LXR uboot/doc/README.ext4

   1U-Boot supports access of both ext2 and ext4 filesystems, either in read-only
   2mode or in read-write mode.
   3
   4First, to enable support for both ext4 (and, automatically, ext2 as well),
   5but without selecting the corresponding commands, enable one of the following:
   6
   7  CONFIG_FS_EXT4        (for read-only)
   8  CONFIG_EXT4_WRITE     (for read-write)
   9
  10Next, to select the ext2-related commands:
  11
  12  * ext2ls
  13  * ext2load
  14
  15or ext4-related commands:
  16
  17  * ext4size
  18  * ext4ls
  19  * ext4load
  20
  21use one or both of:
  22
  23  CONFIG_CMD_EXT2
  24  CONFIG_CMD_EXT4
  25
  26Selecting either of the above automatically selects CONFIG_FS_EXT4 if it
  27wasn't enabled already.
  28
  29In addition, to get the write access command "ext4write", enable:
  30
  31  CONFIG_CMD_EXT4_WRITE
  32
  33which automatically selects CONFIG_EXT4_WRITE if it wasn't defined
  34already.
  35
  36Also relevant are the generic filesystem commands, selected by:
  37
  38  CONFIG_CMD_FS_GENERIC
  39
  40This does not automatically enable EXT4 support for you, you still need
  41to do that yourself.
  42
  43Some sample commands to test ext4 support:
  44
  451. Check that the commands can be seen in the output of U-Boot help:
  46
  47        UBOOT #help
  48        ...
  49        ext4load- load binary file from a Ext4 file system
  50        ext4ls  - list files in a directory (default /)
  51        ext4size - determine a file's size
  52        ext4write- create a file in ext4 formatted partition
  53        ...
  54
  552. To list the files in an ext4-formatted partition, run:
  56
  57        ext4ls <interface> <dev[:part]> [directory]
  58
  59        For example:
  60        UBOOT #ext4ls mmc 0:5 /usr/lib
  61
  623. To read and load a file from an ext4-formatted partition to RAM, run:
  63
  64        ext4load <interface> <dev[:part]> [addr] [filename] [bytes]
  65
  66        For example:
  67        UBOOT #ext4load mmc 2:2 0x30007fc0 uImage
  68
  694. To write a file to an ext4-formatted partition.
  70
  71        a) First load a file to RAM at a particular address for example 0x30007fc0.
  72        Now execute ext4write command:
  73        ext4write <interface> <dev[:part]> [filename] [Address] [sizebytes]
  74
  75        For example:
  76        UBOOT #ext4write mmc 2:2 /boot/uImage 0x30007fc0 6183120
  77        (here 6183120 is the size of the file to be written)
  78        Note: Absolute path is required for the file to be written
  79
  80References :
  81        -- ext4 implementation in Linux Kernel
  82        -- Uboot existing ext2 load and ls implementation
  83        -- Journaling block device JBD2 implementation in linux Kernel
  84