mtd: spi-nor: introduce SR_BP_SHIFT define

The shift variable of SR_BP is conclusive because the first bit of SR_BP
is fixed on all known flashes. Replace ffs operation with SR_BP_SHIFT.

Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 864ed6f..b5ef17b 100644 (file)
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -1767,7 +1767,6 @@ static void stm_get_locked_range(struct spi_nor *nor, u8 sr, loff_t *ofs,
        struct mtd_info *mtd = &nor->mtd;
        u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
        u8 tb_mask = SR_TB_BIT5;
-       int shift = ffs(mask) - 1;
        int pow;
 
        if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
@@ -1778,7 +1777,7 @@ static void stm_get_locked_range(struct spi_nor *nor, u8 sr, loff_t *ofs,
                *ofs = 0;
                *len = 0;
        } else {
-               pow = ((sr & mask) ^ mask) >> shift;
+               pow = ((sr & mask) ^ mask) >> SR_BP_SHIFT;
                *len = mtd->size >> pow;
                if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
                        *ofs = 0;
@@ -1860,7 +1859,7 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
        int ret, status_old, status_new;
        u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
        u8 tb_mask = SR_TB_BIT5;
-       u8 shift = ffs(mask) - 1, pow, val;
+       u8 pow, val;
        loff_t lock_len;
        bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
        bool use_top;
@@ -1909,7 +1908,7 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
         *   pow = ceil(log2(size / len)) = log2(size) - floor(log2(len))
         */
        pow = ilog2(mtd->size) - ilog2(lock_len);
-       val = mask - (pow << shift);
+       val = mask - (pow << SR_BP_SHIFT);
        if (val & ~mask)
                return -EINVAL;
        /* Don't "lock" with no region! */
@@ -1946,7 +1945,7 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
        int ret, status_old, status_new;
        u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
        u8 tb_mask = SR_TB_BIT5;
-       u8 shift = ffs(mask) - 1, pow, val;
+       u8 pow, val;
        loff_t lock_len;
        bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
        bool use_top;
@@ -1997,7 +1996,7 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
        if (lock_len == 0) {
                val = 0; /* fully unlocked */
        } else {
-               val = mask - (pow << shift);
+               val = mask - (pow << SR_BP_SHIFT);
                /* Some power-of-two sizes are not supported */
                if (val & ~mask)
                        return -EINVAL;

diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 5abd91c..61be6ed 100644 (file)
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -137,6 +137,8 @@
 
 #define SR1_QUAD_EN_BIT6       BIT(6)
 
+#define SR_BP_SHIFT            2
+
 /* Enhanced Volatile Configuration Register bits */
 #define EVCR_QUAD_EN_MICRON    BIT(7)  /* Micron Quad I/O */