[PATCH v3 2/2] mtd: spi-nor: parse Serial Flash Discoverable Parameters (SFDP) tables

From: Cyrille Pitchen
Date: Mon Jun 26 2017 - 09:10:31 EST

This patch adds support to the JESD216 rev B standard and parses the SFDP
tables to dynamically initialize the 'struct spi_nor_flash_parameter'.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@xxxxxxxxxxxxx>
---
drivers/mtd/spi-nor/spi-nor.c | 775 +++++++++++++++++++++++++++++++++++++++++-
include/linux/mtd/spi-nor.h | 6 +
2 files changed, 768 insertions(+), 13 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 040ab5d7ac05..dac789ff70ea 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -17,6 +17,7 @@
#include <linux/mutex.h>
#include <linux/math64.h>
#include <linux/sizes.h>
+#include <linux/slab.h>

#include <linux/mtd/mtd.h>
#include <linux/of_platform.h>
@@ -86,6 +87,7 @@ struct flash_info {
* to support memory size above 128Mib.
*/
#define NO_CHIP_ERASE BIT(12) /* Chip does not support chip erase */
+#define SPI_NOR_SKIP_SFDP BIT(13) /* Skip parsing of SFDP tables */
};

#define JEDEC_MFR(info) ((info)->id[0])
@@ -1378,6 +1380,16 @@ static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
return ret;
}

+/**
+ * macronix_quad_enable() - set QE bit in Status Register.
+ * @nor: pointer to a 'struct spi_nor'
+ *
+ * Set the Quad Enable (QE) bit in the Status Register.
+ *
+ * bit 6 of the Status Register is the QE bit for Macronix like QSPI memories.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
static int macronix_quad_enable(struct spi_nor *nor)
{
int ret, val;
@@ -1411,22 +1423,13 @@ static int macronix_quad_enable(struct spi_nor *nor)
* second byte will be written to the configuration register.
* Return negative if error occurred.
*/
-static int write_sr_cr(struct spi_nor *nor, u16 val)
-{
- nor->cmd_buf[0] = val & 0xff;
- nor->cmd_buf[1] = (val >> 8);
-
- return nor->write_reg(nor, SPINOR_OP_WRSR, nor->cmd_buf, 2);
-}
-
-static int spansion_quad_enable(struct spi_nor *nor)
+static int write_sr_cr(struct spi_nor *nor, u8 *sr_cr)
{
int ret;
- int quad_en = CR_QUAD_EN_SPAN << 8;

write_enable(nor);

- ret = write_sr_cr(nor, quad_en);
+ ret = nor->write_reg(nor, SPINOR_OP_WRSR, sr_cr, 2);
if (ret < 0) {
dev_err(nor->dev,
"error while writing configuration register\n");
@@ -1440,6 +1443,41 @@ static int spansion_quad_enable(struct spi_nor *nor)
return ret;
}

+ return 0;
+}
+
+/**
+ * spansion_quad_enable() - set QE bit in Configuraiton Register.
+ * @nor: pointer to a 'struct spi_nor'
+ *
+ * Set the Quad Enable (QE) bit in the Configuration Register.
+ * This function is kept for legacy purpose because it has been used for a
+ * long time without anybody complaining but it should be considered as
+ * deprecated and maybe buggy.
+ * First, this function doesn't care about the previous values of the Status
+ * and Configuration Registers when it sets the QE bit (bit 1) in the
+ * Configuration Register: all other bits are cleared, which may have unwanted
+ * side effects like removing some block protections.
+ * Secondly, it uses the Read Configuration Register (35h) instruction though
+ * some very old and few memories don't support this instruction. If a pull-up
+ * resistor is present on the MISO/IO1 line, we might still be able to pass the
+ * "read back" test because the QSPI memory doesn't recognize the command,
+ * so leaves the MISO/IO1 line state unchanged, hence read_cr() returns 0xFF.
+ *
+ * bit 1 of the Configuration Register is the QE bit for Spansion like QSPI
+ * memories.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int spansion_quad_enable(struct spi_nor *nor)
+{
+ u8 sr_cr[2] = {0, CR_QUAD_EN_SPAN};
+ int ret;
+
+ ret = write_sr_cr(nor, sr_cr);
+ if (ret)
+ return ret;
+
/* read back and check it */
ret = read_cr(nor);
if (!(ret > 0 && (ret & CR_QUAD_EN_SPAN))) {
@@ -1450,6 +1488,140 @@ static int spansion_quad_enable(struct spi_nor *nor)
return 0;
}

