[PATCH -next] mtd: nand: Add support for Toshiba BENAND (Built-in ECC NAND)
KOBAYASHI Yoshitake
yoshitake.kobayashi at toshiba.co.jp
Thu May 25 18:15:35 PDT 2017
This patch enables support for Toshiba BENAND. It was originally posted on
https://lkml.org/lkml/2015/7/24/571
This patch is rewrote to adapt the recent mtd "separate vendor specific code
from core" cleanup process.
Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi at toshiba.co.jp>
---
drivers/mtd/nand/Kconfig | 17 ++++++
drivers/mtd/nand/nand_base.c | 15 ++++++
drivers/mtd/nand/nand_toshiba.c | 112 +++++++++++++++++++++++++++++++++++++++-
include/linux/mtd/nand.h | 1 +
4 files changed, 143 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 0bd2319..6634d4b 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -36,6 +36,23 @@ config MTD_NAND_ECC_BCH
ECC codes. They are used with NAND devices requiring more than 1 bit
of error correction.
+config MTD_NAND_BENAND
+ bool "Support for Toshiba BENAND (Built-in ECC NAND)"
+ default n
+ help
+ This enables support for Toshiba BENAND.
+ Toshiba BENAND is a SLC NAND solution that automatically
+ generates ECC inside NAND chip.
+
+config MTD_NAND_BENAND_ECC_STATUS
+ bool "Enable ECC Status Read Command(0x7A)"
+ depends on MTD_NAND_BENAND
+ default n
+ help
+ This enables support for ECC Status Read Command(0x7A) of BENAND.
+ When this enables, report the real number of bitflips.
+ In other cases, report the assumud number.
+
config MTD_SM_COMMON
tristate
default n
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 43722a8..ab8652e 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -4186,6 +4186,7 @@ static const char * const nand_ecc_modes[] = {
[NAND_ECC_HW_SYNDROME] = "hw_syndrome",
[NAND_ECC_HW_OOB_FIRST] = "hw_oob_first",
[NAND_ECC_ON_DIE] = "on-die",
+ [NAND_ECC_BENAND] = "benand",
};
static int of_get_nand_ecc_mode(struct device_node *np)
@@ -4751,6 +4752,19 @@ int nand_scan_tail(struct mtd_info *mtd)
ecc->write_oob = nand_write_oob_std;
break;
+ case NAND_ECC_BENAND:
+ if (!ecc->read_page || !ecc->read_subpage) {
+ WARN(1, "No ECC functions supplied; benand ECC not possible\n");
+ ret = -EINVAL;
+ goto err_free;
+ }
+ ecc->write_page = nand_write_page_raw;
+ ecc->read_page_raw = nand_read_page_raw;
+ ecc->write_page_raw = nand_write_page_raw;
+ ecc->read_oob = nand_read_oob_std;
+ ecc->write_oob = nand_write_oob_std;
+ break;
+
case NAND_ECC_NONE:
pr_warn("NAND_ECC_NONE selected by board driver. This is not recommended!\n");
ecc->read_page = nand_read_page_raw;
@@ -4831,6 +4845,7 @@ int nand_scan_tail(struct mtd_info *mtd)
/* Large page NAND with SOFT_ECC should support subpage reads */
switch (ecc->mode) {
case NAND_ECC_SOFT:
+ case NAND_ECC_BENAND:
if (chip->page_shift > 9)
chip->options |= NAND_SUBPAGE_READ;
break;
diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c
index fa787ba..bb3c852 100644
--- a/drivers/mtd/nand/nand_toshiba.c
+++ b/drivers/mtd/nand/nand_toshiba.c
@@ -17,6 +17,97 @@
#include <linux/mtd/nand.h>
+/* ECC Status Read Command for BENAND */
+#define NAND_CMD_ECC_STATUS 0x7A
+
+/* Recommended to rewrite for BENAND */
+#define NAND_STATUS_RECOM_REWRT 0x08
+
+
+static int toshiba_nand_benand_status_chk(struct mtd_info *mtd,
+ struct nand_chip *chip)
+{
+ unsigned int max_bitflips = 0;
+ u8 status;
+
+ /* Check Read Status */
+ chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
+ status = chip->read_byte(mtd);
+
+ /* timeout */
+ if (!(status & NAND_STATUS_READY)) {
+ pr_debug("BENAND : Time Out!\n");
+ return -EIO;
+ }
+
+ /* uncorrectable */
+ else if (status & NAND_STATUS_FAIL)
+ mtd->ecc_stats.failed++;
+
+ /* correctable */
+ else if (status & NAND_STATUS_RECOM_REWRT) {
+ if (chip->cmd_ctrl &&
+ IS_ENABLED(CONFIG_MTD_NAND_BENAND_ECC_STATUS)) {
+
+ int i;
+ u8 ecc_status;
+ unsigned int bitflips;
+
+ /* Check Read ECC Status */
+ chip->cmd_ctrl(mtd, NAND_CMD_ECC_STATUS,
+ NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
+ /* Get bitflips info per 512Byte */
+ for (i = 0; i < mtd->writesize >> 9; i++) {
+ ecc_status = chip->read_byte(mtd);
+ bitflips = ecc_status & 0x0f;
+ max_bitflips = max_t(unsigned int,
+ max_bitflips, bitflips);
+ }
+ mtd->ecc_stats.corrected += max_bitflips;
+ } else {
+ /*
+ * If can't use chip->cmd_ctrl,
+ * we can't get real number of bitflips.
