From: Kamal Dasu kdasu.kdev@gmail.com
[ Upstream commit 4551e78ad98add1f16b70cf286d5aad3ce7bcd4c ]
Implement ECC correctable and uncorrectable error handling for EDU reads. If ECC correctable bitflips are encountered on EDU transfer, read page again using PIO. This is needed due to a NAND controller limitation where corrected data is not transferred to the DMA buffer on ECC error. This applies to ECC correctable errors that are reported by the controller hardware based on set number of bitflips threshold in the controller threshold register, bitflips below the threshold are corrected silently and are not reported by the controller hardware.
Fixes: a5d53ad26a8b ("mtd: rawnand: brcmnand: Add support for flash-edu for dma transfers") Signed-off-by: Kamal Dasu kdasu.kdev@gmail.com Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com Link: https://lore.kernel.org/linux-mtd/20200612212902.21347-3-kdasu.kdev@gmail.co... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/mtd/nand/raw/brcmnand/brcmnand.c | 26 ++++++++++++++++++++++++ 1 file changed, 26 insertions(+)
diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c index cdae2311a3b69..0b1ea965cba08 100644 --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c @@ -1859,6 +1859,22 @@ static int brcmnand_edu_trans(struct brcmnand_host *host, u64 addr, u32 *buf, edu_writel(ctrl, EDU_STOP, 0); /* force stop */ edu_readl(ctrl, EDU_STOP);
+ if (!ret && edu_cmd == EDU_CMD_READ) { + u64 err_addr = 0; + + /* + * check for ECC errors here, subpage ECC errors are + * retained in ECC error address register + */ + err_addr = brcmnand_get_uncorrecc_addr(ctrl); + if (!err_addr) { + err_addr = brcmnand_get_correcc_addr(ctrl); + if (err_addr) + ret = -EUCLEAN; + } else + ret = -EBADMSG; + } + return ret; }
@@ -2065,6 +2081,7 @@ static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip, u64 err_addr = 0; int err; bool retry = true; + bool edu_err = false;
dev_dbg(ctrl->dev, "read %llx -> %p\n", (unsigned long long)addr, buf);
@@ -2082,6 +2099,10 @@ static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip, else return -EIO; } + + if (has_edu(ctrl) && err_addr) + edu_err = true; + } else { if (oob) memset(oob, 0x99, mtd->oobsize); @@ -2129,6 +2150,11 @@ static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip, if (mtd_is_bitflip(err)) { unsigned int corrected = brcmnand_count_corrected(ctrl);
+ /* in case of EDU correctable error we read again using PIO */ + if (edu_err) + err = brcmnand_read_by_pio(mtd, chip, addr, trans, buf, + oob, &err_addr); + dev_dbg(ctrl->dev, "corrected error at 0x%llx\n", (unsigned long long)err_addr); mtd->ecc_stats.corrected += corrected;