[PATCH v8 1/4] mtd: spi-nor: add support for Macronix Octal flash

[JaimeLiao]

Follow patch <f6adec1af4b2f5d3012480c6cdce7743b74a6156> (Allow using Micron mt35xu512aba
in Octal DTR mode).
Enable Octal DTR mode with 20 dummy cycles to allow running at the
maximum supported frequency for adding Macronix flash in Octal DTR mode.
 -https://www.mxic.com.tw/Lists/Datasheet/Attachments/7841/MX25LM51245G,%203V,%20512Mb,%20v1.1.pdf

Signed-off-by: JaimeLiao <jaimeliao.tw at gmail.com>
---
 drivers/mtd/spi/spi-nor-core.c | 82 ++++++++++++++++++++++++++++++++++
 include/linux/mtd/spi-nor.h    | 10 +++++
 2 files changed, 92 insertions(+)

diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index 3b7c817c02..5d319e4c0f 100644
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -3526,6 +3526,84 @@ 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() - Enable octal DTR on Macronix flashes.
+ * @nor:	pointer to a 'struct spi_nor'
+ *
+ * Set Macronix max dummy cycles 20 to allow the flash to run at fastest frequency.
+ *
+ * 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'
  *
@@ -3696,6 +3774,10 @@ 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 4ceeae623d..c76235d701 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -119,6 +119,16 @@
 /* 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