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![David Brownell](/assets/img/avatar_default.png)
Remove CONFIG_SYS_DAVINCI_BROKEN_ECC option. It's not just nasty; it's also unused by any current boards, and doesn't even match the main U-Boot distributions from TI (which use soft ECC, or 4-bit ECC on newer chips that support it). DaVinci GIT kernels since 2.6.24, and mainline Linux since 2.6.30, match non-BROKEN code paths for 1-bit HW ECC. The BROKEN code paths do seem to partially match what MontaVista/TI kernels (4.0/2.6.10, and 5.0/2.6.18) do ... but only for small pages. Large page support is really broken (and it's unclear just what software it was trying to match!), and the ECC layout was making three more bytes available for use by filesystem (or whatever) code. Since this option itself seems broken, remove it. Add a comment about the MV/TI compat issue, and the most straightforward way to address it (should someone really need to solve it). Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Scott Wood <scottwood@freescale.com>
154 lines
5.7 KiB
Plaintext
154 lines
5.7 KiB
Plaintext
NAND FLASH commands and notes
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See NOTE below!!!
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# (C) Copyright 2003
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# Dave Ellis, SIXNET, dge@sixnetio.com
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#
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# See file CREDITS for list of people who contributed to this
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# project.
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#
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# This program is free software; you can redistribute it and/or
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# modify it under the terms of the GNU General Public License as
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# published by the Free Software Foundation; either version 2 of
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# the License, or (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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# MA 02111-1307 USA
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Commands:
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nand bad
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Print a list of all of the bad blocks in the current device.
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nand device
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Print information about the current NAND device.
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nand device num
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Make device `num' the current device and print information about it.
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nand erase off|partition size
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nand erase clean [off|partition size]
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Erase `size' bytes starting at offset `off'. Alternatively partition
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name can be specified, in this case size will be eventually limited
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to not exceed partition size (this behaviour applies also to read
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and write commands). Only complete erase blocks can be erased.
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If `erase' is specified without an offset or size, the entire flash
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is erased. If `erase' is specified with partition but without an
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size, the entire partition is erased.
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If `clean' is specified, a JFFS2-style clean marker is written to
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each block after it is erased.
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This command will not erase blocks that are marked bad. There is
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a debug option in cmd_nand.c to allow bad blocks to be erased.
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Please read the warning there before using it, as blocks marked
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bad by the manufacturer must _NEVER_ be erased.
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nand info
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Print information about all of the NAND devices found.
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nand read addr ofs|partition size
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Read `size' bytes from `ofs' in NAND flash to `addr'. Blocks that
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are marked bad are skipped. If a page cannot be read because an
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uncorrectable data error is found, the command stops with an error.
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nand read.oob addr ofs|partition size
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Read `size' bytes from the out-of-band data area corresponding to
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`ofs' in NAND flash to `addr'. This is limited to the 16 bytes of
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data for one 512-byte page or 2 256-byte pages. There is no check
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for bad blocks or ECC errors.
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nand write addr ofs|partition size
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Write `size' bytes from `addr' to `ofs' in NAND flash. Blocks that
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are marked bad are skipped. If a page cannot be read because an
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uncorrectable data error is found, the command stops with an error.
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As JFFS2 skips blocks similarly, this allows writing a JFFS2 image,
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as long as the image is short enough to fit even after skipping the
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bad blocks. Compact images, such as those produced by mkfs.jffs2
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should work well, but loading an image copied from another flash is
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going to be trouble if there are any bad blocks.
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nand write.oob addr ofs|partition size
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Write `size' bytes from `addr' to the out-of-band data area
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corresponding to `ofs' in NAND flash. This is limited to the 16 bytes
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of data for one 512-byte page or 2 256-byte pages. There is no check
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for bad blocks.
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Configuration Options:
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CONFIG_CMD_NAND
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Enables NAND support and commmands.
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CONFIG_MTD_NAND_ECC_JFFS2
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Define this if you want the Error Correction Code information in
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the out-of-band data to be formatted to match the JFFS2 file system.
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CONFIG_MTD_NAND_ECC_YAFFS would be another useful choice for
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someone to implement.
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CONFIG_SYS_MAX_NAND_DEVICE
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The maximum number of NAND devices you want to support.
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CONFIG_SYS_NAND_MAX_CHIPS
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The maximum number of NAND chips per device to be supported.
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NOTE:
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=====
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The current NAND implementation is based on what is in recent
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Linux kernels. The old legacy implementation has been disabled,
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and will be removed soon.
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If you have board code which used CONFIG_NAND_LEGACY, you'll need
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to convert to the current NAND interface for it to continue to work.
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The Disk On Chip driver is currently broken and has been for some time.
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There is a driver in drivers/mtd/nand, taken from Linux, that works with
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the current NAND system but has not yet been adapted to the u-boot
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environment.
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Additional improvements to the NAND subsystem by Guido Classen, 10-10-2006
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JFFS2 related commands:
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implement "nand erase clean" and old "nand erase"
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using both the new code which is able to skip bad blocks
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"nand erase clean" additionally writes JFFS2-cleanmarkers in the oob.
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Miscellaneous and testing commands:
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"markbad [offset]"
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create an artificial bad block (for testing bad block handling)
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"scrub [offset length]"
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like "erase" but don't skip bad block. Instead erase them.
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DANGEROUS!!! Factory set bad blocks will be lost. Use only
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to remove artificial bad blocks created with the "markbad" command.
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NAND locking command (for chips with active LOCKPRE pin)
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"nand lock"
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set NAND chip to lock state (all pages locked)
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"nand lock tight"
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set NAND chip to lock tight state (software can't change locking anymore)
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"nand lock status"
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displays current locking status of all pages
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"nand unlock [offset] [size]"
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unlock consecutive area (can be called multiple times for different areas)
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I have tested the code with board containing 128MiB NAND large page chips
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and 32MiB small page chips.
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