mtd: spi-nor-core: Allow using Micron mt35xu512aba in Octal DTR mode

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.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

3 files changed, 98 insertions, 1 deletions

diff --git a/drivers/mtd/spi/Kconfig b/drivers/mtd/spi/Kconfig
index 98c0b23..1b2ef37 100644
--- a/drivers/mtd/spi/Kconfig
+++ b/drivers/mtd/spi/Kconfig
@@ -180,6 +180,14 @@ config SPI_FLASH_STMICRO
 	help
 	  Add support for various STMicro SPI flash chips (M25Pxxx and N25Qxxx)
 
+config SPI_FLASH_MT35XU
+	bool "Micron MT35XU chip support"
+	depends on SPI_FLASH_STMICRO
+	help
+	 Add support for the Micron MT35XU chip. This is a separate config
+	 because the fixup hooks for this flash add extra size overhead. Boards
+	 that don't use the flash can disable this to save space.
+
 config SPI_FLASH_SST
 	bool "SST SPI flash support"
 	help
diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index 3a1060b..8dd44c0 100644
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -3148,6 +3148,88 @@ static struct spi_nor_fixups s28hs512t_fixups = {
 };
 #endif /* CONFIG_SPI_FLASH_S28HS512T */
 
+#ifdef CONFIG_SPI_FLASH_MT35XU
+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;
+
+	/* 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;
+
+	nor->read_dummy = 20;
+
+	ret = write_enable(nor);
+	if (ret)
+		return ret;
+
+	buf = SPINOR_MT_OCT_DTR;
+	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 void mt35xu512aba_default_init(struct spi_nor *nor)
+{
+	nor->octal_dtr_enable = spi_nor_micron_octal_dtr_enable;
+}
+
+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;
+
+	/*
+	 * The BFPT quad enable field is set to a reserved value so the quad
+	 * enable function is ignored by spi_nor_parse_bfpt(). Make sure we
+	 * disable it.
+	 */
+	params->quad_enable = NULL;
+}
+
+static struct spi_nor_fixups mt35xu512aba_fixups = {
+	.default_init = mt35xu512aba_default_init,
+	.post_sfdp = mt35xu512aba_post_sfdp_fixup,
+};
+#endif /* CONFIG_SPI_FLASH_MT35XU */
+
 /** spi_nor_octal_dtr_enable() - enable Octal DTR I/O if needed
  * @nor:                 pointer to a 'struct spi_nor'
  *
@@ -3295,6 +3377,11 @@ void spi_nor_set_fixups(struct spi_nor *nor)
 	if (!strcmp(nor->info->name, "s28hs512t"))
 		nor->fixups = &s28hs512t_fixups;
 #endif
+
+#ifdef CONFIG_SPI_FLASH_MT35XU
+	if (!strcmp(nor->info->name, "mt35xu512aba"))
+		nor->fixups = &mt35xu512aba_fixups;
+#endif
 }
 
 int spi_nor_scan(struct spi_nor *nor)
diff --git a/drivers/mtd/spi/spi-nor-ids.c b/drivers/mtd/spi/spi-nor-ids.c
index bbed88a..59f2d3e 100644
--- a/drivers/mtd/spi/spi-nor-ids.c
+++ b/drivers/mtd/spi/spi-nor-ids.c
@@ -193,7 +193,9 @@ const struct flash_info spi_nor_ids[] = {
 	{ INFO("n25q00a",     0x20bb21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
 	{ INFO("mt25ql01g",   0x21ba20, 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_OCTAL_READ | SPI_NOR_4B_OPCODES) },
+#ifdef CONFIG_SPI_FLASH_MT35XU
+	{ INFO("mt35xu512aba", 0x2c5b1a, 0,  128 * 1024,  512, USE_FSR | SPI_NOR_OCTAL_READ | SPI_NOR_4B_OPCODES | SPI_NOR_OCTAL_DTR_READ) },
+#endif /* CONFIG_SPI_FLASH_MT35XU */
 	{ INFO("mt35xu02g",  0x2c5b1c, 0, 128 * 1024,  2048, USE_FSR | SPI_NOR_OCTAL_READ | SPI_NOR_4B_OPCODES) },
 #endif
 #ifdef CONFIG_SPI_FLASH_SPANSION	/* SPANSION */