[PATCH linux-next v2 03/14] mtd: spi-nor: select op codes and SPI NOR protocols by manufacturer

[Cyrille Pitchen <cyrille.pitchen@atmel.com>]

This is a transitional patch to prepare the split by Manufacturer of the
support of Single/Dual/Quad SPI modes.

Indeed every QSPI NOR manufacturer (Spansion, Micron, Macronix, Winbond)
supports Dual or Quad SPI modes on its way. Especially the Fast Read op
code and the SPI NOR protocols to use are not quite the same depending on
the manufacturer.

For instance Quad commands can use either the SPI 1-1-4, 1-4-4 or 4-4-4
protocol.

This is why this patch will be completed by fixes for each manufacturer.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 110 ++++++++++++++++++++++++++++++++----------
 include/linux/mtd/spi-nor.h   |  12 +++--
 2 files changed, 92 insertions(+), 30 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 8967319ea7da..8793cebbe5a9 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -1180,17 +1180,61 @@ static int set_quad_mode(struct spi_nor *nor, const struct flash_info *info)
 			dev_err(nor->dev, "Macronix quad-read not enabled\n");
 			return -EINVAL;
 		}
-		return status;
+		/* Check whether Macronix QPI mode is enabled. */
+		if (nor->read_proto != SNOR_PROTO_4_4_4)
+			nor->read_proto = SNOR_PROTO_1_1_4;
+		break;
+
 	case SNOR_MFR_MICRON:
-		return 0;
-	default:
+		/* Check whether Micron Quad mode is enabled. */
+		if (nor->read_proto != SNOR_PROTO_4_4_4)
+			nor->read_proto = SNOR_PROTO_1_1_4;
+		break;
+
+	case SNOR_MFR_SPANSION:
 		status = spansion_quad_enable(nor);
 		if (status) {
 			dev_err(nor->dev, "Spansion quad-read not enabled\n");
 			return -EINVAL;
 		}
-		return status;
+		nor->read_proto = SNOR_PROTO_1_1_4;
+		break;
+
+	default:
+		return -EINVAL;
 	}
+
+	nor->read_opcode = SPINOR_OP_READ_1_1_4;
+	return 0;
+}
+
+static int set_dual_mode(struct spi_nor *nor, const struct flash_info *info)
+{
+	switch (JEDEC_MFR(info)) {
+	case SNOR_MFR_MICRON:
+		/* Check whether Micron Dual mode is enabled. */
+		if (nor->read_proto != SNOR_PROTO_2_2_2)
+			nor->read_proto = SNOR_PROTO_1_1_2;
+		break;
+
+	default:
+		nor->read_proto = SNOR_PROTO_1_1_2;
+		break;
+	}
+
+	nor->read_opcode = SPINOR_OP_READ_1_1_2;
+	return 0;
+}
+
+static int set_single_mode(struct spi_nor *nor, const struct flash_info *info)
+{
+	switch (JEDEC_MFR(info)) {
+	default:
+		nor->read_proto = SNOR_PROTO_1_1_1;
+		break;
+	}
+
+	return 0;
 }
 
 static int spi_nor_check(struct spi_nor *nor)
@@ -1338,7 +1382,30 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
 	if (info->flags & SPI_NOR_NO_FR)
 		nor->flash_read = SPI_NOR_NORMAL;
 
-	/* Quad/Dual-read mode takes precedence over fast/normal */
+	/* Default commands */
+	if (nor->flash_read == SPI_NOR_NORMAL)
+		nor->read_opcode = SPINOR_OP_READ;
+	else
+		nor->read_opcode = SPINOR_OP_READ_FAST;
+
+	nor->program_opcode = SPINOR_OP_PP;
+
+	/*
+	 * Quad/Dual-read mode takes precedence over fast/normal.
+	 *
+	 * Manufacturer specific modes are discovered when reading the JEDEC ID
+	 * and are reported by the nor->read_proto value:
+	 *  - SNOR_PROTO_4_4_4 is either:
+	 *    + Micron Quad mode enabled
+	 *    + Macronix/Winbond QPI mode enabled
+	 *  - SNOR_PROTO_2_2_2 is either:
+	 *    + Micron Dual mode enabled
+	 *
+	 * The opcodes and the protocols are updated depending on the
+	 * manufacturer.
+	 * The read opcode and protocol should be updated by the relevant
+	 * function when entering Quad or Dual mode.
+	 */
 	if (mode == SPI_NOR_QUAD && info->flags & SPI_NOR_QUAD_READ) {
 		ret = set_quad_mode(nor, info);
 		if (ret) {
@@ -1347,30 +1414,21 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
 		}
 		nor->flash_read = SPI_NOR_QUAD;
 	} else if (mode == SPI_NOR_DUAL && info->flags & SPI_NOR_DUAL_READ) {
+		ret = set_dual_mode(nor, info);
+		if (ret) {
+			dev_err(dev, "dual mode not supported\n");
+			return ret;
+		}
 		nor->flash_read = SPI_NOR_DUAL;
+	} else if (info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)) {
+		/* We may need to leave a Quad or Dual mode */
+		ret = set_single_mode(nor, info);
+		if (ret) {
+			dev_err(dev, "failed to switch back to single mode\n");
+			return ret;
+		}
 	}
 