+/**
+ * spansion_no_read_cr_quad_enable() - set QE bit in Configuration Register.
+ * @nor: pointer to a 'struct spi_nor'
+ *
+ * Set the Quad Enable (QE) bit in the Configuration Register.
+ * This function should be used with QSPI memories not supporting the Read
+ * Configuration Register (35h) instruction.
+ *
+ * bit 1 of the Configuration Register is the QE bit for Spansion like QSPI
+ * memories.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int spansion_no_read_cr_quad_enable(struct spi_nor *nor)
+{
+ u8 sr_cr[2];
+ int ret;
+
+ /* Keep the current value of the Status Register. */
+ ret = read_sr(nor);
+ if (ret < 0) {
+ dev_err(nor->dev, "error while reading status register\n");
+ return -EINVAL;
+ }
+ sr_cr[0] = ret;
+ sr_cr[1] = CR_QUAD_EN_SPAN;
+
+ return write_sr_cr(nor, sr_cr);
+}
+
+/**
+ * spansion_read_cr_quad_enable() - set QE bit in Configuration Register.
+ * @nor: pointer to a 'struct spi_nor'
+ *
+ * Set the Quad Enable (QE) bit in the Configuration Register.
+ * This function should be used with QSPI memories supporting the Read
+ * Configuration Register (35h) instruction.
+ *
+ * bit 1 of the Configuration Register is the QE bit for Spansion like QSPI
+ * memories.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int spansion_read_cr_quad_enable(struct spi_nor *nor)
+{
+ struct device *dev = nor->dev;
+ u8 sr_cr[2];
+ int ret;
+
+ /* Check current Quad Enable bit value. */
+ ret = read_cr(nor);
+ if (ret < 0) {
+ dev_err(dev, "error while reading configuration register\n");
+ return -EINVAL;
+ }
+
+ if (ret & CR_QUAD_EN_SPAN)
+ return 0;
+
+ sr_cr[1] = ret | CR_QUAD_EN_SPAN;
+
+ /* Keep the current value of the Status Register. */
+ ret = read_sr(nor);
+ if (ret < 0) {
+ dev_err(dev, "error while reading status register\n");
+ return -EINVAL;
+ }
+ sr_cr[0] = ret;
+
+ ret = write_sr_cr(nor, sr_cr);
+ if (ret)
+ return ret;
+
+ /* Read back and check it. */
+ ret = read_cr(nor);
+ if (!(ret > 0 && (ret & CR_QUAD_EN_SPAN))) {
+ dev_err(nor->dev, "Spansion Quad bit not set\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/**
+ * sr2_bit7_quad_enable() - set QE bit in Status Register 2.
+ * @nor: pointer to a 'struct spi_nor'
+ *
+ * Set the Quad Enable (QE) bit in the Status Register 2.
+ *
+ * This is one of the procedures to set the QE bit described in the SFDP
+ * (JESD216 rev B) specification but no manufacturer using this procedure has
+ * been identified yet, hence the name of the function.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int sr2_bit7_quad_enable(struct spi_nor *nor)
+{
+ u8 sr2;
+ int ret;
+
+ /* Check current Quad Enable bit value. */
+ ret = nor->read_reg(nor, SPINOR_OP_RDSR2, &sr2, 1);
+ if (ret)
+ return ret;
+ if (sr2 & SR2_QUAD_EN_BIT7)
+ return 0;
+
+ /* Update the Quad Enable bit. */
+ sr2 |= SR2_QUAD_EN_BIT7;
+
+ write_enable(nor);
+
+ ret = nor->write_reg(nor, SPINOR_OP_WRSR2, &sr2, 1);
+ if (ret < 0) {
+ dev_err(nor->dev, "error while writing status register 2\n");
+ return -EINVAL;
+ }
+
+ ret = spi_nor_wait_till_ready(nor);
+ if (ret < 0) {
+ dev_err(nor->dev, "timeout while writing status register 2\n");
+ return ret;
+ }
+
+ /* Read back and check it. */
+ ret = nor->read_reg(nor, SPINOR_OP_RDSR2, &sr2, 1);
+ if (!(ret > 0 && (sr2 & SR2_QUAD_EN_BIT7))) {
+ dev_err(nor->dev, "SR2 Quad bit not set\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static int spi_nor_check(struct spi_nor *nor)
{
if (!nor->dev || !nor->read || !nor->write ||
@@ -1589,6 +1761,560 @@ spi_nor_set_pp_settings(struct spi_nor_pp_command *pp,
pp->proto = proto;
}

