Date:   Tue, 11 Feb 2020 19:03:48 +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>
CC:     <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <linux-spi@...r.kernel.org>, Sekhar Nori <nsekhar@...com>,
        Pratyush Yadav <p.yadav@...com>
Subject: [PATCH 9/9] 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. Switch to uniform
sector mode on boot. Use the default 20 dummy cycles for a read fast
command.

The SFDP programming on some older versions of the flash was incorrect.
Fixes for that are included in the fixup hooks.

Signed-off-by: Pratyush Yadav <p.yadav@...com>
---
 drivers/mtd/spi-nor/spi-nor.c | 192 ++++++++++++++++++++++++++++++++++
 include/linux/mtd/spi-nor.h   |  14 +++
 2 files changed, 206 insertions(+)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 78e3475fa2a9..367e3d0f65aa 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -260,6 +260,12 @@ struct flash_info {
 
 #define JEDEC_MFR(info)	((info)->id[0])
 
+/* Forward declarations that will be used by s28hs512t_setup(). */
+static int spi_nor_default_setup(struct spi_nor *nor,
+				 const struct spi_nor_hwcaps *hwcaps);
+static void spi_nor_set_pp_settings(struct spi_nor_pp_command *pp,
+				    u8 opcode, enum spi_nor_protocol proto);
+
 /**
  * spi_nor_spimem_setup_op() - Set up common properties of a spi-mem op.
  * @nor:		pointer to a 'struct spi_nor'
@@ -2241,6 +2247,65 @@ 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)
+{
+	struct spi_mem_op op;
+	u8 *buf = nor->bouncebuf;
+	u8 addr_width = 3;
+	int ret;
+
+	/* 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->params.reads[SNOR_CMD_READ_8_8_8_DTR].num_wait_states = 20;
+	nor->params.reads[SNOR_CMD_READ_8_8_8_DTR].num_mode_clocks = 0;
+
+	/* Set the octal and DTR enable bits. */
+	ret = spi_nor_write_enable(nor);
+	if (ret)
+		return ret;
+
+	*buf = SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_EN;
+	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));
+	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.
@@ -2453,6 +2518,130 @@ static struct spi_nor_fixups gd25q256_fixups = {
 	.default_init = gd25q256_default_init,
 };
 
+static int s28hs512t_setup(struct spi_nor *nor,
+			    const struct spi_nor_hwcaps *hwcaps)
+{
+	struct spi_mem_op op;
+	u8 *buf = nor->bouncebuf;
+	u8 addr_width = 3;
+	int ret;
+
+	if (!nor->spimem) {
+		dev_err(nor->dev,
+			"operation not supported for non-spimem drivers\n");
+		return -ENOTSUPP;
+	}
+
+	/*
+	 * This Cypress flash also supports hybrid sector sizes. Make sure
+	 * uniform sector mode is selected. This is done by setting the bit
+	 * CFR3N[3].
+	 */
+	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_CFR3N, 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;
+
+	ret = spi_nor_write_enable(nor);
+	if (ret)
+		return ret;
+
+	/* Set the uniform sector mode bit. */
+	*buf |= SPINOR_REG_CYPRESS_CFR3N_UNISECT;
+	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_CFR3N, 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_err(nor->dev, "Failed to change to uniform sector mode\n");
+		return ret;
+	}
+
+	ret = spi_nor_wait_till_ready(nor);
+	if (ret)
+		return ret;
+
+	return spi_nor_default_setup(nor, hwcaps);
+}
+
+static void s28hs512t_default_init(struct spi_nor *nor)
+{
+	nor->params.octal_dtr_enable = spi_nor_cypress_octal_enable;
+	nor->params.setup = s28hs512t_setup;
+}
+
+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.
@@ -2715,6 +2904,9 @@ 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)
+		.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 c653f6713cfc..e765272fc0f4 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -150,6 +150,20 @@
 #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_CFR3N		0x00000004
+#define SPINOR_REG_CYPRESS_CFR3V		0x00800004
+#define SPINOR_REG_CYPRESS_CFR3V_PGSZ		BIT(4) /* Page size. */
+#define SPINOR_REG_CYPRESS_CFR3N_UNISECT	BIT(3) /* Uniform sector mode */
+#define SPINOR_REG_CYPRESS_CFR4V		0x00800005
+#define SPINOR_REG_CYPRESS_CFR5V		0x00800006
+#define SPINOR_REG_CYPRESS_CFR5V_OCT_DTR_EN	0x3
+#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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