diff options
| -rw-r--r-- | drivers/mtd/nand/nand_micron.c | 216 | ||||
| -rw-r--r-- | include/linux/mtd/nand.h | 2 |
2 files changed, 218 insertions, 0 deletions
diff --git a/drivers/mtd/nand/nand_micron.c b/drivers/mtd/nand/nand_micron.c index 877011069251..9993f8ead1e2 100644 --- a/drivers/mtd/nand/nand_micron.c +++ b/drivers/mtd/nand/nand_micron.c @@ -17,6 +17,12 @@ #include <linux/mtd/nand.h> +/* + * Special Micron status bit that indicates when the block has been + * corrected by on-die ECC and should be rewritten + */ +#define NAND_STATUS_WRITE_RECOMMENDED BIT(3) + struct nand_onfi_vendor_micron { u8 two_plane_read; u8 read_cache; @@ -66,9 +72,191 @@ static int micron_nand_onfi_init(struct nand_chip *chip) return 0; } +static int micron_nand_on_die_ooblayout_ecc(struct mtd_info *mtd, int section, + struct mtd_oob_region *oobregion) +{ + if (section >= 4) + return -ERANGE; + + oobregion->offset = (section * 16) + 8; + oobregion->length = 8; + + return 0; +} + +static int micron_nand_on_die_ooblayout_free(struct mtd_info *mtd, int section, + struct mtd_oob_region *oobregion) +{ + if (section >= 4) + return -ERANGE; + + oobregion->offset = (section * 16) + 2; + oobregion->length = 6; + + return 0; +} + +static const struct mtd_ooblayout_ops micron_nand_on_die_ooblayout_ops = { + .ecc = micron_nand_on_die_ooblayout_ecc, + .free = micron_nand_on_die_ooblayout_free, +}; + +static int micron_nand_on_die_ecc_setup(struct nand_chip *chip, bool enable) +{ + u8 feature[ONFI_SUBFEATURE_PARAM_LEN] = { 0, }; + + if (enable) + feature[0] |= ONFI_FEATURE_ON_DIE_ECC_EN; + + return chip->onfi_set_features(nand_to_mtd(chip), chip, + ONFI_FEATURE_ON_DIE_ECC, feature); +} + +static int +micron_nand_read_page_on_die_ecc(struct mtd_info *mtd, struct nand_chip *chip, + uint8_t *buf, int oob_required, + int page) +{ + int status; + int max_bitflips = 0; + + micron_nand_on_die_ecc_setup(chip, true); + + chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page); + chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1); + status = chip->read_byte(mtd); + if (status & NAND_STATUS_FAIL) + mtd->ecc_stats.failed++; + /* + * The internal ECC doesn't tell us the number of bitflips + * that have been corrected, but tells us if it recommends to + * rewrite the block. If it's the case, then we pretend we had + * a number of bitflips equal to the ECC strength, which will + * hint the NAND core to rewrite the block. + */ + else if (status & NAND_STATUS_WRITE_RECOMMENDED) + max_bitflips = chip->ecc.strength; + + chip->cmdfunc(mtd, NAND_CMD_READ0, -1, -1); + + nand_read_page_raw(mtd, chip, buf, oob_required, page); + + micron_nand_on_die_ecc_setup(chip, false); + + return max_bitflips; +} + +static int +micron_nand_write_page_on_die_ecc(struct mtd_info *mtd, struct nand_chip *chip, + const uint8_t *buf, int oob_required, + int page) +{ + micron_nand_on_die_ecc_setup(chip, true); + + chip->cmdfunc(mtd, NAND_CMD_SEQIN, 0x00, page); + nand_write_page_raw(mtd, chip, buf, oob_required, page); + chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1); + + micron_nand_on_die_ecc_setup(chip, false); + + return 0; +} + +static int +micron_nand_read_page_raw_on_die_ecc(struct mtd_info *mtd, + struct nand_chip *chip, + uint8_t *buf, int oob_required, + int page) +{ + chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page); + nand_read_page_raw(mtd, chip, buf, oob_required, page); + + return 0; +} + +static int +micron_nand_write_page_raw_on_die_ecc(struct mtd_info *mtd, + struct nand_chip *chip, + const uint8_t *buf, int oob_required, + int