mtd: nand: omap: fix ecclayout->oobfree->offset

1) In current implementation, ecclayout->oobfree->offset is calculated with
 respect to ecclayout->eccpos[0] which is incorrect because ECC bytes may not
 be stored contiguously in OOB.
 So, this patch calculates ecclayout->oobfree->offset with respect to last
 ECC byte-position 'eccpos[ecclayout->eccbytes-1]'.

2) ECC layout of some ecc-schemes expects reserved-markers at specific eccpos[]
 which should not be over-written by any file-system metadata.
 So this patch aligns oobfree->offset taking into account of such markers.

CC: <stable@vger.kernel.org> # 3.13.x+
Tested-by: Enric Balletbo i Serra <eballetbo@gmail.com>
Tested-by: Stefan Roese <sr@denx.de>
Signed-off-by: Pekon Gupta <pekon@ti.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

1 files changed, 15 insertions, 10 deletions

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 34ef941e3bfb..58685ab6d865 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -1832,8 +1832,9 @@ static int omap_nand_probe(struct platform_device *pdev)
                         oob_index               = 1;
                 for (i = 0; i < ecclayout->eccbytes; i++, oob_index++)
                         ecclayout->eccpos[i]    = oob_index;
-                ecclayout->oobfree->offset      = ecclayout->eccpos[0] +
-                                                        ecclayout->eccbytes;
+                /* no reserved-marker in ecclayout for this ecc-scheme */
+                ecclayout->oobfree->offset      =
+                                ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
                 break;
 
         case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
@@ -1856,8 +1857,9 @@ static int omap_nand_probe(struct platform_device *pdev)
                         if (((i + 1) % nand_chip->ecc.bytes) == 0)
                                 oob_index++;
                 }
-                ecclayout->oobfree->offset      = ecclayout->eccpos[0] +
-                                                        ecclayout->eccbytes;
+                /* include reserved-marker in ecclayout->oobfree calculation */
+                ecclayout->oobfree->offset      = 1 +
+                                ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
                 /* software bch library is used for locating errors */
                 nand_chip->ecc.priv             = nand_bch_init(mtd,
                                                         nand_chip->ecc.size,
@@ -1894,8 +1896,9 @@ static int omap_nand_probe(struct platform_device *pdev)
                 oob_index                       = BADBLOCK_MARKER_LENGTH;
                 for (i = 0; i < ecclayout->eccbytes; i++, oob_index++)
                         ecclayout->eccpos[i]    = oob_index;
-                ecclayout->oobfree->offset      = ecclayout->eccpos[0] +
-                                                        ecclayout->eccbytes;
+                /* reserved marker already included in ecclayout->eccbytes */
+                ecclayout->oobfree->offset      =
+                                ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
                 /* This ECC scheme requires ELM H/W block */
                 if (is_elm_present(info, pdata->elm_of_node, BCH4_ECC) < 0) {
                         pr_err("nand: error: could not initialize ELM\n");
@@ -1929,8 +1932,9 @@ static int omap_nand_probe(struct platform_device *pdev)
                         if (((i + 1) % nand_chip->ecc.bytes) == 0)
                                 oob_index++;
                 }
-                ecclayout->oobfree->offset      = ecclayout->eccpos[0] +
-                                                        ecclayout->eccbytes;
+                /* include reserved-marker in ecclayout->oobfree calculation */
+                ecclayout->oobfree->offset      = 1 +
+                                ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
                 /* software bch library is used for locating errors */
                 nand_chip->ecc.priv             = nand_bch_init(mtd,
                                                         nand_chip->ecc.size,
@@ -1974,8 +1978,9 @@ static int omap_nand_probe(struct platform_device *pdev)
                 oob_index                       = BADBLOCK_MARKER_LENGTH;
                 for (i = 0; i < ecclayout->eccbytes; i++, oob_index++)
                         ecclayout->eccpos[i]    = oob_index;
-                ecclayout->oobfree->offset      = ecclayout->eccpos[0] +
-                                                        ecclayout->eccbytes;
+                /* reserved marker already included in ecclayout->eccbytes */
+                ecclayout->oobfree->offset      =
+                                ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
                 break;
 #else
                 pr_err("nand: error: CONFIG_MTD_NAND_OMAP_BCH not enabled\n");