mtd: spi-nor: add support for DTR protocol

Double Transfer Rate (DTR) is SPI protocol in which data is transferred
on each clock edge as opposed to on each clock cycle. Make
framework-level changes to allow supporting flashes in DTR mode.

Right now, mixed DTR modes are not supported. So, for example a mode
like 4S-4D-4D will not work. All phases need to be either DTR or STR.

The xSPI spec says that "The program commands provide SPI backward
compatible commands for programming data...". So 8D-8D-8D page program
opcodes are populated with using 1S-1S-1S opcodes.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20201005153138.6437-4-p.yadav@ti.com

3 files changed, 252 insertions, 83 deletions

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 2f24bde08c90..3cd025d79a98 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -41,6 +41,78 @@
 #define SPI_NOR_MAX_ADDR_WIDTH	4
 
 /**
+ * spi_nor_get_cmd_ext() - Get the command opcode extension based on the
+ *			   extension type.
+ * @nor:		pointer to a 'struct spi_nor'
+ * @op:			pointer to the 'struct spi_mem_op' whose properties
+ *			need to be initialized.
+ *
+ * Right now, only "repeat" and "invert" are supported.
+ *
+ * Return: The opcode extension.
+ */
+static u8 spi_nor_get_cmd_ext(const struct spi_nor *nor,
+			      const struct spi_mem_op *op)
+{
+	switch (nor->cmd_ext_type) {
+	case SPI_NOR_EXT_INVERT:
+		return ~op->cmd.opcode;
+
+	case SPI_NOR_EXT_REPEAT:
+		return op->cmd.opcode;
+
+	default:
+		dev_err(nor->dev, "Unknown command extension type\n");
+		return 0;
+	}
+}
+
+/**
+ * spi_nor_spimem_setup_op() - Set up common properties of a spi-mem op.
+ * @nor:		pointer to a 'struct spi_nor'
+ * @op:			pointer to the 'struct spi_mem_op' whose properties
+ *			need to be initialized.
+ * @proto:		the protocol from which the properties need to be set.
+ */
+void spi_nor_spimem_setup_op(const struct spi_nor *nor,
+			     struct spi_mem_op *op,
+			     const enum spi_nor_protocol proto)
+{
+	u8 ext;
+
+	op->cmd.buswidth = spi_nor_get_protocol_inst_nbits(proto);
+
+	if (op->addr.nbytes)
+		op->addr.buswidth = spi_nor_get_protocol_addr_nbits(proto);
+
+	if (op->dummy.nbytes)
+		op->dummy.buswidth = spi_nor_get_protocol_addr_nbits(proto);
+
+	if (op->data.nbytes)
+		op->data.buswidth = spi_nor_get_protocol_data_nbits(proto);
+
+	if (spi_nor_protocol_is_dtr(proto)) {
+		/*
+		 * SPIMEM supports mixed DTR modes, but right now we can only
+		 * have all phases either DTR or STR. IOW, SPIMEM can have
+		 * something like 4S-4D-4D, but SPI NOR can't. So, set all 4
+		 * phases to either DTR or STR.
+		 */
+		op->cmd.dtr = true;
+		op->addr.dtr = true;
+		op->dummy.dtr = true;
+		op->data.dtr = true;
+
+		/* 2 bytes per clock cycle in DTR mode. */
+		op->dummy.nbytes *= 2;
+
+		ext = spi_nor_get_cmd_ext(nor, op);
+		op->cmd.opcode = (op->cmd.opcode << 8) | ext;
+		op->cmd.nbytes = 2;
+	}
+}
+
+/**
  * spi_nor_spimem_bounce() - check if a bounce buffer is needed for the data
  *                           transfer
  * @nor:        pointer to 'struct spi_nor'
@@ -85,17 +157,26 @@ static int spi_nor_spimem_exec_op(struct spi_nor *nor, struct spi_mem_op *op)
 static int spi_nor_controller_ops_read_reg(struct spi_nor *nor, u8 opcode,
 					   u8 *buf, size_t len)
 {
+	if (spi_nor_protocol_is_dtr(nor->reg_proto))
+		return -EOPNOTSUPP;
+
 	return nor->controller_ops->read_reg(nor, opcode, buf, len);
 }
 
 static int spi_nor_controller_ops_write_reg(struct spi_nor *nor, u8 opcode,
 					    const u8 *buf, size_t len)
 {
+	if (spi_nor_protocol_is_dtr(nor->reg_proto))
+		return -EOPNOTSUPP;
+
 	return nor->controller_ops->write_reg(nor, opcode, buf, len);
 }
 
 static int spi_nor_controller_ops_erase(struct spi_nor *nor, loff_t offs)
 {
+	if (spi_nor_protocol_is_dtr(nor->write_proto))
+		return -EOPNOTSUPP;
+
 	return nor->controller_ops->erase(nor, offs);
 }
 
