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Subject[RFC PATCH v2] mtd: nand: toshiba: Add support for ->exec_op()
Date
This patch is a patch to support TOSHIBA MEMORY CORPORATION BENAND
memory devices. This use vendor specific command
(TOSHIBA_NAND_CMD_ECC_STATUS) to know the exact bitflips. However, I
could not test this patch because I do not have a platform that
supports chip-> exec_op. Therefore, I post this patch as RFC.

As soon as I get a platform that supports chip-> exec_op, I would like
to test and re-post.

Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
---
drivers/mtd/nand/raw/nand_toshiba.c | 53 ++++++++++++++++++++++++++++++++++++-
1 file changed, 52 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/nand_toshiba.c b/drivers/mtd/nand/raw/nand_toshiba.c
index 8aec3fa..3f4683b 100644
--- a/drivers/mtd/nand/raw/nand_toshiba.c
+++ b/drivers/mtd/nand/raw/nand_toshiba.c
@@ -23,14 +23,65 @@
/* Recommended to rewrite for BENAND */
#define TOSHIBA_NAND_STATUS_REWRITE_RECOMMENDED BIT(3)

+/* ECC Status Read Command for BENAND */
+#define TOSHIBA_NAND_CMD_ECC_STATUS_READ 0x7A
+
+/* ECC Status Mask for BENAND */
+#define TOSHIBA_NAND_ECC_STATUS_MASK 0x0F
+
+/* Uncorrectable Error for BENAND */
+#define TOSHIBA_NAND_ECC_STATUS_UNCORR 0x0F
+
+static int toshiba_nand_benand_read_eccstatus_op(struct nand_chip *chip,
+ u8 *buf)
+{
+ u8 *ecc_status = buf;
+
+ if (chip->exec_op) {
+ const struct nand_sdr_timings *sdr =
+ nand_get_sdr_timings(&chip->data_interface);
+ struct nand_op_instr instrs[] = {
+ NAND_OP_CMD(TOSHIBA_NAND_CMD_ECC_STATUS_READ,
+ PSEC_TO_NSEC(sdr->tADL_min)),
+ NAND_OP_8BIT_DATA_IN(chip->ecc.steps, ecc_status, 0),
+ };
+ struct nand_operation op = NAND_OPERATION(instrs);
+
+ return nand_exec_op(chip, &op);
+ }
+
+ return -ENOTSUPP;
+}
+
static int toshiba_nand_benand_eccstatus(struct mtd_info *mtd,
struct nand_chip *chip)
{
int ret;
unsigned int max_bitflips = 0;
- u8 status;
+ u8 status, ecc_status[8];

/* Check Status */
+ ret = toshiba_nand_benand_read_eccstatus_op(chip, ecc_status);
+ if (!ret) {
+ unsigned int i, bitflips = 0;
+
+ for (i = 0; i < chip->ecc.steps; i++) {
+ bitflips = ecc_status[i] & TOSHIBA_NAND_ECC_STATUS_MASK;
+ if (bitflips == TOSHIBA_NAND_ECC_STATUS_UNCORR) {
+ mtd->ecc_stats.failed++;
+ } else {
+ mtd->ecc_stats.corrected += bitflips;
+ max_bitflips = max(max_bitflips, bitflips);
+ }
+ }
+
+ return max_bitflips;
+ }
+
+ /*
+ * Fallback to regular status check if
+ * toshiba_nand_benand_read_eccstatus_op() failed.
+ */
ret = nand_status_op(chip, &status);
if (ret)
return ret;
--
2.7.4
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