+/*
+ * Serial Flash Discoverable Parameters (SFDP) parsing.
+ */
+
+/**
+ * spi_nor_read_sfdp() - read Serial Flash Discoverable Parameters.
+ * @nor: pointer to a 'struct spi_nor'
+ * @addr: offset in the SFDP area to start reading data from
+ * @len: number of bytes to read
+ * @buf: buffer where the SFDP data are copied into
+ *
+ * Whatever the actual numbers of bytes for address and dummy cycles are
+ * for (Fast) Read commands, the Read SFDP (5Ah) instruction is always
+ * followed by a 3-byte address and 8 dummy clock cycles.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int spi_nor_read_sfdp(struct spi_nor *nor, u32 addr,
+ size_t len, void *buf)
+{
+ u8 addr_width, read_opcode, read_dummy;
+ int ret;
+
+ read_opcode = nor->read_opcode;
+ addr_width = nor->addr_width;
+ read_dummy = nor->read_dummy;
+
+ nor->read_opcode = SPINOR_OP_RDSFDP;
+ nor->addr_width = 3;
+ nor->read_dummy = 8;
+
+ while (len) {
+ ret = nor->read(nor, addr, len, (u8 *)buf);
+ if (!ret || ret > len) {
+ ret = -EIO;
+ goto read_err;
+ }
+ if (ret < 0)
+ goto read_err;
+
+ buf += ret;
+ addr += ret;
+ len -= ret;
+ }
+ ret = 0;
+
+read_err:
+ nor->read_opcode = read_opcode;
+ nor->addr_width = addr_width;
+ nor->read_dummy = read_dummy;
+
+ return ret;
+}
+
+struct sfdp_parameter_header {
+ u8 id_lsb;
+ u8 minor;
+ u8 major;
+ u8 length; /* in double words */
+ u8 parameter_table_pointer[3]; /* byte address */
+ u8 id_msb;
+};
+
+#define SFDP_PARAM_HEADER_ID(p) (((p)->id_msb << 8) | (p)->id_lsb)
+#define SFDP_PARAM_HEADER_PTP(p) \
+ (((p)->parameter_table_pointer[2] << 16) | \
+ ((p)->parameter_table_pointer[1] << 8) | \
+ ((p)->parameter_table_pointer[0] << 0))
+
+#define SFDP_BFPT_ID 0xff00 /* Basic Flash Parameter Table */
+#define SFDP_SECTOR_MAP_ID 0xff81 /* Sector Map 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
+
+struct sfdp_header {
+ u32 signature; /* Ox50444653U <=> "SFDP" */
+ u8 minor;
+ u8 major;
+ u8 nph; /* 0-base number of parameter headers */
+ u8 unused;
+
+ /* Basic Flash Parameter Table. */
+ struct sfdp_parameter_header bfpt_header;
+};
+
+/* Basic Flash Parameter Table */
+
+/*
+ * JESD216 rev B defines a Basic Flash Parameter Table of 16 DWORDs.
+ * They are indexed from 1 but C arrays are indexed from 0.
+ */
+#define BFPT_DWORD(i) ((i) - 1)
+#define BFPT_DWORD_MAX 16
+
+/* The first version of JESB216 defined only 9 DWORDs. */
+#define BFPT_DWORD_MAX_JESD216 9
+
+/* 1st DWORD. */
+#define BFPT_DWORD1_FAST_READ_1_1_2 BIT(16)
+#define BFPT_DWORD1_ADDRESS_BYTES_MASK GENMASK(18, 17)
+#define BFPT_DWORD1_ADDRESS_BYTES_3_ONLY (0x0UL << 17)
+#define BFPT_DWORD1_ADDRESS_BYTES_3_OR_4 (0x1UL << 17)
+#define BFPT_DWORD1_ADDRESS_BYTES_4_ONLY (0x2UL << 17)
+#define BFPT_DWORD1_DTR BIT(19)
+#define BFPT_DWORD1_FAST_READ_1_2_2 BIT(20)
+#define BFPT_DWORD1_FAST_READ_1_4_4 BIT(21)
+#define BFPT_DWORD1_FAST_READ_1_1_4 BIT(22)
+
+/* 5th DWORD. */
+#define BFPT_DWORD5_FAST_READ_2_2_2 BIT(0)
+#define BFPT_DWORD5_FAST_READ_4_4_4 BIT(4)
+
+/* 11th DWORD. */
+#define BFPT_DWORD11_PAGE_SIZE_SHIFT 4
+#define BFPT_DWORD11_PAGE_SIZE_MASK GENMASK(7, 4)
+
+/* 15th DWORD. */
+
+/*
+ * (from JESD216 rev B)
+ * Quad Enable Requirements (QER):
+ * - 000b: Device does not have a QE bit. Device detects 1-1-4 and 1-4-4
+ * reads based on instruction. DQ3/HOLD# functions are hold during
+ * instruction phase.
+ * - 001b: QE is bit 1 of status register 2. It is set via Write Status with
+ * two data bytes where bit 1 of the second byte is one.
+ * [...]
+ * Writing only one byte to the status register has the side-effect of
+ * clearing status register 2, including the QE bit. The 100b code is
+ * used if writing one byte to the status register does not modify
+ * status register 2.
+ * - 010b: QE is bit 6 of status register 1. It is set via Write Status with
+ * one data byte where bit 6 is one.
+ * [...]
+ * - 011b: QE is bit 7 of status register 2. It is set via Write status
+ * register 2 instruction 3Eh with one data byte where bit 7 is one.
+ * [...]
+ * The status register 2 is read using instruction 3Fh.
+ * - 100b: QE is bit 1 of status register 2. It is set via Write Status with
