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Subject[RFC PATCH 1/2] mtd: spi-nor: add 4bit block protection support
Date
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@samsung.com>
---
drivers/mtd/spi-nor/spi-nor.c | 61 ++++++++++++++++++++++++++++++-----
include/linux/mtd/spi-nor.h | 4 +++
2 files changed, 57 insertions(+), 8 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 1fdd2834fbcb..c261d8f7bef4 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -90,6 +90,7 @@ struct flash_info {
#define NO_CHIP_ERASE BIT(12) /* Chip does not support chip erase */
#define SPI_NOR_SKIP_SFDP BIT(13) /* Skip parsing of SFDP tables */
#define USE_CLSR BIT(14) /* use CLSR command */
+#define SPI_NOR_HAS_BP3 BIT(15) /* use 4 bits field for block protect */

int (*quad_enable)(struct spi_nor *nor);
};
@@ -898,18 +899,36 @@ static void stm_get_locked_range(struct spi_nor *nor, u8 sr, loff_t *ofs,
int shift = ffs(mask) - 1;
int pow;

+ if (nor->flags & SNOR_F_HAS_SR_BP3)
+ mask |= SR_BP3;
+
if (!(sr & mask)) {
/* No protection */
*ofs = 0;
*len = 0;
+ return;
+ }
+
+ if (nor->flags & SNOR_F_HAS_SR_BP3) {
+ u8 temp = sr & mask;
+
+ if (temp & SR_BP3)
+ temp = (temp & ~SR_BP3) | BIT(5);
+
+ pow = ilog2(nor->n_sectors) + 1 - (temp >> shift);
+ if (pow > 0)
+ *len = mtd->size >> pow;
+ else
+ *len = mtd->size;
} else {
pow = ((sr & mask) ^ mask) >> shift;
*len = mtd->size >> pow;
- if (nor->flags & SNOR_F_HAS_SR_TB && sr & SR_TB)
- *ofs = 0;
- else
- *ofs = mtd->size - *len;
}
+
+ if (nor->flags & SNOR_F_HAS_SR_TB && sr & SR_TB)
+ *ofs = 0;
+ else
+ *ofs = mtd->size - *len;
}

/*
@@ -989,6 +1008,9 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
bool use_top;

+ if (nor->flags & SNOR_F_HAS_SR_BP3)
+ mask |= SR_BP3;
+
status_old = read_sr(nor);
if (status_old < 0)
return status_old;
@@ -1028,7 +1050,16 @@ 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);
+
+ if (nor->flags & SNOR_F_HAS_SR_BP3) {
+ val = ilog2(nor->n_sectors) + 1 - pow;
+ val = val << shift;
+ if (val & BIT(5))
+ val = (val & ~BIT(5)) | SR_BP3;
+ } else {
+ val = mask - (pow << shift);
+ }
+
if (val & ~mask)
return -EINVAL;
/* Don't "lock" with no region! */
@@ -1069,6 +1100,9 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
bool use_top;

+ if (nor->flags & SNOR_F_HAS_SR_BP3)
+ mask |= SR_BP3;
+
status_old = read_sr(nor);
if (status_old < 0)
return status_old;
@@ -1110,13 +1144,19 @@ 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) + 1 - pow;
+ val = val << shift;
+ if (val & BIT(5))
+ val = (val & ~BIT(5)) | SR_BP3;
} else {
val = mask - (pow << 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 & ~SR_TB) | val;

/* Don't protect status register if we're fully unlocked */
@@ -2114,6 +2154,7 @@ 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];
@@ -3251,6 +3292,7 @@ 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 = info->sector_size * info->n_sectors;
params->page_size = info->page_size;

@@ -3793,12 +3835,15 @@ 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 7f0c7303575e..5b7391feb308 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -122,6 +122,7 @@
#define SR_BP1 BIT(3) /* Block protect 1 */
#define SR_BP2 BIT(4) /* Block protect 2 */
#define SR_TB BIT(5) /* Top/Bottom protect */
+#define SR_BP3 BIT(6) /* Block protect 3 */
#define SR_SRWD BIT(7) /* SR write protect */
/* Spansion/Cypress specific status bits */
#define SR_E_ERR BIT(5)
@@ -236,6 +237,7 @@ enum spi_nor_option_flags {
SNOR_F_READY_XSR_RDY = BIT(4),
SNOR_F_USE_CLSR = BIT(5),
SNOR_F_BROKEN_RESET = BIT(6),
+ SNOR_F_HAS_SR_BP3 = BIT(7),
};

/**
@@ -339,6 +341,7 @@ 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
@@ -375,6 +378,7 @@ 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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