Patchwork [v3,1/5] mtd: nand: localize ECC failures per page

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Submitter Brian Norris
Date Jan. 4, 2014, 12:37 a.m.
Message ID <1388795828-24808-1-git-send-email-computersforpeace@gmail.com>
Download mbox | patch
Permalink /patch/306757/
State New
Headers show

Comments

Brian Norris - Jan. 4, 2014, 12:37 a.m.
ECC failures can be tracked at the page level, not the do_read_ops level
(i.e., a potentially multi-page transaction).

This helps prepare for READ RETRY support.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
---
No changes since v1

 drivers/mtd/nand/nand_base.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)
Huang Shijie - Jan. 7, 2014, 7:02 a.m.
On Fri, Jan 03, 2014 at 04:37:04PM -0800, Brian Norris wrote:
> ECC failures can be tracked at the page level, not the do_read_ops level
> (i.e., a potentially multi-page transaction).
> 
> This helps prepare for READ RETRY support.
> 
> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
> ---
> No changes since v1
> 
>  drivers/mtd/nand/nand_base.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> index 9b3bb3c519e9..e85b07f4293d 100644
> --- a/drivers/mtd/nand/nand_base.c
> +++ b/drivers/mtd/nand/nand_base.c
> @@ -1422,7 +1422,6 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
>  {
>  	int chipnr, page, realpage, col, bytes, aligned, oob_required;
>  	struct nand_chip *chip = mtd->priv;
> -	struct mtd_ecc_stats stats;
>  	int ret = 0;
>  	uint32_t readlen = ops->len;
>  	uint32_t oobreadlen = ops->ooblen;
> @@ -1432,7 +1431,7 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
>  	uint8_t *bufpoi, *oob, *buf;
>  	unsigned int max_bitflips = 0;
>  
> -	stats = mtd->ecc_stats;
> +	bool ecc_fail = false;

Please do not put this line here, put it in the above lines.

>  
>  	chipnr = (int)(from >> chip->chip_shift);
>  	chip->select_chip(mtd, chipnr);
> @@ -1447,6 +1446,7 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
>  	oob_required = oob ? 1 : 0;
>  
>  	while (1) {
> +		unsigned int ecc_failures = mtd->ecc_stats.failed;
please add a white line here.


thanks
Huang Shijie

Patch

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 9b3bb3c519e9..e85b07f4293d 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -1422,7 +1422,6 @@  static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
 {
 	int chipnr, page, realpage, col, bytes, aligned, oob_required;
 	struct nand_chip *chip = mtd->priv;
-	struct mtd_ecc_stats stats;
 	int ret = 0;
 	uint32_t readlen = ops->len;
 	uint32_t oobreadlen = ops->ooblen;
@@ -1432,7 +1431,7 @@  static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
 	uint8_t *bufpoi, *oob, *buf;
 	unsigned int max_bitflips = 0;
 
-	stats = mtd->ecc_stats;
+	bool ecc_fail = false;
 
 	chipnr = (int)(from >> chip->chip_shift);
 	chip->select_chip(mtd, chipnr);
@@ -1447,6 +1446,7 @@  static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
 	oob_required = oob ? 1 : 0;
 
 	while (1) {
+		unsigned int ecc_failures = mtd->ecc_stats.failed;
 		bytes = min(mtd->writesize - col, readlen);
 		aligned = (bytes == mtd->writesize);
 
@@ -1483,7 +1483,7 @@  static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
 			/* Transfer not aligned data */
 			if (!aligned) {
 				if (!NAND_HAS_SUBPAGE_READ(chip) && !oob &&
-				    !(mtd->ecc_stats.failed - stats.failed) &&
+				    !(mtd->ecc_stats.failed - ecc_failures) &&
 				    (ops->mode != MTD_OPS_RAW)) {
 					chip->pagebuf = realpage;
 					chip->pagebuf_bitflips = ret;
@@ -1513,6 +1513,9 @@  static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
 				else
 					nand_wait_ready(mtd);
 			}
+
+			if (mtd->ecc_stats.failed - ecc_failures)
+				ecc_fail = true;
 		} else {
 			memcpy(buf, chip->buffers->databuf + col, bytes);
 			buf += bytes;
@@ -1547,7 +1550,7 @@  static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
 	if (ret < 0)
 		return ret;
 
-	if (mtd->ecc_stats.failed - stats.failed)
+	if (ecc_fail)
 		return -EBADMSG;
 
 	return max_bitflips;