X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=doc%2FREADME.nand;h=171380e274fa4a2784a150de29ff9b3fc17598d9;hb=28ac6719108e989429de2b3dfa90312ba7c4d27b;hp=2b9a52966c518cb5bb34d8d4b90e18ce4a3a9265;hpb=fb883a521e04437acfe989de3e152b2e4866856b;p=platform%2Fkernel%2Fu-boot.git diff --git a/doc/README.nand b/doc/README.nand index 2b9a529..171380e 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. @@ -53,36 +56,29 @@ Commands: 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 @@ -90,8 +86,8 @@ Commands: 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 @@ -188,13 +184,8 @@ We now use a complete rewrite of the NAND code based on what is 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 @@ -209,7 +200,6 @@ 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: @@ -218,12 +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)