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-rw-r--r--drivers/mtd/spi-nor/spi-nor.c70
-rw-r--r--include/linux/mtd/spi-nor.h2
2 files changed, 65 insertions, 7 deletions
diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index d1edafc51cbb..2aebf18f7c36 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -70,6 +70,11 @@ struct flash_info {
#define SPI_NOR_QUAD_READ BIT(6) /* Flash supports Quad Read */
#define USE_FSR BIT(7) /* use flag status register */
#define SPI_NOR_HAS_LOCK BIT(8) /* Flash supports lock/unlock via SR */
+#define SPI_NOR_HAS_TB BIT(9) /*
+ * Flash SR has Top/Bottom (TB) protect
+ * bit. Must be used with
+ * SPI_NOR_HAS_LOCK.
+ */
};
#define JEDEC_MFR(info) ((info)->id[0])
@@ -435,7 +440,10 @@ static void stm_get_locked_range(struct spi_nor *nor, u8 sr, loff_t *ofs,
} else {
pow = ((sr & mask) ^ mask) >> shift;
*len = mtd->size >> pow;
- *ofs = mtd->size - *len;
+ if (nor->flags & SNOR_F_HAS_SR_TB && sr & SR_TB)
+ *ofs = 0;
+ else
+ *ofs = mtd->size - *len;
}
}
@@ -476,12 +484,14 @@ static int stm_is_unlocked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
/*
* Lock a region of the flash. Compatible with ST Micro and similar flash.
- * Supports only the block protection bits BP{0,1,2} in the status register
+ * Supports the block protection bits BP{0,1,2} in the status register
* (SR). Does not support these features found in newer SR bitfields:
- * - TB: top/bottom protect - only handle TB=0 (top protect)
* - SEC: sector/block protect - only handle SEC=0 (block protect)
* - CMP: complement protect - only support CMP=0 (range is not complemented)
*
+ * Support for the following is provided conditionally for some flash:
+ * - TB: top/bottom protect
+ *
* Sample table portion for 8MB flash (Winbond w25q64fw):
*
* SEC | TB | BP2 | BP1 | BP0 | Prot Length | Protected Portion
@@ -494,6 +504,13 @@ static int stm_is_unlocked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
* 0 | 0 | 1 | 0 | 1 | 2 MB | Upper 1/4
* 0 | 0 | 1 | 1 | 0 | 4 MB | Upper 1/2
* X | X | 1 | 1 | 1 | 8 MB | ALL
+ * ------|-------|-------|-------|-------|---------------|-------------------
+ * 0 | 1 | 0 | 0 | 1 | 128 KB | Lower 1/64
+ * 0 | 1 | 0 | 1 | 0 | 256 KB | Lower 1/32
+ * 0 | 1 | 0 | 1 | 1 | 512 KB | Lower 1/16
+ * 0 | 1 | 1 | 0 | 0 | 1 MB | Lower 1/8
+ * 0 | 1 | 1 | 0 | 1 | 2 MB | Lower 1/4
+ * 0 | 1 | 1 | 1 | 0 | 4 MB | Lower 1/2
*
* Returns negative on errors, 0 on success.
*/
@@ -504,6 +521,8 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
u8 shift = ffs(mask) - 1, pow, val;
loff_t lock_len;
+ bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
+ bool use_top;
int ret;
status_old = read_sr(nor);
@@ -514,13 +533,26 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
if (stm_is_locked_sr(nor, ofs, len, status_old))
return 0;
+ /* If anything below us is unlocked, we can't use 'bottom' protection */
+ if (!stm_is_locked_sr(nor, 0, ofs, status_old))
+ can_be_bottom = false;
+
/* If anything above us is unlocked, we can't use 'top' protection */
if (!stm_is_locked_sr(nor, ofs + len, mtd->size - (ofs + len),
status_old))
+ can_be_top = false;
+
+ if (!can_be_bottom && !can_be_top)
return -EINVAL;
+ /* Prefer top, if both are valid */
+ use_top = can_be_top;
+
/* lock_len: length of region that should end up locked */
- lock_len = mtd->size - ofs;
+ if (use_top)
+ lock_len = mtd->size - ofs;
+ else
+ lock_len = ofs + len;
/*
* Need smallest pow such that:
@@ -539,11 +571,14 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
if (!(val & mask))
return -EINVAL;
- status_new = (status_old & ~mask) | val;
+ status_new = (status_old & ~mask & ~SR_TB) | val;
/* Disallow further writes if WP pin is asserted */
status_new |= SR_SRWD;
+ if (!use_top)
+ status_new |= SR_TB;
+
/* Don't bother if they're the same */
if (status_new == status_old)
return 0;
@@ -571,6 +606,8 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
u8 shift = ffs(mask) - 1, pow, val;
loff_t lock_len;
+ bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
+ bool use_top;
int ret;
status_old = read_sr(nor);
@@ -583,10 +620,24 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
/* If anything below us is locked, we can't use 'top' protection */
if (!stm_is_unlocked_sr(nor, 0, ofs, status_old))
+ can_be_top = false;
+
+ /* If anything above us is locked, we can't use 'bottom' protection */
+ if (!stm_is_unlocked_sr(nor, ofs + len, mtd->size - (ofs + len),
+ status_old))
+ can_be_bottom = false;
+
+ if (!can_be_bottom && !can_be_top)
return -EINVAL;
+ /* Prefer top, if both are valid */
+ use_top = can_be_top;
+
/* lock_len: length of region that should remain locked */
- lock_len = mtd->size - (ofs + len);
+ if (use_top)
+ lock_len = mtd->size - (ofs + len);
+ else
+ lock_len = ofs;
/*
* Need largest pow such that:
@@ -607,12 +658,15 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
return -EINVAL;
}
- status_new = (status_old & ~mask) | val;
+ status_new = (status_old & ~mask & ~SR_TB) | val;
/* Don't protect status register if we're fully unlocked */
if (lock_len == mtd->size)
status_new &= ~SR_SRWD;
+ if (!use_top)
+ status_new |= SR_TB;
+
/* Don't bother if they're the same */
if (status_new == status_old)
return 0;
@@ -1277,6 +1331,8 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
if (info->flags & USE_FSR)
nor->flags |= SNOR_F_USE_FSR;
+ if (info->flags & SPI_NOR_HAS_TB)
+ nor->flags |= SNOR_F_HAS_SR_TB;
#ifdef CONFIG_MTD_SPI_NOR_USE_4K_SECTORS
/* prefer "small sector" erase if possible */
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 62356d50815b..3c36113a88e1 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -85,6 +85,7 @@
#define SR_BP0 BIT(2) /* Block protect 0 */
#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_SRWD BIT(7) /* SR write protect */
#define SR_QUAD_EN_MX BIT(6) /* Macronix Quad I/O */
@@ -116,6 +117,7 @@ enum spi_nor_ops {
enum spi_nor_option_flags {
SNOR_F_USE_FSR = BIT(0),
+ SNOR_F_HAS_SR_TB = BIT(1),
};
/**