[MTD] OneNAND: Single bit error detection

Idea from Jarkko Lavinen

Signed-off-by: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

3 files changed, 15 insertions, 5 deletions

diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index bef4f26ad2ed..fc84ddc4987f 100644
--- a/drivers/mtd/onenand/onenand_base.c
+++ b/drivers/mtd/onenand/onenand_base.c
@@ -331,9 +331,12 @@ static int onenand_wait(struct mtd_info *mtd, int state)
 
         if (interrupt & ONENAND_INT_READ) {
                 ecc = this->read_word(this->base + ONENAND_REG_ECC_STATUS);
-                if (ecc & ONENAND_ECC_2BIT_ALL) {
+                if (ecc) {
                         DEBUG(MTD_DEBUG_LEVEL0, "onenand_wait: ECC error = 0x%04x\n", ecc);
-                        return -EBADMSG;
+                        if (ecc & ONENAND_ECC_2BIT_ALL)
+                                mtd->ecc_stats.failed++;
+                        else if (ecc & ONENAND_ECC_1BIT_ALL)
+                                mtd->ecc_stats.corrected++;
                 }
         }
 
@@ -715,6 +718,7 @@ static int onenand_read(struct mtd_info *mtd, loff_t from, size_t len,
         size_t *retlen, u_char *buf)
 {
         struct onenand_chip *this = mtd->priv;
+        struct mtd_ecc_stats stats;
         int read = 0, column;
         int thislen;
         int ret = 0;
@@ -733,6 +737,7 @@ static int onenand_read(struct mtd_info *mtd, loff_t from, size_t len,
 
         /* TODO handling oob */
 
+        stats = mtd->ecc_stats;
         while (read < len) {
                 thislen = min_t(int, mtd->writesize, len - read);
 
@@ -774,7 +779,11 @@ out:
          * retlen == desired len and result == -EBADMSG
          */
         *retlen = read;
-        return ret;
+
+        if (mtd->ecc_stats.failed - stats.failed)
+                return -EBADMSG;
+
+        return mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;
 }
 
 /**
@@ -1390,7 +1399,6 @@ static int onenand_lock(struct mtd_info *mtd, loff_t ofs, size_t len)
         return onenand_do_lock_cmd(mtd, ofs, len, ONENAND_CMD_LOCK);
 }
 
-
 /**
  * onenand_unlock - [MTD Interface] Unlock block(s)
  * @param mtd           MTD device structure
@@ -1900,7 +1908,7 @@ static int onenand_probe(struct mtd_info *mtd)
         /* Read manufacturer and device IDs from Register */
         maf_id = this->read_word(this->base + ONENAND_REG_MANUFACTURER_ID);
         dev_id = this->read_word(this->base + ONENAND_REG_DEVICE_ID);
-        ver_id= this->read_word(this->base + ONENAND_REG_VERSION_ID);
+        ver_id = this->read_word(this->base + ONENAND_REG_VERSION_ID);
 
         /* Check OneNAND device */
         if (maf_id != bram_maf_id || dev_id != bram_dev_id)
diff --git a/drivers/mtd/onenand/onenand_bbt.c b/drivers/mtd/onenand/onenand_bbt.c
index 1b00dac3d7d6..c8067b8f20a6 100644
--- a/drivers/mtd/onenand/onenand_bbt.c
+++ b/drivers/mtd/onenand/onenand_bbt.c
@@ -100,6 +100,7 @@ static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr
                                 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
                                 printk(KERN_WARNING "Bad eraseblock %d at 0x%08x\n",
                                         i >> 1, (unsigned int) from);
+                                mtd->ecc_stats.badblocks++;
                                 break;
                         }
                 }
diff --git a/include/linux/mtd/onenand_regs.h b/include/linux/mtd/onenand_regs.h
index 9e409fe6ded6..e31c8f5d4271 100644
--- a/include/linux/mtd/onenand_regs.h
+++ b/include/linux/mtd/onenand_regs.h
@@ -179,6 +179,7 @@
  * ECC Status Reigser FF00h (R)
  */
 #define ONENAND_ECC_1BIT                (1 << 0)
+#define ONENAND_ECC_1BIT_ALL            (0x5555)
 #define ONENAND_ECC_2BIT                (1 << 1)
 #define ONENAND_ECC_2BIT_ALL            (0xAAAA)