "elftosb" binary. The "install" target is missing, so just
  65 +copy the binary by hand:
  66 +
  67 + $ sudo cp bld/linux/elftosb /usr/local/bin/
  68 +
  69 +Make sure the "elftosb" binary can be found in your $PATH, in this case this
  70 +means "/usr/local/bin/" has to be in your $PATH.
  71 +
  72 +2) Compiling U-Boot for M28
  73 +---------------------------
  74 +
  75 +Compiling the U-Boot for M28 is straightforward and done as compiling U-Boot
  76 +for any other ARM device. For cross-compiler setup, please refer to ELDK5.0
  77 +documentation. First, clean up the source code:
  78 +
  79 + $ make mrproper
  80 +
  81 +Next, configure U-Boot for M28EVK:
  82 +
  83 + $ make m28evk_config
  84 +
  85 +Lastly, compile U-Boot and prepare a "BootStream". The "BootStream" is a special
  86 +type of file, which the i.MX28 CPU can boot. This is handled by the following
  87 +command:
  88 +
  89 + $ make u-boot.sb
  90 +
  91 +HINT: To speed-up the build process, you can add -j<N>, where N is number of
  92 + compiler instances that'll run in parallel.
  93 +
  94 +The code produces "u-boot.sb" file. This file needs to be augmented with a
  95 +proper header to allow successful boot from SD or NAND. Adding the header is
  96 +discussed in the following chapters.
  97 +
  98 +3) Installation of U-Boot for M28EVK to SD card
  99 +-----------------------------------------------
  100 +
  101 +To boot an M28 from SD, set the boot mode DIP switches according to i.MX28
  102 +manual chapter 12.2.1 (Table 12-2), PORT=SSP0, SD/MMC master on SSP0, 3.3V.
  103 +
  104 +An SD card the i.MX28 CPU can use to boot U-Boot must contain a DOS partition
  105 +table, which in turn carries a partition of special type and which contains a
  106 +special header. The rest of partitions in the DOS partition table can be used
  107 +by the user.
  108 +
  109 +To prepare such partition, use your favourite partitioning tool. The partition
  110 +must have the following parameters:
  111 +
  112 + * Start sector .......... sector 2048
  113 + * Partition size ........ at least 1024 kb
  114 + * Partition type ........ 0x53 (sometimes "OnTrack DM6 Aux3")
  115 +
  116 +For example in Linux fdisk, the sequence for a clear card is the following:
  117 +
  118 + * o ..................... create a clear partition table
  119 + * n ..................... create new partition
  120 + * p ............. primary partition
  121 + * 1 ............. first partition
  122 + * 2048 .......... first sector is 2048
  123 + * +1M ........... make the partition 1Mb big
  124 + * t 1 ................... change first partition ID
  125 + * 53 ............ change the ID to 0x53 (OnTrack DM6 Aux3)
  126 + * <create other partitions>
  127 + * w ..................... write partition table to disk
  128 +
  129 +The partition layout is ready, next the special partition must be filled with
  130 +proper contents. The contents is generated by running the following command (see
  131 +chapter 2)):
  132 +
  133 + $ ./tools/mxsboot sd u-boot.sb u-boot.sd
  134 +
  135 +The resulting file, "u-boot.sd", shall then be written to the partition. In this
  136 +case, we assume the first partition of the SD card is /dev/mmcblk0p1:
  137 +
  138 + $ dd if=u-boot.sd of=/dev/mmcblk0p1
  139 +
  140 +Last step is to insert the card into M28EVK and boot.
  141 +
  142 +NOTE: If the user needs to adjust the start sector, the "mxsboot" tool contains
  143 + a "-p" switch for that purpose. The "-p" switch takes the sector number as
  144 + an argument.
  145 +
  146 +4) Installation of U-Boot for M28 to NAND flash
  147 +-----------------------------------------------
  148 +
  149 +To boot an M28 from NAND, set the boot mode DIP switches according to i.MX28
  150 +manual chapter 12.2.1 (Table 12-2), PORT=GPMI, NAND 1.8 V.
  151 +
  152 +There are two possibilities when preparing an image writable to NAND flash.
  153 +
  154 + I) The NAND wasn't written at all yet or the BCB is broken
  155 + ----------------------------------------------------------
  156 + In this case, both BCB (FCB and DBBT) and firmware needs to be
  157 + written to NAND. To generate NAND image containing all these,
  158 + there is a tool called "mxsboot" in the "tools/" directory. The tool
  159 + is invoked on "u-boot.sb" file from chapter 2):
  160 +
  161 + $ ./tools/mxsboot nand u-boot.sb u-boot.nand
  162 +
  163 + NOTE: The above invokation works for NAND flash with geometry of
  164 + 2048b per page, 64b OOB data, 128kb erase size. If your chip
  165 + has a different geometry, please use:
  166 +
  167 + -w <size> change page size (default 2048 b)
  168 + -o <size> change oob size (default 64 b)
  169 + -e <size> change erase size (default 131072 b)
  170 +
  171 + The geometry information can be obtained from running U-Boot
  172 + on M28 by issuing the "nand info" command.
  173 +
  174 + The resulting file, "u-boot.nand" can be written directly to NAND
  175 + from the U-Boot prompt. To simplify the process, the U-Boot default
  176 + environment contains script "update_nand_full" to update the system.
  177 +
  178 + This script expects a working TFTP server containing the file
  179 + "u-boot.nand" in it's root directory. This can be changed by
  180 + adjusting the "update_nand_full_filename" varible.
  181 +
  182 + To update the system, run the following in U-Boot prompt:
  183 +
  184 + => run update_nand_full
  185 +
  186 + In case you would only need to update the bootloader in future,
  187 + see II) below.
  188 +
  189 + II) The NAND was already written with a good BCB
  190 + ------------------------------------------------
  191 + This part applies after the part I) above was done at least once.
  192 +
  193 + If part I) above was done correctly already, there is no need to
  194 + write the FCB and DBBT parts of NAND again. It's possible to upgrade
  195 + only the bootloader image.
  196 +
  197 + To simplify the process of firmware update, the U-Boot default
  198 + environment contains script "update_nand_firmware" to update only
  199 + the firmware, without rewriting FCB and DBBT.
  200 +
  201 + This script expects a working TFTP server containing the file
  202 + "u-boot.sb" in it's root directory. This can be changed by
  203 + adjusting the "update_nand_firmware_filename" varible.
  204 +
  205 + To update the system, run the following in U-Boot prompt:
  206 +
  207 + => run update_nand_firmware
  208 +
  209 + III) Special settings for the update scripts
  210 + --------------------------------------------
  211 + There is a slight possibility of the user wanting to adjust the
  212 + STRIDE and COUNT options of the NAND boot. For description of these,
  213 + see i.MX28 manual section 12.12.1.2 and 12.12.1.3.
  214 +
  215 + The update scripts take this possibility into account. In case the
  216 + user changes STRIDE by blowing fuses, the user also has to change
  217 + "update_nand_stride" variable. In case the user changes COUNT by
  218 + blowing fuses, the user also has to change "update_nand_count"
  219 + variable for the update scripts to work correctly.
  220 +
  221 + In case the user needs to boot a firmware image bigger than 1Mb, the
  222 + user has to adjust the "update_nand_firmware_maxsz" variable for the
  223 + update scripts to work properly.