mtd: kill MTD_NAND_VERIFY_WRITE

Just as Artem suggested:

"Both UBI and JFFS2 are able to read verify what they wrote already.
There are also MTD tests which do this verification. So I think there
is no reason to keep this in the NAND layer, let alone wasting RAM in
the driver to support this feature. Besides, it does not work for sub-pages
and many drivers have it broken. It hurts more than it provides benefits."

So kill MTD_NAND_VERIFY_WRITE entirely.

Signed-off-by: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 0 insertions, 53 deletions

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 996cc483688..6a8e15d6b40 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -243,25 +243,6 @@ static void nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
 }
 
 /**
- * nand_verify_buf - [DEFAULT] Verify chip data against buffer
- * @mtd: MTD device structure
- * @buf: buffer containing the data to compare
- * @len: number of bytes to compare
- *
- * Default verify function for 8bit buswidth.
- */
-static int nand_verify_buf(struct mtd_info *mtd, const uint8_t *buf, int len)
-{
-	int i;
-	struct nand_chip *chip = mtd->priv;
-
-	for (i = 0; i < len; i++)
-		if (buf[i] != readb(chip->IO_ADDR_R))
-			return -EFAULT;
-	return 0;
-}
-
-/**
  * nand_write_buf16 - [DEFAULT] write buffer to chip
  * @mtd: MTD device structure
  * @buf: data buffer
@@ -301,28 +282,6 @@ static void nand_read_buf16(struct mtd_info *mtd, uint8_t *buf, int len)
 }
 
 /**
- * nand_verify_buf16 - [DEFAULT] Verify chip data against buffer
- * @mtd: MTD device structure
- * @buf: buffer containing the data to compare
- * @len: number of bytes to compare
- *
- * Default verify function for 16bit buswidth.
- */
-static int nand_verify_buf16(struct mtd_info *mtd, const uint8_t *buf, int len)
-{
-	int i;
-	struct nand_chip *chip = mtd->priv;
-	u16 *p = (u16 *) buf;
-	len >>= 1;
-
-	for (i = 0; i < len; i++)
-		if (p[i] != readw(chip->IO_ADDR_R))
-			return -EFAULT;
-
-	return 0;
-}
-
-/**
  * nand_block_bad - [DEFAULT] Read bad block marker from the chip
  * @mtd: MTD device structure
  * @ofs: offset from device start
@@ -2120,16 +2079,6 @@ static int nand_write_page(struct mtd_info *mtd, struct nand_chip *chip,
 		status = chip->waitfunc(mtd, chip);
 	}
 
-#ifdef CONFIG_MTD_NAND_VERIFY_WRITE
-	/* Send command to read back the data */
-	chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
-
-	if (chip->verify_buf(mtd, buf, mtd->writesize))
-		return -EIO;
-
-	/* Make sure the next page prog is preceded by a status read */
-	chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
-#endif
 	return 0;
 }
 
@@ -2804,8 +2753,6 @@ static void nand_set_defaults(struct nand_chip *chip, int busw)
 		chip->write_buf = busw ? nand_write_buf16 : nand_write_buf;
 	if (!chip->read_buf)
 		chip->read_buf = busw ? nand_read_buf16 : nand_read_buf;
-	if (!chip->verify_buf)
-		chip->verify_buf = busw ? nand_verify_buf16 : nand_verify_buf;
 	if (!chip->scan_bbt)
 		chip->scan_bbt = nand_default_bbt;