[PATCH v4 08/16] mtd: spi-nor: parse xSPI Profile 1.0 table

[Pratyush Yadav <p.yadav@xxxxxx>]

This table is indication that the flash is xSPI compliant and hence
supports octal DTR mode. Extract information like the fast read opcode,
the number of dummy cycles needed for a Read Status Register command,
and the number of address bytes needed for a Read Status Register
command.

The default dummy cycles for a fast octal DTR read are set to 20. Since
there is no simple way of determining the dummy cycles needed for the
fast read command, flashes that use a different value should update it
in their flash-specific hooks.

Since we want to set read settings, expose spi_nor_set_read_settings()
in core.h.

Signed-off-by: Pratyush Yadav <p.yadav@xxxxxx>
---
 drivers/mtd/spi-nor/core.c |  2 +-
 drivers/mtd/spi-nor/core.h | 10 +++++
 drivers/mtd/spi-nor/sfdp.c | 80 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 91 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index c8c1a3260e91..9c92fc897fb4 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -2355,7 +2355,7 @@ static int spi_nor_check(struct spi_nor *nor)
 	return 0;
 }
 
-static void
+void
 spi_nor_set_read_settings(struct spi_nor_read_command *read,
 			  u8 num_mode_clocks,
 			  u8 num_wait_states,
diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
index de1e3917889f..7e6df8322da0 100644
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h
@@ -192,6 +192,9 @@ struct spi_nor_locking_ops {
  *
  * @size:		the flash memory density in bytes.
  * @page_size:		the page size of the SPI NOR flash memory.
+ * @rdsr_dummy:		dummy cycles needed for Read Status Register command.
+ * @rdsr_addr_nbytes:	dummy address bytes needed for Read Status Register
+ *			command.
  * @hwcaps:		describes the read and page program hardware
  *			capabilities.
  * @reads:		read capabilities ordered by priority: the higher index
@@ -214,6 +217,8 @@ struct spi_nor_locking_ops {
 struct spi_nor_flash_parameter {
 	u64				size;
 	u32				page_size;
+	u8				rdsr_dummy;
+	u8				rdsr_addr_nbytes;
 
 	struct spi_nor_hwcaps		hwcaps;
 	struct spi_nor_read_command	reads[SNOR_CMD_READ_MAX];
@@ -424,6 +429,11 @@ ssize_t spi_nor_write_data(struct spi_nor *nor, loff_t to, size_t len,
 
 int spi_nor_hwcaps_read2cmd(u32 hwcaps);
 u8 spi_nor_convert_3to4_read(u8 opcode);
+void spi_nor_set_read_settings(struct spi_nor_read_command *read,
+			      u8 num_mode_clocks,
+			      u8 num_wait_states,
+			      u8 opcode,
+			      enum spi_nor_protocol proto);
 void spi_nor_set_pp_settings(struct spi_nor_pp_command *pp, u8 opcode,
 			     enum spi_nor_protocol proto);
 
diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c
index ab086aa4746f..cef8554ada19 100644
--- a/drivers/mtd/spi-nor/sfdp.c
+++ b/drivers/mtd/spi-nor/sfdp.c
@@ -4,6 +4,7 @@
  * Copyright (C) 2014, Freescale Semiconductor, Inc.
  */
 
+#include <linux/bitfield.h>
 #include <linux/slab.h>
 #include <linux/sort.h>
 #include <linux/mtd/spi-nor.h>
@@ -19,12 +20,14 @@
 #define SFDP_BFPT_ID		0xff00	/* Basic Flash Parameter Table */
 #define SFDP_SECTOR_MAP_ID	0xff81	/* Sector Map Table */
 #define SFDP_4BAIT_ID		0xff84  /* 4-byte Address Instruction Table */
+#define SFDP_PROFILE1_ID	0xff05	/* xSPI Profile 1.0 table. */
 