+ * So, we set max_bitflips mtd->bitflip_threshold.
+ */
+ max_bitflips = mtd->bitflip_threshold;
+ mtd->ecc_stats.corrected += max_bitflips;
+ }
+ }
+
+ return max_bitflips;
+}
+
+static int toshiba_nand_read_page_benand(struct mtd_info *mtd,
+ struct nand_chip *chip, uint8_t *buf,
+ int oob_required, int page)
+{
+ unsigned int max_bitflips = 0;
+
+ chip->ecc.read_page_raw(mtd, chip, buf, oob_required, page);
+ max_bitflips = toshiba_nand_benand_status_chk(mtd, chip);
+
+ return max_bitflips;
+}
+
+static int toshiba_nand_read_subpage_benand(struct mtd_info *mtd,
+ struct nand_chip *chip, uint32_t data_offs,
+ uint32_t readlen, uint8_t *bufpoi, int page)
+{
+ uint8_t *p;
+ unsigned int max_bitflips = 0;
+
+ if (data_offs != 0)
+ chip->cmdfunc(mtd, NAND_CMD_RNDOUT, data_offs, -1);
+
+ p = bufpoi + data_offs;
+ chip->read_buf(mtd, p, readlen);
+
+ max_bitflips = toshiba_nand_benand_status_chk(mtd, chip);
+
+ return max_bitflips;
+}
+
static void toshiba_nand_decode_id(struct nand_chip *chip)
{
struct mtd_info *mtd = nand_to_mtd(chip);
@@ -33,15 +124,32 @@ static void toshiba_nand_decode_id(struct nand_chip *chip)
*/
if (chip->id.len >= 6 && nand_is_slc(chip) &&
(chip->id.data[5] & 0x7) == 0x6 /* 24nm */ &&
- !(chip->id.data[4] & 0x80) /* !BENAND */)
- mtd->oobsize = 32 * mtd->writesize >> 9;
+ (chip->id.data[4] & 0x80) /* BENAND */) {
+ if (IS_ENABLED(CONFIG_MTD_NAND_BENAND))
+ chip->ecc.mode = NAND_ECC_BENAND;
+ } else {
+ mtd->oobsize = 32 * mtd->writesize >> 9; /* !BENAND */
+ }
}
static int toshiba_nand_init(struct nand_chip *chip)
{
+ struct mtd_info *mtd = nand_to_mtd(chip);
+
if (nand_is_slc(chip))
chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;
+ if (chip->ecc.mode == NAND_ECC_BENAND) {
+ chip->ecc.options = NAND_ECC_CUSTOM_PAGE_ACCESS;
+ chip->ecc.bytes = 0;
+ chip->ecc.strength = 8;
+ chip->ecc.total = 0;
+ chip->ecc.read_page = toshiba_nand_read_page_benand;
+ chip->ecc.read_subpage = toshiba_nand_read_subpage_benand;
+
+ mtd_set_ooblayout(mtd, &nand_ooblayout_lp_ops);
+ }
+
return 0;
}
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 3a6a77f..6821334 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -117,6 +117,7 @@ typedef enum {
NAND_ECC_HW_SYNDROME,
NAND_ECC_HW_OOB_FIRST,
NAND_ECC_ON_DIE,
+ NAND_ECC_BENAND,
} nand_ecc_modes_t;
enum nand_ecc_algo {
--
2.7.4
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