| Message ID | 20210224080210.23686-1-noltari@gmail.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v2] nand: brcmnand: fix OOB R/W with Hamming ECC | expand |
On Wed, Feb 24, 2021 at 12:02 AM Álvaro Fernández Rojas <noltari@gmail.com> wrote: > Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom STB NAND controller") FWIW, I could believe this was broken. We weren't testing Hamming ECC (nor JFFS2) at the time, so it could easily have obvious bugs like this. And since I got this far, and I'm still in MAINTAINERS, I guess: Acked-by: Brian Norris <computersforpeace@gmail.com>
Hi Álvaro, Brian Norris <computersforpeace@gmail.com> wrote on Wed, 24 Feb 2021 13:01:13 -0800: > On Wed, Feb 24, 2021 at 12:02 AM Álvaro Fernández Rojas > <noltari@gmail.com> wrote: > > Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom STB NAND controller") > > FWIW, I could believe this was broken. We weren't testing Hamming ECC > (nor JFFS2) at the time, so it could easily have obvious bugs like > this. Right, you should probably limit the backport to the time when raw accessors got introduced/fixed. Thanks, Miquèl
Hi Miquel, > El 25 feb 2021, a las 8:48, Miquel Raynal <miquel.raynal@bootlin.com> escribió: > > Hi Álvaro, > > Brian Norris <computersforpeace@gmail.com> wrote on Wed, 24 Feb 2021 > 13:01:13 -0800: > >> On Wed, Feb 24, 2021 at 12:02 AM Álvaro Fernández Rojas >> <noltari@gmail.com> wrote: >>> Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom STB NAND controller") >> >> FWIW, I could believe this was broken. We weren't testing Hamming ECC >> (nor JFFS2) at the time, so it could easily have obvious bugs like >> this. > > Right, you should probably limit the backport to the time when raw > accessors got introduced/fixed. What do you mean? Those accessors have been there since the first commit (27c5b17cd1b10564fa36f8f51e4b4b41436ecc32): https://github.com/torvalds/linux/blob/27c5b17cd1b10564fa36f8f51e4b4b41436ecc32/drivers/mtd/nand/brcmnand/brcmnand.c#L1896-L1899 > > Thanks, > Miquèl Best regards, Álvaro.
Hi Álvaro, Álvaro Fernández Rojas <noltari@gmail.com> wrote on Thu, 25 Feb 2021 08:54:09 +0100: > Hi Miquel, > > > El 25 feb 2021, a las 8:48, Miquel Raynal <miquel.raynal@bootlin.com> escribió: > > > > Hi Álvaro, > > > > Brian Norris <computersforpeace@gmail.com> wrote on Wed, 24 Feb 2021 > > 13:01:13 -0800: > > > >> On Wed, Feb 24, 2021 at 12:02 AM Álvaro Fernández Rojas > >> <noltari@gmail.com> wrote: > >>> Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom STB NAND controller") > >> > >> FWIW, I could believe this was broken. We weren't testing Hamming ECC > >> (nor JFFS2) at the time, so it could easily have obvious bugs like > >> this. > > > > Right, you should probably limit the backport to the time when raw > > accessors got introduced/fixed. > > What do you mean? > Those accessors have been there since the first commit (27c5b17cd1b10564fa36f8f51e4b4b41436ecc32): > https://github.com/torvalds/linux/blob/27c5b17cd1b10564fa36f8f51e4b4b41436ecc32/drivers/mtd/nand/brcmnand/brcmnand.c#L1896-L1899 I misunderstood Brian's answer. This commit is not that old and looks legit.
On Wed, 2021-02-24 at 08:02:10 UTC, =?utf-8?q?=C3=81lvaro_Fern=C3=A1ndez_Rojas?= wrote: > Hamming ECC doesn't cover the OOB data, so reading or writing OOB shall > always be done without ECC enabled. > This is a problem when adding JFFS2 cleanmarkers to erased blocks. If JFFS2 > clenmarkers are added to the OOB with ECC enabled, OOB bytes will be changed > from ff ff ff to 00 00 00, reporting incorrect ECC errors. > > Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom STB NAND controller") > Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com> > Acked-by: Brian Norris <computersforpeace@gmail.com> Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git nand/next, thanks. Miquel
diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c index 659eaa6f0980..5ff4291380c5 100644 --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c @@ -2688,6 +2688,12 @@ static int brcmnand_attach_chip(struct nand_chip *chip) ret = brcmstb_choose_ecc_layout(host); + /* If OOB is written with ECC enabled it will cause ECC errors */ + if (is_hamming_ecc(host->ctrl, &host->hwcfg)) { + chip->ecc.write_oob = brcmnand_write_oob_raw; + chip->ecc.read_oob = brcmnand_read_oob_raw; + } + return ret; }
Hamming ECC doesn't cover the OOB data, so reading or writing OOB shall always be done without ECC enabled. This is a problem when adding JFFS2 cleanmarkers to erased blocks. If JFFS2 clenmarkers are added to the OOB with ECC enabled, OOB bytes will be changed from ff ff ff to 00 00 00, reporting incorrect ECC errors. Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom STB NAND controller") Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com> --- v2: Add fixed tag. drivers/mtd/nand/raw/brcmnand/brcmnand.c | 6 ++++++ 1 file changed, 6 insertions(+)