 #define SFDP_SIGNATURE		0x50444653U
 #define SFDP_JESD216_MAJOR	1
 #define SFDP_JESD216_MINOR	0
 #define SFDP_JESD216A_MINOR	5
 #define SFDP_JESD216B_MINOR	6
+#define SFDP_JESD216D_MINOR	8
 
 struct sfdp_header {
 	u32		signature; /* Ox50444653U <=> "SFDP" */
@@ -70,6 +73,11 @@ struct sfdp_bfpt_erase {
 	u32			shift;
 };
 
+/* xSPI Profile 1.0 table (from JESD216D.01). */
+#define PROFILE1_DWORD1_RD_FAST_CMD		GENMASK(15, 8)
+#define PROFILE1_DWORD1_RDSR_DUMMY		BIT(28)
+#define PROFILE1_DWORD1_RDSR_ADDR_BYTES		BIT(29)
+
 #define SMPT_CMD_ADDRESS_LEN_MASK		GENMASK(23, 22)
 #define SMPT_CMD_ADDRESS_LEN_0			(0x0UL << 22)
 #define SMPT_CMD_ADDRESS_LEN_3			(0x1UL << 22)
@@ -1110,6 +1118,74 @@ static int spi_nor_parse_4bait(struct spi_nor *nor,
 	return ret;
 }
 
+/**
+ * spi_nor_parse_profile1() - parse the xSPI Profile 1.0 table
+ * @nor:		pointer to a 'struct spi_nor'
+ * @param_header:	pointer to the 'struct sfdp_parameter_header' describing
+ *			the 4-Byte Address Instruction Table length and version.
+ * @params:		pointer to the 'struct spi_nor_flash_parameter' to be.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int spi_nor_parse_profile1(struct spi_nor *nor,
+				  const struct sfdp_parameter_header *profile1_header,
+				  struct spi_nor_flash_parameter *params)
+{
+	u32 *table, opcode, addr;
+	size_t len;
+	int ret, i;
+
+	len = profile1_header->length * sizeof(*table);
+	table = kmalloc(len, GFP_KERNEL);
+	if (!table)
+		return -ENOMEM;
+
+	addr = SFDP_PARAM_HEADER_PTP(profile1_header);
+	ret = spi_nor_read_sfdp(nor, addr, len, table);
+	if (ret)
+		goto out;
+
+	/* Fix endianness of the table DWORDs. */
+	for (i = 0; i < profile1_header->length; i++)
+		table[i] = le32_to_cpu(table[i]);
+
+	/* Get 8D-8D-8D fast read opcode and dummy cycles. */
+	opcode = FIELD_GET(PROFILE1_DWORD1_RD_FAST_CMD, table[0]);
+
+	/*
+	 * Update the fast read settings. We set the default dummy cycles to 20
+	 * here. Flashes can change this value if they need to when enabling
+	 * octal mode.
+	 */
+	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, opcode,
+				  SNOR_PROTO_8_8_8_DTR);
+
+	/*
+	 * Since the flash supports xSPI DTR reads, it should also support DTR
+	 * Page Program opcodes.
+	 */
+	params->hwcaps.mask |= SNOR_HWCAPS_PP_8_8_8_DTR;
+
+	/*
+	 * Set the Read Status Register dummy cycles and dummy address bytes.
+	 */
+	if (table[0] & PROFILE1_DWORD1_RDSR_DUMMY)
+		params->rdsr_dummy = 8;
+	else
+		params->rdsr_dummy = 4;
+
+	if (table[0] & PROFILE1_DWORD1_RDSR_ADDR_BYTES)
+		params->rdsr_addr_nbytes = 4;
+	else
+		params->rdsr_addr_nbytes = 0;
+
+out:
+	kfree(table);
+	return ret;
+}
+
 /**
  * spi_nor_parse_sfdp() - parse the Serial Flash Discoverable Parameters.
  * @nor:		pointer to a 'struct spi_nor'
@@ -1211,6 +1287,10 @@ int spi_nor_parse_sfdp(struct spi_nor *nor,
 			err = spi_nor_parse_4bait(nor, param_header, params);
 			break;
 
+		case SFDP_PROFILE1_ID:
+			err = spi_nor_parse_profile1(nor, param_header, params);
+			break;
+
 		default:
 			break;
 		}
-- 
2.25.0