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Diffstat (limited to 'doc/README.nand')
| -rw-r--r-- | doc/README.nand | 74 |
1 files changed, 60 insertions, 14 deletions
diff --git a/doc/README.nand b/doc/README.nand index f2d6a5b..b5171f4 100644 --- a/doc/README.nand +++ b/doc/README.nand @@ -1,9 +1,7 @@ NAND FLASH commands and notes - See NOTE below!!! - # (C) Copyright 2003 # Dave Ellis, SIXNET, dge@sixnetio.com # @@ -36,14 +34,19 @@ Commands: 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. @@ -53,28 +56,28 @@ Commands: nand info Print information about all of the NAND devices found. - nand read addr ofs size + nand read addr ofs|partition 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 + nand read.jffs2 addr ofs|partition 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.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 + nand write addr ofs|partition 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.jffs2 addr ofs size + nand write.jffs2 addr ofs|partition 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 @@ -82,7 +85,7 @@ Commands: 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 @@ -207,3 +210,46 @@ As mentioned above, the legacy code is still used by the DoC subsystem. The consequence of this is that the legacy NAND can't be removed from the tree until the DoC is ported to use the new NAND support (or boards with DoC will break). + + +Additional improvements to the NAND subsystem by Guido Classen, 10-10-2006 + +JFFS2 related commands: + + implement "nand erase clean" and old "nand erase" + 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) + + "scrub [offset length]" + like "erase" but don't skip bad block. Instead erase them. + DANGEROUS!!! Factory set bad blocks will be lost. Use only + to remove artificial bad blocks created with the "markbad" command. + + +NAND locking command (for chips with active LOCKPRE pin) + + "nand lock" + set NAND chip to lock state (all pages locked) + + "nand lock tight" + set NAND chip to lock tight state (software can't change locking anymore) + + "nand lock status" + displays current locking status of all pages + + "nand unlock [offset] [size]" + unlock consecutive area (can be called multiple times for different areas) + + +I have tested the code with board containing 128MiB NAND large page chips +and 32MiB small page chips. |