Messages in this thread | | | Date | Thu, 18 May 2017 09:09:57 +0200 | From | Boris Brezillon <> | Subject | Re: [PATCH 1/2] mtd: nand: add generic helpers to check, match, maximize ECC settings |
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On Thu, 18 May 2017 15:27:11 +0900 Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
> Hi Boris, > > > > 2017-05-15 20:54 GMT+09:00 Boris Brezillon <boris.brezillon@free-electrons.com>: > > Hi Masahiro, > > > > Sorry for the late reply. > > > > On Mon, 8 May 2017 12:40:47 +0900 > > Masahiro Yamada <yamada.masahiro@socionext.com> wrote: > > > >> Hi Boris, > >> > >> > >> 2017-04-29 1:32 GMT+09:00 Boris Brezillon <boris.brezillon@free-electrons.com>: > >> > >> >> + for (setting = caps->ecc_settings; setting->step; setting++) { > >> >> + /* If chip->ecc.size is already set, respect it. */ > >> >> + if (chip->ecc.size && setting->step != chip->ecc.size) > >> >> + continue; > >> >> + > >> >> + /* If chip->ecc.strength is already set, respect it. */ > >> >> + if (chip->ecc.strength && > >> >> + setting->strength != chip->ecc.strength) > >> >> + continue; > >> > > >> > Hm, I don't get it. If chip->ecc.strength and chip->ecc.size are > >> > explicitly set, you should just call nand_check_ecc_caps() and skip > >> > nand_try_to_match_ecc_req(). Why would you call > >> > nand_try_to_match_ecc_req() in this case? > >> > >> > >> I want to call this function if > >> ecc.size is specified but ecc.strength is not > >> (or vice versa). > > > > That's not a valid combination. I accepted the case where > > nand-ecc-step-size is not defined in the DT just because sometime you > > only have one possible setting which is imposed by the controller. In > > this case ecc.size should be explicitly set by the driver not left to 0. > > > >> > >> > >> If both ecc.size and ecc.strength are already specified, > >> you are right, no need to call this function. > >> This function can check the sanity of the specified > >> combination of (step, strength), but this is the same > >> as what nand_check_ecc_caps() does. > > > I am working on the next version because I really need to > merge all of my Denali controller patches for my SoCs.
Okay.
> > > One question about this part. > > > /* If chip->ecc.size is already set, respect it. */ > if (chip->ecc.size && step_size != chip->ecc.size) > continue; > > Does this make sense for nand_try_to_maximize_ecc()? > > (In other words, can nand-ecc-maximize stand together with nand-ecc-step-size?)
It could make sense if one wants to maximize the strength for a specific step-size, but most of the time the user will let the driver choose the best step-size+strength pair.
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