[PATCH v7 4/7] mtd: spi-nor: sfdp: Get the 8D-8D-8D byte order from BFPT

[Jaime Liao]

From: JaimeLiao <jaimeliao at mxic.com.tw>

Parse BFPT in order to retrieve the byte order in 8D-8D-8D mode.

This info flag will be used as a basis to determine whether
there is byte swapping of data for SPI NOR flash in octal
DTR mode.

The controller driver will check whether byte swapping is supported
to determin whether the corresponding operation are supported, thus
avoiding the generation of unexpected data order.

Signed-off-by: Tudor Ambarus <tudor.ambarus at linaro.org>
Signed-off-by: JaimeLiao <jaimeliao at mxic.com.tw>
---
 drivers/mtd/spi-nor/sfdp.c | 4 ++++
 drivers/mtd/spi-nor/sfdp.h | 1 +
 2 files changed, 5 insertions(+)

diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c
index b3b11dfed789..2241207556bf 100644
--- a/drivers/mtd/spi-nor/sfdp.c
+++ b/drivers/mtd/spi-nor/sfdp.c
@@ -650,6 +650,10 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
 		return -EOPNOTSUPP;
 	}
 
+	/* Byte order in 8D-8D-8D mode */
+	if (bfpt.dwords[SFDP_DWORD(18)] & BFPT_DWORD18_BYTE_ORDER_SWAPPED)
+		nor->flags |= SNOR_F_DTR_SWAB16;
+
 	return spi_nor_post_bfpt_fixups(nor, bfpt_header, &bfpt);
 }
 
diff --git a/drivers/mtd/spi-nor/sfdp.h b/drivers/mtd/spi-nor/sfdp.h
index 6eb99e1cdd61..eba760941d43 100644
--- a/drivers/mtd/spi-nor/sfdp.h
+++ b/drivers/mtd/spi-nor/sfdp.h
@@ -123,6 +123,7 @@ struct sfdp_bfpt {
 #define BFPT_DWORD18_CMD_EXT_INV		(0x1UL << 29) /* Invert */
 #define BFPT_DWORD18_CMD_EXT_RES		(0x2UL << 29) /* Reserved */
 #define BFPT_DWORD18_CMD_EXT_16B		(0x3UL << 29) /* 16-bit opcode */
+#define BFPT_DWORD18_BYTE_ORDER_SWAPPED		BIT(31) /* Byte order of 16-bit words in 8D-8D-8D mode */
 
 struct sfdp_parameter_header {
 	u8		id_lsb;
-- 
2.25.1