drm/rockchip: Don't change hdmi reference clock rate

[drm/drm-misc.git] / drivers / mtd / spi-nor / sfdp.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2005, Intec Automation Inc.
 * Copyright (C) 2014, Freescale Semiconductor, Inc.
 */

#include <linux/bitfield.h>
#include <linux/mtd/spi-nor.h>
#include <linux/slab.h>
#include <linux/sort.h>

#include "core.h"

#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_PARAM_HEADER_PARAM_LEN(p) ((p)->length * 4)

#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_SCCR_MAP_ID        0xff87  /*
                                         * Status, Control and Configuration
                                         * Register Map.
                                         */
#define SFDP_SCCR_MAP_MC_ID     0xff88  /*
                                         * Status, Control and Configuration
                                         * Register Map Offsets for Multi-Chip
                                         * SPI Memory Devices.
                                         */

#define SFDP_SIGNATURE          0x50444653U

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;
};

/* Fast Read settings. */
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;
};

struct sfdp_bfpt_erase {
        /*
         * The half-word at offset <shift> in DWORD <dword> encodes the
         * op code and erase sector size to be used by Sector Erase commands.
         */
        u32                     dword;
        u32                     shift;
};

#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)
#define SMPT_CMD_ADDRESS_LEN_4                  (0x2UL << 22)
#define SMPT_CMD_ADDRESS_LEN_USE_CURRENT        (0x3UL << 22)

#define SMPT_CMD_READ_DUMMY_MASK                GENMASK(19, 16)
#define SMPT_CMD_READ_DUMMY_SHIFT               16
#define SMPT_CMD_READ_DUMMY(_cmd) \
        (((_cmd) & SMPT_CMD_READ_DUMMY_MASK) >> SMPT_CMD_READ_DUMMY_SHIFT)
#define SMPT_CMD_READ_DUMMY_IS_VARIABLE         0xfUL

#define SMPT_CMD_READ_DATA_MASK                 GENMASK(31, 24)
#define SMPT_CMD_READ_DATA_SHIFT                24
#define SMPT_CMD_READ_DATA(_cmd) \
        (((_cmd) & SMPT_CMD_READ_DATA_MASK) >> SMPT_CMD_READ_DATA_SHIFT)

#define SMPT_CMD_OPCODE_MASK                    GENMASK(15, 8)
#define SMPT_CMD_OPCODE_SHIFT                   8
#define SMPT_CMD_OPCODE(_cmd) \
        (((_cmd) & SMPT_CMD_OPCODE_MASK) >> SMPT_CMD_OPCODE_SHIFT)

#define SMPT_MAP_REGION_COUNT_MASK              GENMASK(23, 16)
#define SMPT_MAP_REGION_COUNT_SHIFT             16
#define SMPT_MAP_REGION_COUNT(_header) \
        ((((_header) & SMPT_MAP_REGION_COUNT_MASK) >> \
          SMPT_MAP_REGION_COUNT_SHIFT) + 1)

#define SMPT_MAP_ID_MASK                        GENMASK(15, 8)
#define SMPT_MAP_ID_SHIFT                       8
#define SMPT_MAP_ID(_header) \
        (((_header) & SMPT_MAP_ID_MASK) >> SMPT_MAP_ID_SHIFT)

#define SMPT_MAP_REGION_SIZE_MASK               GENMASK(31, 8)
#define SMPT_MAP_REGION_SIZE_SHIFT              8
#define SMPT_MAP_REGION_SIZE(_region) \
        (((((_region) & SMPT_MAP_REGION_SIZE_MASK) >> \
           SMPT_MAP_REGION_SIZE_SHIFT) + 1) * 256)

#define SMPT_MAP_REGION_ERASE_TYPE_MASK         GENMASK(3, 0)
#define SMPT_MAP_REGION_ERASE_TYPE(_region) \
        ((_region) & SMPT_MAP_REGION_ERASE_TYPE_MASK)

#define SMPT_DESC_TYPE_MAP                      BIT(1)
#define SMPT_DESC_END                           BIT(0)

#define SFDP_4BAIT_DWORD_MAX    2

struct sfdp_4bait {
        /* The hardware capability. */
        u32             hwcaps;

        /*
         * The <supported_bit> bit in DWORD1 of the 4BAIT tells us whether
         * the associated 4-byte address op code is supported.
         */
        u32             supported_bit;
};

/**
 * spi_nor_read_raw() - raw read of serial flash memory. read_opcode,
 *                      addr_nbytes and read_dummy members of the struct spi_nor
 *                      should be previously set.
 * @nor:        pointer to a 'struct spi_nor'
 * @addr:       offset in the serial flash memory
 * @len:        number of bytes to read
 * @buf:        buffer where the data is copied into (dma-safe memory)
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_read_raw(struct spi_nor *nor, u32 addr, size_t len, u8 *buf)
{
        ssize_t ret;

        while (len) {
                ret = spi_nor_read_data(nor, addr, len, buf);
                if (ret < 0)
                        return ret;
                if (!ret || ret > len)
                        return -EIO;

                buf += ret;
                addr += ret;
                len -= ret;
        }
        return 0;
}

