[PATCH v5 01/11] mtd: add datasheet's ECC information to nand_chip{}

Huang Shijie b32955 at freescale.com
Thu May 16 04:06:16 EDT 2013


于 2013年05月16日 15:14, Artem Bityutskiy 写道:
> On Thu, 2013-05-16 at 10:16 +0800, Huang Shijie wrote:
>> 于 2013年05月15日 20:11, Artem Bityutskiy 写道:
>>> On Wed, 2013-05-15 at 16:40 +0800, Huang Shijie wrote:
>>>> + * @ecc_strength:	[INTERN] ECC correctability from the datasheet.
>>>> + *			Minimum amount of bit errors per @ecc_step guaranteed to
>>>> + *			be correctable. If unknown, set to zero.
>>>> + * @ecc_step:		[INTERN] ECC step required by the @ecc_strength,
>>>> + *                      also from the datasheet. It is the recommended ECC step
>>>> + *			size, if known; if unknown, set to zero.
>>> Here and in other places you talk about "datasheet". Do you assume that
>>> the real ECC strength/step used by NAND chips may be different? Or you
>>> assume it must be the same?
>>>
>> The two fields are used to store the ecc info from the datasheet.
>> The two fields are just for a reference.
>>
>> [1] The nand controller may do not use these two fields, it's ok;
>>       For example, the datasheet requires "4bits per 512 bytes".
>>       The nand controller can uses 8bits per 512 bytes.
>>
>>
>> [2] but sometimes the nand controller must use these two fields.
>>       For example, the datasheet requires "40bits per 1024 bytes".
>>       For the hardware limit, the nand controller(BCH) may supports the
>> 40bits ecc in the maximum.
>>       So the nand controller must use these two fields now.
> I wonder if it makes sense to name things so that it is clear form the
> names whether that is the "theoretical" datasheet values or the real
> ones. I would prefer to clearly distinguish between them, in names and
> comments. Thoughts?
>
what's about add the "_datasheet" for these two fields?
such as

ecc_strength__datasheet;ecc_step__datasheet


Huang Shijie





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