[PATCH 8/9] mtd: spi-nor: parse Serial Flash Discoverable Parameters (SFDP) tables

From: Cyrille Pitchen
Date: Mon Jun 20 2016 - 12:59:56 EST

This patch adds support the the JESD216B standard and parse the SFDP
tables to dynamically initialize the spi_nor_basic_flash_parameter
structure.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@xxxxxxxxx>
---
drivers/mtd/spi-nor/spi-nor.c | 423 +++++++++++++++++++++++++++++++++++++++++-
include/linux/mtd/spi-nor.h | 1 +
2 files changed, 423 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 43f104fc7fac..2d53c65f5795 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>
@@ -79,6 +80,7 @@ struct flash_info {
* Use dedicated 4byte address op codes
* to support memory size above 128Mib.
*/
+#define SPI_NOR_SKIP_SFDP BIT(11) /* Skip read of SFDP tables */
};

#define JEDEC_MFR(info) ((info)->id[0])
@@ -1314,6 +1316,53 @@ static int spansion_quad_enable(struct spi_nor *nor)
return 0;
}

+static int spansion_new_quad_enable(struct spi_nor *nor)
+{
+ u8 sr_cr[2];
+ int ret;
+
+ /* Check current Quad Enable bit value. */
+ ret = read_cr(nor);
+ if (ret < 0) {
+ dev_err(nor->dev,
+ "error while reading configuration register\n");
+ return -EINVAL;
+ }
+ sr_cr[1] = ret;
+ if (sr_cr[1] & CR_QUAD_EN_SPAN)
+ return 0;
+
+ dev_info(nor->dev, "setting Spansion Quad Enable (non-volatile) bit\n");
+
+ /* 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;
+
+ write_enable(nor);
+
+ ret = nor->write_reg(nor, SPINOR_OP_WRSR, sr_cr, 2);
+ if (ret < 0) {
+ dev_err(nor->dev,
+ "error while writing configuration register\n");
+ return -EINVAL;
+ }
+
+ /* 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;
+}
+
static int spi_nor_check(struct spi_nor *nor)
{
if (!nor->dev || !nor->read || !nor->write ||
@@ -1342,11 +1391,382 @@ static inline void spi_nor_set_erase_settings(struct spi_nor_erase_type *erase,
erase->opcode = opcode;
}