/**
 * 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 (dma-safe memory)
 *
 * 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_nbytes, read_opcode, read_dummy;
        int ret;

        read_opcode = nor->read_opcode;
        addr_nbytes = nor->addr_nbytes;
        read_dummy = nor->read_dummy;

        nor->read_opcode = SPINOR_OP_RDSFDP;
        nor->addr_nbytes = 3;
        nor->read_dummy = 8;

        ret = spi_nor_read_raw(nor, addr, len, buf);

        nor->read_opcode = read_opcode;
        nor->addr_nbytes = addr_nbytes;
        nor->read_dummy = read_dummy;

        return ret;
}

/**
 * spi_nor_read_sfdp_dma_unsafe() - 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
 *
 * Wrap spi_nor_read_sfdp() using a kmalloc'ed bounce buffer as @buf is now not
 * guaranteed to be dma-safe.
 *
 * Return: -ENOMEM if kmalloc() fails, the return code of spi_nor_read_sfdp()
 *          otherwise.
 */
static int spi_nor_read_sfdp_dma_unsafe(struct spi_nor *nor, u32 addr,
                                        size_t len, void *buf)
{
        void *dma_safe_buf;
        int ret;

        dma_safe_buf = kmalloc(len, GFP_KERNEL);
        if (!dma_safe_buf)
                return -ENOMEM;

        ret = spi_nor_read_sfdp(nor, addr, len, dma_safe_buf);
        memcpy(buf, dma_safe_buf, len);
        kfree(dma_safe_buf);

        return ret;
}

static 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;
}

static const struct sfdp_bfpt_read sfdp_bfpt_reads[] = {
        /* Fast Read 1-1-2 */
        {
                SNOR_HWCAPS_READ_1_1_2,
                SFDP_DWORD(1), BIT(16), /* Supported bit */
                SFDP_DWORD(4), 0,       /* Settings */
                SNOR_PROTO_1_1_2,
        },

        /* Fast Read 1-2-2 */
        {
                SNOR_HWCAPS_READ_1_2_2,
                SFDP_DWORD(1), BIT(20), /* Supported bit */
                SFDP_DWORD(4), 16,      /* Settings */
                SNOR_PROTO_1_2_2,
        },

        /* Fast Read 2-2-2 */
        {
                SNOR_HWCAPS_READ_2_2_2,
                SFDP_DWORD(5),  BIT(0), /* Supported bit */
                SFDP_DWORD(6), 16,      /* Settings */
                SNOR_PROTO_2_2_2,
        },

        /* Fast Read 1-1-4 */
        {
                SNOR_HWCAPS_READ_1_1_4,
                SFDP_DWORD(1), BIT(22), /* Supported bit */
                SFDP_DWORD(3), 16,      /* Settings */
                SNOR_PROTO_1_1_4,
        },

        /* Fast Read 1-4-4 */
        {
                SNOR_HWCAPS_READ_1_4_4,
                SFDP_DWORD(1), BIT(21), /* Supported bit */
                SFDP_DWORD(3), 0,       /* Settings */
                SNOR_PROTO_1_4_4,
        },

        /* Fast Read 4-4-4 */
        {
                SNOR_HWCAPS_READ_4_4_4,
                SFDP_DWORD(5), BIT(4),  /* Supported bit */
                SFDP_DWORD(7), 16,      /* Settings */
                SNOR_PROTO_4_4_4,
        },
};

static const struct sfdp_bfpt_erase sfdp_bfpt_erases[] = {
        /* Erase Type 1 in DWORD8 bits[15:0] */
        {SFDP_DWORD(8), 0},

        /* Erase Type 2 in DWORD8 bits[31:16] */
        {SFDP_DWORD(8), 16},

        /* Erase Type 3 in DWORD9 bits[15:0] */
        {SFDP_DWORD(9), 0},

        /* Erase Type 4 in DWORD9 bits[31:16] */
        {SFDP_DWORD(9), 16},
};

/**
 * spi_nor_set_erase_settings_from_bfpt() - set erase type settings from BFPT
 * @erase:      pointer to a structure that describes a SPI NOR erase type
 * @size:       the size of the sector/block erased by the erase type
 * @opcode:     the SPI command op code to erase the sector/block
 * @i:          erase type index as sorted in the Basic Flash Parameter Table
 *
 * The supported Erase Types will be sorted at init in ascending order, with
 * the smallest Erase Type size being the first member in the erase_type array
 * of the spi_nor_erase_map structure. Save the Erase Type index as sorted in
 * the Basic Flash Parameter Table since it will be used later on to
 * synchronize with the supported Erase Types defined in SFDP optional tables.
 */
static void
spi_nor_set_erase_settings_from_bfpt(struct spi_nor_erase_type *erase,
                                     u32 size, u8 opcode, u8 i)
{
        erase->idx = i;
        spi_nor_set_erase_type(erase, size, opcode);
}

/**
 * spi_nor_map_cmp_erase_type() - compare the map's erase types by size
 * @l:  member in the left half of the map's erase_type array
 * @r:  member in the right half of the map's erase_type array
 *
 * Comparison function used in the sort() call to sort in ascending order the
 * map's erase types, the smallest erase type size being the first member in the
 * sorted erase_type array.
 *
 * Return: the result of @l->size - @r->size
 */
static int spi_nor_map_cmp_erase_type(const void *l, const void *r)
{
        const struct spi_nor_erase_type *left = l, *right = r;

        return left->size - right->size;
}

/**
 * spi_nor_sort_erase_mask() - sort erase mask
 * @map:        the erase map of the SPI NOR
 * @erase_mask: the erase type mask to be sorted
 *
 * Replicate the sort done for the map's erase types in BFPT: sort the erase
 * mask in ascending order with the smallest erase type size starting from
 * BIT(0) in the sorted erase mask.
 *
 * Return: sorted erase mask.
 */
static u8 spi_nor_sort_erase_mask(struct spi_nor_erase_map *map, u8 erase_mask)
{
        struct spi_nor_erase_type *erase_type = map->erase_type;
        int i;
        u8 sorted_erase_mask = 0;

        if (!erase_mask)
                return 0;

