mtd: nand: toshiba: Retrieve ECC requirements from extended ID

Upstream linux commit fb3bff5b407e58.

This patch enables support to read the ECC strength and size from the
NAND flash using Toshiba Memory SLC NAND extended-ID. This patch is
based on the information of the 6th ID byte of the Toshiba Memory SLC
NAND.

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>

diff --git a/drivers/mtd/nand/raw/nand_toshiba.c b/drivers/mtd/nand/raw/nand_toshiba.c
index f7426fa59f5124f1695c6a231a2140423779004a..99dc44df671a01394628b5f814bab3aa47119226 100644 (file)
--- a/drivers/mtd/nand/raw/nand_toshiba.c
+++ b/drivers/mtd/nand/raw/nand_toshiba.c
@@ -37,6 +37,32 @@ static void toshiba_nand_decode_id(struct nand_chip *chip)
            (chip->id.data[5] & 0x7) == 0x6 /* 24nm */ &&
            !(chip->id.data[4] & 0x80) /* !BENAND */)
                mtd->oobsize = 32 * mtd->writesize >> 9;
+
+       /*
+        * Extract ECC requirements from 6th id byte.
+        * For Toshiba SLC, ecc requrements are as follows:
+        *  - 43nm: 1 bit ECC for each 512Byte is required.
+        *  - 32nm: 4 bit ECC for each 512Byte is required.
+        *  - 24nm: 8 bit ECC for each 512Byte is required.
+        */
+       if (chip->id.len >= 6 && nand_is_slc(chip)) {
+               chip->ecc_step_ds = 512;
+               switch (chip->id.data[5] & 0x7) {
+               case 0x4:
+                       chip->ecc_strength_ds = 1;
+                       break;
+               case 0x5:
+                       chip->ecc_strength_ds = 4;
+                       break;
+               case 0x6:
+                       chip->ecc_strength_ds = 8;
+                       break;
+               default:
+                       WARN(1, "Could not get ECC info");
+                       chip->ecc_step_ds = 0;
+                       break;
+               }
+       }
 }
 
 static int toshiba_nand_init(struct nand_chip *chip)