+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;
+
+ ret = nor->read(nor, addr, len, (u8 *)buf);
+
+ nor->read_opcode = read_opcode;
+ nor->addr_width = addr_width;
+ nor->read_dummy = read_dummy;
+
+ return (ret < 0) ? ret : 0;
+}
+
+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) ((u16)(((p)->id_msb << 8) | (p)->id_lsb))
+#define SFDP_PARAM_HEADER_PTP(p) \
+ ((u32)(((p)->parameter_table_pointer[2] << 16) | \
+ ((p)->parameter_table_pointer[1] << 8) | \
+ ((p)->parameter_table_pointer[0] << 0)))
+
+
+#define SFDP_BFPT_ID 0xff00u /* Basic Flash Parameter 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; /* Ox50444653 <=> "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 */
+
+/* 1st DWORD. */
+#define BFPT_WORD0_FAST_READ_1_1_2 BIT(16)
+#define BFPT_WORD0_ADDRESS_BYTES_MASK GENMASK(18, 17)
+#define BFPT_WORD0_ADDRESS_BYTES_3_ONLY (0u << 17)
+#define BFPT_WORD0_ADDRESS_BYTES_3_OR_4 (1u << 17)
+#define BFPT_WORD0_ADDRESS_BYTES_4_ONLY (2u << 17)
+#define BFPT_WORD0_DTR BIT(19)
+#define BFPT_WORD0_FAST_READ_1_2_2 BIT(20)
+#define BFPT_WORD0_FAST_READ_1_4_4 BIT(21)
+#define BFPT_WORD0_FAST_READ_1_1_4 BIT(22)
+
+/* 15th DWORD. */
+
+/*
+ * (from JESD216B)
+ * 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 pahse.
+ * - 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_WORD14_QER_MASK GENMASK(22, 20)
+#define BFPT_WORD14_QER_NONE (0 << 20) /* Micron */
+#define BFPT_WORD14_QER_SR2_BIT1_BUGGY (1 << 20)
+#define BFPT_WORD14_QER_SR1_BIT6 (2 << 20) /* Macronix */
+#define BFPT_WORD14_QER_SR2_BIT7 (3 << 20)
+#define BFPT_WORD14_QER_SR2_BIT1_NO_RD (4 << 20)
+#define BFPT_WORD14_QER_SR2_BIT1 (5 << 20) /* Spansion */
+
+/* JESD216B defines a Basic Flash Parameter Table of 16 words. */
+#define SFDP_BFPT_MAX_WORDS 16
+
+struct sfdp_bfpt {
+ u32 word[SFDP_BFPT_MAX_WORDS];
+};
+
+/* Fast Read settings. */
+#define BFPT_FAST_READ_WAIT_STATES(half) ((((u16)(half)) >> 0) & 0x1f)
+#define BFPT_FAST_READ_MODE_CLOCKS(half) ((((u16)(half)) >> 5) & 0x07)
+#define BFPT_FAST_READ_OP_CODE(half) ((((u16)(half)) >> 8) & 0xff)
+
+struct sfdp_read {
+ /* The protocol index of SPI x-y-z. */
+ enum spi_nor_protocol_index pindex;
+
+ /*
+ * The bit <wbit> in DWORD<windex> tells us whether the
+ * Fast Read x-y-z command is supported.
+ */
+ int windex;
+ int wbit;
+
+ /*
+ * The half-word at offset <hshift> in DWORD<hindex> encodes the
+ * op code, the number of mode clocks and the number of wait states
+ * to be used by Fast Read x-y-z commands.
+ */
+ int hindex;
+ int hshift;
+};
+
+static const struct sfdp_read sfdp_reads[] = {
+ /* Supported: DWORD0 bit 16, Settings: DWORD3 bit[15:0] */
+ {SNOR_PINDEX_1_1_2, 0, 16, 3, 0},
+
+ /* Supported: DWORD0 bit 20, Settings: DWORD3 bit[31:16] */
+ {SNOR_PINDEX_1_2_2, 0, 20, 3, 16},
+
+ /* Supported: DWORD4 bit 0, Settings: DWORD5 bit[31:16] */
+ {SNOR_PINDEX_2_2_2, 4, 0, 5, 16},
+
+ /* Supported: DWORD0 bit 22, Settings: DWORD2 bit[31:16] */
+ {SNOR_PINDEX_1_1_4, 0, 22, 2, 16},
+
+ /* Supported: DWORD0 bit 21, Settings: DWORD2 bit[15:0] */
+ {SNOR_PINDEX_1_4_4, 0, 21, 2, 0},
+
+ /* Supported: DWORD4 bit 4, Settings: DWORD6 bit[31:16] */
+ {SNOR_PINDEX_4_4_4, 4, 4, 6, 16},
+};
+
+
+/* Sector Erase settings. */
+#define BFPT_ERASE_SIZE(half) ((((u16)(half)) >> 0) & 0xff)
+#define BFPT_ERASE_OP_CODE(half) ((((u16)(half)) >> 8) & 0xff)
+
+struct sfdp_erase {
+ /*
+ * The half-word at offset <hshift> in DWORD<hindex> encodes the
+ * op code and erase sector size to be used by Sector Erase commands.
+ */
+ int hindex;
+ int hshift;
+};
+
+static const struct sfdp_erase sfdp_erases[SNOR_MAX_ERASE_TYPES] = {
+ /* Erase Type 1 in DWORD7 bits[15:0] */
+ {7, 0},
+
+ /* Erase Type 2 in DWORD7 bits[31:16] */
+ {7, 16},
+
+ /* Erase Type 3 in DWORD8 bits[15:0] */
+ {8, 0},
+
+ /* Erase Type 4: in DWORD8 bits[31:16] */
+ {8, 16},
+};
+
+
+static int spi_nor_parse_bfpt(struct spi_nor *nor,
+ const struct flash_info *info,
+ const struct sfdp_parameter_header *bfpt_header,
+ struct spi_nor_basic_flash_parameter *params)
+{
+ struct sfdp_bfpt bfpt;
+ size_t len;
+ int i, err;
+ u32 addr;
+ u16 half;
+
+ /* JESD216 Basic Flash Parameter Table length is at least 9 words. */
+ if (bfpt_header->length < 9)
+ return -EINVAL;
+
+ /* Read the Basic Flash Parameter Table. */
+ len = min_t(size_t, sizeof(bfpt),