        /* Replicate the sort done for the map's erase types. */
        for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++)
                if (erase_type[i].size && erase_mask & BIT(erase_type[i].idx))
                        sorted_erase_mask |= BIT(i);

        return sorted_erase_mask;
}

/**
 * spi_nor_regions_sort_erase_types() - sort erase types in each region
 * @map:        the erase map of the SPI NOR
 *
 * Function assumes that the erase types defined in the erase map are already
 * sorted in ascending order, with the smallest erase type size being the first
 * member in the erase_type array. It replicates the sort done for the map's
 * erase types. Each region's erase bitmask will indicate which erase types are
 * supported from the sorted erase types defined in the erase map.
 * Sort the all region's erase type at init in order to speed up the process of
 * finding the best erase command at runtime.
 */
static void spi_nor_regions_sort_erase_types(struct spi_nor_erase_map *map)
{
        struct spi_nor_erase_region *region = map->regions;
        u8 sorted_erase_mask;
        unsigned int i;

        for (i = 0; i < map->n_regions; i++) {
                sorted_erase_mask =
                        spi_nor_sort_erase_mask(map, region[i].erase_mask);

                /* Overwrite erase mask. */
                region[i].erase_mask = sorted_erase_mask;
        }
}

/**
 * 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
 *
 * 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 = nor->params;
        struct spi_nor_erase_map *map = &params->erase_map;
        struct spi_nor_erase_type *erase_type = map->erase_type;
        struct sfdp_bfpt bfpt;
        size_t len;
        int i, cmd, err;
        u32 addr, val;
        u32 dword;
        u16 half;
        u8 erase_mask;
        u8 wait_states, mode_clocks, opcode;

        /* 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_dma_unsafe(nor,  addr, len, &bfpt);
        if (err < 0)
                return err;

        /* Fix endianness of the BFPT DWORDs. */
        le32_to_cpu_array(bfpt.dwords, BFPT_DWORD_MAX);

        /* Number of address bytes. */
        switch (bfpt.dwords[SFDP_DWORD(1)] & BFPT_DWORD1_ADDRESS_BYTES_MASK) {
        case BFPT_DWORD1_ADDRESS_BYTES_3_ONLY:
        case BFPT_DWORD1_ADDRESS_BYTES_3_OR_4:
                params->addr_nbytes = 3;
                params->addr_mode_nbytes = 3;
                break;

        case BFPT_DWORD1_ADDRESS_BYTES_4_ONLY:
                params->addr_nbytes = 4;
                params->addr_mode_nbytes = 4;
                break;

        default:
                break;
        }

        /* Flash Memory Density (in bits). */
        val = bfpt.dwords[SFDP_DWORD(2)];
        if (val & BIT(31)) {
                val &= ~BIT(31);

                /*
                 * Prevent overflows on params->size. Anyway, a NOR of 2^64
                 * bits is unlikely to exist so this error probably means
                 * the BFPT we are reading is corrupted/wrong.
                 */
                if (val > 63)
                        return -EINVAL;

                params->size = 1ULL << val;
        } else {
                params->size = val + 1;
        }
        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. Reinitialize the uniform erase map using the
         * Erase Types defined in the bfpt table.
         */
        erase_mask = 0;
        memset(&params->erase_map, 0, sizeof(params->erase_map));
        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;
                erase_mask |= BIT(i);
                spi_nor_set_erase_settings_from_bfpt(&erase_type[i], erasesize,
                                                     opcode, i);
        }
        spi_nor_init_uniform_erase_map(map, erase_mask, params->size);
        /*
         * Sort all the map's Erase Types in ascending order with the smallest
         * erase size being the first member in the erase_type array.
         */
        sort(erase_type, SNOR_ERASE_TYPE_MAX, sizeof(erase_type[0]),
             spi_nor_map_cmp_erase_type, NULL);
        /*
         * Sort the erase types in the uniform region in order to update the
         * uniform_erase_type bitmask. The bitmask will be used later on when
         * selecting the uniform erase.
         */
        spi_nor_regions_sort_erase_types(map);

        /* Stop here if not JESD216 rev A or later. */
        if (bfpt_header->length == BFPT_DWORD_MAX_JESD216)
                return spi_nor_post_bfpt_fixups(nor, bfpt_header, &bfpt);

        /* Page size: this field specifies 'N' so the page size = 2^N bytes. */
        val = bfpt.dwords[SFDP_DWORD(11)];
        val &= BFPT_DWORD11_PAGE_SIZE_MASK;
        val >>= BFPT_DWORD11_PAGE_SIZE_SHIFT;
        params->page_size = 1U << val;

        /* Quad Enable Requirements. */
        switch (bfpt.dwords[SFDP_DWORD(15)] & BFPT_DWORD15_QER_MASK) {
        case BFPT_DWORD15_QER_NONE:
                params->quad_enable = NULL;
                break;

        case BFPT_DWORD15_QER_SR2_BIT1_BUGGY:
                /*
                 * Writing only one byte to the Status Register has the
                 * side-effect of clearing Status Register 2.
                 */
        case BFPT_DWORD15_QER_SR2_BIT1_NO_RD:
                /*
                 * Read Configuration Register (35h) instruction is not
                 * supported.
                 */
                nor->flags |= SNOR_F_HAS_16BIT_SR | SNOR_F_NO_READ_CR;
                params->quad_enable = spi_nor_sr2_bit1_quad_enable;
                break;

        case BFPT_DWORD15_QER_SR1_BIT6:
                nor->flags &= ~SNOR_F_HAS_16BIT_SR;
                params->quad_enable = spi_nor_sr1_bit6_quad_enable;
                break;

        case BFPT_DWORD15_QER_SR2_BIT7:
                nor->flags &= ~SNOR_F_HAS_16BIT_SR;
                params->quad_enable = spi_nor_sr2_bit7_quad_enable;
                break;

        case BFPT_DWORD15_QER_SR2_BIT1:
                /*
                 * JESD216 rev B or later does not specify if writing only one
                 * byte to the Status Register clears or not the Status
                 * Register 2, so let's be cautious and keep the default
                 * assumption of a 16-bit Write Status (01h) command.
                 */
                nor->flags |= SNOR_F_HAS_16BIT_SR;

                params->quad_enable = spi_nor_sr2_bit1_quad_enable;
                break;

        default:
                dev_dbg(nor->dev, "BFPT QER reserved value used\n");
                break;
        }

