diff options
| -rw-r--r-- | drivers/mtd/nand/nand_base.c | 56 | ||||
| -rw-r--r-- | include/linux/mtd/nand.h | 6 |
2 files changed, 58 insertions, 4 deletions
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index b5c3768b32ae..4c2f39f351da 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -1410,6 +1410,30 @@ static uint8_t *nand_transfer_oob(struct nand_chip *chip, uint8_t *oob, } /** + * nand_setup_read_retry - [INTERN] Set the READ RETRY mode + * @mtd: MTD device structure + * @retry_mode: the retry mode to use + * + * Some vendors supply a special command to shift the Vt threshold, to be used + * when there are too many bitflips in a page (i.e., ECC error). After setting + * a new threshold, the host should retry reading the page. + */ +static int nand_setup_read_retry(struct mtd_info *mtd, int retry_mode) +{ + struct nand_chip *chip = mtd->priv; + + pr_debug("setting READ RETRY mode %d\n", retry_mode); + + if (retry_mode >= chip->read_retries) + return -EINVAL; + + if (!chip->setup_read_retry) + return -EOPNOTSUPP; + + return chip->setup_read_retry(mtd, retry_mode); +} + +/** * nand_do_read_ops - [INTERN] Read data with ECC * @mtd: MTD device structure * @from: offset to read from @@ -1430,6 +1454,7 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from, uint8_t *bufpoi, *oob, *buf; unsigned int max_bitflips = 0; + int retry_mode = 0; bool ecc_fail = false; chipnr = (int)(from >> chip->chip_shift); @@ -1454,6 +1479,7 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from, if (realpage != chip->pagebuf || oob) { bufpoi = aligned ? buf : chip->buffers->databuf; +read_retry: chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page); /* @@ -1494,8 +1520,6 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from, memcpy(buf, chip->buffers->databuf + col, bytes); } - buf += bytes; - if (unlikely(oob)) { int toread = min(oobreadlen, max_oobsize); @@ -1514,8 +1538,24 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from, nand_wait_ready(mtd); } - if (mtd->ecc_stats.failed - ecc_failures) - ecc_fail = true; + if (mtd->ecc_stats.failed - ecc_failures) { + if (retry_mode + 1 <= chip->read_retries) { + retry_mode++; + ret = nand_setup_read_retry(mtd, + retry_mode); + if (ret < 0) + break; + + /* Reset failures; retry */ + mtd->ecc_stats.failed = ecc_failures; + goto read_retry; + } else { + /* No more retry modes; real failure */ + ecc_fail = true; + } + } + + buf += bytes; } else { memcpy(buf, chip->buffers->databuf + col, bytes); buf += bytes; @@ -1525,6 +1565,14 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from, readlen -= bytes; + /* Reset to retry mode 0 */ + if (retry_mode) { + ret = nand_setup_read_retry(mtd, 0); + if (ret < 0) + break; + retry_mode = 0; + } + if (!readlen) break; diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index 029fe5948dc4..267d61dd89dd 100644 --- a/include/linux/mtd/nand.h +++ b/include/linux/mtd/nand.h @@ -472,6 +472,8 @@ struct nand_buffers { * commands to the chip. * @waitfunc: [REPLACEABLE] hardwarespecific function for wait on * ready. + * @setup_read_retry: [FLASHSPECIFIC] flash (vendor) specific function for + * setting the read-retry mode. Mostly needed for MLC NAND. * @ecc: [BOARDSPECIFIC] ECC control structure * @buffers: buffer structure for read/write * @hwcontrol: platform-specific hardware control structure @@ -518,6 +520,7 @@ struct nand_buffers { * non 0 if ONFI supported. * @onfi_params: [INTERN] holds the ONFI page parameter when ONFI is * supported, 0 otherwise. + * @read_retries: [INTERN] the number of read retry modes supported * @onfi_set_features: [REPLACEABLE] set the features for ONFI nand * @onfi_get_features: [REPLACEABLE] get the features for ONFI nand * @bbt: [INTERN] bad block table pointer @@ -565,6 +568,7 @@ struct nand_chip { int feature_addr, uint8_t *subfeature_para); int (*onfi_get_features)(struct mtd_info *mtd, struct nand_chip *chip, int feature_addr, uint8_t *subfeature_para); + int (*setup_read_retry)(struct mtd_info *mtd, int retry_mode); int chip_delay; unsigned int options; @@ -589,6 +593,8 @@ struct nand_chip { int onfi_version; struct nand_onfi_params onfi_params; + int read_retries; + flstate_t state; uint8_t *oob_poi; |