+ bfpt_header->length * sizeof(uint32_t));
+ addr = SFDP_PARAM_HEADER_PTP(bfpt_header);
+ memset(&bfpt, 0, sizeof(bfpt));
+ err = spi_nor_read_sfdp(nor, addr, len, &bfpt);
+ if (err)
+ return err;
+
+ for (i = 0; i < SFDP_BFPT_MAX_WORDS; ++i)
+ bfpt.word[i] = le32_to_cpu(bfpt.word[i]);
+
+ memset(params, 0, sizeof(*params));
+
+ /* Fast Read settings. */
+ params->rd_modes = (SNOR_MODE_SLOW | SNOR_MODE_1_1_1);
+ spi_nor_set_read_settings(&params->reads[SNOR_PINDEX_SLOW],
+ 0, 0, SPINOR_OP_READ);
+ spi_nor_set_read_settings(&params->reads[SNOR_PINDEX_1_1_1],
+ 0, 8, SPINOR_OP_READ_FAST);
+
+ for (i = 0; i < ARRAY_SIZE(sfdp_reads); ++i) {
+ const struct sfdp_read *rd_info = &sfdp_reads[i];
+ struct spi_nor_read *read = &params->reads[rd_info->pindex];
+
+ if (!(bfpt.word[rd_info->windex] & BIT(rd_info->wbit)))
+ continue;
+
+ params->rd_modes |= BIT(rd_info->pindex);
+ half = bfpt.word[rd_info->hindex] >> rd_info->hshift;
+ read->num_mode_clocks = BFPT_FAST_READ_MODE_CLOCKS(half);
+ read->num_wait_states = BFPT_FAST_READ_WAIT_STATES(half);
+ read->opcode = BFPT_FAST_READ_OP_CODE(half);
+ }
+
+ /* Page Program settings. */
+ params->wr_modes = SNOR_MODE_1_1_1;
+ params->page_programs[SNOR_PINDEX_1_1_1] = SPINOR_OP_PP;
+
+ /* Sector Erase settings. */
+ for (i = 0; i < SNOR_MAX_ERASE_TYPES; ++i) {
+ const struct sfdp_erase *er_info = &sfdp_erases[i];
+ struct spi_nor_erase_type *erase = &params->erase_types[i];
+
+ half = bfpt.word[er_info->hindex] >> er_info->hshift;
+ erase->size = BFPT_ERASE_SIZE(half);
+ erase->opcode = BFPT_ERASE_OP_CODE(half);
+ }
+
+ /* Stop here if not JESD216 rev B or later. */
+ if (bfpt_header->length < 15)
+ return 0;
+
+ /* Enable Quad I/O. */
+ switch (bfpt.word[14] & BFPT_WORD14_QER_MASK) {
+ default:
+ case BFPT_WORD14_QER_NONE:
+ break;
+
+ case BFPT_WORD14_QER_SR2_BIT1_BUGGY:
+ case BFPT_WORD14_QER_SR2_BIT1_NO_RD:
+ params->enable_quad_io = spansion_quad_enable;
+ break;
+
+ case BFPT_WORD14_QER_SR1_BIT6:
+ params->enable_quad_io = macronix_quad_enable;
+ break;
+
+ case BFPT_WORD14_QER_SR2_BIT7:
+ // TODO:
+ break;
+
+ case BFPT_WORD14_QER_SR2_BIT1:
+ params->enable_quad_io = spansion_new_quad_enable;
+ break;
+ }
+
+ return 0;
+}
+
+static int spi_nor_parse_sfdp(struct spi_nor *nor,
+ const struct flash_info *info,
+ struct spi_nor_basic_flash_parameter *params)
+{
+ const struct sfdp_parameter_header *param_header, *bfpt_header;
+ struct sfdp_parameter_header *param_headers = NULL;
+ struct sfdp_header header;
+ size_t psize;
+ int i, err;
+
+ /* Get the SFDP header. */
+ err = spi_nor_read_sfdp(nor, 0, sizeof(header), &header);
+ if (err)
+ 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 for parameter headers. */
+ if (header.nph) {
+ psize = header.nph * sizeof(*param_headers);
+
+ param_headers = kmalloc(psize, GFP_KERNEL);
+ if (!param_headers) {
+ dev_err(nor->dev,
+ "failed to allocate memory for SFDP parameter headers\n");
+ return -ENOMEM;
+ }
+
+ err = spi_nor_read_sfdp(nor, sizeof(header),
+ psize, param_headers);
+ if (err) {
+ dev_err(nor->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, info, bfpt_header, params);
+ if (err)
+ goto exit;
+
+exit:
+ kfree(param_headers);
+ return (err) ? err : bfpt_header->minor;
+}
+
static int spi_nor_init_params(struct spi_nor *nor,
const struct flash_info *info,
struct spi_nor_basic_flash_parameter *params)
{
- // TODO: parse SFDP table
+ int jesd216_minor = -EINVAL;
+
+ /* First trying to parse SFDP tables. */
+ if (!(info->flags & SPI_NOR_SKIP_SFDP)) {
+ jesd216_minor = spi_nor_parse_sfdp(nor, info, params);
+
+ if (jesd216_minor >= SFDP_JESD216B_MINOR)
+ return 0;
+
+ if (jesd216_minor >= SFDP_JESD216_MINOR)
+ goto set_enable_quad_io;
+ }

/* If SFDP tables are not available, use legacy settings. */
memset(params, 0, sizeof(*params));
@@ -1385,6 +1805,7 @@ static int spi_nor_init_params(struct spi_nor *nor,
spi_nor_set_erase_settings(&params->erase_types[1],
SNOR_ERASE_4K, SPINOR_OP_BE_4K_PMC);

+set_enable_quad_io:
/* Select the procedure to set the Quad Enable bit. */
if (params->rd_modes & (SNOR_MODE_1_1_4 |
SNOR_MODE_1_4_4 |
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 730f33dce1ea..4fcb4225097e 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -56,6 +56,7 @@
#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 */

--
1.8.2.2