        dword = bfpt.dwords[SFDP_DWORD(16)] & BFPT_DWORD16_4B_ADDR_MODE_MASK;
        if (SFDP_MASK_CHECK(dword, BFPT_DWORD16_4B_ADDR_MODE_BRWR))
                params->set_4byte_addr_mode = spi_nor_set_4byte_addr_mode_brwr;
        else if (SFDP_MASK_CHECK(dword, BFPT_DWORD16_4B_ADDR_MODE_WREN_EN4B_EX4B))
                params->set_4byte_addr_mode = spi_nor_set_4byte_addr_mode_wren_en4b_ex4b;
        else if (SFDP_MASK_CHECK(dword, BFPT_DWORD16_4B_ADDR_MODE_EN4B_EX4B))
                params->set_4byte_addr_mode = spi_nor_set_4byte_addr_mode_en4b_ex4b;
        else
                dev_dbg(nor->dev, "BFPT: 4-Byte Address Mode method is not recognized or not implemented\n");

        /* Soft Reset support. */
        if (bfpt.dwords[SFDP_DWORD(16)] & BFPT_DWORD16_SWRST_EN_RST)
                nor->flags |= SNOR_F_SOFT_RESET;

        /* Stop here if not JESD216 rev C or later. */
        if (bfpt_header->length == BFPT_DWORD_MAX_JESD216B)
                return spi_nor_post_bfpt_fixups(nor, bfpt_header, &bfpt);

        /* Parse 1-1-8 read instruction */
        opcode = FIELD_GET(BFPT_DWORD17_RD_1_1_8_CMD, bfpt.dwords[SFDP_DWORD(17)]);
        if (opcode) {
                mode_clocks = FIELD_GET(BFPT_DWORD17_RD_1_1_8_MODE_CLOCKS,
                                        bfpt.dwords[SFDP_DWORD(17)]);
                wait_states = FIELD_GET(BFPT_DWORD17_RD_1_1_8_WAIT_STATES,
                                        bfpt.dwords[SFDP_DWORD(17)]);
                params->hwcaps.mask |= SNOR_HWCAPS_READ_1_1_8;
                spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ_1_1_8],
                                          mode_clocks, wait_states, opcode,
                                          SNOR_PROTO_1_1_8);
        }

        /* Parse 1-8-8 read instruction */
        opcode = FIELD_GET(BFPT_DWORD17_RD_1_8_8_CMD, bfpt.dwords[SFDP_DWORD(17)]);
        if (opcode) {
                mode_clocks = FIELD_GET(BFPT_DWORD17_RD_1_8_8_MODE_CLOCKS,
                                        bfpt.dwords[SFDP_DWORD(17)]);
                wait_states = FIELD_GET(BFPT_DWORD17_RD_1_8_8_WAIT_STATES,
                                        bfpt.dwords[SFDP_DWORD(17)]);
                params->hwcaps.mask |= SNOR_HWCAPS_READ_1_8_8;
                spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ_1_8_8],
                                          mode_clocks, wait_states, opcode,
                                          SNOR_PROTO_1_8_8);
        }

        /* 8D-8D-8D command extension. */
        switch (bfpt.dwords[SFDP_DWORD(18)] & BFPT_DWORD18_CMD_EXT_MASK) {
        case BFPT_DWORD18_CMD_EXT_REP:
                nor->cmd_ext_type = SPI_NOR_EXT_REPEAT;
                break;

        case BFPT_DWORD18_CMD_EXT_INV:
                nor->cmd_ext_type = SPI_NOR_EXT_INVERT;
                break;

        case BFPT_DWORD18_CMD_EXT_RES:
                dev_dbg(nor->dev, "Reserved command extension used\n");
                break;

        case BFPT_DWORD18_CMD_EXT_16B:
                dev_dbg(nor->dev, "16-bit opcodes not supported\n");
                return -EOPNOTSUPP;
        }

        /* Byte order in 8D-8D-8D mode */
        if (bfpt.dwords[SFDP_DWORD(18)] & BFPT_DWORD18_BYTE_ORDER_SWAPPED)
                nor->flags |= SNOR_F_SWAP16;

        return spi_nor_post_bfpt_fixups(nor, bfpt_header, &bfpt);
}

/**
 * spi_nor_smpt_addr_nbytes() - return the number of address bytes used in the
 *                             configuration detection command.
 * @nor:        pointer to a 'struct spi_nor'
 * @settings:   configuration detection command descriptor, dword1
 */
static u8 spi_nor_smpt_addr_nbytes(const struct spi_nor *nor, const u32 settings)
{
        switch (settings & SMPT_CMD_ADDRESS_LEN_MASK) {
        case SMPT_CMD_ADDRESS_LEN_0:
                return 0;
        case SMPT_CMD_ADDRESS_LEN_3:
                return 3;
        case SMPT_CMD_ADDRESS_LEN_4:
                return 4;
        case SMPT_CMD_ADDRESS_LEN_USE_CURRENT:
        default:
                return nor->params->addr_mode_nbytes;
        }
}

/**
 * spi_nor_smpt_read_dummy() - return the configuration detection command read
 *                             latency, in clock cycles.
 * @nor:        pointer to a 'struct spi_nor'
 * @settings:   configuration detection command descriptor, dword1
 *
 * Return: the number of dummy cycles for an SMPT read
 */
static u8 spi_nor_smpt_read_dummy(const struct spi_nor *nor, const u32 settings)
{
        u8 read_dummy = SMPT_CMD_READ_DUMMY(settings);

        if (read_dummy == SMPT_CMD_READ_DUMMY_IS_VARIABLE)
                return nor->read_dummy;
        return read_dummy;
}