@@ -113,22 +194,20 @@ static ssize_t spi_nor_spimem_read_data(struct spi_nor *nor, loff_t from,
 					size_t len, u8 *buf)
 {
 	struct spi_mem_op op =
-		SPI_MEM_OP(SPI_MEM_OP_CMD(nor->read_opcode, 1),
-			   SPI_MEM_OP_ADDR(nor->addr_width, from, 1),
-			   SPI_MEM_OP_DUMMY(nor->read_dummy, 1),
-			   SPI_MEM_OP_DATA_IN(len, buf, 1));
+		SPI_MEM_OP(SPI_MEM_OP_CMD(nor->read_opcode, 0),
+			   SPI_MEM_OP_ADDR(nor->addr_width, from, 0),
+			   SPI_MEM_OP_DUMMY(nor->read_dummy, 0),
+			   SPI_MEM_OP_DATA_IN(len, buf, 0));
 	bool usebouncebuf;
 	ssize_t nbytes;
 	int error;
 
-	/* get transfer protocols. */
-	op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->read_proto);
-	op.addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->read_proto);
-	op.dummy.buswidth = op.addr.buswidth;
-	op.data.buswidth = spi_nor_get_protocol_data_nbits(nor->read_proto);
+	spi_nor_spimem_setup_op(nor, &op, nor->read_proto);
 
 	/* convert the dummy cycles to the number of bytes */
 	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
+	if (spi_nor_protocol_is_dtr(nor->read_proto))
+		op.dummy.nbytes *= 2;
 
 	usebouncebuf = spi_nor_spimem_bounce(nor, &op);
 
@@ -179,20 +258,18 @@ static ssize_t spi_nor_spimem_write_data(struct spi_nor *nor, loff_t to,
 					 size_t len, const u8 *buf)
 {
 	struct spi_mem_op op =
-		SPI_MEM_OP(SPI_MEM_OP_CMD(nor->program_opcode, 1),
-			   SPI_MEM_OP_ADDR(nor->addr_width, to, 1),
+		SPI_MEM_OP(SPI_MEM_OP_CMD(nor->program_opcode, 0),
+			   SPI_MEM_OP_ADDR(nor->addr_width, to, 0),
 			   SPI_MEM_OP_NO_DUMMY,
-			   SPI_MEM_OP_DATA_OUT(len, buf, 1));
+			   SPI_MEM_OP_DATA_OUT(len, buf, 0));
 	ssize_t nbytes;
 	int error;
 
-	op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->write_proto);
-	op.addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->write_proto);
-	op.data.buswidth = spi_nor_get_protocol_data_nbits(nor->write_proto);
-
 	if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second)
 		op.addr.nbytes = 0;
 
+	spi_nor_spimem_setup_op(nor, &op, nor->write_proto);
+
 	if (spi_nor_spimem_bounce(nor, &op))
 		memcpy(nor->bouncebuf, buf, op.data.nbytes);
 
@@ -239,11 +316,13 @@ int spi_nor_write_enable(struct spi_nor *nor)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WREN, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WREN, 0),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
 				   SPI_MEM_OP_NO_DATA);
 
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
+
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
 		ret = spi_nor_controller_ops_write_reg(nor, SPINOR_OP_WREN,
@@ -268,11 +347,13 @@ int spi_nor_write_disable(struct spi_nor *nor)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WRDI, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WRDI, 0),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
 				   SPI_MEM_OP_NO_DATA);
 
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
+
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
 		ret = spi_nor_controller_ops_write_reg(nor, SPINOR_OP_WRDI,
@@ -299,10 +380,12 @@ static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDSR, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDSR, 0),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
-				   SPI_MEM_OP_DATA_IN(1, sr, 1));
+				   SPI_MEM_OP_DATA_IN(1, sr, 0));
+
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
 
