[PATCH] mtd: OneNAND: Detect the correct NOP when 4KiB pagesize

[Kyungmin Park]

On Wed, Jun 8, 2011 at 8:03 PM, Artem Bityutskiy <dedekind1 at gmail.com> wrote:
> On Wed, 2011-06-08 at 10:56 +0900, Kyungmin Park wrote:
>> From: Kyungmin Park <kyungmin.park at samsung.com>
>>
>> There are two different 4KiB pagesize chips
>> KFM4G16Q4M series have NOP 4 with version ID 0x0131
>> But KFM4G16Q5M has NOP 1 with versoin ID 0x013e
>>
>> Note that Q5M means that it has NOP 1.
>>
>> Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
>> ---
>> diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
>> index ac9e959..2adca63 100644
>> --- a/drivers/mtd/onenand/onenand_base.c
>> +++ b/drivers/mtd/onenand/onenand_base.c
>> @@ -3429,6 +3429,13 @@ static void onenand_check_features(struct mtd_info *mtd)
>>               else if (numbufs == 1) {
>>                       this->options |= ONENAND_HAS_4KB_PAGE;
>>                       this->options |= ONENAND_HAS_CACHE_PROGRAM;
>> +                     /*
>> +                      * There are two different 4KiB pagesize chips
>> +                      * KFM4G16Q4M has NOP 4 with version ID 0x0131
>> +                      * KFM4G16Q5M has NOP 1 with versoin ID 0x013e
>> +                      */
>
> If you confirm that it is impossible to detect NOP and distinguish
> between KFM4G16Q4M and KFM4G16Q5M, then can we take the following steps:
>
> 1. Add a comment that this is a hacky quirk to work around HW
>   identification flaw, to make it clear for the people who read the
>   code.

For the record, chip maker (memory) made different chips for each
vendor (Samsung Mobile, and Nokia)
with the design flaw, it made a workaround, not hacky quirk.

> 2. Make sure the default is NOP4 (you already do).
> 3. Compare _both_ device ID and version ID. This means that we'll end up
>   with NOP1 only for your device, all the other will be NOP4. If then
>   someone has issues, they'll have to reporte about them and add their
>   device ID to this hack.

Okay no problem to compare the device ID.

Thank you,
Kyungmin Park
>
> --
> Best Regards,
> Artem Bityutskiy (Артём Битюцкий)
>
>
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