/**
 * spi_nor_get_map_in_use() - get the configuration map in use
 * @nor:        pointer to a 'struct spi_nor'
 * @smpt:       pointer to the sector map parameter table
 * @smpt_len:   sector map parameter table length
 *
 * Return: pointer to the map in use, ERR_PTR(-errno) otherwise.
 */
static const u32 *spi_nor_get_map_in_use(struct spi_nor *nor, const u32 *smpt,
                                         u8 smpt_len)
{
        const u32 *ret;
        u8 *buf;
        u32 addr;
        int err;
        u8 i;
        u8 addr_nbytes, read_opcode, read_dummy;
        u8 read_data_mask, map_id;

        /* Use a kmalloc'ed bounce buffer to guarantee it is DMA-able. */
        buf = kmalloc(sizeof(*buf), GFP_KERNEL);
        if (!buf)
                return ERR_PTR(-ENOMEM);

        addr_nbytes = nor->addr_nbytes;
        read_dummy = nor->read_dummy;
        read_opcode = nor->read_opcode;

        map_id = 0;
        /* Determine if there are any optional Detection Command Descriptors */
        for (i = 0; i < smpt_len; i += 2) {
                if (smpt[i] & SMPT_DESC_TYPE_MAP)
                        break;

                read_data_mask = SMPT_CMD_READ_DATA(smpt[i]);
                nor->addr_nbytes = spi_nor_smpt_addr_nbytes(nor, smpt[i]);
                nor->read_dummy = spi_nor_smpt_read_dummy(nor, smpt[i]);
                nor->read_opcode = SMPT_CMD_OPCODE(smpt[i]);
                addr = smpt[i + 1];

                err = spi_nor_read_raw(nor, addr, 1, buf);
                if (err) {
                        ret = ERR_PTR(err);
                        goto out;
                }

                /*
                 * Build an index value that is used to select the Sector Map
                 * Configuration that is currently in use.
                 */
                map_id = map_id << 1 | !!(*buf & read_data_mask);
        }

        /*
         * If command descriptors are provided, they always precede map
         * descriptors in the table. There is no need to start the iteration
         * over smpt array all over again.
         *
         * Find the matching configuration map.
         */
        ret = ERR_PTR(-EINVAL);
        while (i < smpt_len) {
                if (SMPT_MAP_ID(smpt[i]) == map_id) {
                        ret = smpt + i;
                        break;
                }

                /*
                 * If there are no more configuration map descriptors and no
                 * configuration ID matched the configuration identifier, the
                 * sector address map is unknown.
                 */
                if (smpt[i] & SMPT_DESC_END)
                        break;

                /* increment the table index to the next map */
                i += SMPT_MAP_REGION_COUNT(smpt[i]) + 1;
        }

        /* fall through */
out:
        kfree(buf);
        nor->addr_nbytes = addr_nbytes;
        nor->read_dummy = read_dummy;
        nor->read_opcode = read_opcode;
        return ret;
}

/**
 * spi_nor_region_check_overlay() - set overlay bit when the region is overlaid
 * @region:     pointer to a structure that describes a SPI NOR erase region
 * @erase:      pointer to a structure that describes a SPI NOR erase type
 * @erase_type: erase type bitmask
 */
static void
spi_nor_region_check_overlay(struct spi_nor_erase_region *region,
                             const struct spi_nor_erase_type *erase,
                             const u8 erase_type)
{
        int i;

        for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++) {
                if (!(erase[i].size && erase_type & BIT(erase[i].idx)))
                        continue;
                if (region->size & erase[i].size_mask) {
                        region->overlaid = true;
                        return;
                }
        }
}

/**
 * spi_nor_init_non_uniform_erase_map() - initialize the non-uniform erase map
 * @nor:        pointer to a 'struct spi_nor'
 * @smpt:       pointer to the sector map parameter table
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_init_non_uniform_erase_map(struct spi_nor *nor,
                                              const u32 *smpt)
{
        struct spi_nor_erase_map *map = &nor->params->erase_map;
        struct spi_nor_erase_type *erase = map->erase_type;
        struct spi_nor_erase_region *region;
        u64 offset;
        u32 region_count;
        int i, j;
        u8 uniform_erase_type, save_uniform_erase_type;
        u8 erase_type, regions_erase_type;

        region_count = SMPT_MAP_REGION_COUNT(*smpt);
        /*
         * The regions will be freed when the driver detaches from the
         * device.
         */
        region = devm_kcalloc(nor->dev, region_count, sizeof(*region),
                              GFP_KERNEL);
        if (!region)
                return -ENOMEM;
        map->regions = region;
        map->n_regions = region_count;

        uniform_erase_type = 0xff;
        regions_erase_type = 0;
        offset = 0;
        /* Populate regions. */
        for (i = 0; i < region_count; i++) {
                j = i + 1; /* index for the region dword */
                region[i].offset = offset;
                region[i].size = SMPT_MAP_REGION_SIZE(smpt[j]);
                erase_type = SMPT_MAP_REGION_ERASE_TYPE(smpt[j]);
                region[i].erase_mask = erase_type;

                spi_nor_region_check_overlay(&region[i], erase, erase_type);

                /*
                 * Save the erase types that are supported in all regions and
                 * can erase the entire flash memory.
                 */
                uniform_erase_type &= erase_type;

                /*
                 * regions_erase_type mask will indicate all the erase types
                 * supported in this configuration map.
                 */
                regions_erase_type |= erase_type;

                offset = region[i].offset + region[i].size;
        }

        save_uniform_erase_type = map->uniform_region.erase_mask;
        map->uniform_region.erase_mask =
                                spi_nor_sort_erase_mask(map,
                                                        uniform_erase_type);

        if (!regions_erase_type) {
                /*
                 * Roll back to the previous uniform_erase_type mask, SMPT is
                 * broken.
                 */
                map->uniform_region.erase_mask = save_uniform_erase_type;
                return -EINVAL;
        }

