[MTD] [NAND] S3C2410 Allow unset ecc to be ignored for ecc correction

If a block's ecc field is all 0xff, then ignore the ECC
correction. This is for systems where some of the blocks,
such as the initial cramfs are written without ECC and
need to be loaded on start.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

2 files changed, 10 insertions, 0 deletions

diff --git a/drivers/mtd/nand/s3c2410.c b/drivers/mtd/nand/s3c2410.c
index 15397e0f3965..35401f7b9302 100644
--- a/drivers/mtd/nand/s3c2410.c
+++ b/drivers/mtd/nand/s3c2410.c
@@ -357,6 +357,14 @@ static int s3c2410_nand_correct_data(struct mtd_info *mtd, u_char *dat,
         if (diff0 == 0 && diff1 == 0 && diff2 == 0)
                 return 0;               /* ECC is ok */
 
+        /* sometimes people do not think about using the ECC, so check
+         * to see if we have an 0xff,0xff,0xff read ECC and then ignore
+         * the error, on the assumption that this is an un-eccd page.
+         */
+        if (read_ecc[0] == 0xff && read_ecc[1] == 0xff && read_ecc[2] == 0xff
+            && info->platform->ignore_unset_ecc)
+                return 0;
+
         /* Can we correct this ECC (ie, one row and column change).
          * Note, this is similar to the 256 error code on smartmedia */
 
diff --git a/include/asm-arm/plat-s3c/nand.h b/include/asm-arm/plat-s3c/nand.h
index 8816f7f9cee1..ab278d5f63dd 100644
--- a/include/asm-arm/plat-s3c/nand.h
+++ b/include/asm-arm/plat-s3c/nand.h
@@ -36,6 +36,8 @@ struct s3c2410_platform_nand {
         int     twrph0; /* active time for nWE/nOE */
         int     twrph1; /* time for release CLE/ALE from nWE/nOE inactive */
 
+        unsigned int    ignore_unset_ecc : 1;
+
         int                     nr_sets;
         struct s3c2410_nand_set *sets;