NAND FLASH commands and notes
-
See NOTE below!!!
-
# (C) Copyright 2003
# Dave Ellis, SIXNET, dge@sixnetio.com
#
nand device num
Make device `num' the current device and print information about it.
- nand erase off size
- nand erase clean [off size]
- Erase `size' bytes starting at offset `off'. Only complete erase
- blocks can be erased.
+ nand erase off|partition size
+ nand erase clean [off|partition size]
+ Erase `size' bytes starting at offset `off'. Alternatively partition
+ name can be specified, in this case size will be eventually limited
+ to not exceed partition size (this behaviour applies also to read
+ and write commands). Only complete erase blocks can be erased.
+
+ If `erase' is specified without an offset or size, the entire flash
+ is erased. If `erase' is specified with partition but without an
+ size, the entire partition is erased.
If `clean' is specified, a JFFS2-style clean marker is written to
- each block after it is erased. If `clean' is specified without an
- offset or size, the entire flash is erased.
+ each block after it is erased.
This command will not erase blocks that are marked bad. There is
a debug option in cmd_nand.c to allow bad blocks to be erased.
nand info
Print information about all of the NAND devices found.
- nand read addr ofs size
- Read `size' bytes from `ofs' in NAND flash to `addr'. If a page
- cannot be read because it is marked bad or an uncorrectable data
- error is found the command stops with an error.
-
- nand read.jffs2 addr ofs size
- Like `read', but the data for blocks that are marked bad is read as
- 0xff. This gives a readable JFFS2 image that can be processed by
- the JFFS2 commands such as ls and fsload.
+ nand read addr ofs|partition size
+ Read `size' bytes from `ofs' in NAND flash to `addr'. Blocks that
+ are marked bad are skipped. If a page cannot be read because an
+ uncorrectable data error is found, the command stops with an error.
- nand read.oob addr ofs size
+ nand read.oob addr ofs|partition size
Read `size' bytes from the out-of-band data area corresponding to
`ofs' in NAND flash to `addr'. This is limited to the 16 bytes of
data for one 512-byte page or 2 256-byte pages. There is no check
for bad blocks or ECC errors.
- nand write addr ofs size
- Write `size' bytes from `addr' to `ofs' in NAND flash. If a page
- cannot be written because it is marked bad or the write fails the
- command stops with an error.
+ nand write addr ofs|partition size
+ Write `size' bytes from `addr' to `ofs' in NAND flash. Blocks that
+ are marked bad are skipped. If a page cannot be read because an
+ uncorrectable data error is found, the command stops with an error.
- nand write.jffs2 addr ofs size
- Like `write', but blocks that are marked bad are skipped and the
- is written to the next block instead. This allows writing writing
- a JFFS2 image, as long as the image is short enough to fit even
- after skipping the bad blocks. Compact images, such as those
- produced by mkfs.jffs2 should work well, but loading an image copied
- from another flash is going to be trouble if there are any bad blocks.
+ As JFFS2 skips blocks similarly, this allows writing a JFFS2 image,
+ as long as the image is short enough to fit even after skipping the
+ bad blocks. Compact images, such as those produced by mkfs.jffs2
+ should work well, but loading an image copied from another flash is
+ going to be trouble if there are any bad blocks.
- nand write.oob addr ofs size
+ nand write.oob addr ofs|partition size
Write `size' bytes from `addr' to the out-of-band data area
corresponding to `ofs' in NAND flash. This is limited to the 16 bytes
of data for one 512-byte page or 2 256-byte pages. There is no check
Configuration Options:
- CFG_CMD_NAND
- A good one to add to CONFIG_COMMANDS since it enables NAND support.
+ CONFIG_CMD_NAND
+ Enables NAND support and commmands.
CONFIG_MTD_NAND_ECC_JFFS2
Define this if you want the Error Correction Code information in
The old NAND handling code has been re-factored and is now confined
to only board-specific files and - unfortunately - to the DoC code
(see below). A new configuration variable has been introduced:
-CFG_NAND_LEGACY, which has to be defined in the board config file if
-that board uses legacy code. If CFG_NAND_LEGACY is defined, the board
-specific config.mk file should also have "BOARDLIBS =
-drivers/nand_legacy/libnand_legacy.a". For boards using the new NAND
-approach (PPChameleon and netstar at the moment) no variable is
-necessary, but the config.mk should have "BOARDLIBS =
-drivers/nand/libnand.a".
+CONFIG_NAND_LEGACY, which has to be defined in the board config file if
+that board uses legacy code.
The necessary changes have been made to all affected boards, and no
build breakage has been introduced, except for NETTA and NETTA_ISDN
with DoC will break).
-
Additional improvements to the NAND subsystem by Guido Classen, 10-10-2006
JFFS2 related commands:
using both the new code which is able to skip bad blocks
"nand erase clean" additionally writes JFFS2-cleanmarkers in the oob.
- "nand write.jffs2"
- like "nand write" but skip found bad eraseblocks
-
- "nand read.jffs2"
- like "nand read" but skip found bad eraseblocks
-
Miscellaneous and testing commands:
"markbad [offset]"
create an artificial bad block (for testing bad block handling)
projects / platform / kernel / u-boot.git / blobdiff