[U-Boot] [PATCH] MTD: nand: mxs_nand: Allow driver to auto setup ECC in SPL

[Adam Ford]

On Sat, Feb 2, 2019 at 11:17 AM Jörg Krause <joerg.krause at embedded.rocks> wrote:
>
> Hi,
>
> On Thu, 2019-01-17 at 07:16 -0600, Adam Ford wrote:
> > The initialization of the NAND in SPL hard-coded ecc.bytes,
> > ecc.size, and ecc.strength which may work for some NAND parts,
> > but it not appropriate for others.  With the pending patch
> > "mxs_nand: Fix BCH read timeout error on boards requiring ECC"
> > the driver can auto configure the ECC when these entries are
> > blank.  This patch has been tested in NAND flash with oob 64
> > and oob 128.
> >
> > Signed-off-by: Adam Ford <aford173 at gmail.com>
>
> Maybe you can give me a hint where the driver actually does the auto
> configuration?
>
> I've tested the patch on a custom i.MX6ULL board with a Micron NAND
> flash. The SPL loader is able to boot from NAND with and without this
> patch.

I am traveling right now, so I don;t have my editor or source code,
but I can tell you that the patch found in
http://patchwork.ozlabs.org/patch/1020160/  sets up the ECC, and if
these values are not set they will get set.  I won't be back to the
office until a week from Monday.

The reason I found I needed this patch was because I have boards with
different flash parts that used different ECC values.  One my board
boards didn't need the patch because the ECC matched the values
hard-coded here, but my other board would get ECC errors during SPL
because these values didn't match what U-Boot used when it wrote to
flash.

If your board works with and without the patch, I am guessing the ECC
values generated by the above mentioned patch probably set them to the
same values that were hard coded before.

adam
>
> Tested-by: Jörg Krause <joerg.krause at embedded.rocks>
>
> > diff --git a/drivers/mtd/nand/raw/mxs_nand.c b/drivers/mtd/nand/raw/mxs_nand.c
> > index 2d84bfffe2..95fa452cef 100644
> > --- a/drivers/mtd/nand/raw/mxs_nand.c
> > +++ b/drivers/mtd/nand/raw/mxs_nand.c
> > @@ -1191,9 +1191,6 @@ int mxs_nand_init_spl(struct nand_chip *nand)
> >       nand->ecc.read_page     = mxs_nand_ecc_read_page;
> >
> >       nand->ecc.mode          = NAND_ECC_HW;
> > -     nand->ecc.bytes         = 9;
> > -     nand->ecc.size          = 512;
> > -     nand->ecc.strength      = 8;
> >
> >       return 0;
> >  }
>