[PATCH v4 4/5] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee <js07.lee@xxxxxxxxxxx>]

Currently, we are supporting block protection only for
flash chips with 3 block protection bits in the SR register.
This patch enables block protection support for some flash with
4 block protection bits(bp0-3).

Because this feature is not universal to all flash that support
lock/unlock, control it via a new flag.

Signed-off-by: Jungseung Lee <js07.lee@xxxxxxxxxxx>
---
 drivers/mtd/spi-nor/spi-nor.c | 107 ++++++++++++++++++++++++++--------
 include/linux/mtd/spi-nor.h   |   5 ++
 2 files changed, 88 insertions(+), 24 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 6d9c63ab6e51..0fee22068d94 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -96,6 +96,7 @@ enum spi_nor_pp_command_index {
 struct spi_nor_flash_parameter {
 	u64				size;
 	u32				page_size;
+	u16				n_sectors;
 
 	struct spi_nor_hwcaps		hwcaps;
 	struct spi_nor_read_command	reads[SNOR_CMD_READ_MAX];
@@ -250,7 +251,7 @@ struct flash_info {
 	u16		page_size;
 	u16		addr_width;
 
-	u16		flags;
+	u32		flags;
 #define SECT_4K			BIT(0)	/* SPINOR_OP_BE_4K works uniformly */
 #define SPI_NOR_NO_ERASE	BIT(1)	/* No erase command needed */
 #define SST_WRITE		BIT(2)	/* use SST byte programming */
@@ -279,6 +280,7 @@ struct flash_info {
 #define SPI_NOR_SKIP_SFDP	BIT(13)	/* Skip parsing of SFDP tables */
 #define USE_CLSR		BIT(14)	/* use CLSR command */
 #define SPI_NOR_OCTAL_READ	BIT(15)	/* Flash supports Octal Read */
+#define SPI_NOR_HAS_BP3		BIT(16)	/* use 4 bits filed for block protect */
 
 	/* Part specific fixup hooks. */
 	const struct spi_nor_fixups *fixups;
@@ -1088,26 +1090,49 @@ static void stm_get_locked_range(struct spi_nor *nor, u8 sr, loff_t *ofs,
 				 uint64_t *len)
 {
 	struct mtd_info *mtd = &nor->mtd;
-	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
-	u8 mask_tb = SR_TB_BIT5;
-	int pow;
+	u8 mask_tb = SR_TB_BIT5, mask_bp3 = SR_BP3_BIT6;
+	u8 sr_masked, mask, tmp;
+	int pow = 0;
 
 	if (JEDEC_MFR(nor->info) == SNOR_MFR_WINBOND ||
-	    JEDEC_MFR(nor->info) == SNOR_MFR_GIGADEVICE)
+	    JEDEC_MFR(nor->info) == SNOR_MFR_GIGADEVICE) {
 		mask_tb = SR_TB_BIT6;
+		mask_bp3 = SR_BP3_BIT5;
+	}
+
+	if (nor->flags & SNOR_F_HAS_SR_BP3)
+		mask = mask_bp3 | SR_BP2 | SR_BP1 | SR_BP0;
+	else
+		mask = SR_BP2 | SR_BP1 | SR_BP0;
+
+	sr_masked = sr & mask;
 
-	if (!(sr & mask)) {
+	if (!sr_masked) {
 		/* No protection */
 		*ofs = 0;
 		*len = 0;
-	} else {
-		pow = ((sr & mask) ^ mask) >> SR_BP_SHIFT;
-		*len = mtd->size >> pow;
-		if (nor->flags & SNOR_F_HAS_SR_TB && sr & mask_tb)
-			*ofs = 0;
+		return;
+	}
+
+	if (nor->flags & SNOR_F_HAS_SR_BP3) {
+		if (sr_masked & mask_bp3 && mask_bp3 == SR_BP3_BIT6)
+			tmp = (sr_masked & ~SR_BP3_BIT6) | BIT(5);
 		else
-			*ofs = mtd->size - *len;
+			tmp = sr_masked;
+
+		tmp >>= SR_BP_SHIFT;
+
+		if (ilog2(nor->n_sectors) >= tmp)
+			pow = ilog2(nor->n_sectors) - tmp + 1;
+	} else {
+		pow = (sr_masked ^ mask) >> SR_BP_SHIFT;
 	}
+
+	*len = mtd->size >> pow;
+	if (nor->flags & SNOR_F_HAS_SR_TB && sr & mask_tb)
+		*ofs = 0;
+	else
+		*ofs = mtd->size - *len;
 }
 
 /*
@@ -1181,9 +1206,8 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 {
 	struct mtd_info *mtd = &nor->mtd;
 	int status_old, status_new;
-	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
-	u8 mask_tb = SR_TB_BIT5;
-	u8 pow, val;
+	u8 mask_tb = SR_TB_BIT5, mask_bp3 = SR_BP3_BIT6;
+	u8 mask, pow, val;
 	loff_t lock_len;
 	bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
 	bool use_top;
@@ -1218,8 +1242,15 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 		lock_len = ofs + len;
 
 	if (JEDEC_MFR(nor->info) == SNOR_MFR_WINBOND ||
-	    JEDEC_MFR(nor->info) == SNOR_MFR_GIGADEVICE)
+	    JEDEC_MFR(nor->info) == SNOR_MFR_GIGADEVICE) {
 		mask_tb = SR_TB_BIT6;
+		mask_bp3 = SR_BP3_BIT5;
+	}
+
+	if (nor->flags & SNOR_F_HAS_SR_BP3)
+		mask = mask_bp3 | SR_BP2 | SR_BP1 | SR_BP0;
+	else
+		mask = SR_BP2 | SR_BP1 | SR_BP0;
 