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
@@ -330,10 +413,12 @@ static int spi_nor_read_fsr(struct spi_nor *nor, u8 *fsr)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDFSR, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDFSR, 0),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
-				   SPI_MEM_OP_DATA_IN(1, fsr, 1));
+				   SPI_MEM_OP_DATA_IN(1, fsr, 0));
+
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
 
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
@@ -362,10 +447,12 @@ static int spi_nor_read_cr(struct spi_nor *nor, u8 *cr)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDCR, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDCR, 0),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
-				   SPI_MEM_OP_DATA_IN(1, cr, 1));
+				   SPI_MEM_OP_DATA_IN(1, cr, 0));
+
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
 
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
@@ -396,11 +483,13 @@ int spi_nor_set_4byte_addr_mode(struct spi_nor *nor, bool enable)
 			SPI_MEM_OP(SPI_MEM_OP_CMD(enable ?
 						  SPINOR_OP_EN4B :
 						  SPINOR_OP_EX4B,
-						  1),
+						  0),
 				  SPI_MEM_OP_NO_ADDR,
 				  SPI_MEM_OP_NO_DUMMY,
 				  SPI_MEM_OP_NO_DATA);
 
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
+
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
 		ret = spi_nor_controller_ops_write_reg(nor,
@@ -432,10 +521,12 @@ static int spansion_set_4byte_addr_mode(struct spi_nor *nor, bool enable)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_BRWR, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_BRWR, 0),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
-				   SPI_MEM_OP_DATA_OUT(1, nor->bouncebuf, 1));
+				   SPI_MEM_OP_DATA_OUT(1, nor->bouncebuf, 0));
+
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
 
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
@@ -464,10 +555,12 @@ int spi_nor_write_ear(struct spi_nor *nor, u8 ear)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WREAR, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WREAR, 0),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
-				   SPI_MEM_OP_DATA_OUT(1, nor->bouncebuf, 1));
+				   SPI_MEM_OP_DATA_OUT(1, nor->bouncebuf, 0));
+
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
 
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
@@ -495,10 +588,12 @@ int spi_nor_xread_sr(struct spi_nor *nor, u8 *sr)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_XRDSR, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_XRDSR, 0),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
-				   SPI_MEM_OP_DATA_IN(1, sr, 1));
+				   SPI_MEM_OP_DATA_IN(1, sr, 0));
+
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
 
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
@@ -540,11 +635,13 @@ static void spi_nor_clear_sr(struct spi_nor *nor)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_CLSR, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_CLSR, 0),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
 				   SPI_MEM_OP_NO_DATA);
 
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
+
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
 		ret = spi_nor_controller_ops_write_reg(nor, SPINOR_OP_CLSR,
@@ -604,11 +701,13 @@ static void spi_nor_clear_fsr(struct spi_nor *nor)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_CLFSR, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_CLFSR, 0),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
 				   SPI_MEM_OP_NO_DATA);
 
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
+
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
 		ret = spi_nor_controller_ops_write_reg(nor, SPINOR_OP_CLFSR,
@@ -748,10 +847,12 @@ static int spi_nor_write_sr(struct spi_nor *nor, const u8 *sr, size_t len)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WRSR, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WRSR, 0),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
-				   SPI_MEM_OP_DATA_OUT(len, sr, 1));
+				   SPI_MEM_OP_DATA_OUT(len, sr, 0));
+
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
 
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
@@ -950,10 +1051,12 @@ static int spi_nor_write_sr2(struct spi_nor *nor, const u8 *sr2)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WRSR2, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WRSR2, 0),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
-				   SPI_MEM_OP_DATA_OUT(1, sr2, 1));
+				   SPI_MEM_OP_DATA_OUT(1, sr2, 0));
+
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
 
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
@@ -984,10 +1087,12 @@ static int spi_nor_read_sr2(struct spi_nor *nor, u8 *sr2)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDSR2, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDSR2, 0),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
-				   SPI_MEM_OP_DATA_IN(1, sr2, 1));
+				   SPI_MEM_OP_DATA_IN(1, sr2, 0));
+
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
 
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
@@ -1015,11 +1120,13 @@ static int spi_nor_erase_chip(struct spi_nor *nor)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_CHIP_ERASE, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_CHIP_ERASE, 0),
 				   SPI_MEM_OP_NO_ADDR,
 				   SPI_MEM_OP_NO_DUMMY,
 				   SPI_MEM_OP_NO_DATA);
 
