[PATCH v4 09/25] mtd: spi-nor: winbond: Prepare introduction of W25QxxRV-Q/N parts

[Miquel Raynal]

There is an ID collision between the JV and RV families. Both chips are
very similar in practice, it is mostly a matter of electrical
differences (mostly power consumption being lower).

As a significant difference, RV chips identify themselves as supporting
the new SFDP (rev F) field which forces an alternate write SR2 opcode
(0x31). They also do not require the multi-die fixups which must remain
assigned to the JV chips.

Finally, since they share the IDs but not the names, we must hide the
names using a fixup.

Reviewed-by: Takahiro Kuwano <takahiro.kuwano at infineon.com>
Reviewed-by: Michael Walle <mwalle at kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
---
 drivers/mtd/spi-nor/sfdp.c    | 11 ++++++++
 drivers/mtd/spi-nor/sfdp.h    |  2 ++
 drivers/mtd/spi-nor/winbond.c | 60 ++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 70 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c
index c40099a27cb5..e35b19b6a5fa 100644
--- a/drivers/mtd/spi-nor/sfdp.c
+++ b/drivers/mtd/spi-nor/sfdp.c
@@ -1656,3 +1656,14 @@ int spi_nor_parse_sfdp(struct spi_nor *nor)
 	kfree(param_headers);
 	return err;
 }
+
+/**
+ * spi_nor_sfdp_get_header() - retrieves the SFDP header
+ * @nor: pointer to a 'struct spi_nor' with a valid SFDP field
+ *
+ * Return: the cached SFDP header.
+ */
+struct sfdp_header *spi_nor_sfdp_get_header(const struct spi_nor *nor)
+{
+	return (struct sfdp_header *)nor->sfdp->dwords;
+}
diff --git a/drivers/mtd/spi-nor/sfdp.h b/drivers/mtd/spi-nor/sfdp.h
index 2cbe22246c5e..1e49ed548a7e 100644
--- a/drivers/mtd/spi-nor/sfdp.h
+++ b/drivers/mtd/spi-nor/sfdp.h
@@ -160,4 +160,6 @@ struct sfdp_header {
 	struct sfdp_parameter_header	bfpt_header;
 };
 
+struct sfdp_header *spi_nor_sfdp_get_header(const struct spi_nor *nor);
+
 #endif /* __LINUX_MTD_SFDP_H */
diff --git a/drivers/mtd/spi-nor/winbond.c b/drivers/mtd/spi-nor/winbond.c
index 583b1669270f..9f164c5a1de5 100644
--- a/drivers/mtd/spi-nor/winbond.c
+++ b/drivers/mtd/spi-nor/winbond.c
@@ -24,6 +24,39 @@
 		   SPI_MEM_OP_NO_DUMMY,					\
 		   SPI_MEM_OP_DATA_OUT(1, buf, 0))
 
+static bool is_w25qxxrv(const struct spi_nor *nor)
+{
+	struct sfdp_header *sfdp_h = spi_nor_sfdp_get_header(nor);
+
+	/*
+	 * W25QxxRV chips re-use the same ID as the W25QxxJV family.
+	 *
+	 * Chips are very similar, W25QxxRV brings mostly performance and power
+	 * consumption improvements. The RV family does not require the multi
+	 * die fixup.
+	 *
+	 * They can be distinguished based on their SFDP minor revision:
+	 * W25QxxJV:        JESD216A, minor revision == 05h
+	 * W25Q512/01/02JV: JESD216B, minor revision == 06h
+	 * W25QxxRV:        JESD216F, minor revision >= 0Ah
+	 */
+	return sfdp_h->minor >= SFDP_JESD216F_MINOR;
+}
+
+/*
+ * Since SFDP is populated after ->default_init(), the match functions using
+ * nor->sfdp as discriminant cannot be used for this specific early fixup.
+ */
+static bool winbond_jv_match(const struct spi_nor *nor)
+{
+	return !nor->sfdp || !is_w25qxxrv(nor);
+}
+
+static bool winbond_rv_match(const struct spi_nor *nor)
+{
+	return nor->sfdp && is_w25qxxrv(nor);
+}
+
 static int
 w25q128_post_bfpt_fixups(struct spi_nor *nor,
 			 const struct sfdp_parameter_header *bfpt_header,
@@ -146,6 +179,22 @@ static const struct spi_nor_fixups winbond_nor_multi_die_fixups = {
 	.post_sfdp = winbond_nor_multi_die_post_sfdp_fixups,
 };
 
+static int winbond_nor_partname_post_sfdp_fixups(struct spi_nor *nor)
+{
+	/*
+	 * W25QxxRV parts re-use the JEDEC IDs of the JV family. Their name
+	 * being a legacy field, it is kept for the already established JV parts
+	 * but must not be exposed by the newer RV ones.
+	 */
+	nor->partname = NULL;
+
+	return 0;
+}
+
+static const struct spi_nor_fixups winbond_nor_partname_fixups = {
+	.post_sfdp = winbond_nor_partname_post_sfdp_fixups,
+};
+
 static const struct flash_info winbond_nor_parts[] = {
 	{
 		.id = SNOR_ID(0xef, 0x30, 0x10),
@@ -552,9 +601,14 @@ static const struct spi_nor_fixup winbond_fixups[] = {
 	{ .fixups = &winbond_nor_fixups },
 	{ .id = SNOR_ID(0xef, 0x40, 0x18), .fixups = &w25q128_fixups },
 	{ .id = SNOR_ID(0xef, 0x40, 0x19), .fixups = &w25q256_fixups },
-	{ .id = SNOR_ID(0xef, 0x40, 0x21), .fixups = &winbond_nor_multi_die_fixups },
-	{ .id = SNOR_ID(0xef, 0x70, 0x21), .fixups = &winbond_nor_multi_die_fixups },
-	{ .id = SNOR_ID(0xef, 0x70, 0x22), .fixups = &winbond_nor_multi_die_fixups },
+	{ .id = SNOR_ID(0xef, 0x40), .match = winbond_rv_match,
+	  .fixups = &winbond_nor_partname_fixups },
+	{ .id = SNOR_ID(0xef, 0x40, 0x21), .match = winbond_jv_match,
+	  .fixups = &winbond_nor_multi_die_fixups },
+	{ .id = SNOR_ID(0xef, 0x70, 0x21), .match = winbond_jv_match,
+	  .fixups = &winbond_nor_multi_die_fixups },
+	{ .id = SNOR_ID(0xef, 0x70, 0x22), .match = winbond_jv_match,
+	  .fixups = &winbond_nor_multi_die_fixups },
 };
 
 const struct spi_nor_manufacturer spi_nor_winbond = {

-- 
2.54.0