The ONFI spec clearly says that FAIL bit is only valid for PROGRAM, ERASE and READ-with-on-die-ECC operations, and should be ignored otherwise.
It seems that checking it after sending a SET_FEATURES is a bad idea because a previous READ, PROGRAM or ERASE op may have failed, and depending on the implementation, the FAIL bit is not cleared until a new READ, PROGRAM or ERASE is started.
This leads to ->set_features() returning -EIO while it actually worked, which can sometimes stop a batch of READ/PROGRAM ops.
Note that we only fix the ->exec_op() path here, because some drivers are abusing the NAND_STATUS_FAIL flag in their ->waitfunc() implementation to propagate other kind of errors, like wait-ready-timeout or controller-related errors. Let's not try to fix those drivers since they worked fine so far.
Fixes: 8878b126df76 ("mtd: nand: add ->exec_op() implementation") Cc: stable@vger.kernel.org Signed-off-by: Boris Brezillon boris.brezillon@bootlin.com --- This patch is fixing a problem we had with on-die ECC on Micron NANDs [1]. On these chips, when you have an ECC failure, the FAIL bit is set and it's not cleared until the next READ operation, which led the following SET_FEATURES (used to re-enable on-die ECC) to fail with -EIO and stopped the batch of page reads started by UBIFS, which in turn led to unmountable FS.
[1]http://patchwork.ozlabs.org/patch/907874/ --- drivers/mtd/nand/raw/nand_base.c | 27 +++++++++------------------ 1 file changed, 9 insertions(+), 18 deletions(-)
diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c index f28c3a555861..ee29f34562ab 100644 --- a/drivers/mtd/nand/raw/nand_base.c +++ b/drivers/mtd/nand/raw/nand_base.c @@ -2174,7 +2174,6 @@ static int nand_set_features_op(struct nand_chip *chip, u8 feature, struct mtd_info *mtd = nand_to_mtd(chip); const u8 *params = data; int i, ret; - u8 status;
if (chip->exec_op) { const struct nand_sdr_timings *sdr = @@ -2188,26 +2187,18 @@ static int nand_set_features_op(struct nand_chip *chip, u8 feature, }; struct nand_operation op = NAND_OPERATION(instrs);
- ret = nand_exec_op(chip, &op); - if (ret) - return ret; - - ret = nand_status_op(chip, &status); - if (ret) - return ret; - } else { - chip->cmdfunc(mtd, NAND_CMD_SET_FEATURES, feature, -1); - for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i) - chip->write_byte(mtd, params[i]); + return nand_exec_op(chip, &op); + }
- ret = chip->waitfunc(mtd, chip); - if (ret < 0) - return ret; + chip->cmdfunc(mtd, NAND_CMD_SET_FEATURES, feature, -1); + for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i) + chip->write_byte(mtd, params[i]);
- status = ret; - } + ret = chip->waitfunc(mtd, chip); + if (ret < 0) + return ret;
- if (status & NAND_STATUS_FAIL) + if (ret & NAND_STATUS_FAIL) return -EIO;
return 0;