        /*
         * BFPT advertises all the erase types supported by all the possible
         * map configurations. Mask out the erase types that are not supported
         * by the current map configuration.
         */
        for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++)
                if (!(regions_erase_type & BIT(erase[i].idx)))
                        spi_nor_mask_erase_type(&erase[i]);

        return 0;
}

/**
 * spi_nor_parse_smpt() - parse Sector Map Parameter Table
 * @nor:                pointer to a 'struct spi_nor'
 * @smpt_header:        sector map parameter table header
 *
 * This table is optional, but when available, we parse it to identify the
 * location and size of sectors within the main data array of the flash memory
 * device and to identify which Erase Types are supported by each sector.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_parse_smpt(struct spi_nor *nor,
                              const struct sfdp_parameter_header *smpt_header)
{
        const u32 *sector_map;
        u32 *smpt;
        size_t len;
        u32 addr;
        int ret;

        /* Read the Sector Map Parameter Table. */
        len = smpt_header->length * sizeof(*smpt);
        smpt = kmalloc(len, GFP_KERNEL);
        if (!smpt)
                return -ENOMEM;

        addr = SFDP_PARAM_HEADER_PTP(smpt_header);
        ret = spi_nor_read_sfdp(nor, addr, len, smpt);
        if (ret)
                goto out;

        /* Fix endianness of the SMPT DWORDs. */
        le32_to_cpu_array(smpt, smpt_header->length);

        sector_map = spi_nor_get_map_in_use(nor, smpt, smpt_header->length);
        if (IS_ERR(sector_map)) {
                ret = PTR_ERR(sector_map);
                goto out;
        }

        ret = spi_nor_init_non_uniform_erase_map(nor, sector_map);
        if (ret)
                goto out;

        spi_nor_regions_sort_erase_types(&nor->params->erase_map);
        /* fall through */
out:
        kfree(smpt);
        return ret;
}

/**
 * spi_nor_parse_4bait() - parse the 4-Byte Address Instruction 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.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_parse_4bait(struct spi_nor *nor,
                               const struct sfdp_parameter_header *param_header)
{
        static const struct sfdp_4bait reads[] = {
                { SNOR_HWCAPS_READ,             BIT(0) },
                { SNOR_HWCAPS_READ_FAST,        BIT(1) },
                { SNOR_HWCAPS_READ_1_1_2,       BIT(2) },
                { SNOR_HWCAPS_READ_1_2_2,       BIT(3) },
                { SNOR_HWCAPS_READ_1_1_4,       BIT(4) },
                { SNOR_HWCAPS_READ_1_4_4,       BIT(5) },
                { SNOR_HWCAPS_READ_1_1_1_DTR,   BIT(13) },
                { SNOR_HWCAPS_READ_1_2_2_DTR,   BIT(14) },
                { SNOR_HWCAPS_READ_1_4_4_DTR,   BIT(15) },
                { SNOR_HWCAPS_READ_1_1_8,       BIT(20) },
                { SNOR_HWCAPS_READ_1_8_8,       BIT(21) },
        };
        static const struct sfdp_4bait programs[] = {
                { SNOR_HWCAPS_PP,               BIT(6) },
                { SNOR_HWCAPS_PP_1_1_4,         BIT(7) },
                { SNOR_HWCAPS_PP_1_4_4,         BIT(8) },
        };
        static const struct sfdp_4bait erases[SNOR_ERASE_TYPE_MAX] = {
                { 0u /* not used */,            BIT(9) },
                { 0u /* not used */,            BIT(10) },
                { 0u /* not used */,            BIT(11) },
                { 0u /* not used */,            BIT(12) },
        };
        struct spi_nor_flash_parameter *params = nor->params;
        struct spi_nor_pp_command *params_pp = params->page_programs;
        struct spi_nor_erase_map *map = &params->erase_map;
        struct spi_nor_erase_type *erase_type = map->erase_type;
        u32 *dwords;
        size_t len;
        u32 addr, discard_hwcaps, read_hwcaps, pp_hwcaps, erase_mask;
        int i, ret;

        if (param_header->major != SFDP_JESD216_MAJOR ||
            param_header->length < SFDP_4BAIT_DWORD_MAX)
                return -EINVAL;

        /* Read the 4-byte Address Instruction Table. */
        len = sizeof(*dwords) * SFDP_4BAIT_DWORD_MAX;

        /* Use a kmalloc'ed bounce buffer to guarantee it is DMA-able. */
        dwords = kmalloc(len, GFP_KERNEL);
        if (!dwords)
                return -ENOMEM;

        addr = SFDP_PARAM_HEADER_PTP(param_header);
        ret = spi_nor_read_sfdp(nor, addr, len, dwords);
        if (ret)
                goto out;

        /* Fix endianness of the 4BAIT DWORDs. */
        le32_to_cpu_array(dwords, SFDP_4BAIT_DWORD_MAX);

        /*
         * Compute the subset of (Fast) Read commands for which the 4-byte
         * version is supported.
         */
        discard_hwcaps = 0;
        read_hwcaps = 0;
        for (i = 0; i < ARRAY_SIZE(reads); i++) {
                const struct sfdp_4bait *read = &reads[i];

                discard_hwcaps |= read->hwcaps;
                if ((params->hwcaps.mask & read->hwcaps) &&
                    (dwords[SFDP_DWORD(1)] & read->supported_bit))
                        read_hwcaps |= read->hwcaps;
        }

        /*
         * Compute the subset of Page Program commands for which the 4-byte
         * version is supported.
         */
        pp_hwcaps = 0;
        for (i = 0; i < ARRAY_SIZE(programs); i++) {
                const struct sfdp_4bait *program = &programs[i];

                /*
                 * The 4 Byte Address Instruction (Optional) Table is the only
                 * SFDP table that indicates support for Page Program Commands.
                 * Bypass the params->hwcaps.mask and consider 4BAIT the biggest
                 * authority for specifying Page Program support.
                 */
                discard_hwcaps |= program->hwcaps;
                if (dwords[SFDP_DWORD(1)] & program->supported_bit)
                        pp_hwcaps |= program->hwcaps;
        }

