mtd: spi-nor: use 16-bit WRR command when QE is set on spansion flashes

SPI memory devices from different manufacturers have widely
different configurations for Status, Control and Configuration
registers. JEDEC 216C defines a new map for these common register
bits and their functions, and describes how the individual bits may
be accessed for a specific device. For the JEDEC 216B compliant
flashes, we can partially deduce Status and Configuration registers
functions by inspecting the 16th DWORD of BFPT. Older flashes that
don't declare the SFDP tables (SPANSION FL512SAIFG1 311QQ063 A ©11
SPANSION) let the software decide how to interact with these registers.

The commit dcb4b22eeaf4 ("spi-nor: s25fl512s supports region locking")
uncovered a probe error for s25fl512s, when the Quad Enable bit CR[1]
was set to one in the bootloader. When this bit is one, only the Write
Status (01h) command with two data byts may be used, the 01h command with
one data byte is not recognized and hence the error when trying to clear
the block protection bits.

Fix the above by using the Write Status (01h) command with two data bytes
when the Quad Enable bit is one.

Backward compatibility should be fine. The newly introduced
spi_nor_spansion_clear_sr_bp() is tightly coupled with the
spansion_quad_enable() function. Both assume that the Write Register
with 16 bits, together with the Read Configuration Register (35h)
instructions are supported.

Fixes: dcb4b22eeaf44f91 ("spi-nor: s25fl512s supports region locking")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Tested-by: Jonas Bonn <jonas@norrbonn.se>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>
Tested-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index b3d360b0ee3d..9f57cdfcc93d 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -373,6 +373,8 @@ struct flash_info;
  * @flash_unlock:	[FLASH-SPECIFIC] unlock a region of the SPI NOR
  * @flash_is_locked:	[FLASH-SPECIFIC] check if a region of the SPI NOR is
  * @quad_enable:	[FLASH-SPECIFIC] enables SPI NOR quad mode
+ * @clear_sr_bp:	[FLASH-SPECIFIC] clears the Block Protection Bits from
+ *			the SPI NOR Status Register.
  *			completely locked
  * @priv:		the private data
  */
@@ -410,6 +412,7 @@ struct spi_nor {
 	int (*flash_unlock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
 	int (*flash_is_locked)(struct spi_nor *nor, loff_t ofs, uint64_t len);
 	int (*quad_enable)(struct spi_nor *nor);
+	int (*clear_sr_bp)(struct spi_nor *nor);
 
 	void *priv;
 };