2 files changed, 16 insertions, 5 deletions

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index ed34364f7620..64ee59eb01b7 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -3093,6 +3093,16 @@ static int nand_id_len(u8 *id_data, int arrlen)
         return arrlen;
 }
 
+/* Extract the bits of per cell from the 3rd byte of the extended ID */
+static int nand_get_bits_per_cell(u8 cellinfo)
+{
+        int bits;
+
+        bits = cellinfo & NAND_CI_CELLTYPE_MSK;
+        bits >>= NAND_CI_CELLTYPE_SHIFT;
+        return bits + 1;
+}
+
 /*
  * Many new NAND share similar device ID codes, which represent the size of the
  * chip. The rest of the parameters must be decoded according to generic or
@@ -3103,7 +3113,7 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
 {
         int extid, id_len;
         /* The 3rd id byte holds MLC / multichip data */
-        chip->cellinfo = id_data[2];
+        chip->bits_per_cell = nand_get_bits_per_cell(id_data[2]);
         /* The 4th id byte is the important one */
         extid = id_data[3];
 
@@ -3303,7 +3313,7 @@ static bool find_full_id_nand(struct mtd_info *mtd, struct nand_chip *chip,
                 mtd->erasesize = type->erasesize;
                 mtd->oobsize = type->oobsize;
 
-                chip->cellinfo = id_data[2];
+                chip->bits_per_cell = nand_get_bits_per_cell(id_data[2]);
                 chip->chipsize = (uint64_t)type->chipsize << 20;
                 chip->options |= type->options;
                 chip->ecc_strength_ds = NAND_ECC_STRENGTH(type);
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 8911709653fe..8646589b3fe8 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -198,6 +198,7 @@ typedef enum {
 /* Cell info constants */
 #define NAND_CI_CHIPNR_MSK      0x03
 #define NAND_CI_CELLTYPE_MSK    0x0C
+#define NAND_CI_CELLTYPE_SHIFT  2
 
 /* Keep gcc happy */
 struct nand_chip;
@@ -440,7 +441,7 @@ struct nand_buffers {
  * @badblockbits:       [INTERN] minimum number of set bits in a good block's
  *                      bad block marker position; i.e., BBM == 11110111b is
  *                      not bad when badblockbits == 7
- * @cellinfo:           [INTERN] MLC/multichip data from chip ident
+ * @bits_per_cell:      [INTERN] number of bits per cell. i.e., 1 means SLC.
  * @ecc_strength_ds:    [INTERN] ECC correctability from the datasheet.
  *                      Minimum amount of bit errors per @ecc_step_ds guaranteed
  *                      to be correctable. If unknown, set to zero.
@@ -521,7 +522,7 @@ struct nand_chip {
         int pagebuf;
         unsigned int pagebuf_bitflips;
         int subpagesize;
-        uint8_t cellinfo;
+        uint8_t bits_per_cell;
         uint16_t ecc_strength_ds;
         uint16_t ecc_step_ds;
         int badblockpos;
@@ -765,6 +766,6 @@ static inline int onfi_get_sync_timing_mode(struct nand_chip *chip)
  */
 static inline bool nand_is_slc(struct nand_chip *chip)
 {
-        return !(chip->cellinfo & NAND_CI_CELLTYPE_MSK);
+        return chip->bits_per_cell == 1;
 }
 #endif /* __LINUX_MTD_NAND_H */