        /*
         * Compute the subset of Sector Erase commands for which the 4-byte
         * version is supported.
         */
        erase_mask = 0;
        for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++) {
                const struct sfdp_4bait *erase = &erases[i];

                if (dwords[SFDP_DWORD(1)] & erase->supported_bit)
                        erase_mask |= BIT(i);
        }

        /* Replicate the sort done for the map's erase types in BFPT. */
        erase_mask = spi_nor_sort_erase_mask(map, erase_mask);

        /*
         * We need at least one 4-byte op code per read, program and erase
         * operation; the .read(), .write() and .erase() hooks share the
         * nor->addr_nbytes value.
         */
        if (!read_hwcaps || !pp_hwcaps || !erase_mask)
                goto out;

        /*
         * Discard all operations from the 4-byte instruction set which are
         * not supported by this memory.
         */
        params->hwcaps.mask &= ~discard_hwcaps;
        params->hwcaps.mask |= (read_hwcaps | pp_hwcaps);

        /* Use the 4-byte address instruction set. */
        for (i = 0; i < SNOR_CMD_READ_MAX; i++) {
                struct spi_nor_read_command *read_cmd = &params->reads[i];

                read_cmd->opcode = spi_nor_convert_3to4_read(read_cmd->opcode);
        }

        /* 4BAIT is the only SFDP table that indicates page program support. */
        if (pp_hwcaps & SNOR_HWCAPS_PP) {
                spi_nor_set_pp_settings(&params_pp[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(&params_pp[SNOR_CMD_PP_8_8_8_DTR],
                                        SPINOR_OP_PP_4B, SNOR_PROTO_8_8_8_DTR);
        }
        if (pp_hwcaps & SNOR_HWCAPS_PP_1_1_4)
                spi_nor_set_pp_settings(&params_pp[SNOR_CMD_PP_1_1_4],
                                        SPINOR_OP_PP_1_1_4_4B,
                                        SNOR_PROTO_1_1_4);
        if (pp_hwcaps & SNOR_HWCAPS_PP_1_4_4)
                spi_nor_set_pp_settings(&params_pp[SNOR_CMD_PP_1_4_4],
                                        SPINOR_OP_PP_1_4_4_4B,
                                        SNOR_PROTO_1_4_4);

        for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++) {
                if (erase_mask & BIT(i))
                        erase_type[i].opcode = (dwords[SFDP_DWORD(2)] >>
                                                erase_type[i].idx * 8) & 0xFF;
                else
                        spi_nor_mask_erase_type(&erase_type[i]);
        }

        /*
         * We set SNOR_F_HAS_4BAIT in order to skip spi_nor_set_4byte_opcodes()
         * later because we already did the conversion to 4byte opcodes. Also,
         * this latest function implements a legacy quirk for the erase size of
         * Spansion memory. However this quirk is no longer needed with new
         * SFDP compliant memories.
         */
        params->addr_nbytes = 4;
        nor->flags |= SNOR_F_4B_OPCODES | SNOR_F_HAS_4BAIT;

        /* fall through */
out:
        kfree(dwords);
        return ret;
}

#define PROFILE1_DWORD1_RDSR_ADDR_BYTES         BIT(29)
#define PROFILE1_DWORD1_RDSR_DUMMY              BIT(28)
#define PROFILE1_DWORD1_RD_FAST_CMD             GENMASK(15, 8)
#define PROFILE1_DWORD4_DUMMY_200MHZ            GENMASK(11, 7)
#define PROFILE1_DWORD5_DUMMY_166MHZ            GENMASK(31, 27)
#define PROFILE1_DWORD5_DUMMY_133MHZ            GENMASK(21, 17)
#define PROFILE1_DWORD5_DUMMY_100MHZ            GENMASK(11, 7)

/**
 * spi_nor_parse_profile1() - parse the xSPI Profile 1.0 table
 * @nor:                pointer to a 'struct spi_nor'
 * @profile1_header:    pointer to the 'struct sfdp_parameter_header' describing
 *                      the Profile 1.0 Table length and version.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_parse_profile1(struct spi_nor *nor,
                                  const struct sfdp_parameter_header *profile1_header)
{
        u32 *dwords, addr;
        size_t len;
        int ret;
        u8 dummy, opcode;

        len = profile1_header->length * sizeof(*dwords);
        dwords = kmalloc(len, GFP_KERNEL);
        if (!dwords)
                return -ENOMEM;

        addr = SFDP_PARAM_HEADER_PTP(profile1_header);
        ret = spi_nor_read_sfdp(nor, addr, len, dwords);
        if (ret)
                goto out;

        le32_to_cpu_array(dwords, profile1_header->length);

        /* Get 8D-8D-8D fast read opcode and dummy cycles. */
        opcode = FIELD_GET(PROFILE1_DWORD1_RD_FAST_CMD, dwords[SFDP_DWORD(1)]);

         /* Set the Read Status Register dummy cycles and dummy address bytes. */
        if (dwords[SFDP_DWORD(1)] & PROFILE1_DWORD1_RDSR_DUMMY)
                nor->params->rdsr_dummy = 8;
        else
                nor->params->rdsr_dummy = 4;

        if (dwords[SFDP_DWORD(1)] & PROFILE1_DWORD1_RDSR_ADDR_BYTES)
                nor->params->rdsr_addr_nbytes = 4;
        else
                nor->params->rdsr_addr_nbytes = 0;

