[PATCH 1/2] mtd: spi-nor-core: allow overriding 4-byte OPCODE support

[Robert Marko]

Currently, the only way to indicate 4-byte OPCODE support is by setting
the SPI_NOR_4B_OPCODES feature flag for each JEDEC ID in spi_nor_ids[].

However, its becoming increasingly common practice for vendors to reuse
the same JEDEC ID for new revisions of current parts.
For example Winbond W25Q256FV does not fully support 4-byte OPCODE-s while
newer W25Q256JV revision does fully support them but they share the same
JEDEC ID thus currently its not possible to advertise support for 4-byte
OPCODE-s on W25Q256JV.

Luckily for us, there usually is a way to differentiate between parts with
the same JEDEC ID by differences in SFDP tables, so in order to be able to
apply a fixup after they are parsed lets add a feature flag that we can
override.

Signed-off-by: Robert Marko <robert.marko at sartura.hr>
---
 drivers/mtd/spi/spi-nor-core.c | 6 ++++--
 include/linux/mtd/spi-nor.h    | 1 +
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index f86003ca8c..7615ba602f 100644
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -3879,7 +3879,7 @@ static int spi_nor_init(struct spi_nor *nor)
 	if (nor->addr_width == 4 &&
 	    !(nor->info->flags & SPI_NOR_OCTAL_DTR_READ) &&
 	    (JEDEC_MFR(nor->info) != SNOR_MFR_SPANSION) &&
-	    !(nor->info->flags & SPI_NOR_4B_OPCODES)) {
+	    !(nor->flags & SNOR_F_4B_OPCODES)) {
 		/*
 		 * If the RESET# pin isn't hooked up properly, or the system
 		 * otherwise doesn't perform a reset command in the boot
@@ -4118,6 +4118,8 @@ int spi_nor_scan(struct spi_nor *nor)
 		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
 	if (info->flags & USE_CLSR)
 		nor->flags |= SNOR_F_USE_CLSR;
+	if (info->flags & SPI_NOR_4B_OPCODES)
+		nor->flags |= SNOR_F_4B_OPCODES;
 
 	if (info->flags & SPI_NOR_NO_ERASE)
 		mtd->flags |= MTD_NO_ERASE;
@@ -4156,7 +4158,7 @@ int spi_nor_scan(struct spi_nor *nor)
 		/* enable 4-byte addressing if the device exceeds 16MiB */
 		nor->addr_width = 4;
 		if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
-		    info->flags & SPI_NOR_4B_OPCODES)
+		    nor->flags & SNOR_F_4B_OPCODES)
 			spi_nor_set_4byte_opcodes(nor, info);
 #else
 	/* Configure the BAR - discover bank cmds and read current bank */
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index d1dbf3eadb..80e56cf308 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -294,6 +294,7 @@ enum spi_nor_option_flags {
 	SNOR_F_BROKEN_RESET	= BIT(6),
 	SNOR_F_SOFT_RESET	= BIT(7),
 	SNOR_F_IO_MODE_EN_VOLATILE = BIT(8),
+	SNOR_F_4B_OPCODES 	= BIT(9),
 };
 
 struct spi_nor;
-- 
2.44.0