The u-boot from CVS 4.4 has CONFIG_MTD_NAND_ECC_JFFS commented out by default. This results in NAND_NOOB_ECCPOS5 being defined for ECC. The header file sets defines this as position 5....right below the badblock pos is set position 5. An ECC value will be written to the bad block spot when calculated...turn on JFFS2 and this problem goes away...however, something is fishy in the bad_block and position 5 resolution code for some reason. The codes addressing doesn't look like whats in the kernel tree.

At some point I'll submit a patch, but if someone else does it first that's just fine.

Richard W.

-----Original Message----- From: Dave Ellis [mailto:dge@sixnetio.com] Sent: Thursday, July 24, 2003 2:00 PM To: Woodruff, Richard Cc: u-boot-users@lists.sourceforge.net Subject: RE: [U-Boot-Users] RE: Nand OOB layout, u-boot and the kernel sources do not agree.. ??

Richard Woodruff wrote:

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Sent: Thursday, July 24, 2003 1:57 PM

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-----Original Message----- From: Woodruff, Richard Sent: Thursday, July 24, 2003 12:45 PM While trying to resolve what the OOB data layout should be I see that the kernel headers as of 8-10-2002 have changed such that both the NAND_JFFS2 and NAND_NOOB use position 5 for bad block data. The u-boot headers do not reflect this change...doesn't this mean u-boot will be incompatible with more recent kernels? Should u-boot's headers be updated here?

Position 5 is where the chip makers mark bad sectors, so we do not get a choice. The NAND_NOOB values in U-BOOT are wrong and should be changed to match the new ones in the Linux kernel. I think the original cmd_nand.c was based on a very old version of MTD.

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... Having more up to date definitions would seem better....as raw nand doesn't seem to be well supported except with jffs2 & possibly yaffs I don't suppose the NAND_NOOB is such a concern.

I don't know what software (if any) uses NAND_NOOB, but I think the definitions still should be fixed (or removed). In my patch to cmd_nand.c I hard coded the bad block position at 5, so they can't be used as they are.

Dave

Dave Ellis

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