mtd: omap3: nand: report corrected ecc errors

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>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 28af71c..d7a4e25 100644 (file)
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -517,6 +517,8 @@ 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 */
@@ -622,7 +624,7 @@ 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 &&
@@ -643,8 +645,11 @@ 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)
@@ -652,6 +657,7 @@ 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) &&
@@ -665,12 +671,14 @@ 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;
 }
 
 /**