+		spi_nor_spimem_setup_op(nor, &op, nor->write_proto);
+
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
 		ret = spi_nor_controller_ops_write_reg(nor,
@@ -1158,11 +1265,13 @@ static int spi_nor_erase_sector(struct spi_nor *nor, u32 addr)
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(nor->erase_opcode, 1),
-				   SPI_MEM_OP_ADDR(nor->addr_width, addr, 1),
+			SPI_MEM_OP(SPI_MEM_OP_CMD(nor->erase_opcode, 0),
+				   SPI_MEM_OP_ADDR(nor->addr_width, addr, 0),
 				   SPI_MEM_OP_NO_DUMMY,
 				   SPI_MEM_OP_NO_DATA);
 
+		spi_nor_spimem_setup_op(nor, &op, nor->write_proto);
+
 		return spi_mem_exec_op(nor->spimem, &op);
 	} else if (nor->controller_ops->erase) {
 		return spi_nor_controller_ops_erase(nor, addr);
@@ -2272,6 +2381,7 @@ int spi_nor_hwcaps_read2cmd(u32 hwcaps)
 		{ SNOR_HWCAPS_READ_1_8_8,	SNOR_CMD_READ_1_8_8 },
 		{ SNOR_HWCAPS_READ_8_8_8,	SNOR_CMD_READ_8_8_8 },
 		{ SNOR_HWCAPS_READ_1_8_8_DTR,	SNOR_CMD_READ_1_8_8_DTR },
+		{ SNOR_HWCAPS_READ_8_8_8_DTR,	SNOR_CMD_READ_8_8_8_DTR },
 	};
 
 	return spi_nor_hwcaps2cmd(hwcaps, hwcaps_read2cmd,
@@ -2288,6 +2398,7 @@ static int spi_nor_hwcaps_pp2cmd(u32 hwcaps)
 		{ SNOR_HWCAPS_PP_1_1_8,		SNOR_CMD_PP_1_1_8 },
 		{ SNOR_HWCAPS_PP_1_8_8,		SNOR_CMD_PP_1_8_8 },
 		{ SNOR_HWCAPS_PP_8_8_8,		SNOR_CMD_PP_8_8_8 },
+		{ SNOR_HWCAPS_PP_8_8_8_DTR,	SNOR_CMD_PP_8_8_8_DTR },
 	};
 
 	return spi_nor_hwcaps2cmd(hwcaps, hwcaps_pp2cmd,
@@ -2336,17 +2447,17 @@ static int spi_nor_spimem_check_op(struct spi_nor *nor,
 static int spi_nor_spimem_check_readop(struct spi_nor *nor,
 				       const struct spi_nor_read_command *read)
 {
-	struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(read->opcode, 1),
-					  SPI_MEM_OP_ADDR(3, 0, 1),
-					  SPI_MEM_OP_DUMMY(0, 1),
-					  SPI_MEM_OP_DATA_IN(0, NULL, 1));
+	struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(read->opcode, 0),
+					  SPI_MEM_OP_ADDR(3, 0, 0),
+					  SPI_MEM_OP_DUMMY(1, 0),
+					  SPI_MEM_OP_DATA_IN(1, NULL, 0));
 
-	op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(read->proto);
-	op.addr.buswidth = spi_nor_get_protocol_addr_nbits(read->proto);
-	op.data.buswidth = spi_nor_get_protocol_data_nbits(read->proto);
-	op.dummy.buswidth = op.addr.buswidth;
-	op.dummy.nbytes = (read->num_mode_clocks + read->num_wait_states) *
-			  op.dummy.buswidth / 8;
+	spi_nor_spimem_setup_op(nor, &op, read->proto);
+
+	/* convert the dummy cycles to the number of bytes */
+	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
+	if (spi_nor_protocol_is_dtr(nor->read_proto))
+		op.dummy.nbytes *= 2;
 
 	return spi_nor_spimem_check_op(nor, &op);
 }
@@ -2362,14 +2473,12 @@ static int spi_nor_spimem_check_readop(struct spi_nor *nor,
 static int spi_nor_spimem_check_pp(struct spi_nor *nor,
 				   const struct spi_nor_pp_command *pp)
 {
-	struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(pp->opcode, 1),
-					  SPI_MEM_OP_ADDR(3, 0, 1),
+	struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(pp->opcode, 0),
+					  SPI_MEM_OP_ADDR(3, 0, 0),
 					  SPI_MEM_OP_NO_DUMMY,
-					  SPI_MEM_OP_DATA_OUT(0, NULL, 1));
+					  SPI_MEM_OP_DATA_OUT(1, NULL, 0));
 
