From mboxrd@z Thu Jan 1 00:00:00 1970 From: boris.brezillon@free-electrons.com (Boris Brezillon) Date: Fri, 25 Nov 2016 11:27:25 +0100 Subject: [PATCH] mtd: nand: mxc: Fix mxc_v1 ooblayout In-Reply-To: <58eed307-ee50-9727-7b64-891d1b969790@gmail.com> References: <1480065209-4179-1-git-send-email-boris.brezillon@free-electrons.com> <58eed307-ee50-9727-7b64-891d1b969790@gmail.com> Message-ID: <20161125112725.0ee9d49d@bbrezillon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, 25 Nov 2016 10:58:26 +0100 Marek Vasut wrote: > On 11/25/2016 10:13 AM, Boris Brezillon wrote: > > Commit a894cf6c5a82 ("mtd: nand: mxc: switch to mtd_ooblayout_ops") > > introduced a bug in the OOB layout description. Even if the driver claims > > that 3 ECC bytes are reserved to protect 512 bytes of data, it's actually > > 5 ECC bytes to protect 512+6 bytes of data (some OOB bytes are also > > protected using extra ECC bytes). > > > > Fix the mxc_v1_ooblayout_{free,ecc}() functions to reflect this behavior. > > > > Signed-off-by: Boris Brezillon > > Fixes: a894cf6c5a82 ("mtd: nand: mxc: switch to mtd_ooblayout_ops") > > Cc: > > --- > > drivers/mtd/nand/mxc_nand.c | 5 ++--- > > 1 file changed, 2 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c > > index 61ca020c5272..c19ec4f0983e 100644 > > --- a/drivers/mtd/nand/mxc_nand.c > > +++ b/drivers/mtd/nand/mxc_nand.c > > @@ -886,7 +886,7 @@ static int mxc_v1_ooblayout_ecc(struct mtd_info *mtd, int section, > > return -ERANGE; > > > > oobregion->offset = (section * 16) + 6; > > - oobregion->length = nand_chip->ecc.bytes; > > + oobregion->length = 5; > > Use a macro instead of hard-coding a value please :) Ideally, we should change ->eccbytes value in the imx27_nand_devtype_data and imx21_nand_devtype_data definitions, but I fear it could break other things. I'll define a macro. > > > return 0; > > } > > @@ -908,8 +908,7 @@ static int mxc_v1_ooblayout_free(struct mtd_info *mtd, int section, > > oobregion->length = 4; > > } > > } else { > > - oobregion->offset = ((section - 1) * 16) + > > - nand_chip->ecc.bytes + 6; > > + oobregion->offset = ((section - 1) * 16) + 5 + 6; > > DTTO here, the math here is cryptic enough. > > > if (section < nand_chip->ecc.steps) > > oobregion->length = (section * 16) + 6 - > > oobregion->offset; > > > >