page) +{ + chip->cmdfunc(mtd, NAND_CMD_SEQIN, 0x00, page); + nand_write_page_raw(mtd, chip, buf, oob_required, page); + chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1); + + return 0; +} + +enum { + /* The NAND flash doesn't support on-die ECC */ + MICRON_ON_DIE_UNSUPPORTED, + + /* + * The NAND flash supports on-die ECC and it can be + * enabled/disabled by a set features command. + */ + MICRON_ON_DIE_SUPPORTED, + + /* + * The NAND flash supports on-die ECC, and it cannot be + * disabled. + */ + MICRON_ON_DIE_MANDATORY, +}; + +/* + * Try to detect if the NAND support on-die ECC. To do this, we enable + * the feature, and read back if it has been enabled as expected. We + * also check if it can be disabled, because some Micron NANDs do not + * allow disabling the on-die ECC and we don't support such NANDs for + * now. + * + * This function also has the side effect of disabling on-die ECC if + * it had been left enabled by the firmware/bootloader. + */ +static int micron_supports_on_die_ecc(struct nand_chip *chip) +{ + u8 feature[ONFI_SUBFEATURE_PARAM_LEN] = { 0, }; + int ret; + + if (chip->onfi_version == 0) + return MICRON_ON_DIE_UNSUPPORTED; + + if (chip->bits_per_cell != 1) + return MICRON_ON_DIE_UNSUPPORTED; + + ret = micron_nand_on_die_ecc_setup(chip, true); + if (ret) + return MICRON_ON_DIE_UNSUPPORTED; + + chip->onfi_get_features(nand_to_mtd(chip), chip, + ONFI_FEATURE_ON_DIE_ECC, feature); + if ((feature[0] & ONFI_FEATURE_ON_DIE_ECC_EN) == 0) + return MICRON_ON_DIE_UNSUPPORTED; + + ret = micron_nand_on_die_ecc_setup(chip, false); + if (ret) + return MICRON_ON_DIE_UNSUPPORTED; + + chip->onfi_get_features(nand_to_mtd(chip), chip, + ONFI_FEATURE_ON_DIE_ECC, feature); + if (feature[0] & ONFI_FEATURE_ON_DIE_ECC_EN) + return MICRON_ON_DIE_MANDATORY; + + /* + * Some Micron NANDs have an on-die ECC of 4/512, some other + * 8/512. We only support the former. + */ + if (chip->onfi_params.ecc_bits != 4) + return MICRON_ON_DIE_UNSUPPORTED; + + return MICRON_ON_DIE_SUPPORTED; +} + static int micron_nand_init(struct nand_chip *chip) { struct mtd_info *mtd = nand_to_mtd(chip); + int ondie; int ret; ret = micron_nand_onfi_init(chip); @@ -78,6 +266,34 @@ static int micron_nand_init(struct nand_chip *chip) if (mtd->writesize == 2048) chip->bbt_options |= NAND_BBT_SCAN2NDPAGE; + ondie = micron_supports_on_die_ecc(chip); + + if (ondie == MICRON_ON_DIE_MANDATORY) { + pr_err("On-die ECC forcefully enabled, not supported\n"); + return -EINVAL; + } + + if (chip->ecc.mode == NAND_ECC_ON_DIE) { + if (ondie == MICRON_ON_DIE_UNSUPPORTED) { + pr_err("On-die ECC selected but not supported\n"); + return -EINVAL; + } + + chip->ecc.options = NAND_ECC_CUSTOM_PAGE_ACCESS; + chip->ecc.bytes = 8; + chip->ecc.size = 512; + chip->ecc.strength = 4; + chip->ecc.algo = NAND_ECC_BCH; + chip->ecc.read_page = micron_nand_read_page_on_die_ecc; + chip->ecc.write_page = micron_nand_write_page_on_die_ecc; + chip->ecc.read_page_raw = + micron_nand_read_page_raw_on_die_ecc; + chip->ecc.write_page_raw = + micron_nand_write_page_raw_on_die_ecc; + + mtd_set_ooblayout(mtd, µn_nand_on_die_ooblayout_ops); + } + return 0; } diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index 28f7dd9177e9..893d0ce08030 100644 --- a/include/linux/mtd/nand.h +++ b/include/linux/mtd/nand.h @@ -258,6 +258,8 @@ struct nand_chip; /* Vendor-specific feature address (Micron) */ #define ONFI_FEATURE_ADDR_READ_RETRY 0x89 +#define ONFI_FEATURE_ON_DIE_ECC 0x90 +#define ONFI_FEATURE_ON_DIE_ECC_EN BIT(3) /* ONFI subfeature parameters length */ #define ONFI_SUBFEATURE_PARAM_LEN 4 |