+ * two data bytes where bit 1 of the second byte is one.
+ * [...]
+ * In contrast to the 001b code, writing one byte to the status
+ * register does not modify status register 2.
+ * - 101b: QE is bit 1 of status register 2. Status register 1 is read using
+ * Read Status instruction 05h. Status register2 is read using
+ * instruction 35h. QE is set via Writ Status instruction 01h with
+ * two data bytes where bit 1 of the second byte is one.
+ * [...]
+ */
+#define BFPT_DWORD15_QER_MASK GENMASK(22, 20)
+#define BFPT_DWORD15_QER_NONE (0x0UL << 20) /* Micron */
+#define BFPT_DWORD15_QER_SR2_BIT1_BUGGY (0x1UL << 20)
+#define BFPT_DWORD15_QER_SR1_BIT6 (0x2UL << 20) /* Macronix */
+#define BFPT_DWORD15_QER_SR2_BIT7 (0x3UL << 20)
+#define BFPT_DWORD15_QER_SR2_BIT1_NO_RD (0x4UL << 20)
+#define BFPT_DWORD15_QER_SR2_BIT1 (0x5UL << 20) /* Spansion */
+
+struct sfdp_bfpt {
+ u32 dwords[BFPT_DWORD_MAX];
+};
+
+/* Fast Read settings. */
+
+static inline void
+spi_nor_set_read_settings_from_bfpt(struct spi_nor_read_command *read,
+ u16 half,
+ enum spi_nor_protocol proto)
+{
+ read->num_mode_clocks = (half >> 5) & 0x07;
+ read->num_wait_states = (half >> 0) & 0x1f;
+ read->opcode = (half >> 8) & 0xff;
+ read->proto = proto;
+}
+
+struct sfdp_bfpt_read {
+ /* The Fast Read x-y-z hardware capability in params->hwcaps.mask. */
+ u32 hwcaps;
+
+ /*
+ * The <supported_bit> bit in <supported_dword> BFPT DWORD tells us
+ * whether the Fast Read x-y-z command is supported.
+ */
+ u32 supported_dword;
+ u32 supported_bit;
+
+ /*
+ * The half-word at offset <setting_shift> in <setting_dword> BFPT DWORD
+ * encodes the op code, the number of mode clocks and the number of wait
+ * states to be used by Fast Read x-y-z command.
+ */
+ u32 settings_dword;
+ u32 settings_shift;
+
+ /* The SPI protocol for this Fast Read x-y-z command. */
+ enum spi_nor_protocol proto;
+};
+
+static const struct sfdp_bfpt_read sfdp_bfpt_reads[] = {
+ /* Fast Read 1-1-2 */
+ {
+ SNOR_HWCAPS_READ_1_1_2,
+ BFPT_DWORD(1), BIT(16), /* Supported bit */
+ BFPT_DWORD(4), 0, /* Settings */
+ SNOR_PROTO_1_1_2,
+ },
+
+ /* Fast Read 1-2-2 */
+ {
+ SNOR_HWCAPS_READ_1_2_2,
+ BFPT_DWORD(1), BIT(20), /* Supported bit */
+ BFPT_DWORD(4), 16, /* Settings */
+ SNOR_PROTO_1_2_2,
+ },
+
+ /* Fast Read 2-2-2 */
+ {
+ SNOR_HWCAPS_READ_2_2_2,
+ BFPT_DWORD(5), BIT(0), /* Supported bit */
+ BFPT_DWORD(6), 16, /* Settings */
+ SNOR_PROTO_2_2_2,
+ },
+
+ /* Fast Read 1-1-4 */
+ {
+ SNOR_HWCAPS_READ_1_1_4,
+ BFPT_DWORD(1), BIT(22), /* Supported bit */
+ BFPT_DWORD(3), 16, /* Settings */
+ SNOR_PROTO_1_1_4,
+ },
+
+ /* Fast Read 1-4-4 */
+ {
+ SNOR_HWCAPS_READ_1_4_4,
+ BFPT_DWORD(1), BIT(21), /* Supported bit */
+ BFPT_DWORD(3), 0, /* Settings */
+ SNOR_PROTO_1_4_4,
+ },
+
+ /* Fast Read 4-4-4 */
+ {
+ SNOR_HWCAPS_READ_4_4_4,
+ BFPT_DWORD(5), BIT(4), /* Supported bit */
+ BFPT_DWORD(7), 16, /* Settings */
+ SNOR_PROTO_4_4_4,
+ },
+};
+
+struct sfdp_bfpt_erase {
+ /*
+ * The half-word at offset <shift> in DWORD <dwoard> encodes the
+ * op code and erase sector size to be used by Sector Erase commands.
+ */
+ u32 dword;
+ u32 shift;
+};
+
+static const struct sfdp_bfpt_erase sfdp_bfpt_erases[] = {
+ /* Erase Type 1 in DWORD8 bits[15:0] */
+ {BFPT_DWORD(8), 0},
+
+ /* Erase Type 2 in DWORD8 bits[31:16] */
+ {BFPT_DWORD(8), 16},
+
+ /* Erase Type 3 in DWORD9 bits[15:0] */
+ {BFPT_DWORD(9), 0},
+
+ /* Erase Type 4 in DWORD9 bits[31:16] */
+ {BFPT_DWORD(9), 16},
+};
+
+static int spi_nor_hwcaps_read2cmd(u32 hwcaps);
+
+/**
+ * spi_nor_parse_bfpt() - read and parse the Basic Flash Parameter Table.
+ * @nor: pointer to a 'struct spi_nor'
+ * @bfpt_header: pointer to the 'struct sfdp_parameter_header' describing
+ * the Basic Flash Parameter Table length and version
+ * @params: pointer to the 'struct spi_nor_flash_parameter' to be
+ * filled
+ *
+ * The Basic Flash Parameter Table is the main and only mandatory table as
+ * defined by the SFDP (JESD216) specification.
+ * It provides us with the total size (memory density) of the data array and
+ * the number of address bytes for Fast Read, Page Program and Sector Erase
