Re: [PATCH v4 04/23] mtd: nand: denali: avoid hard-coding ECC step, strength, bytes

[Masahiro Yamada]

Hi Boris,


2017-06-07 16:02 GMT+09:00 Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>:
> On Wed, 7 Jun 2017 12:09:31 +0900
> Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> wrote:
>
>> >> +
>> >> +static int denali_ecc_setup(struct mtd_info *mtd, struct nand_chip *chip,
>> >> +                         struct denali_nand_info *denali)
>> >> +{
>> >> +     struct nand_ecc_caps caps;
>> >> +     int ret;
>> >> +
>> >> +     caps.stepinfos = denali->stepinfo;
>> >> +     caps.nstepinfos = 1;
>> >> +     caps.calc_ecc_bytes = denali_calc_ecc_bytes;
>> >> +     caps.oob_reserve_bytes = denali->bbtskipbytes;
>> >
>> > If you get rid of this oob_reserve_bytes field, you can define caps as
>> > a static const and even directly store ecc_caps in denali_nand_info.
>>
>> To make caps static const, denali_calc_ecc_bytes must be exported
>> to be referenced from denali_dt/denali_pci.
>> I am reluctant to do it.
>
> You already duplicate other information in denali_dt.c and
> denali_pci.c,

The ECC step-size and strength are tightly associated to each IP variant.
I see duplication between denali_dt and denali_pci, but it is just because
Intel and Altera happened to have the same parameters.

On the other hand, denali_calc_ecc_bytes() is common to all variants
because ECC algorithm is not customizable.


> so what prevents you from duplicating this one-line
> function?
>
> Also, denali core already exports 2 functions,

They are entries for probe/remove.

> I don't see the problem
> in exporting the common nand_ecc_caps object. Why are you reluctant to
> that?

denali_calc_ecc_bytes() is independent of DT, PCI, or whatever.
I see less reason to expose it.

caps is only used on probing, so I used a local variable.
I do not think it is a big problem.

-- 
Best Regards
Masahiro Yamada