-	/* Default commands */
-	switch (nor->flash_read) {
-	case SPI_NOR_QUAD:
-		nor->read_opcode = SPINOR_OP_READ_1_1_4;
-		break;
-	case SPI_NOR_DUAL:
-		nor->read_opcode = SPINOR_OP_READ_1_1_2;
-		break;
-	case SPI_NOR_FAST:
-		nor->read_opcode = SPINOR_OP_READ_FAST;
-		break;
-	case SPI_NOR_NORMAL:
-		nor->read_opcode = SPINOR_OP_READ;
-		break;
-	default:
-		dev_err(dev, "No Read opcode defined\n");
-		return -EINVAL;
-	}
-
-	nor->program_opcode = SPINOR_OP_PP;
-
 	if (info->addr_width)
 		nor->addr_width = info->addr_width;
 	else if (mtd->size > 0x1000000) {
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 53932c87bcf2..89e3228ec1d0 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -42,8 +42,10 @@
 #define SPINOR_OP_WRSR		0x01	/* Write status register 1 byte */
 #define SPINOR_OP_READ		0x03	/* Read data bytes (low frequency) */
 #define SPINOR_OP_READ_FAST	0x0b	/* Read data bytes (high frequency) */
-#define SPINOR_OP_READ_1_1_2	0x3b	/* Read data bytes (Dual SPI) */
-#define SPINOR_OP_READ_1_1_4	0x6b	/* Read data bytes (Quad SPI) */
+#define SPINOR_OP_READ_1_1_2	0x3b	/* Read data bytes (Dual Output SPI) */
+#define SPINOR_OP_READ_1_2_2	0xbb	/* Read data bytes (Dual I/O SPI) */
+#define SPINOR_OP_READ_1_1_4	0x6b	/* Read data bytes (Quad Output SPI) */
+#define SPINOR_OP_READ_1_4_4	0xeb	/* Read data bytes (Quad I/O SPI) */
 #define SPINOR_OP_PP		0x02	/* Page program (up to 256 bytes) */
 #define SPINOR_OP_BE_4K		0x20	/* Erase 4KiB block */
 #define SPINOR_OP_BE_4K_PMC	0xd7	/* Erase 4KiB block on PMC chips */
@@ -57,8 +59,10 @@
 /* 4-byte address opcodes - used on Spansion and some Macronix flashes. */
 #define SPINOR_OP_READ4		0x13	/* Read data bytes (low frequency) */
 #define SPINOR_OP_READ4_FAST	0x0c	/* Read data bytes (high frequency) */
-#define SPINOR_OP_READ4_1_1_2	0x3c	/* Read data bytes (Dual SPI) */
-#define SPINOR_OP_READ4_1_1_4	0x6c	/* Read data bytes (Quad SPI) */
+#define SPINOR_OP_READ4_1_1_2	0x3c	/* Read data bytes (Dual Output SPI) */
+#define SPINOR_OP_READ4_1_2_2	0xbc	/* Read data bytes (Dual I/O SPI) */
+#define SPINOR_OP_READ4_1_1_4	0x6c	/* Read data bytes (Quad Output SPI) */
+#define SPINOR_OP_READ4_1_4_4	0xec	/* Read data bytes (Quad I/O SPI) */
 #define SPINOR_OP_PP_4B		0x12	/* Page program (up to 256 bytes) */
 #define SPINOR_OP_SE_4B		0xdc	/* Sector erase (usually 64KiB) */
 
-- 
1.8.2.2