+ * commands.
+ * For Fast READ commands, it also gives the number of mode clock cycles and
+ * wait states (regrouped in the number of dummy clock cycles) for each
+ * supported instruction op code.
+ * For Page Program, the page size is now available since JESD216 rev A, however
+ * the supported instruction op codes are still not provided.
+ * For Sector Erase commands, this table stores the supported instruction op
+ * codes and the associated sector sizes.
+ * Finally, the Quad Enable Requirements (QER) are also available since JESD216
+ * rev A. The QER bits encode the manufacturer dependent procedure to be
+ * executed to set the Quad Enable (QE) bit in some internal register of the
+ * Quad SPI memory. Indeed the QE bit, when it exists, must be set before
+ * sending any Quad SPI command to the memory. Actually, setting the QE bit
+ * tells the memory to reassign its WP# and HOLD#/RESET# pins to functions IO2
+ * and IO3 hence enabling 4 (Quad) I/O lines.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int spi_nor_parse_bfpt(struct spi_nor *nor,
+ const struct sfdp_parameter_header *bfpt_header,
+ struct spi_nor_flash_parameter *params)
+{
+ struct mtd_info *mtd = &nor->mtd;
+ struct sfdp_bfpt bfpt;
+ size_t len;
+ int i, cmd, err;
+ u32 addr;
+ u16 half;
+
+ /* JESD216 Basic Flash Parameter Table length is at least 9 DWORDs. */
+ if (bfpt_header->length < BFPT_DWORD_MAX_JESD216)
+ return -EINVAL;
+
+ /* Read the Basic Flash Parameter Table. */
+ len = min_t(size_t, sizeof(bfpt),
+ bfpt_header->length * sizeof(u32));
+ addr = SFDP_PARAM_HEADER_PTP(bfpt_header);
+ memset(&bfpt, 0, sizeof(bfpt));
+ err = spi_nor_read_sfdp(nor, addr, len, &bfpt);
+ if (err < 0)
+ return err;
+
+ /* Fix endianness of the BFPT DWORDs. */
+ for (i = 0; i < BFPT_DWORD_MAX; i++)
+ bfpt.dwords[i] = le32_to_cpu(bfpt.dwords[i]);
+
+ /* Number of address bytes. */
+ switch (bfpt.dwords[BFPT_DWORD(1)] & BFPT_DWORD1_ADDRESS_BYTES_MASK) {
+ case BFPT_DWORD1_ADDRESS_BYTES_3_ONLY:
+ nor->addr_width = 3;
+ break;
+
+ case BFPT_DWORD1_ADDRESS_BYTES_4_ONLY:
+ nor->addr_width = 4;
+ break;
+
+ default:
+ break;
+ }
+
+ /* Flash Memory Density (in bits). */
+ params->size = bfpt.dwords[BFPT_DWORD(2)];
+ if (params->size & BIT(31)) {
+ params->size &= ~BIT(31);
+ params->size = 1ULL << params->size;
+ } else {
+ params->size++;
+ }
+ params->size >>= 3; /* Convert to bytes. */
+
+ /* Fast Read settings. */
+ for (i = 0; i < ARRAY_SIZE(sfdp_bfpt_reads); i++) {
+ const struct sfdp_bfpt_read *rd = &sfdp_bfpt_reads[i];
+ struct spi_nor_read_command *read;
+
+ if (!(bfpt.dwords[rd->supported_dword] & rd->supported_bit)) {
+ params->hwcaps.mask &= ~rd->hwcaps;
+ continue;
+ }
+
+ params->hwcaps.mask |= rd->hwcaps;
+ cmd = spi_nor_hwcaps_read2cmd(rd->hwcaps);
+ read = &params->reads[cmd];
+ half = bfpt.dwords[rd->settings_dword] >> rd->settings_shift;
+ spi_nor_set_read_settings_from_bfpt(read, half, rd->proto);
+ }
+
+ /* Sector Erase settings. */
+ for (i = 0; i < ARRAY_SIZE(sfdp_bfpt_erases); i++) {
+ const struct sfdp_bfpt_erase *er = &sfdp_bfpt_erases[i];
+ u32 erasesize;
+ u8 opcode;
+
+ half = bfpt.dwords[er->dword] >> er->shift;
+ erasesize = half & 0xff;
+
+ /* erasesize == 0 means this Erase Type is not supported. */
+ if (!erasesize)
+ continue;
+
+ erasesize = 1U << erasesize;
+ opcode = (half >> 8) & 0xff;
+#ifdef CONFIG_MTD_SPI_NOR_USE_4K_SECTORS
+ if (erasesize == SZ_4K) {
+ nor->erase_opcode = opcode;
+ mtd->erasesize = erasesize;
+ break;
+ }
+#endif
+ if (!mtd->erasesize || mtd->erasesize < erasesize) {
+ nor->erase_opcode = opcode;
+ mtd->erasesize = erasesize;
+ }
+ }
+
+ /* Stop here if not JESD216 rev A or later. */
+ if (bfpt_header->length < BFPT_DWORD_MAX)
+ return 0;
+
+ /* Page size: this field specifies 'N' so the page size = 2^N bytes. */
+ params->page_size = bfpt.dwords[BFPT_DWORD(11)];
+ params->page_size &= BFPT_DWORD11_PAGE_SIZE_MASK;
+ params->page_size >>= BFPT_DWORD11_PAGE_SIZE_SHIFT;
+ params->page_size = 1U << params->page_size;
+
+ /* Quad Enable Requirements. */
+ switch (bfpt.dwords[BFPT_DWORD(15)] & BFPT_DWORD15_QER_MASK) {
