[PATCH v3 17/17] mtd: spi-nor-core: Allow using Micron mt35xu512aba in Octal DTR mode

[Pratyush Yadav <p.yadav@ti.com>]

Since this flash doesn't have a Profile 1.0 table, the Octal DTR
capabilities are enabled in the post SFDP fixup, along with the 8D-8D-8D
fast read settings.

Enable Octal DTR mode with 20 dummy cycles to allow running at the
maximum supported frequency of 200Mhz.

The flash supports the soft reset sequence. So, add the flag in the
flash's info.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
---
 drivers/mtd/spi/sf_internal.h  |  4 ++
 drivers/mtd/spi/spi-nor-core.c | 87 ++++++++++++++++++++++++++++++++++
 drivers/mtd/spi/spi-nor-ids.c  |  2 +-
 include/linux/mtd/spi-nor.h    | 10 +++-
 4 files changed, 100 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/spi/sf_internal.h b/drivers/mtd/spi/sf_internal.h
index d017c857d0..6a6b743dfe 100644
--- a/drivers/mtd/spi/sf_internal.h
+++ b/drivers/mtd/spi/sf_internal.h
@@ -80,6 +80,10 @@ extern const struct flash_info spi_nor_ids[];
 extern struct spi_nor_fixups s28hs512t_fixups;
 #endif
 
+#ifdef CONFIG_SPI_FLASH_STMICRO
+extern struct spi_nor_fixups mt35xu512aba_fixups;
+#endif
+
 #define JEDEC_MFR(info)	((info)->id[0])
 #define JEDEC_ID(info)		(((info)->id[1]) << 8 | ((info)->id[2]))
 
diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index f6f72f8a32..3711ba6e23 100644
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -2956,6 +2956,93 @@ struct spi_nor_fixups s28hs512t_fixups = {
 };
 #endif /* CONFIG_SPI_FLASH_SPANSION */
 
