Boris, On 18/04/16 17:57, Boris Brezillon wrote: > 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. > > Will do. > > Thanks, > > Boris After all the changes we discussed in [1] I was able to test nand/next-with-gpmc-rework and it worked fine. [1] - http://thread.gmane.org/gmane.comp.hardware.netbook.arm.sunxi/22596/focus=22936 I'd be happy to test the branch again after you've incorporated all changes. Since you are gong to do a push -f anyways, I was wondering if you want to pull in my gpmc branch first to avoid the merge conflict. But it is totally up to you. -- cheers, -roger -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