+ case BFPT_DWORD15_QER_NONE:
+ params->quad_enable = NULL;
+ break;
+
+ case BFPT_DWORD15_QER_SR2_BIT1_BUGGY:
+ case BFPT_DWORD15_QER_SR2_BIT1_NO_RD:
+ params->quad_enable = spansion_no_read_cr_quad_enable;
+ break;
+
+ case BFPT_DWORD15_QER_SR1_BIT6:
+ params->quad_enable = macronix_quad_enable;
+ break;
+
+ case BFPT_DWORD15_QER_SR2_BIT7:
+ params->quad_enable = sr2_bit7_quad_enable;
+ break;
+
+ case BFPT_DWORD15_QER_SR2_BIT1:
+ params->quad_enable = spansion_read_cr_quad_enable;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/**
+ * spi_nor_parse_sfdp() - parse the Serial Flash Discoverable Parameters.
+ * @nor: pointer to a 'struct spi_nor'
+ * @params: pointer to the 'struct spi_nor_flash_parameter' to be
+ * filled
+ *
+ * The Serial Flash Discoverable Parameters are described by the JEDEC JESD216
+ * specification. This is a standard which tends to supported by almost all
+ * (Q)SPI memory manufacturers. Those hard-coded tables allow us to learn at
+ * runtime the main parameters needed to perform basic SPI flash operations such
+ * as Fast Read, Page Program or Sector Erase commands.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int spi_nor_parse_sfdp(struct spi_nor *nor,
+ struct spi_nor_flash_parameter *params)
+{
+ const struct sfdp_parameter_header *param_header, *bfpt_header;
+ struct sfdp_parameter_header *param_headers = NULL;
+ struct sfdp_header header;
+ struct device *dev = nor->dev;
+ size_t psize;
+ int i, err;
+
+ /* Get the SFDP header. */
+ err = spi_nor_read_sfdp(nor, 0, sizeof(header), &header);
+ if (err < 0)
+ return err;
+
+ /* Check the SFDP header version. */
+ if (le32_to_cpu(header.signature) != SFDP_SIGNATURE ||
+ header.major != SFDP_JESD216_MAJOR ||
+ header.minor < SFDP_JESD216_MINOR)
+ return -EINVAL;
+
+ /*
+ * Verify that the first and only mandatory parameter header is a
+ * Basic Flash Parameter Table header as specified in JESD216.
+ */
+ bfpt_header = &header.bfpt_header;
+ if (SFDP_PARAM_HEADER_ID(bfpt_header) != SFDP_BFPT_ID ||
+ bfpt_header->major != SFDP_JESD216_MAJOR)
+ return -EINVAL;
+
+ /*
+ * Allocate memory then read all parameter headers with a single
+ * Read SFDP command. These parameter headers will actually be parsed
+ * twice: a first time to get the latest revision of the basic flash
+ * parameter table, then a second time to handle the supported optional
+ * tables.
+ * Hence we read the parameter headers once for all to reduce the
+ * processing time. Also we use kmalloc() instead of devm_kmalloc()
+ * because we don't need to keep these parameter headers: the allocated
+ * memory is always released with kfree() before exiting this function.
+ */
+ if (header.nph) {
+ psize = header.nph * sizeof(*param_headers);
+
+ param_headers = kmalloc(psize, GFP_KERNEL);
+ if (!param_headers)
+ return -ENOMEM;
+
+ err = spi_nor_read_sfdp(nor, sizeof(header),
+ psize, param_headers);
+ if (err < 0) {
+ dev_err(dev, "failed to read SFDP parameter headers\n");
+ goto exit;
+ }
+ }
+
+ /*
+ * Check other parameter headers to get the latest revision of
+ * the basic flash parameter table.
+ */
+ for (i = 0; i < header.nph; i++) {
+ param_header = &param_headers[i];
+
+ if (SFDP_PARAM_HEADER_ID(param_header) == SFDP_BFPT_ID &&
+ param_header->major == SFDP_JESD216_MAJOR &&
+ (param_header->minor > bfpt_header->minor ||
+ (param_header->minor == bfpt_header->minor &&
+ param_header->length > bfpt_header->length)))
+ bfpt_header = param_header;
+ }
+
+ err = spi_nor_parse_bfpt(nor, bfpt_header, params);
+ if (err)
+ goto exit;
+
+ /* Parse other parameter headers. */
+ for (i = 0; i < header.nph; i++) {
+ param_header = &param_headers[i];
+
+ switch (SFDP_PARAM_HEADER_ID(param_header)) {
+ case SFDP_SECTOR_MAP_ID:
+ dev_info(dev, "non-uniform erase sector maps are not supported yet.\n");
+ break;
+
+ default:
+ break;
+ }
+
+ if (err)
+ goto exit;
+ }
+
+exit:
+ kfree(param_headers);
+ return err;
+}
+
static int spi_nor_init_params(struct spi_nor *nor,
const struct flash_info *info,
struct spi_nor_flash_parameter *params)
@@ -1644,11 +2370,28 @@ static int spi_nor_init_params(struct spi_nor *nor,
break;

