[PATCH v2 0/3] mtd: spi-nor: add Global Block Unlock support

[PATCH v2 0/3] mtd: spi-nor: add Global Block Unlock support

[Tudor Ambarus]

To avoid inadvertent writes during power-up, SST26 flash memories are
write-protected by default after a power-on reset cycle. Unlock the serial
flash memory by using the Global Block Protection Unlock command - it offers
a single command cycle that unlocks the entire memory array.

v2:
- add Cyrille's reviewed-by tag
- add cover letter
- fix link to initial work done by Anurag Kumar Vulisha

Tudor Ambarus (3):
  mtd: spi-nor: add Global Block Unlock support
  mtd: spi-nor: unlock global block protection on sst26vf064b
  mtd: spi-nor: add support for Microchip SST26 QSPI flash memories

 drivers/mtd/spi-nor/spi-nor.c | 47 ++++++++++++++++++++++++++++++++++++++++++-
 include/linux/mtd/spi-nor.h   |  1 +
 2 files changed, 47 insertions(+), 1 deletion(-)

-- 
2.9.4

[PATCH v2 1/3] mtd: spi-nor: add Global Block Unlock support

[Tudor Ambarus]

We can't determine this purely by manufacturer type and it's not
autodetectable by anything like SFDP, so make a new flag for it:
UNLOCK_GLOBAL_BLOCK.

Note that the Global Block Unlock command has different names
depending on the manufacturer, but always the same command value:
0x98. Macronix's MX25U12835F names it Gang Block Unlock,
Winbound's W25Q128FV names it Global Block Unlock and
Microchip's SST26VF064B names it Global Block Protection Unlock.

Based on initial work done by Anurag Kumar Vulisha:
https://lkml.org/lkml/2015/11/13/307

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Cyrille Pitchen <cyrille.pitchen@microchip.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 21 +++++++++++++++++++++
 include/linux/mtd/spi-nor.h   |  1 +
 2 files changed, 22 insertions(+)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index f028277..d3134fd 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -89,6 +89,7 @@ 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 UNLOCK_GLOBAL_BLOCK	BIT(15)	/* Unlock global block protection */
 
 	int	(*quad_enable)(struct spi_nor *nor);
 };
@@ -2730,6 +2731,17 @@ static int spi_nor_setup(struct spi_nor *nor, const struct flash_info *info,
 	return 0;
 }
 
+static int spi_nor_unlock_global_block_protection(struct spi_nor *nor)
+{
+	int ret;
+
+	write_enable(nor);
+	ret = nor->write_reg(nor, SPINOR_OP_GBULK, NULL, 0);
+	if (ret < 0)
+		return ret;
+	return spi_nor_wait_till_ready(nor);
+}
+
 static int spi_nor_init(struct spi_nor *nor)
 {
 	int err;
@@ -2747,6 +2759,15 @@ static int spi_nor_init(struct spi_nor *nor)
 		spi_nor_wait_till_ready(nor);
 	}
 
+	if (nor->info->flags & UNLOCK_GLOBAL_BLOCK) {
+		err = spi_nor_unlock_global_block_protection(nor);
+		if (err) {
+			dev_err(nor->dev,
+				"Cannot unlock the global block protection\n");
+			return err;
+		}
+	}
+
 	if (nor->quad_enable) {
 		err = nor->quad_enable(nor);
 		if (err) {
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index c922e97..09a10fd 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -64,6 +64,7 @@
 #define SPINOR_OP_CLFSR		0x50	/* Clear flag status register */
 #define SPINOR_OP_RDEAR		0xc8	/* Read Extended Address Register */
 #define SPINOR_OP_WREAR		0xc5	/* Write Extended Address Register */
+#define SPINOR_OP_GBULK		0x98	/* Global Block Unlock Protection */
 
 /* 4-byte address opcodes - used on Spansion and some Macronix flashes. */
 #define SPINOR_OP_READ_4B	0x13	/* Read data bytes (low frequency) */
-- 
2.9.4

[PATCH v2 2/3] mtd: spi-nor: unlock global block protection on sst26vf064b

[Tudor Ambarus]

To avoid inadvertent writes during power-up, sst26vf064b is
write-protected by default after a power-on reset cycle.
Unlock the serial flash memory by using the Global Block Protection
Unlock command - it offers a single command cycle that unlocks
the entire memory array.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index d3134fd..ba0fd8b 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -1163,7 +1163,11 @@ static const struct flash_info spi_nor_ids[] = {
 	{ "sst25wf040b", INFO(0x621613, 0, 64 * 1024,  8, SECT_4K) },
 	{ "sst25wf040",  INFO(0xbf2504, 0, 64 * 1024,  8, SECT_4K | SST_WRITE) },
 	{ "sst25wf080",  INFO(0xbf2505, 0, 64 * 1024, 16, SECT_4K | SST_WRITE) },
-	{ "sst26vf064b", INFO(0xbf2643, 0, 64 * 1024, 128, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
+	{
+		"sst26vf064b", INFO(0xbf2643, 0, 64 * 1024, 128,
+			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
+			UNLOCK_GLOBAL_BLOCK)
+	},
 
 	/* ST Microelectronics -- newer production may have feature updates */
 	{ "m25p05",  INFO(0x202010,  0,  32 * 1024,   2, 0) },
-- 
2.9.4

[PATCH v2 3/3] mtd: spi-nor: add support for Microchip SST26 QSPI flash memories

[Tudor Ambarus]

The flash memories are write-protected by default at power-on and
must be unlocked first, before being erased, then programmed.

The erase block sizes are not uniform. The memory layout is uniform
just for the 4K sector blocks.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index ba0fd8b..dc8757e 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -1164,10 +1164,30 @@ static const struct flash_info spi_nor_ids[] = {
 	{ "sst25wf040",  INFO(0xbf2504, 0, 64 * 1024,  8, SECT_4K | SST_WRITE) },
 	{ "sst25wf080",  INFO(0xbf2505, 0, 64 * 1024, 16, SECT_4K | SST_WRITE) },
 	{
+		"sst26vf016b", INFO(0xbf2641, 0, 64 * 1024, 32,
+			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
+			UNLOCK_GLOBAL_BLOCK)
+	},
+	{
+		"sst26vf032b", INFO(0xbf2642, 0, 64 * 1024, 64,
+			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
+			UNLOCK_GLOBAL_BLOCK)
+	},
+	{
 		"sst26vf064b", INFO(0xbf2643, 0, 64 * 1024, 128,
 			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
 			UNLOCK_GLOBAL_BLOCK)
 	},
+	{
+		"sst26vf040b", INFO(0xbf2654, 0, 64 * 1024, 8,
+			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
+			UNLOCK_GLOBAL_BLOCK)
+	},
+	{
+		"sst26vf080b", INFO(0xbf2658, 0, 64 * 1024, 16,
+			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
+			UNLOCK_GLOBAL_BLOCK)
+	},
 
 	/* ST Microelectronics -- newer production may have feature updates */
 	{ "m25p05",  INFO(0x202010,  0,  32 * 1024,   2, 0) },
-- 
2.9.4