-	op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(pp->proto);
-	op.addr.buswidth = spi_nor_get_protocol_addr_nbits(pp->proto);
-	op.data.buswidth = spi_nor_get_protocol_data_nbits(pp->proto);
+	spi_nor_spimem_setup_op(nor, &op, pp->proto);
 
 	return spi_nor_spimem_check_op(nor, &op);
 }
@@ -2387,12 +2496,16 @@ spi_nor_spimem_adjust_hwcaps(struct spi_nor *nor, u32 *hwcaps)
 	struct spi_nor_flash_parameter *params = nor->params;
 	unsigned int cap;
 
-	/* DTR modes are not supported yet, mask them all. */
-	*hwcaps &= ~SNOR_HWCAPS_DTR;
-
 	/* X-X-X modes are not supported yet, mask them all. */
 	*hwcaps &= ~SNOR_HWCAPS_X_X_X;
 
+	/*
+	 * If the reset line is broken, we do not want to enter a stateful
+	 * mode.
+	 */
+	if (nor->flags & SNOR_F_BROKEN_RESET)
+		*hwcaps &= ~(SNOR_HWCAPS_X_X_X | SNOR_HWCAPS_X_X_X_DTR);
+
 	for (cap = 0; cap < sizeof(*hwcaps) * BITS_PER_BYTE; cap++) {
 		int rdidx, ppidx;
 
@@ -2647,7 +2760,7 @@ static int spi_nor_default_setup(struct spi_nor *nor,
 		 * controller directly implements the spi_nor interface.
 		 * Yet another reason to switch to spi-mem.
 		 */
-		ignored_mask = SNOR_HWCAPS_X_X_X;
+		ignored_mask = SNOR_HWCAPS_X_X_X | SNOR_HWCAPS_X_X_X_DTR;
 		if (shared_mask & ignored_mask) {
 			dev_dbg(nor->dev,
 				"SPI n-n-n protocols are not supported.\n");
@@ -2792,11 +2905,28 @@ static void spi_nor_info_init_params(struct spi_nor *nor)
 					  SNOR_PROTO_1_1_8);
 	}
 
+	if (info->flags & SPI_NOR_OCTAL_DTR_READ) {
+		params->hwcaps.mask |= SNOR_HWCAPS_READ_8_8_8_DTR;
+		spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ_8_8_8_DTR],
+					  0, 20, SPINOR_OP_READ_FAST,
+					  SNOR_PROTO_8_8_8_DTR);
+	}
+
 	/* Page Program settings. */
 	params->hwcaps.mask |= SNOR_HWCAPS_PP;
 	spi_nor_set_pp_settings(&params->page_programs[SNOR_CMD_PP],
 				SPINOR_OP_PP, SNOR_PROTO_1_1_1);
 
+	if (info->flags & SPI_NOR_OCTAL_DTR_PP) {
+		params->hwcaps.mask |= SNOR_HWCAPS_PP_8_8_8_DTR;
+		/*
+		 * Since xSPI Page Program opcode is backward compatible with
+		 * Legacy SPI, use Legacy SPI opcode there as well.
+		 */
+		spi_nor_set_pp_settings(&params->page_programs[SNOR_CMD_PP_8_8_8_DTR],
+					SPINOR_OP_PP, SNOR_PROTO_8_8_8_DTR);
+	}
+
 	/*
 	 * Sector Erase settings. Sort Erase Types in ascending order, with the
 	 * smallest erase size starting at BIT(0).
@@ -2904,7 +3034,8 @@ static int spi_nor_init_params(struct spi_nor *nor)
 
 	spi_nor_manufacturer_init_params(nor);
 
-	if ((nor->info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)) &&
+	if ((nor->info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
+				 SPI_NOR_OCTAL_READ | SPI_NOR_OCTAL_DTR_READ)) &&
 	    !(nor->info->flags & SPI_NOR_SKIP_SFDP))
 		spi_nor_sfdp_init_params(nor);
 
@@ -2966,7 +3097,9 @@ static int spi_nor_init(struct spi_nor *nor)
 		return err;
 	}
 