default:
+ /* Kept only for backward compatibility purpose. */
params->quad_enable = spansion_quad_enable;
break;
}
}

+ /* Override the parameters with data read from SFDP tables. */
+ nor->addr_width = 0;
+ nor->mtd.erasesize = 0;
+ if ((info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)) &&
+ !(info->flags & SPI_NOR_SKIP_SFDP)) {
+ struct spi_nor_flash_parameter sfdp_params;
+
+ memcpy(&sfdp_params, params, sizeof(sfdp_params));
+ if (spi_nor_parse_sfdp(nor, &sfdp_params)) {
+ nor->addr_width = 0;
+ nor->mtd.erasesize = 0;
+ } else {
+ memcpy(params, &sfdp_params, sizeof(*params));
+ }
+ }
+
return 0;
}

@@ -1760,6 +2503,10 @@ static int spi_nor_select_erase(struct spi_nor *nor,
{
struct mtd_info *mtd = &nor->mtd;

+ /* Do nothing if already configured from SFDP. */
+ if (mtd->erasesize)
+ return 0;
+
#ifdef CONFIG_MTD_SPI_NOR_USE_4K_SECTORS
/* prefer "small sector" erase if possible */
if (info->flags & SECT_4K) {
@@ -1992,9 +2739,11 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
if (ret)
return ret;

