Merge git://git.denx.de/u-boot-socfpga

[people/ms/u-boot.git] / doc / README.ext4

diff --git a/doc/README.ext4 b/doc/README.ext4
index b7d0ad3930d042c89b23e49ba1a933824f2632ce..2b0eab5ddec3170800cf0e34f3b34f568a3d6df3 100644 (file)
--- a/doc/README.ext4
+++ b/doc/README.ext4
@@ -1,57 +1,81 @@
-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
+U-Boot supports access of both ext2 and ext4 filesystems, either in read-only
+mode or in read-write mode.
+
+First, to enable support for both ext4 (and, automatically, ext2 as well),
+but without selecting the corresponding commands, use one of:
+
+  #define CONFIG_FS_EXT4       (for read-only)
+  #define CONFIG_EXT4_WRITE    (for read-write)
+
+Next, to select the ext2-related commands:
+
+  * ext2ls
+  * ext2load
+
+or ext4-related commands:
+
+  * ext4size
+  * ext4ls
+  * ext4load
+
+use one or both of:
+
+  #define CONFIG_CMD_EXT2
+  #define CONFIG_CMD_EXT4
+
+Selecting either of the above automatically defines CONFIG_FS_EXT4 if it
+wasn't defined already.
+
+In addition, to get the write access command "ext4write", use:
+
+  #define CONFIG_CMD_EXT4_WRITE
+
+which automatically defines CONFIG_EXT4_WRITE if it wasn't defined
+already.
+
+Also relevant are the generic filesystem commands, selected by:
+
+  #define CONFIG_CMD_FS_GENERIC
+
+This does not automatically enable EXT4 support for you, you still need
+to do that yourself.
+
+Some sample commands to test ext4 support:
+
+1. Check that the commands can be seen in the output of U-Boot help:
+
+       UBOOT #help
+       ...
+       ext4load- load binary file from a Ext4 file system
+       ext4ls  - list files in a directory (default /)
+       ext4size - determine a file's size
+       ext4write- create a file in ext4 formatted partition
+       ...
+
+2. To list the files in an ext4-formatted partition, run:
+
+       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, run:
+
+       ext4load <interface> <dev[:part]> [addr] [filename] [bytes]
+
+       For example:
+       UBOOT #ext4load mmc 2:2 0x30007fc0 uImage
+
+4. To write a file to an 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