[PATCH 2/3] mtd: nand: read (from DT) and store ECC algorithm

[Rafał Miłecki]

On 1 April 2016 at 22:07, Brian Norris <computersforpeace at gmail.com> wrote:
> On Fri, Apr 01, 2016 at 09:32:40PM +0200, Rafał Miłecki wrote:
>> On 1 April 2016 at 18:07, Brian Norris <computersforpeace at gmail.com> wrote:
>> > On Fri, Feb 12, 2016 at 07:11:24PM +0100, Rafał Miłecki wrote:
>> >> This will allow drivers handle ECC properly.
>> >>
>> >> Signed-off-by: Rafał Miłecki <zajec5 at gmail.com>
>> >> ---
>> >>  drivers/mtd/nand/nand_base.c | 6 +++++-
>> >>  include/linux/mtd/nand.h     | 1 +
>> >>  2 files changed, 6 insertions(+), 1 deletion(-)
>> >>
>> >> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
>> >> index f2c8ff3..ef977f3 100644
>> >> --- a/drivers/mtd/nand/nand_base.c
>> >> +++ b/drivers/mtd/nand/nand_base.c
>> >> @@ -3979,7 +3979,7 @@ ident_done:
>> >>  static int nand_dt_init(struct nand_chip *chip)
>> >>  {
>> >>       struct device_node *dn = nand_get_flash_node(chip);
>> >> -     int ecc_mode, ecc_strength, ecc_step;
>> >> +     int ecc_mode, ecc_algo, ecc_strength, ecc_step;
>> >>
>> >>       if (!dn)
>> >>               return 0;
>> >> @@ -3991,6 +3991,7 @@ static int nand_dt_init(struct nand_chip *chip)
>> >>               chip->bbt_options |= NAND_BBT_USE_FLASH;
>> >>
>> >>       ecc_mode = of_get_nand_ecc_mode(dn);
>> >> +     ecc_algo = of_get_nand_ecc_algo(dn);
>> >>       ecc_strength = of_get_nand_ecc_strength(dn);
>> >>       ecc_step = of_get_nand_ecc_step_size(dn);
>> >>
>> >> @@ -4003,6 +4004,9 @@ static int nand_dt_init(struct nand_chip *chip)
>> >>       if (ecc_mode >= 0)
>> >>               chip->ecc.mode = ecc_mode;
>> >>
>> >> +     if (ecc_algo >= 0)
>> >> +             chip->ecc.algo = ecc_algo;
>> >> +
>> >
>> > While this might appear to handle the absence of the nand-ecc-algo
>> > property correctly, this isn't safe. This means that any existing DT
>> > without the property will get treated as Hamming ECC. Perhaps we need
>> > the enum to have a 0 value of 'NAND_ECC_ALGO_UNKNOWN' or something like
>> > that?
>>
>> You're commenting on an old series. If you take a look at:
>> https://patchwork.ozlabs.org/patch/601180/
>> that also got applied to the:
>> https://github.com/linux-nand/linux/commits/nand/next
>> repo, you'll see we have NAND_ECC_UNKNOWN there.
>
> Ah, I guess I missed that because I was searching for the patch to
> brcmnand (i.e., fixing the original problem you saw). AFAICT, this v2
> series doesn't actually resolve your issue with brcmnand, no?

That's correct. I'm planning to clean NAND subsystem first, then patch brcmnand.

-- 
Rafał