mtd: nand: add a helper to check the SLC/MLC nand chip

Add a helper to check if a nand chip is SLC or MLC.
This helper makes the code more readable.
Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/nand/denali.c

@@ -1520,7 +1520,7 @@ int denali_init(struct denali_nand_info *denali)
 	 * so just let controller do 15bit ECC for MLC and 8bit ECC for
 	 * SLC if possible.
 	 * */
-	if (denali->nand.cellinfo & NAND_CI_CELLTYPE_MSK &&
+	if (!nand_is_slc(&denali->nand) &&
 			(denali->mtd.oobsize > (denali->bbtskipbytes +
 			ECC_15BITS * (denali->mtd.writesize /
 			ECC_SECTOR_SIZE)))) {

drivers/mtd/nand/nand_base.c

@@ -3108,8 +3108,7 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
 	 * ID to decide what to do.
 	 */
 	if (id_len == 6 && id_data[0] == NAND_MFR_SAMSUNG &&
-			(chip->cellinfo & NAND_CI_CELLTYPE_MSK) &&
-			id_data[5] != 0x00) {
+			!nand_is_slc(chip) && id_data[5] != 0x00) {
 		/* Calc pagesize */
 		mtd->writesize = 2048 << (extid & 0x03);
 		extid >>= 2;
@@ -3141,7 +3140,7 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
 			(((extid >> 1) & 0x04) | (extid & 0x03));
 		*busw = 0;
 	} else if (id_len == 6 && id_data[0] == NAND_MFR_HYNIX &&
-			(chip->cellinfo & NAND_CI_CELLTYPE_MSK)) {
+			!nand_is_slc(chip)) {
 		unsigned int tmp;
 
 		/* Calc pagesize */
@@ -3204,7 +3203,7 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
 		 * - ID byte 5, bit[7]:    1 -> BENAND, 0 -> raw SLC
 		 */
 		if (id_len >= 6 && id_data[0] == NAND_MFR_TOSHIBA &&
-				!(chip->cellinfo & NAND_CI_CELLTYPE_MSK) &&
+				nand_is_slc(chip) &&
 				(id_data[5] & 0x7) == 0x6 /* 24nm */ &&
 				!(id_data[4] & 0x80) /* !BENAND */) {
 			mtd->oobsize = 32 * mtd->writesize >> 9;
@@ -3265,11 +3264,11 @@ static void nand_decode_bbm_options(struct mtd_info *mtd,
 	 * Micron devices with 2KiB pages and on SLC Samsung, Hynix, Toshiba,
 	 * AMD/Spansion, and Macronix.  All others scan only the first page.
 	 */
-	if ((chip->cellinfo & NAND_CI_CELLTYPE_MSK) &&
+	if (!nand_is_slc(chip) &&
 			(maf_id == NAND_MFR_SAMSUNG ||
 			 maf_id == NAND_MFR_HYNIX))
 		chip->bbt_options |= NAND_BBT_SCANLASTPAGE;
-	else if ((!(chip->cellinfo & NAND_CI_CELLTYPE_MSK) &&
+	else if ((nand_is_slc(chip) &&
 				(maf_id == NAND_MFR_SAMSUNG ||
 				 maf_id == NAND_MFR_HYNIX ||
 				 maf_id == NAND_MFR_TOSHIBA ||
@@ -3745,8 +3744,7 @@ int nand_scan_tail(struct mtd_info *mtd)
 	chip->ecc.total = chip->ecc.steps * chip->ecc.bytes;
 
 	/* Allow subpage writes up to ecc.steps. Not possible for MLC flash */
-	if (!(chip->options & NAND_NO_SUBPAGE_WRITE) &&
-	    !(chip->cellinfo & NAND_CI_CELLTYPE_MSK)) {
+	if (!(chip->options & NAND_NO_SUBPAGE_WRITE) && nand_is_slc(chip)) {
 		switch (chip->ecc.steps) {
 		case 2:
 			mtd->subpage_sft = 1;

include/linux/mtd/nand.h

@@ -795,4 +795,13 @@ static inline int onfi_get_sync_timing_mode(struct nand_chip *chip)
 	return le16_to_cpu(chip->onfi_params.src_sync_timing_mode);
 }
 
+/*
+ * Check if it is a SLC nand.
+ * The !nand_is_slc() can be used to check the MLC/TLC nand chips.
+ * We do not distinguish the MLC and TLC now.
+ */
+static inline bool nand_is_slc(struct nand_chip *chip)
+{
+	return !(chip->cellinfo & NAND_CI_CELLTYPE_MSK);
+}
 #endif /* __LINUX_MTD_NAND_H */