 	/*
 	 * Need smallest pow such that:
@@ -1231,7 +1262,17 @@ 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 << SR_BP_SHIFT);
+
+	if (nor->flags & SNOR_F_HAS_SR_BP3) {
+		val = ilog2(nor->n_sectors) - pow + 1;
+		val = val << SR_BP_SHIFT;
+
+		if (val & BIT(5) && mask_bp3 == SR_BP3_BIT6)
+			val = (val & ~BIT(5)) | SR_BP3_BIT6;
+	} else {
+		val = mask - (pow << SR_BP_SHIFT);
+	}
+
 	if (val & ~mask)
 		return -EINVAL;
 	/* Don't "lock" with no region! */
@@ -1266,9 +1307,8 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 {
 	struct mtd_info *mtd = &nor->mtd;
 	int status_old, status_new;
-	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
-	u8 mask_tb = SR_TB_BIT5;
-	u8 pow, val;
+	u8 mask_tb = SR_TB_BIT5, mask_bp3 = SR_BP3_BIT6;
+	u8 mask, pow, val;
 	loff_t lock_len;
 	bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
 	bool use_top;
@@ -1303,8 +1343,16 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 		lock_len = ofs;
 
 	if (JEDEC_MFR(nor->info) == SNOR_MFR_WINBOND ||
-	    JEDEC_MFR(nor->info) == SNOR_MFR_GIGADEVICE)
+	    JEDEC_MFR(nor->info) == SNOR_MFR_GIGADEVICE) {
 		mask_tb = SR_TB_BIT6;
+		mask_bp3 = SR_BP3_BIT5;
+	}
+
+	if (nor->flags & SNOR_F_HAS_SR_BP3)
+		mask = mask_bp3 | SR_BP2 | SR_BP1 | SR_BP0;
+	else
+		mask = SR_BP2 | SR_BP1 | SR_BP0;
+
 	/*
 	 * Need largest pow such that:
 	 *
@@ -1317,13 +1365,20 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 	pow = ilog2(mtd->size) - order_base_2(lock_len);
 	if (lock_len == 0) {
 		val = 0; /* fully unlocked */
+	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
+		val = ilog2(nor->n_sectors) - pow + 1;
+		val = val << SR_BP_SHIFT;
+
+		if (val & BIT(5) && mask_bp3 == SR_BP3_BIT6)
+			val = (val & ~BIT(5)) | SR_BP3_BIT6;
 	} else {
 		val = mask - (pow << SR_BP_SHIFT);
-		/* Some power-of-two sizes are not supported */
-		if (val & ~mask)
-			return -EINVAL;
 	}
 
+	/* Some power-of-two sizes are not supported */
+	if (val & ~mask)
+		return -EINVAL;
+
 	status_new = (status_old & ~mask & ~mask_tb) | val;
 
 	/* Don't protect status register if we're fully unlocked */
@@ -3714,6 +3769,7 @@ static int spi_nor_init_params(struct spi_nor *nor,
 	memset(params, 0, sizeof(*params));
 
 	/* Set SPI NOR sizes. */
+	params->n_sectors = info->n_sectors;
 	params->size = (u64)info->sector_size * info->n_sectors;
 	params->page_size = info->page_size;
 
@@ -4233,12 +4289,15 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
 		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
 	if (info->flags & USE_CLSR)
 		nor->flags |= SNOR_F_USE_CLSR;
+	if (info->flags & SPI_NOR_HAS_BP3)
+		nor->flags |= SNOR_F_HAS_SR_BP3;
 
 	if (info->flags & SPI_NOR_NO_ERASE)
 		mtd->flags |= MTD_NO_ERASE;
 
 	mtd->dev.parent = dev;
 	nor->page_size = params.page_size;
+	nor->n_sectors = params.n_sectors;
 	mtd->writebufsize = nor->page_size;
 
 	if (np) {
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 97f0c3a05f86..243c522dbaa2 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -127,7 +127,9 @@
 #define SR_BP1			BIT(3)	/* Block protect 1 */
 #define SR_BP2			BIT(4)	/* Block protect 2 */
 #define SR_TB_BIT5		BIT(5)	/* Top/Bottom protect */
+#define SR_BP3_BIT5		BIT(5)	/* Block protect 3 (on Winbond/GigaDevice)*/
 #define SR_TB_BIT6		BIT(6)	/* Top/Bottom protect (on Winbond/GigaDevice) */
+#define SR_BP3_BIT6		BIT(6)	/* Block protect 3 */
 #define SR_SRWD			BIT(7)	/* SR write protect */
 /* Spansion/Cypress specific status bits */
 #define SR_E_ERR		BIT(5)
@@ -246,6 +248,7 @@ enum spi_nor_option_flags {
 	SNOR_F_BROKEN_RESET	= BIT(6),
 	SNOR_F_4B_OPCODES	= BIT(7),
 	SNOR_F_HAS_4BAIT	= BIT(8),
+	SNOR_F_HAS_SR_BP3	= BIT(9),
 };
 
 /**
@@ -349,6 +352,7 @@ struct flash_info;
  * @dev:		point to a spi device, or a spi nor controller device.
  * @info:		spi-nor part JDEC MFR id and other info
  * @page_size:		the page size of the SPI NOR
+ * @n_sectors:		number of sector
  * @addr_width:		number of address bytes
  * @erase_opcode:	the opcode for erasing a sector
  * @read_opcode:	the read opcode
@@ -387,6 +391,7 @@ struct spi_nor {
 	struct device		*dev;
 	const struct flash_info	*info;
 	u32			page_size;
+	u16			n_sectors;
 	u8			addr_width;
 	u8			erase_opcode;
 	u8			read_opcode;
-- 
2.17.1


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