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); /* Calculate ecc bytes */ chip->ecc.calculate(mtd, buf, ecc_calc); -- 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
