[PATCH v6 1/4] mtd: spi-nor: macronix: add support for Macronix Octal

[JaimeLiao <jaimeliao.tw@gmail.com>]

Follow patch "f6adec1af4b2f5d3012480c6cdce7743b74a6156" for adding
Macronix flash in Octal DTR mode.

Enable Octal DTR mode with 20 dummy cycles to allow running at the
maximum supported frequency.
 -https://www.mxic.com.tw/Lists/Datasheet/Attachments/7841/MX25LM51245G,%203V,%20512Mb,%20v1.1.pdf

Signed-off-by: JaimeLiao <jaimeliao.tw@gmail.com>
---
 drivers/mtd/spi/spi-nor-core.c | 83 ++++++++++++++++++++++++++++++++++
 include/linux/mtd/spi-nor.h    | 12 ++++-
 2 files changed, 93 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index d5d905fa5a..0a6550984b 100644
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -3489,6 +3489,85 @@ static struct spi_nor_fixups mt35xu512aba_fixups = {
 };
 #endif /* CONFIG_SPI_FLASH_MT35XU */
 
+#if CONFIG_IS_ENABLED(SPI_FLASH_MACRONIX)
+/**
+ * spi_nor_macronix_octal_dtr_enable() - set DTR OPI Enable bit in Configuration Register 2.
+ * @nor:	pointer to a 'struct spi_nor'
+ *
+ * Set the DTR OPI Enable (DOPI) bit in Configuration Register 2.
+ * Bit 2 of  Configuration Register 2 is the DOPI bit for Macronix like OPI memories.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int spi_nor_macronix_octal_dtr_enable(struct spi_nor *nor)
+{
+	struct spi_mem_op op;
+	int ret;
+	u8 buf;
+
+	ret = write_enable(nor);
+	if (ret)
+		return ret;
+
+	buf = SPINOR_REG_MXIC_DC_20;
+	op = (struct spi_mem_op)
+		SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_CR2, 1),
+			   SPI_MEM_OP_ADDR(4, SPINOR_REG_MXIC_CR2_DC, 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;
+
+	nor->read_dummy = MXIC_MAX_DC;
+	ret = write_enable(nor);
+	if (ret)
+		return ret;
+
+	buf = SPINOR_REG_MXIC_OPI_DTR_EN;
+	op = (struct spi_mem_op)
+		SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_CR2, 1),
+			   SPI_MEM_OP_ADDR(4, SPINOR_REG_MXIC_CR2_MODE, 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;
+	}
+	nor->reg_proto = SNOR_PROTO_8_8_8_DTR;
+
+	return 0;
+}
+
+static void macronix_octal_default_init(struct spi_nor *nor)
+{
+	nor->octal_dtr_enable = spi_nor_macronix_octal_dtr_enable;
+}
+
+static void macronix_octal_post_sfdp_fixup(struct spi_nor *nor,
+					 struct spi_nor_flash_parameter *params)
+{
+	/*
+	 * Adding SNOR_HWCAPS_PP_8_8_8_DTR in hwcaps.mask when
+	 * SPI_NOR_OCTAL_DTR_READ flag exists.
+	 */
+	if (params->hwcaps.mask & SNOR_HWCAPS_READ_8_8_8_DTR)
+		params->hwcaps.mask |= SNOR_HWCAPS_PP_8_8_8_DTR;
+}
+
+static struct spi_nor_fixups macronix_octal_fixups = {
+	.default_init = macronix_octal_default_init,
+	.post_sfdp = macronix_octal_post_sfdp_fixup,
+};
+#endif /* CONFIG_SPI_FLASH_MACRONIX */
+
 /** spi_nor_octal_dtr_enable() - enable Octal DTR I/O if needed
  * @nor:                 pointer to a 'struct spi_nor'
  *
@@ -3655,6 +3734,10 @@ void spi_nor_set_fixups(struct spi_nor *nor)
 	if (!strcmp(nor->info->name, "mt35xu512aba"))
 		nor->fixups = &mt35xu512aba_fixups;
 #endif
+
+#if CONFIG_IS_ENABLED(SPI_FLASH_MACRONIX)
+	nor->fixups = &macronix_octal_fixups;
+#endif /* SPI_FLASH_MACRONIX */
 }
 
 int spi_nor_scan(struct spi_nor *nor)
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 7ddc4ba2bf..8682368f2f 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -116,8 +116,16 @@
 #define XSR_RDY			BIT(7)	/* Ready */
 
 /* Used for Macronix and Winbond flashes. */
-#define SPINOR_OP_EN4B		0xb7	/* Enter 4-byte mode */
-#define SPINOR_OP_EX4B		0xe9	/* Exit 4-byte mode */
+#define SPINOR_OP_EN4B			0xb7		/* Enter 4-byte mode */
+#define SPINOR_OP_EX4B			0xe9		/* Exit 4-byte mode */
+#define SPINOR_OP_RD_CR2		0x71		/* Read configuration register 2 */
+#define SPINOR_OP_WR_CR2		0x72		/* Write configuration register 2 */
+#define SPINOR_OP_MXIC_DTR_RD		0xee		/* Fast Read opcode in DTR mode */
+#define SPINOR_REG_MXIC_CR2_MODE	0x00000000	/* For setting octal DTR mode */
+#define SPINOR_REG_MXIC_OPI_DTR_EN	0x2		/* Enable Octal DTR */
+#define SPINOR_REG_MXIC_CR2_DC		0x00000300	/* For setting dummy cycles */
+#define SPINOR_REG_MXIC_DC_20		0x0		/* Setting dummy cycles to 20 */
+#define MXIC_MAX_DC			20		/* Maximum value of dummy cycles */
 
 /* Used for Spansion flashes only. */
 #define SPINOR_OP_BRWR		0x17	/* Bank register write */
-- 
2.17.1