[PATCH v2 1/1] omap3: nand: report corrected ecc errors

John Ogness
2011-02-28T12:13:15Z

From: John Ogness <john.ogness@linutronix.de>

The number of corrected ECC errors should be reported since other MTD
systems make use of this information (such as UBI data scrubbing).

Signed-off-by: John Ogness <john.ogness@linutronix.de>
---
Patch v2:
o Patch against linux-next-20110225.
o Added comments explaining return codes.

drivers/mtd/nand/omap2.c | 16 ++++++++++++----
1 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 4e33972..6324230 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -668,6 +668,8 @@ static void gen_true_ecc(u8 *ecc_buf)
*
* This function compares two ECC's and indicates if there is an error.
* If the error can be corrected it will be corrected to the buffer.
+ * If there is no error, %0 is returned. If there is an error but it
+ * was corrected, %1 is returned. Otherwise, %-1 is returned.
*/
static int omap_compare_ecc(u8 *ecc_data1, /* read from NAND memory */
u8 *ecc_data2, /* read from register */
@@ -773,7 +775,7 @@ static int omap_compare_ecc(u8 *ecc_data1, /* read from NAND memory */

page_data[find_byte] ^= (1 << find_bit);

- return 0;
+ return 1;
default:
if (isEccFF) {
if (ecc_data2[0] == 0 &&
@@ -794,8 +796,11 @@ static int omap_compare_ecc(u8 *ecc_data1, /* read from NAND memory */
* @calc_ecc: ecc read from HW ECC registers
*
* Compares the ecc read from nand spare area with ECC registers values
- * and if ECC's mismached, it will call 'omap_compare_ecc' for error detection
- * and correction.
+ * and if ECC's mismatched, it will call 'omap_compare_ecc' for error
+ * detection and correction. If there are no errors, %0 is returned. If
+ * there were errors and all of the errors were corrected, the number of
+ * corrected errors is returned. If uncorrectable errors exist, %-1 is
+ * returned.
*/
static int omap_correct_data(struct mtd_info *mtd, u_char *dat,
u_char *read_ecc, u_char *calc_ecc)
@@ -803,6 +808,7 @@ static int omap_correct_data(struct mtd_info *mtd, u_char *dat,
struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd);
int blockCnt = 0, i = 0, ret = 0;
+ int stat = 0;

/* Ex NAND_ECC_HW12_2048 */
if ((info->nand.ecc.mode == NAND_ECC_HW) &&
@@ -816,12 +822,14 @@ static int omap_correct_data(struct mtd_info *mtd, u_char *dat,
ret = omap_compare_ecc(read_ecc, calc_ecc, dat);
if (ret < 0)
return ret;
+ /* keep track of the number of corrected errors */
+ stat += ret;
}
read_ecc += 3;
calc_ecc += 3;
dat += 512;
}
- return 0;
+ return stat;
}

/**
--
1.5.6.5