mtd: nand: add ooblayout for old hamming layout

The old 1-bit hamming layout requires ECC data to be placed at a
fixed offset, and not necessarily at the end of the OOB area.
Add this old layout back in order to fix legacy setups.

Fixes: 4d04f724ce5b ("mtd: nand: implement the default mtd_ooblayout_ops")
Cc: <stable@vger.kernel.org>
Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index ed49a1d634b04487998c0296ecdaf681e9d4da3f..d474378ed810b3c3ab19d8a4e85e77e0eb15511c 100644 (file)
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -139,6 +139,74 @@ const struct mtd_ooblayout_ops nand_ooblayout_lp_ops = {
 };
 EXPORT_SYMBOL_GPL(nand_ooblayout_lp_ops);
 
+/*
+ * Support the old "large page" layout used for 1-bit Hamming ECC where ECC
+ * are placed at a fixed offset.
+ */
+static int nand_ooblayout_ecc_lp_hamming(struct mtd_info *mtd, int section,
+                                        struct mtd_oob_region *oobregion)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct nand_ecc_ctrl *ecc = &chip->ecc;
+
+       if (section)
+               return -ERANGE;
+
+       switch (mtd->oobsize) {
+       case 64:
+               oobregion->offset = 40;
+               break;
+       case 128:
+               oobregion->offset = 80;
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       oobregion->length = ecc->total;
+       if (oobregion->offset + oobregion->length > mtd->oobsize)
+               return -ERANGE;
+
+       return 0;
+}
+
+static int nand_ooblayout_free_lp_hamming(struct mtd_info *mtd, int section,
+                                         struct mtd_oob_region *oobregion)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct nand_ecc_ctrl *ecc = &chip->ecc;
+       int ecc_offset = 0;
+
+       if (section < 0 || section > 1)
+               return -ERANGE;
+
+       switch (mtd->oobsize) {
+       case 64:
+               ecc_offset = 40;
+               break;
+       case 128:
+               ecc_offset = 80;
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       if (section == 0) {
+               oobregion->offset = 2;
+               oobregion->length = ecc_offset - 2;
+       } else {
+               oobregion->offset = ecc_offset + ecc->total;
+               oobregion->length = mtd->oobsize - oobregion->offset;
+       }
+
+       return 0;
+}
+
+const struct mtd_ooblayout_ops nand_ooblayout_lp_hamming_ops = {
+       .ecc = nand_ooblayout_ecc_lp_hamming,
+       .free = nand_ooblayout_free_lp_hamming,
+};
+
 static int check_offs_len(struct mtd_info *mtd,
                                        loff_t ofs, uint64_t len)
 {
@@ -4559,7 +4627,7 @@ int nand_scan_tail(struct mtd_info *mtd)
                        break;
                case 64:
                case 128:
-                       mtd_set_ooblayout(mtd, &nand_ooblayout_lp_ops);
+                       mtd_set_ooblayout(mtd, &nand_ooblayout_lp_hamming_ops);
                        break;
                default:
                        WARN(1, "No oob scheme defined for oobsize %d\n",