+#ifdef CONFIG_SPI_FLASH_STMICRO
+static int spi_nor_micron_octal_dtr_enable(struct spi_nor *nor)
+{
+	struct spi_mem_op op;
+	u8 buf;
+	u8 addr_width = 3;
+	int ret;
+
+	ret = write_enable(nor);
+	if (ret)
+		return ret;
+
+	buf = SPINOR_MT_DTR_NO_DQS;
+	op = (struct spi_mem_op)
+		SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_MT_WR_ANY_REG, 1),
+			   SPI_MEM_OP_ADDR(addr_width, SPINOR_REG_MT_CFR0V, 1),
+			   SPI_MEM_OP_NO_DUMMY,
+			   SPI_MEM_OP_DATA_OUT(1, &buf, 1));
+	ret = spi_mem_exec_op(nor->spi, &op);
+	if (ret) {
+		dev_err(nor->dev, "Failed to enable octal DTR mode\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int mt35xu512aba_setup(struct spi_nor *nor,
+			      const struct flash_info *info,
+			      const struct spi_nor_flash_parameter *params,
+			      const struct spi_nor_hwcaps *hwcaps)
+{
+	struct spi_mem_op op;
+	u8 buf;
+	u8 addr_width = 3;
+	int ret;
+
+	/* Set dummy cycles for Fast Read to the default of 20. */
+	ret = write_enable(nor);
+	if (ret)
+		return ret;
+
+	buf = 20;
+	op = (struct spi_mem_op)
+		SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_MT_WR_ANY_REG, 1),
+			   SPI_MEM_OP_ADDR(addr_width, SPINOR_REG_MT_CFR1V, 1),
+			   SPI_MEM_OP_NO_DUMMY,
+			   SPI_MEM_OP_DATA_OUT(1, &buf, 1));
+	ret = spi_mem_exec_op(nor->spi, &op);
+	if (ret)
+		return ret;
+
+	ret = spi_nor_wait_till_ready(nor);
+	if (ret)
+		return ret;
+
+	return spi_nor_default_setup(nor, info, params, hwcaps);
+}
+
+static void mt35xu512aba_default_init(struct spi_nor *nor)
+{
+	nor->octal_dtr_enable = spi_nor_micron_octal_dtr_enable;
+	nor->setup = mt35xu512aba_setup;
+}
+
+static void mt35xu512aba_post_sfdp_fixup(struct spi_nor *nor,
+					 struct spi_nor_flash_parameter *params)
+{
+	/* Set the Fast Read settings. */
+	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_MT_DTR_RD,
+				  SNOR_PROTO_8_8_8_DTR);
+
+	params->hwcaps.mask |= SNOR_HWCAPS_PP_8_8_8_DTR;
+
+	nor->cmd_ext_type = SPI_NOR_EXT_REPEAT;
+	params->rdsr_dummy = 8;
+	params->rdsr_addr_nbytes = 0;
+}
+
+struct spi_nor_fixups mt35xu512aba_fixups = {
+	.default_init = mt35xu512aba_default_init,
+	.post_sfdp = mt35xu512aba_post_sfdp_fixup,
+};
+#endif /* CONFIG_SPI_FLASH_STMICRO */
+
 /** spi_nor_octal_dtr_enable() - enable Octal DTR I/O if needed
  * @nor:                 pointer to a 'struct spi_nor'
  *
diff --git a/drivers/mtd/spi/spi-nor-ids.c b/drivers/mtd/spi/spi-nor-ids.c
index 33e6915c16..2f9498eced 100644
--- a/drivers/mtd/spi/spi-nor-ids.c
+++ b/drivers/mtd/spi/spi-nor-ids.c
@@ -182,7 +182,7 @@ const struct flash_info spi_nor_ids[] = {
 	{ INFO("n25q00",      0x20ba21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
 	{ INFO("n25q00a",     0x20bb21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
 	{ INFO("mt25qu02g",   0x20bb22, 0, 64 * 1024, 4096, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
-	{ INFO("mt35xu512aba", 0x2c5b1a, 0,  128 * 1024,  512, USE_FSR | SPI_NOR_4B_OPCODES) },
+	{ INFO("mt35xu512aba", 0x2c5b1a, 0,  128 * 1024,  512,  USE_FSR | SPI_NOR_4B_OPCODES | SPI_NOR_OCTAL_DTR_READ | SPI_NOR_SOFT_RESET) .fixups = &mt35xu512aba_fixups },
 	{ INFO("mt35xu02g",  0x2c5b1c, 0, 128 * 1024,  2048, USE_FSR | SPI_NOR_4B_OPCODES) },
 #endif
 #ifdef CONFIG_SPI_FLASH_SPANSION	/* SPANSION */
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index fcb7f7aa20..d59d217842 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -123,8 +123,14 @@
 #define SPINOR_OP_CLSR		0x30	/* Clear status register 1 */
 
 /* Used for Micron flashes only. */
-#define SPINOR_OP_RD_EVCR      0x65    /* Read EVCR register */
-#define SPINOR_OP_WD_EVCR      0x61    /* Write EVCR register */
+#define SPINOR_OP_RD_EVCR	0x65	/* Read EVCR register */
+#define SPINOR_OP_WD_EVCR	0x61	/* Write EVCR register */
+#define SPINOR_OP_MT_DTR_RD	0xfd	/* Fast Read opcode in DTR mode */
+#define SPINOR_OP_MT_RD_ANY_REG	0x85	/* Read volatile register */
+#define SPINOR_OP_MT_WR_ANY_REG	0x81	/* Write volatile register */
+#define SPINOR_REG_MT_CFR0V	0x00	/* For setting octal DTR mode */
+#define SPINOR_REG_MT_CFR1V	0x01	/* For setting dummy cycles */
+#define SPINOR_MT_DTR_NO_DQS	0xc7	/* Enable Octal DTR without DQS. */
 
 /* Status Register bits. */
 #define SR_WIP			BIT(0)	/* Write in progress */
-- 
2.25.0