mtd: nand: mxc: oobfree layout?
Sascha Hauer
s.hauer at pengutronix.de
Wed Nov 21 04:25:40 EST 2012
On Tue, Nov 20, 2012 at 09:05:18PM +0100, Benoît Thébaudeau wrote:
> Dear Sascha Hauer,
>
> I've seen in the history of mxc_nand.c that you have worked on the
> nand_ecclayout structs. The following things look abnormal. Can you confirm?
> - nandv1_hw_eccoob_smallpage and nandv2_hw_eccoob_smallpage:
> * Why are bytes 0 and 1 in oobfree? These bytes are used for bad block
> information on the 16-bit variants of these 512-byte-page NANDs.
This is probably a bug. Very few people seem to use 16bit flashes.
> - nandv1_hw_eccoob_largepage:
> * According to the i.MX31 reference manual, the BI bytes of the spare area
> buffers are not free to use. So why are bytes 5, 11, 27, 43 and 59 in
> oobfree? On the contrary, if this note is a mistake in the RM, then why
> are bytes 21, 37 and 53 not in oobfree?
> - nandv2_hw_eccoob_smallpage, nandv2_hw_eccoob_largepage and
> nandv2_hw_eccoob_4k:
> * Why is byte 6 not in oobfree?
Probably bugs aswell. Most people do not use filesystems requiring OOB
data anymore, so bugs may stay uncovered for longer.
Sascha
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