> -----Original Message-----
> From: Troy Kisky [mailto:[email protected]]
> Sent: Thursday, May 07, 2009 6:37 PM
> To: David Brownell
> Cc: Narnakaje, Snehaprabha; [email protected]; davinci-linux-open-
> [email protected]; [email protected];
> [email protected]; [email protected]
> Subject: Re: [PATCH 2/2] NAND on DM355: Add 4-bit ECC support for large
> page NAND chips
>
> >>>> +static struct nand_ecclayout hwecc4_2048 __initconst = {
> >>>> + .eccbytes = 10,
> >>> Not ".eccbytes = 40"? This is 4 chunks, 10 ecc bytes each...
> >> No, .eccbytes is for each chips->ecc.steps.
> >
> > So it's the same as ecc.bytes, which is not exported to userspace.
> >
> >
> >> And all nand read/write
> >> APIs, we handle ecc.steps (for loop). There is chips->ecc.total that
> >> is initialized as (chips->ecc.steps * chips->ecc.bytes).
> >>
> >> It is strange that .eccbytes is for each chunk, while eccpos[] and
> >> .oobfree[] have to handle/cover all chunks.
>
> No, eccbytes should equal ecc.total
Thanks Troy and Dave.
Yes, it should indeed be 40 --> total size. eccbytes in the nand_ecclayout is
different from chip->ecc.bytes. We do set the chip->ecc.bytes to 10 which is
for each trunk.
I will change this and test it.
>
>
> i.e. from nand_base.c
>
> static struct nand_ecclayout nand_oob_64 = {
> .eccbytes = 24,
> .eccpos = {
> 40, 41, 42, 43, 44, 45, 46, 47,
> 48, 49, 50, 51, 52, 53, 54, 55,
> 56, 57, 58, 59, 60, 61, 62, 63},
> .oobfree = {
> {.offset = 2,
> .length = 38}}
> };
> Troy
>
>
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