GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

2026-09-06 03:52:57 +08:00
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+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, enable one of the following:
+
+  CONFIG_FS_EXT4	(for read-only)
+  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:
+
+  CONFIG_CMD_EXT2
+  CONFIG_CMD_EXT4
+
+Selecting either of the above automatically selects CONFIG_FS_EXT4 if it
+wasn't enabled already.
+
+In addition, to get the write access command "ext4write", enable:
+
+  CONFIG_CMD_EXT4_WRITE
+
+which automatically selects CONFIG_EXT4_WRITE if it wasn't defined
+already.
+
+Also relevant are the generic filesystem commands, selected by:
+
+  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
+	-- Uboot existing ext2 load and ls implementation
+	-- Journaling block device JBD2 implementation in linux Kernel