Date:   Fri, 13 Mar 2020 21:16:45 +0530
From:   Pratyush Yadav <p.yadav@...com>
To:     Tudor Ambarus <tudor.ambarus@...rochip.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        Mark Brown <broonie@...nel.org>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Ludovic Desroches <ludovic.desroches@...rochip.com>
CC:     Pratyush Yadav <p.yadav@...com>, <linux-mtd@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <linux-spi@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        Sekhar Nori <nsekhar@...com>
Subject: [PATCH v3 12/12] mtd: spi-nor: add support for Cypress Semper flash

The Cypress Semper flash is an xSPI compliant octal DTR flash. Add
support for using it in octal DTR mode.

The flash by default boots in a hybrid sector mode. But the sector map
table on the part I had was programmed incorrectly and the SMPT values
on the flash don't match the public datasheet. Specifically, in some
places erase type 3 was used instead of 4. In addition, the region sizes
were incorrect in some places. So, for testing I set CFR3N[3] to enable
uniform sector sizes. Since the uniform sector mode bit is a
non-volatile bit, this series does not change it to avoid making any
permanent changes to the flash configuration. The correct data to
implement a fixup is not available right now and will be done in a
follow-up patch if needed.

Signed-off-by: Pratyush Yadav <p.yadav@...com>
---
 drivers/mtd/spi-nor/spi-nor.c | 156 ++++++++++++++++++++++++++++++++++
 include/linux/mtd/spi-nor.h   |  13 +++
 2 files changed, 169 insertions(+)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 32f7ecbc38d4..daaff3dc7376 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -264,6 +264,10 @@ struct flash_info {
 #define SPI_NOR_SRST_SLEEP_MIN	200
 #define SPI_NOR_SRST_SLEEP_MAX	400
 
+/* Forward declaration that will be used by s28hs512t_post_sfdp_fixup(). */
+static void spi_nor_set_pp_settings(struct spi_nor_pp_command *pp,
+				    u8 opcode, enum spi_nor_protocol proto);
+
 /**
  * spi_nor_get_cmd_ext() - Get the command opcode extension based on the
  *			   extension type.
@@ -2297,6 +2301,84 @@ static int spi_nor_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 	return ret;
 }
 
+/**
+ * spi_nor_cypress_octal_enable() - Enable octal DTR mode on Cypress flashes.
+ * @nor:		pointer to a 'struct spi_nor'
+ *
+ * This also sets the memory access latency cycles to 20, which is the default
+ * in the spi-nor framework.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int spi_nor_cypress_octal_enable(struct spi_nor *nor, bool enable)
+{
+	struct spi_mem_op op;
+	u8 *buf = nor->bouncebuf;
+	u8 addr_width;
+	int ret;
+
+	if (enable)
+		addr_width = 3;
+	else
+		addr_width = 4;
+
+	if (enable) {
+		/* Use 20 dummy cycles for memory array reads. */
+		ret = spi_nor_write_enable(nor);
+		if (ret)
+			return ret;
+
+		*buf = SPINOR_REG_CYPRESS_CFR2V_MEMLAT_8_20;
+		op = (struct spi_mem_op)
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_ANY_REG, 1),
+				   SPI_MEM_OP_ADDR(addr_width,
+						   SPINOR_REG_CYPRESS_CFR2V,
+						   1),
+				   SPI_MEM_OP_NO_DUMMY,
+				   SPI_MEM_OP_DATA_OUT(1, buf, 1));
+		ret = spi_mem_exec_op(nor->spimem, &op);
+		if (ret) {
+			dev_warn(nor->dev,
+				 "failed to set default memory latency value: %d\n",
+				 ret);
+			return ret;
+		}
+		ret = spi_nor_wait_till_ready(nor);
+		if (ret)
+			return ret;
+
+		nor->read_dummy = 20;
+	}
+
+	/* Set/unset the octal and DTR enable bits. */
+	ret = spi_nor_write_enable(nor);
+	if (ret)
+		return ret;
+
+	if (enable)
+		*buf = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_EN;
+	else
+		*buf = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_DS;
+	op = (struct spi_mem_op)
+		SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_ANY_REG, 1),
+			   SPI_MEM_OP_ADDR(addr_width,
+					   SPINOR_REG_CYPRESS_CFR5V,
+					   1),
+			   SPI_MEM_OP_NO_DUMMY,
+			   SPI_MEM_OP_DATA_OUT(1, buf, 1));
+
+	if (!enable)
+		spi_nor_spimem_setup_op(nor, &op, SNOR_PROTO_8_8_8_DTR);
+
+	ret = spi_mem_exec_op(nor->spimem, &op);
+	if (ret) {
+		dev_warn(nor->dev, "Failed to enable octal DTR mode\n");
+		return ret;
+	}
+
+	return 0;
+}
+
 /**
  * spi_nor_sr1_bit6_quad_enable() - Set the Quad Enable BIT(6) in the Status
  * Register 1.
@@ -2509,6 +2591,77 @@ static struct spi_nor_fixups gd25q256_fixups = {
 	.default_init = gd25q256_default_init,
 };
 
