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author | Scott Wood <scottwood@freescale.com> | 2008-06-12 22:13:23 +0400 |
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committer | Scott Wood <scottwood@freescale.com> | 2008-08-12 20:31:27 +0400 |
commit | 984e03cdf1431bb593aeaa1b74c445d616f955d3 (patch) | |
tree | 9ca147809a8266bd016050a0789d4b19913d7e40 /doc/README.nand | |
parent | e1c3dbada349992875934575c97b328ab2cb33ca (diff) | |
download | u-boot-984e03cdf1431bb593aeaa1b74c445d616f955d3.tar.xz |
NAND: Always skip blocks on read/write/boot.
Use of the non-skipping versions was almost always (if not always)
an error, and no valid use case has been identified.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Diffstat (limited to 'doc/README.nand')
-rw-r--r-- | doc/README.nand | 37 |
1 files changed, 12 insertions, 25 deletions
diff --git a/doc/README.nand b/doc/README.nand index 647a6b8e67..0ad5e18dd3 100644 --- a/doc/README.nand +++ b/doc/README.nand @@ -57,14 +57,9 @@ Commands: Print information about all of the NAND devices found. 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|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. + 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|partition size Read `size' bytes from the out-of-band data area corresponding to @@ -73,17 +68,15 @@ Commands: for bad blocks or ECC errors. 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|partition size - Like `write', but blocks that are marked bad are skipped and the - data is written to the next block instead. 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. + 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. + + 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|partition size Write `size' bytes from `addr' to the out-of-band data area @@ -215,12 +208,6 @@ 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) |