On Mon, 18 Apr 2016 17:39:01 +0300 Roger Quadros <rogerq@xxxxxx> wrote: > On 18/04/16 17:10, Boris Brezillon wrote: > > On Mon, 18 Apr 2016 16:48:26 +0300 > > Roger Quadros <rogerq@xxxxxx> wrote: > > > >> Boris, > >> > >> On 18/04/16 16:13, Boris Brezillon wrote: > >>> Hi Roger, > >>> > >>> On Mon, 18 Apr 2016 15:52:58 +0300 > >>> Roger Quadros <rogerq@xxxxxx> wrote: > >>> > >>>> On 18/04/16 15:31, Roger Quadros wrote: > >>>>> On 16/04/16 11:57, Boris Brezillon wrote: > >>>>>> On Fri, 15 Apr 2016 09:19:51 -0700 > >>>>>> Tony Lindgren <tony@xxxxxxxxxxx> wrote: > >>>>>> > >>>>>>> > >>>>>>>> Or should I just pull this immutable branch in my current nand/next and > >>>>>>>> let you pull the same immutable branch in omap-soc. I mean, would this > >>>>>>>> prevent conflicts when our branches are merged into linux-next, no > >>>>>>>> matter the order. > >>>>>>> > >>>>>>> Ideally just one or more branches with just minimal changes in > >>>>>>> them against -rc1. But you may have other dependencies in > >>>>>>> your NAND tree so that may no longer be doable :) Usually if > >>>>>>> I merge something that may need to get merged into other > >>>>>>> branches, I just apply them into a separate branch against -rc1 > >>>>>>> to start with, then merge that branch in. > >>>>>> > >>>>>> Okay, in this case, that's pretty much what I did from the beginning, > >>>>>> except the immutable branch was provided by Roger (based on 4.6-rc1). > >>>>>> Thanks for this detailed explanation, I'll try to remember that when > >>>>>> I'll need to provide an immutable branch for another subsystem. > >>>>>> > >>>>>> Roger, my request remains, could you check/test my conflict resolution > >>>>>> (branch nand/next-with-gpmc-rework)? > >>>>> > >>>>> I couldn't test that branch yet as nand/next is broken on omap platforms > >>>>> (at least on dra7-evm). > >>>>> > >>>>> The commit where it breaks is: > >>>>> a662ef4 mtd: nand: omap2: use mtd_ooblayout_xxx() helpers where appropriate > >>>>> > >>>>> I'm trying to figure out what went wrong there. Failure log below. > >>>> > >>>> OK. I was able to fix it when at commit a662ef4 with the below patch. > >>> > >>> Thanks for debugging that. > >>> > >>>> > >>>> Looks like we need to read exactly the ECC bytes through the ECC engine and not > >>>> the entire OOB region. > >>> > >>> Hm, it looks like there's a bug somewhere else, because I don't see any > >>> reason why the controller wouldn't be able to read the full OOB region. > >> > >> The controller can read the full OOB region but we only want it to read just > >> the ECC bytes because that is the way the ELM ECC engine works. > > > > Ok, I think I got it: the ECC correction is pipelined with data read, > > and the controller expect to have ECC bytes right after the in-band > > data, is that correct? > > That is correct. > > > > >> > >>>> > >>>> diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c > >>>> index e622a1b..46b61d2 100644 > >>>> --- a/drivers/mtd/nand/omap2.c > >>>> +++ b/drivers/mtd/nand/omap2.c > >>>> @@ -1547,8 +1547,8 @@ static int omap_read_page_bch(struct mtd_info *mtd, struct nand_chip *chip, > >>>> chip->read_buf(mtd, buf, mtd->writesize); > >>>> > >>>> /* Read oob bytes */ > >>>> - chip->cmdfunc(mtd, NAND_CMD_RNDOUT, mtd->writesize, -1); > >>>> - chip->read_buf(mtd, chip->oob_poi, mtd->oobsize); > >>>> + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, mtd->writesize + chip->ecc.layout->eccpos[0], -1); > >>> > >>> The whole point of this series is to get rid of chip->ecc.layout, so > >>> we'd rather use the mtd_ooblayout_find_eccregion() instead of > >>> chip->ecc.layout->eccpos[0]. > >> > >> We just need the position of the first ECC byte offset. > >> Is that the most optimal way to get it? > > > > For the BCH case, it seems that ECC bytes always start at offset > > BADBLOCK_MARKER_LENGTH, so you can just pass > > mtd->writesize + BADBLOCK_MARKER_LENGTH. > > > > Let me know if this works, and I'll squash those changes into the > > faulty commit (I know this implies a rebase + push -f, but IMO that's > > better than breaking bisectability). > > > > > > So, the below patch works as well. Please feel free to fold it with your patch. > > -- > cheers, > -roger > > diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c > index e622a1b..eb85d6b 100644 > --- a/drivers/mtd/nand/omap2.c > +++ b/drivers/mtd/nand/omap2.c > @@ -1547,8 +1547,8 @@ static int omap_read_page_bch(struct mtd_info *mtd, struct nand_chip *chip, > chip->read_buf(mtd, buf, mtd->writesize); > > /* Read oob bytes */ > - chip->cmdfunc(mtd, NAND_CMD_RNDOUT, mtd->writesize, -1); > - chip->read_buf(mtd, chip->oob_poi, mtd->oobsize); > + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, mtd->writesize + BADBLOCK_MARKER_LENGTH, -1); > + chip->read_buf(mtd, chip->oob_poi, chip->ecc.total); Are you sure this patch works? Cause it seems to me that it should be chip->read_buf(mtd, chip->oob_poi + BADBLOCK_MARKER_LENGTH, chip->ecc.total); -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
