From 623978de362a5faeb18d8395fa86089650642626 Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Tue, 20 Sep 2011 18:35:34 -0700 Subject: [PATCH] mtd: nand: scrub BBT on ECC errors Now that `read_bbt()' returns ECC error codes properly, we handle those codes when checking the integrity of our flash-based BBT. The modifications can be described by this new policy: *) On any uncorrected ECC error, we invalidate the corresponding table and retry our version-checking integrity logic. *) On corrected bitflips, we mark both tables for re-writing to flash (a.k.a. scrubbing). Current integrity checks (i.e., comparing version numbers, etc.) should take care of all the cases that result in rescanning the device for bad blocks or falling back to the BBT as found in the mirror descriptor. Signed-off-by: Brian Norris Signed-off-by: Artem Bityutskiy --- drivers/mtd/nand/nand_bbt.c | 29 ++++++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-) diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c index 0ed8591dbd26..11185aa6273c 100644 --- a/drivers/mtd/nand/nand_bbt.c +++ b/drivers/mtd/nand/nand_bbt.c @@ -882,7 +882,7 @@ static inline int nand_memory_bbt(struct mtd_info *mtd, struct nand_bbt_descr *b */ static int check_create(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd) { - int i, chips, writeops, create, chipsel, res; + int i, chips, writeops, create, chipsel, res, res2; struct nand_chip *this = mtd->priv; struct nand_bbt_descr *td = this->bbt_td; struct nand_bbt_descr *md = this->bbt_md; @@ -899,6 +899,7 @@ static int check_create(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_desc create = 0; rd = NULL; rd2 = NULL; + res = res2 = 0; /* Per chip or per device? */ chipsel = (td->options & NAND_BBT_PERCHIP) ? i : -1; /* Mirrored table available? */ @@ -951,11 +952,29 @@ static int check_create(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_desc } /* Read back first? */ - if (rd) - read_abs_bbt(mtd, buf, rd, chipsel); + if (rd) { + res = read_abs_bbt(mtd, buf, rd, chipsel); + if (mtd_is_eccerr(res)) { + /* Mark table as invalid */ + rd->pages[i] = -1; + i--; + continue; + } + } /* If they weren't versioned, read both */ - if (rd2) - read_abs_bbt(mtd, buf, rd2, chipsel); + if (rd2) { + res2 = read_abs_bbt(mtd, buf, rd2, chipsel); + if (mtd_is_eccerr(res2)) { + /* Mark table as invalid */ + rd2->pages[i] = -1; + i--; + continue; + } + } + + /* Scrub the flash table(s)? */ + if (mtd_is_bitflip(res) || mtd_is_bitflip(res2)) + writeops = 0x03; /* Write the bad block table to the device? */ if ((writeops & 0x01) && (td->options & NAND_BBT_WRITE)) { -- 2.39.5