[PATCH] mtd: nand: Fix Spansion sparearea size detection

[Nikolay Martynov]

Hi.

  Thanks for your response!
  I'm sorry, I only have board with S34ML02G2 and I've tested by
change on it - it works fine. But unfortunately I do not have any way
to test S34ML01G2.
  It looks like that logic can be simplified if just check id_data[1]
is one of 0xda, 0xdc, 0xca, 0xcc - this should be safer option.

  I'm sorry, I'm very new to all this. This patch made kernel boot on
a board that I have. The kernel was 'oldish' - 3.18. So I'm not sure
why ONFI is not used here, I will see if I can figure it out.

Thanks!


2015-11-30 15:35 GMT-05:00 Brian Norris <computersforpeace at gmail.com>:
> Hi Nikolay,
>
> On Thu, Nov 26, 2015 at 01:25:22AM -0500, Nikolay Martynov wrote:
>> According to datasheet S34ML02G2 and S34ML04G2 have
>> larger sparea area size than was detected.
>>
>> Signed-off-by: Nikolay Martynov <mar.kolya at gmail.com>
>> ---
>>  drivers/mtd/nand/nand_base.c | 9 +++++++++
>>  1 file changed, 9 insertions(+)
>>
>> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
>> index ceb68ca..2c01f9e 100644
>> --- a/drivers/mtd/nand/nand_base.c
>> +++ b/drivers/mtd/nand/nand_base.c
>> @@ -3415,6 +3415,7 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
>>       /*
>>        * Field definitions are in the following datasheets:
>>        * Old style (4,5 byte ID): Samsung K9GAG08U0M (p.32)
>> +      *                          Spansion S34ML02G2 (p.33)
>>        * New Samsung (6 byte ID): Samsung K9GAG08U0F (p.44)
>>        * Hynix MLC   (6 byte ID): Hynix H27UBG8T2B (p.22)
>>        *
>> @@ -3512,6 +3513,14 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
>>               *busw = (extid & 0x01) ? NAND_BUSWIDTH_16 : 0;
>>
>>               /*
>> +              * Spansion S34ML0[24]G2 have oobsize twice as large
>> +              * as S34ML01G2 encoded in the same bit. We
>> +              * differentiate them by their ID length
>
> Hmm, are you sure the ID length heuristic works correctly for these
> particular flash? i.e., did you actually test both of these flash?
> Sometimes it's hard to tell if a device has a 4-byte or 5-byte ID just
> from reading out bytes, since a "4-byte ID" NAND may just have a "don't
> care" byte for the 5th one, and so we might still compute id_len == 5.
>
> Also, why do you even need nand_decode_ext_id() for these flash?
> According to the datasheet, these flash support ONFI.
>
> Brian
>
>> +              */
>> +             if (id_len == 5 && id_data[0] == NAND_MFR_AMD)
>> +                     mtd->oobsize *= 2;
>> +
>> +             /*
>>                * Toshiba 24nm raw SLC (i.e., not BENAND) have 32B OOB per
>>                * 512B page. For Toshiba SLC, we decode the 5th/6th byte as
>>                * follows:
>> --
>> 2.6.3
>>



-- 
Martynov Nikolay.
Email: mar.kolya at gmail.com