mtd: nand: samsung: Disable subpage writes on E-die NAND

Samsung E-die SLC NAND manufactured using 21nm process (K9F1G08U0E)
does not support partial page programming, so disable subpage writes
for it. Manufacturing process is stored in lowest two bits of 5th ID
byte.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

diff --git a/drivers/mtd/nand/nand_samsung.c b/drivers/mtd/nand/nand_samsung.c
index f6b0a63a068c7413507f607727af1338fa6415bd..ef022f62f74c18b612025732dc2eae13c9078d59 100644 (file)
--- a/drivers/mtd/nand/nand_samsung.c
+++ b/drivers/mtd/nand/nand_samsung.c
@@ -92,10 +92,23 @@ static void samsung_nand_decode_id(struct nand_chip *chip)
        } else {
                nand_decode_ext_id(chip);
 
-               /* Datasheet values for SLC Samsung K9F4G08U0D-S[I|C]B0(T00) */
-               if (nand_is_slc(chip) && chip->id.data[1] == 0xDC) {
-                       chip->ecc_step_ds = 512;
-                       chip->ecc_strength_ds = 1;
+               if (nand_is_slc(chip)) {
+                       switch (chip->id.data[1]) {
+                       /* K9F4G08U0D-S[I|C]B0(T00) */
+                       case 0xDC:
+                               chip->ecc_step_ds = 512;
+                               chip->ecc_strength_ds = 1;
+                               break;
+
+                       /* K9F1G08U0E 21nm chips do not support subpage write */
+                       case 0xF1:
+                               if (chip->id.len > 4 &&
+                                   (chip->id.data[4] & GENMASK(1, 0)) == 0x1)
+                                       chip->options |= NAND_NO_SUBPAGE_WRITE;
+                               break;
+                       default:
+                               break;
+                       }
                }
        }
 }