- if (info->addr_width)
+ if (nor->addr_width) {
+ /* already configured from SFDP */
+ } else if (info->addr_width) {
nor->addr_width = info->addr_width;
- else if (mtd->size > 0x1000000) {
+ } else if (mtd->size > 0x1000000) {
/* enable 4-byte addressing if the device exceeds 16MiB */
nor->addr_width = 4;
if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 55faa2f07cca..0df3638ff0b8 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -41,6 +41,8 @@
#define SPINOR_OP_WREN 0x06 /* Write enable */
#define SPINOR_OP_RDSR 0x05 /* Read status register */
#define SPINOR_OP_WRSR 0x01 /* Write status register 1 byte */
+#define SPINOR_OP_RDSR2 0x3f /* Read status register 2 */
+#define SPINOR_OP_WRSR2 0x3e /* Write status register 2 */
#define SPINOR_OP_READ 0x03 /* Read data bytes (low frequency) */
#define SPINOR_OP_READ_FAST 0x0b /* Read data bytes (high frequency) */
#define SPINOR_OP_READ_1_1_2 0x3b /* Read data bytes (Dual Output SPI) */
@@ -56,6 +58,7 @@
#define SPINOR_OP_CHIP_ERASE 0xc7 /* Erase whole flash chip */
#define SPINOR_OP_SE 0xd8 /* Sector erase (usually 64KiB) */
#define SPINOR_OP_RDID 0x9f /* Read JEDEC ID */
+#define SPINOR_OP_RDSFDP 0x5a /* Read SFDP */
#define SPINOR_OP_RDCR 0x35 /* Read configuration register */
#define SPINOR_OP_RDFSR 0x70 /* Read flag status register */

@@ -128,6 +131,9 @@
/* Configuration Register bits. */
#define CR_QUAD_EN_SPAN BIT(1) /* Spansion Quad I/O */

+/* Status Register 2 bits. */
+#define SR2_QUAD_EN_BIT7 BIT(7)
+
/* Supported SPI protocols */
#define SNOR_PROTO_INST_MASK GENMASK(23, 16)
#define SNOR_PROTO_INST_SHIFT 16
--
2.7.4