Re: [PATCH] MTD: NAND: fsl_elbc_nand: fix OOB workability for large page NAND chips

Scott Wood
2008-06-27T14:43:28Z

Anton Vorontsov wrote:
> On Thu, Jun 26, 2008 at 01:59:45PM -0500, Scott Wood wrote:
>> Anton Vorontsov wrote:
>>> For large page chips, nand_bbt is looking into OOB area, and checking
>>> for "0xff 0xff" pattern at OOB offset 0. That is, two bytes should be
>>> reserved for bbt means.
>> Interesting... both the 8313 manual and the manual for a random large
>> page NAND chip say that the bad block indicator is one byte.
>
> Ok, great. If I understood David correctly, second byte is used (by some
> chips?) for redundancy, thus should not be a big problem if we'll ignore
> it. So, would you ack this part? Then I'll resend it with some typos
> fixed. ;-)

Acked-by: Scott Wood <scottwood@freescale.com>

>> BTW, I was just looking at NAND boot on this chip, and it seems that it
>> expects ECCM=1 for large page devices, so we should make that the
>> default (preferably at the same time as we fix this problem, so that we
>> don't break compatibility with a working version).
>
> Ugh. I think driver should support both. If we'll change (force) this in
> Linux, we'll break older u-boots (especially FSL U-Boots with NAND
> support enabled).

I'm not aware of a Freescale board with large page NAND...

> I believe that simply changing ECCM to 1 in the newer
> community u-boots would be less pain for everybody, no?

OK, though we'll have to load the existing FMR[ECCM] into priv->fmr on
init, rather than starting with zero.

-Scott