[PATCH 2/2] mtd: rawnand: brcmnand: Ecc error handling on EDU transfers

Kamal Dasu
2020-06-11T05:45:11Z

Implemented 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 controller lmitation
where read and corrected data is not transferred to the DMA buffer on ECC
errors. This holds true for ECC correctable errors beyond set threshold.

Fixes: a5d53ad26a8b ("mtd: rawnand: brcmnand: Add support for flash-edu for dma transfers")
Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
---
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 0c1d6e543586..d7daa83c8a58 100644
--- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
@@ -1855,6 +1855,22 @@ 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 == 0 && edu_cmd == EDU_CMD_READ) {
+ u64 err_addr = 0;
+
+ /*
+ * check for ecc errors here, subpage ecc erros are
+ * retained in ecc error addr 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;
}

@@ -2058,6 +2074,7 @@ static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip,
u64 err_addr = 0;
int err;
bool retry = true;
+ bool edu_read = false;

dev_dbg(ctrl->dev, "read %llx -> %p\n", (unsigned long long)addr, buf);

@@ -2075,6 +2092,10 @@ static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip,
else
return -EIO;
}
+
+ if (has_edu(ctrl))
+ edu_read = true;
+
} else {
if (oob)
memset(oob, 0x99, mtd->oobsize);
@@ -2122,6 +2143,11 @@ 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_read)
+ 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;
--
2.17.1