-	if (nor->addr_width == 4 && !(nor->flags & SNOR_F_4B_OPCODES)) {
+	if (nor->addr_width == 4 &&
+	    nor->read_proto != SNOR_PROTO_8_8_8_DTR &&
+	    !(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
@@ -3025,6 +3158,20 @@ static int spi_nor_set_addr_width(struct spi_nor *nor)
 {
 	if (nor->addr_width) {
 		/* already configured from SFDP */
+	} else if (nor->read_proto == SNOR_PROTO_8_8_8_DTR) {
+		/*
+		 * In 8D-8D-8D mode, one byte takes half a cycle to transfer. So
+		 * in this protocol an odd address width cannot be used because
+		 * then the address phase would only span a cycle and a half.
+		 * Half a cycle would be left over. We would then have to start
+		 * the dummy phase in the middle of a cycle and so too the data
+		 * phase, and we will end the transaction with half a cycle left
+		 * over.
+		 *
+		 * Force all 8D-8D-8D flashes to use an address width of 4 to
+		 * avoid this situation.
+		 */
+		nor->addr_width = 4;
 	} else if (nor->info->addr_width) {
 		nor->addr_width = nor->info->addr_width;
 	} else {
@@ -3255,23 +3402,28 @@ EXPORT_SYMBOL_GPL(spi_nor_scan);
 static int spi_nor_create_read_dirmap(struct spi_nor *nor)
 {
 	struct spi_mem_dirmap_info info = {
-		.op_tmpl = SPI_MEM_OP(SPI_MEM_OP_CMD(nor->read_opcode, 1),
-				      SPI_MEM_OP_ADDR(nor->addr_width, 0, 1),
-				      SPI_MEM_OP_DUMMY(nor->read_dummy, 1),
-				      SPI_MEM_OP_DATA_IN(0, NULL, 1)),
+		.op_tmpl = SPI_MEM_OP(SPI_MEM_OP_CMD(nor->read_opcode, 0),
+				      SPI_MEM_OP_ADDR(nor->addr_width, 0, 0),
+				      SPI_MEM_OP_DUMMY(nor->read_dummy, 0),
+				      SPI_MEM_OP_DATA_IN(0, NULL, 0)),
 		.offset = 0,
 		.length = nor->mtd.size,
 	};
 	struct spi_mem_op *op = &info.op_tmpl;
 
-	/* get transfer protocols. */
-	op->cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->read_proto);
-	op->addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->read_proto);
-	op->dummy.buswidth = op->addr.buswidth;
-	op->data.buswidth = spi_nor_get_protocol_data_nbits(nor->read_proto);
+	spi_nor_spimem_setup_op(nor, op, nor->read_proto);
 
 	/* convert the dummy cycles to the number of bytes */
 	op->dummy.nbytes = (nor->read_dummy * op->dummy.buswidth) / 8;
+	if (spi_nor_protocol_is_dtr(nor->read_proto))
+		op->dummy.nbytes *= 2;
+
+	/*
+	 * Since spi_nor_spimem_setup_op() only sets buswidth when the number
+	 * of data bytes is non-zero, the data buswidth won't be set here. So,
+	 * do it explicitly.
+	 */
+	op->data.buswidth = spi_nor_get_protocol_data_nbits(nor->read_proto);
 
 	nor->dirmap.rdesc = devm_spi_mem_dirmap_create(nor->dev, nor->spimem,
 						       &info);
@@ -3281,24 +3433,27 @@ static int spi_nor_create_read_dirmap(struct spi_nor *nor)
 static int spi_nor_create_write_dirmap(struct spi_nor *nor)
 {
 	struct spi_mem_dirmap_info info = {
-		.op_tmpl = SPI_MEM_OP(SPI_MEM_OP_CMD(nor->program_opcode, 1),
-				      SPI_MEM_OP_ADDR(nor->addr_width, 0, 1),
+		.op_tmpl = SPI_MEM_OP(SPI_MEM_OP_CMD(nor->program_opcode, 0),
+				      SPI_MEM_OP_ADDR(nor->addr_width, 0, 0),
 				      SPI_MEM_OP_NO_DUMMY,
-				      SPI_MEM_OP_DATA_OUT(0, NULL, 1)),
+				      SPI_MEM_OP_DATA_OUT(0, NULL, 0)),
 		.offset = 0,
 		.length = nor->mtd.size,
 	};
 	struct spi_mem_op *op = &info.op_tmpl;
 
