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* [PATCH v2 1/3] mtd: spi-nor: introduce SR_BP_SHIFT define
@ 2020-01-13  5:37 Jungseung Lee
       [not found] ` <CGME20200113053757epcas1p343bae16b96761ee4ead6bdfc6712ad68@epcas1p3.samsung.com>
  0 siblings, 1 reply; 6+ messages in thread
From: Jungseung Lee @ 2020-01-13  5:37 UTC (permalink / raw)
  To: Tudor Ambarus, Vignesh Raghavendra, linux-mtd, js07.lee, js07.lee

The shift variable of SR_BP is conclusive because the first bit of SR_BP
is fixed on all known flashes.

Introduce SR_BP_SHIFT define and let them used by stm_* functions
to replace ffs operation to get shift value.

Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 11 +++++------
 include/linux/mtd/spi-nor.h   |  2 ++
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index addb6319fcbb..e3da6a8654a8 100644
--- 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 7e32adce72f7..541c06d042e8 100644
--- 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 */
 
-- 
2.17.1


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Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
     [not found] <CGME20200318120801epcas1p3845986eadf5f4aea47233f71e4e60508@epcas1p3.samsung.com>
2020-03-18 12:06 ` [PATCH v2 1/3] mtd: spi-nor: reimplement block protection handling Jungseung Lee
     [not found]   ` <CGME20200318120803epcas1p34570b795db84b2fd429b299a9ab317bd@epcas1p3.samsung.com>
2020-03-18 12:06     ` [PATCH v2 2/3] mtd: spi-nor: add 4bit block protection support Jungseung Lee
2020-03-21 20:47       ` Michael Walle
     [not found]   ` <CGME20200318120804epcas1p37b89db641c44ac84a778447bc6d7fbf2@epcas1p3.samsung.com>
2020-03-18 12:06     ` [PATCH v2 3/3] mtd: spi-nor: support lock/unlock for a few Micron chips Jungseung Lee
2020-03-21 20:48   ` [PATCH v2 1/3] mtd: spi-nor: reimplement block protection handling Michael Walle
2020-01-13  5:37 [PATCH v2 1/3] mtd: spi-nor: introduce SR_BP_SHIFT define Jungseung Lee
     [not found] ` <CGME20200113053757epcas1p343bae16b96761ee4ead6bdfc6712ad68@epcas1p3.samsung.com>
2020-01-13  5:37   ` [PATCH v2 3/3] mtd: spi-nor: support lock/unlock for a few Micron chips Jungseung Lee

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