This patch series adds support for ext4 ls,load and write features in uboot
  Journaling is supported for write feature.

  To enable support for the ext4 (and ext2) filesystem implementation,
  #define CONFIG_FS_EXT4
  
  If you want write support,
  #define CONFIG_EXT4_WRITE

  To Enable ext2 ls and load commands, modify the board specific config file with
  #define CONFIG_CMD_EXT2

  This automatically defines CONFIG_FS_EXT4 for you.

  
  To Enable ext4 ls and load commands, modify the board specific config file with
  #define CONFIG_CMD_EXT4

  This automatically defines CONFIG_FS_EXT4 for you.

  
  To enable ext4 write command, modify the board specific config file with
  #define CONFIG_CMD_EXT4
  #define CONFIG_CMD_EXT4_WRITE

  These automatically define CONFIG_FS_EXT4 and CONFIG_EXT4_WRITE for you.
  
  Also relevant are the generic filesystem commands,
  #define CONFIG_CMD_FS_GENERIC
  This does not automatically enable EXT4 support for you.

  
  Steps to test:
  
  1. After applying the patch, ext4 specific commands can be seen
     in the boot loader prompt using

  	UBOOT #help

  	ext4load- load binary file from a Ext4 file system
  	ext4ls  - list files in a directory (default /)
  	ext4write- create a file in ext4 formatted partition

  
  2. To list the files in ext4 formatted partition, execute

  	ext4ls <interface> <dev[:part]> [directory]
  	For example:
  	UBOOT #ext4ls mmc 0:5 /usr/lib

  
  3. To read and load a file from an ext4 formatted partition to RAM, execute

  	ext4load <interface> <dev[:part]> [addr] [filename] [bytes]
  	For example:
  	UBOOT #ext4load mmc 2:2 0x30007fc0 uImage

  
  4. To write a file to a ext4 formatted partition.

  	a) First load a file to RAM at a particular address for example 0x30007fc0.
  	Now execute ext4write command
  	ext4write <interface> <dev[:part]> [filename] [Address] [sizebytes]
  	For example:
  	UBOOT #ext4write mmc 2:2 /boot/uImage 0x30007fc0 6183120
  	(here 6183120 is the size of the file to be written)
  	Note: Absolute path is required for the file to be written

  
  References :
  	-- ext4 implementation in Linux Kernel
  	-- Uboot existing ext2 load and ls implementation
  	-- Journaling block device JBD2 implementation in linux Kernel