enable the W#/Vpp signal to disable writing to the status
register on ST MICRON flashes like the N25Q128 thorugh
the new config option CONFIG_SYS_SPI_ST_ENABLE_WP_PIN
Signed-off-by: Heiko Schocher <h...@denx.de>
Cc: Jagannadha Sutradharudu Teki <jagannadh.t...@gmail.com>
---
- changes for v4:
none
README | 11 +++++++++++
drivers/mtd/spi/sf_internal.h | 4 ++++
drivers/mtd/spi/sf_probe.c | 30 ++++++++++++++++++++++++++++++
3 files changed, 45 insertions(+)
diff --git a/README b/README
index 9f07831..63617ce 100644
--- a/README
+++ b/README
@@ -2937,6 +2937,17 @@ CBFS (Coreboot Filesystem) support
CONFIG_SPI_FLASH_MTD
add MTD translation layer driver.
+ CONFIG_SYS_SPI_ST_ENABLE_WP_PIN
+ enable the W#/Vpp signal to disable writing to the status
+ register on ST MICRON flashes like the N25Q128.
+ The status register write enable/disable bit, combined with
+ the W#/VPP signal provides hardware data protection for the
+ device as follows: When the enable/disable bit is set to 1,
+ and the W#/VPP signal is driven LOW, the status register
+ nonvolatile bits become read-only and the WRITE STATUS REGISTER
+ operation will not execute. The only way to exit this
+ hardware-protected mode is to drive W#/VPP HIGH.
+
- SystemACE Support:
CONFIG_SYSTEMACE
diff --git a/drivers/mtd/spi/sf_internal.h b/drivers/mtd/spi/sf_internal.h
index 5c66d9f..a9f97d1 100644
--- a/drivers/mtd/spi/sf_internal.h
+++ b/drivers/mtd/spi/sf_internal.h
@@ -60,6 +60,10 @@
#define STATUS_QEB_MXIC (1 << 6)
#define STATUS_PEC (1 << 7)
+#ifdef CONFIG_SYS_SPI_ST_ENABLE_WP_PIN
+#define STATUS_SRWD (1 << 7) /* SR write protect */
+#endif
+
/* Flash timeout values */
#define SPI_FLASH_PROG_TIMEOUT (2 * CONFIG_SYS_HZ)
#define SPI_FLASH_PAGE_ERASE_TIMEOUT (5 * CONFIG_SYS_HZ)
diff --git a/drivers/mtd/spi/sf_probe.c b/drivers/mtd/spi/sf_probe.c
index f6d793b..6c50766 100644
--- a/drivers/mtd/spi/sf_probe.c
+++ b/drivers/mtd/spi/sf_probe.c
@@ -281,6 +281,34 @@ int spi_flash_decode_fdt(const void *blob, struct
spi_flash *flash)
}
#endif /* CONFIG_OF_CONTROL */
+#ifdef CONFIG_SYS_SPI_ST_ENABLE_WP_PIN
+/* enable the W#/Vpp signal to disable writing to the status register */
+static int spi_enable_wp_pin(struct spi_flash *flash)
+{
+ u8 status;
+ int ret;
+
+ ret = spi_flash_cmd_read_status(flash, &status);
+ if (ret < 0)
+ return ret;
+
+ ret = spi_flash_cmd_write_status(flash, STATUS_SRWD);
+ if (ret < 0)
+ return ret;
+
+ ret = spi_flash_cmd_write_disable(flash);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+#else
+static int spi_enable_wp_pin(struct spi_flash *flash)
+{
+ return 0;
+}
+#endif
+
static struct spi_flash *spi_flash_probe_slave(struct spi_slave *spi)
{
struct spi_flash *flash = NULL;
@@ -351,6 +379,8 @@ static struct spi_flash *spi_flash_probe_slave(struct
spi_slave *spi)
puts(" Full access #define CONFIG_SPI_FLASH_BAR\n");
}
#endif
+ if (spi_enable_wp_pin(flash))
+ puts("Enable WP pin failed\n");
/* Release spi bus */
spi_release_bus(spi);
--
1.8.3.1
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