mtd: spi-nor: core: Introduce SPI_NOR_DTR_BSWAP16 no_sfdp_flag

Introduce SPI_NOR_DTR_BSWAP16 flag for flashes that don't define the
mandatory BFPT table. When set it indicates that the byte order of 16-bit
words is swapped when read in 8D-8D-8D mode compared to 1-1-1 mode.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>

Author: ambarus

drivers/mtd/spi-nor/core.c

@@ -2776,7 +2776,7 @@ static void spi_nor_no_sfdp_init_params(struct spi_nor *nor)
 {
 	struct spi_nor_flash_parameter *params = nor->params;
 	struct spi_nor_erase_map *map = &params->erase_map;
-	const u8 no_sfdp_flags = nor->info->no_sfdp_flags;
+	const u16 no_sfdp_flags = nor->info->no_sfdp_flags;
 	u8 i, erase_mask;
 
 	if (no_sfdp_flags & SPI_NOR_DUAL_READ) {
@@ -2817,6 +2817,9 @@ static void spi_nor_no_sfdp_init_params(struct spi_nor *nor)
 					SPINOR_OP_PP, SNOR_PROTO_8_8_8_DTR);
 	}
 
+	if (no_sfdp_flags & SPI_NOR_DTR_BSWAP16)
+		nor->flags |= SNOR_F_DTR_BSWAP16;
+
 	/*
 	 * Sector Erase settings. Sort Erase Types in ascending order, with the
 	 * smallest erase size starting at BIT(0).

drivers/mtd/spi-nor/core.h

@@ -484,6 +484,8 @@ struct spi_nor_fixups {
  *   SPI_NOR_OCTAL_READ:      flash supports Octal Read.
  *   SPI_NOR_OCTAL_DTR_READ:  flash supports octal DTR Read.
  *   SPI_NOR_OCTAL_DTR_PP:    flash supports Octal DTR Page Program.
+ *   SPI_NOR_DTR_BSWAP16:     the byte order of 16-bit words is swapped when
+ *			      read or written in DTR mode compared to STR mode.
  *
  * @fixup_flags:    flags that indicate support that can be discovered via SFDP
  *                  ideally, but can not be discovered for this particular flash
@@ -528,14 +530,15 @@ struct flash_info {
 #define SPI_NOR_QUAD_PP			BIT(9)
 #define SPI_NOR_RWW			BIT(10)
 
-	u8 no_sfdp_flags;
+	u16 no_sfdp_flags;
 #define SPI_NOR_SKIP_SFDP		BIT(0)
 #define SECT_4K				BIT(1)
 #define SPI_NOR_DUAL_READ		BIT(3)
 #define SPI_NOR_QUAD_READ		BIT(4)
 #define SPI_NOR_OCTAL_READ		BIT(5)
 #define SPI_NOR_OCTAL_DTR_READ		BIT(6)
 #define SPI_NOR_OCTAL_DTR_PP		BIT(7)
+#define SPI_NOR_DTR_BSWAP16		BIT(8)
 
 	u8 fixup_flags;
 #define SPI_NOR_4B_OPCODES		BIT(0)