+static void s28hs512t_default_init(struct spi_nor *nor)
+{
+	nor->params.octal_dtr_enable = spi_nor_cypress_octal_enable;
+}
+
+static void s28hs512t_post_sfdp_fixup(struct spi_nor *nor)
+{
+	/*
+	 * On older versions of the flash the xSPI Profile 1.0 table has the
+	 * 8D-8D-8D Fast Read opcode as 0x00. But it actually should be 0xEE.
+	 */
+	if (nor->params.reads[SNOR_CMD_READ_8_8_8_DTR].opcode == 0)
+		nor->params.reads[SNOR_CMD_READ_8_8_8_DTR].opcode =
+			SPINOR_OP_CYPRESS_RD_FAST;
+
+	/* This flash is also missing the 4-byte Page Program opcode bit. */
+	spi_nor_set_pp_settings(&nor->params.page_programs[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(&nor->params.page_programs[SNOR_CMD_PP_8_8_8_DTR],
+				SPINOR_OP_PP_4B, SNOR_PROTO_8_8_8_DTR);
+
+	/*
+	 * The xSPI Profile 1.0 table advertises the number of additional
+	 * address bytes needed for Read Status Register command as 0 but the
+	 * actual value for that is 4.
+	 */
+	nor->params.rdsr_addr_nbytes = 4;
+}
+
+static int s28hs512t_post_bfpt_fixup(struct spi_nor *nor,
+				     const struct sfdp_parameter_header *bfpt_header,
+				     const struct sfdp_bfpt *bfpt,
+				     struct spi_nor_flash_parameter *params)
+{
+	struct spi_mem_op op;
+	u8 *buf = nor->bouncebuf;
+	u8 addr_width = 3;
+	int ret;
+
+	/*
+	 * The BFPT table advertises a 512B page size but the page size is
+	 * actually configurable (with the default being 256B). Read from
+	 * CFR3V[4] and set the correct size.
+	 */
+	op = (struct spi_mem_op)
+		SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RD_ANY_REG, 1),
+			   SPI_MEM_OP_ADDR(addr_width, SPINOR_REG_CYPRESS_CFR3V, 1),
+			   SPI_MEM_OP_NO_DUMMY,
+			   SPI_MEM_OP_DATA_IN(1, buf, 1));
+	ret = spi_mem_exec_op(nor->spimem, &op);
+	if (ret)
+		return ret;
+
+	if (*buf & SPINOR_REG_CYPRESS_CFR3V_PGSZ)
+		params->page_size = 512;
+	else
+		params->page_size = 256;
+
+	return 0;
+}
+
+static struct spi_nor_fixups s28hs512t_fixups = {
+	.default_init = s28hs512t_default_init,
+	.post_sfdp = s28hs512t_post_sfdp_fixup,
+	.post_bfpt = s28hs512t_post_bfpt_fixup,
+};
+
 /* NOTE: double check command sets and memory organization when you add
  * more nor chips.  This current list focusses on newer chips, which
  * have been converging on command sets which including JEDEC ID.
@@ -2771,6 +2924,9 @@ static const struct flash_info spi_nor_ids[] = {
 	{ "s25fl064l",  INFO(0x016017,      0,  64 * 1024, 128, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
 	{ "s25fl128l",  INFO(0x016018,      0,  64 * 1024, 256, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
 	{ "s25fl256l",  INFO(0x016019,      0,  64 * 1024, 512, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
+	{ "s28hs512t",  INFO(0x345b1a,      0, 256 * 1024, 256, SECT_4K | SPI_NOR_OCTAL_DTR_READ | SPI_NOR_SOFT_RESET)
+		.fixups = &s28hs512t_fixups,
+	},
 
 	/* SST -- large erase sizes are "overlays", "sectors" are 4K */
 	{ "sst25vf040b", INFO(0xbf258d, 0, 64 * 1024,  8, SECT_4K | SST_WRITE) },
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 13679197dec1..20337bcda207 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -154,6 +154,19 @@
 #define SR2_QUAD_EN_BIT1	BIT(1)
 #define SR2_QUAD_EN_BIT7	BIT(7)
 
+/* For Cypress flash. */
+#define SPINOR_OP_RD_ANY_REG			0x65	/* Read any register */
+#define SPINOR_OP_WR_ANY_REG			0x71	/* Write any register */
+#define SPINOR_REG_CYPRESS_CFR2V		0x00800003
+#define SPINOR_REG_CYPRESS_CFR2V_MEMLAT_8_20	0x8
+#define SPINOR_REG_CYPRESS_CFR3V		0x00800004
+#define SPINOR_REG_CYPRESS_CFR3V_PGSZ		BIT(4) /* Page size. */
+#define SPINOR_REG_CYPRESS_CFR4V		0x00800005
+#define SPINOR_REG_CYPRESS_CFR5V		0x00800006
+#define SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_EN	0x3
+#define SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_DS	0
+#define SPINOR_OP_CYPRESS_RD_FAST		0xee
+
 /* Supported SPI protocols */
 #define SNOR_PROTO_INST_MASK	GENMASK(23, 16)
 #define SNOR_PROTO_INST_SHIFT	16
-- 
2.25.0

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