-	/* get transfer protocols. */
-	op->cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->write_proto);
-	op->addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->write_proto);
-	op->dummy.buswidth = op->addr.buswidth;
-	op->data.buswidth = spi_nor_get_protocol_data_nbits(nor->write_proto);
-
 	if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second)
 		op->addr.nbytes = 0;
 
+	spi_nor_spimem_setup_op(nor, op, nor->write_proto);
+
+	/*
+	 * Since spi_nor_spimem_setup_op() only sets buswidth when the number
+	 * of data bytes is non-zero, the data buswidth won't be set here. So,
+	 * do it explicitly.
+	 */
+	op->data.buswidth = spi_nor_get_protocol_data_nbits(nor->write_proto);
+
 	nor->dirmap.wdesc = devm_spi_mem_dirmap_create(nor->dev, nor->spimem,
 						       &info);
 	return PTR_ERR_OR_ZERO(nor->dirmap.wdesc);
diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
index 6f2f6b27173f..5d95b4183a33 100644
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h
@@ -62,6 +62,7 @@ enum spi_nor_read_command_index {
 	SNOR_CMD_READ_1_8_8,
 	SNOR_CMD_READ_8_8_8,
 	SNOR_CMD_READ_1_8_8_DTR,
+	SNOR_CMD_READ_8_8_8_DTR,
 
 	SNOR_CMD_READ_MAX
 };
@@ -78,6 +79,7 @@ enum spi_nor_pp_command_index {
 	SNOR_CMD_PP_1_1_8,
 	SNOR_CMD_PP_1_8_8,
 	SNOR_CMD_PP_8_8_8,
+	SNOR_CMD_PP_8_8_8_DTR,
 
 	SNOR_CMD_PP_MAX
 };
@@ -311,6 +313,8 @@ struct flash_info {
 					 * BP3 is bit 6 of status register.
 					 * Must be used with SPI_NOR_4BIT_BP.
 					 */
+#define SPI_NOR_OCTAL_DTR_READ	BIT(19) /* Flash supports octal DTR Read. */
+#define SPI_NOR_OCTAL_DTR_PP	BIT(20) /* Flash supports Octal DTR Page Program */
 
 	/* Part specific fixup hooks. */
 	const struct spi_nor_fixups *fixups;
@@ -399,6 +403,9 @@ extern const struct spi_nor_manufacturer spi_nor_winbond;
 extern const struct spi_nor_manufacturer spi_nor_xilinx;
 extern const struct spi_nor_manufacturer spi_nor_xmc;
 
+void spi_nor_spimem_setup_op(const struct spi_nor *nor,
+			     struct spi_mem_op *op,
+			     const enum spi_nor_protocol proto);
 int spi_nor_write_enable(struct spi_nor *nor);
 int spi_nor_write_disable(struct spi_nor *nor);
 int spi_nor_set_4byte_addr_mode(struct spi_nor *nor, bool enable);
diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c
index e2a43d39eb5f..21fa9ab78eae 100644
--- a/drivers/mtd/spi-nor/sfdp.c
+++ b/drivers/mtd/spi-nor/sfdp.c
@@ -1047,9 +1047,16 @@ static int spi_nor_parse_4bait(struct spi_nor *nor,
 	}
 
 	/* 4BAIT is the only SFDP table that indicates page program support. */
-	if (pp_hwcaps & SNOR_HWCAPS_PP)
+	if (pp_hwcaps & SNOR_HWCAPS_PP) {
 		spi_nor_set_pp_settings(&params_pp[SNOR_CMD_PP],
 					SPINOR_OP_PP_4B, SNOR_PROTO_1_1_1);
+		/*
+		 * Since xSPI Page Program opcode is backward compatible with
+		 * Legacy SPI, use Legacy SPI opcode there as well.
+		 */
+		spi_nor_set_pp_settings(&params_pp[SNOR_CMD_PP_8_8_8_DTR],
+					SPINOR_OP_PP_4B, SNOR_PROTO_8_8_8_DTR);
+	}
 	if (pp_hwcaps & SNOR_HWCAPS_PP_1_1_4)
 		spi_nor_set_pp_settings(&params_pp[SNOR_CMD_PP_1_1_4],
 					SPINOR_OP_PP_1_1_4_4B,