        /*
         * We don't know what speed the controller is running at. Find the
         * dummy cycles for the fastest frequency the flash can run at to be
         * sure we are never short of dummy cycles. A value of 0 means the
         * frequency is not supported.
         *
         * Default to PROFILE1_DUMMY_DEFAULT if we don't find anything, and let
         * flashes set the correct value if needed in their fixup hooks.
         */
        dummy = FIELD_GET(PROFILE1_DWORD4_DUMMY_200MHZ, dwords[SFDP_DWORD(4)]);
        if (!dummy)
                dummy = FIELD_GET(PROFILE1_DWORD5_DUMMY_166MHZ,
                                  dwords[SFDP_DWORD(5)]);
        if (!dummy)
                dummy = FIELD_GET(PROFILE1_DWORD5_DUMMY_133MHZ,
                                  dwords[SFDP_DWORD(5)]);
        if (!dummy)
                dummy = FIELD_GET(PROFILE1_DWORD5_DUMMY_100MHZ,
                                  dwords[SFDP_DWORD(5)]);
        if (!dummy)
                dev_dbg(nor->dev,
                        "Can't find dummy cycles from Profile 1.0 table\n");

        /* Round up to an even value to avoid tripping controllers up. */
        dummy = round_up(dummy, 2);

        /* Update the fast read settings. */
        nor->params->hwcaps.mask |= SNOR_HWCAPS_READ_8_8_8_DTR;
        spi_nor_set_read_settings(&nor->params->reads[SNOR_CMD_READ_8_8_8_DTR],
                                  0, dummy, opcode,
                                  SNOR_PROTO_8_8_8_DTR);

        /*
         * Page Program is "Required Command" in the xSPI Profile 1.0. Update
         * the params->hwcaps.mask here.
         */
        nor->params->hwcaps.mask |= SNOR_HWCAPS_PP_8_8_8_DTR;

out:
        kfree(dwords);
        return ret;
}

#define SCCR_DWORD22_OCTAL_DTR_EN_VOLATILE              BIT(31)

/**
 * spi_nor_parse_sccr() - Parse the Status, Control and Configuration Register
 *                        Map.
 * @nor:                pointer to a 'struct spi_nor'
 * @sccr_header:        pointer to the 'struct sfdp_parameter_header' describing
 *                      the SCCR Map table length and version.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_parse_sccr(struct spi_nor *nor,
                              const struct sfdp_parameter_header *sccr_header)
{
        struct spi_nor_flash_parameter *params = nor->params;
        u32 *dwords, addr;
        size_t len;
        int ret;

        len = sccr_header->length * sizeof(*dwords);
        dwords = kmalloc(len, GFP_KERNEL);
        if (!dwords)
                return -ENOMEM;

        addr = SFDP_PARAM_HEADER_PTP(sccr_header);
        ret = spi_nor_read_sfdp(nor, addr, len, dwords);
        if (ret)
                goto out;

        le32_to_cpu_array(dwords, sccr_header->length);

        /* Address offset for volatile registers (die 0) */
        if (!params->vreg_offset) {
                params->vreg_offset = devm_kmalloc(nor->dev, sizeof(*dwords),
                                                   GFP_KERNEL);
                if (!params->vreg_offset) {
                        ret = -ENOMEM;
                        goto out;
                }
        }
        params->vreg_offset[0] = dwords[SFDP_DWORD(1)];
        params->n_dice = 1;

        if (FIELD_GET(SCCR_DWORD22_OCTAL_DTR_EN_VOLATILE,
                      dwords[SFDP_DWORD(22)]))
                nor->flags |= SNOR_F_IO_MODE_EN_VOLATILE;

out:
        kfree(dwords);
        return ret;
}

/**
 * spi_nor_parse_sccr_mc() - Parse the Status, Control and Configuration
 *                           Register Map Offsets for Multi-Chip SPI Memory
 *                           Devices.
 * @nor:                pointer to a 'struct spi_nor'
 * @sccr_mc_header:     pointer to the 'struct sfdp_parameter_header' describing
 *                      the SCCR Map offsets table length and version.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_parse_sccr_mc(struct spi_nor *nor,
                                 const struct sfdp_parameter_header *sccr_mc_header)
{
        struct spi_nor_flash_parameter *params = nor->params;
        u32 *dwords, addr;
        u8 i, n_dice;
        size_t len;
        int ret;

        len = sccr_mc_header->length * sizeof(*dwords);
        dwords = kmalloc(len, GFP_KERNEL);
        if (!dwords)
                return -ENOMEM;

        addr = SFDP_PARAM_HEADER_PTP(sccr_mc_header);
        ret = spi_nor_read_sfdp(nor, addr, len, dwords);
        if (ret)
                goto out;

        le32_to_cpu_array(dwords, sccr_mc_header->length);

        /*
         * Pair of DOWRDs (volatile and non-volatile register offsets) per
         * additional die. Hence, length = 2 * (number of additional dice).
         */
        n_dice = 1 + sccr_mc_header->length / 2;

        /* Address offset for volatile registers of additional dice */
        params->vreg_offset =
                        devm_krealloc(nor->dev, params->vreg_offset,
                                      n_dice * sizeof(*dwords),
                                      GFP_KERNEL);
        if (!params->vreg_offset) {
                ret = -ENOMEM;
                goto out;
        }

        for (i = 1; i < n_dice; i++)
                params->vreg_offset[i] = dwords[SFDP_DWORD(i) * 2];

        params->n_dice = n_dice;

out:
        kfree(dwords);
        return ret;
}

/**
 * spi_nor_post_sfdp_fixups() - Updates the flash's parameters and settings
 * after SFDP has been parsed. Called only for flashes that define JESD216 SFDP
 * tables.
 * @nor:        pointer to a 'struct spi_nor'
 *
 * Used to tweak various flash parameters when information provided by the SFDP
 * tables are wrong.
 */
static int spi_nor_post_sfdp_fixups(struct spi_nor *nor)
{
        int ret;

        if (nor->manufacturer && nor->manufacturer->fixups &&
            nor->manufacturer->fixups->post_sfdp) {
                ret = nor->manufacturer->fixups->post_sfdp(nor);
                if (ret)
                        return ret;
        }

        if (nor->info->fixups && nor->info->fixups->post_sfdp)
                return nor->info->fixups->post_sfdp(nor);

        return 0;
}

/**
 * spi_nor_check_sfdp_signature() - check for a valid SFDP signature
 * @nor:        pointer to a 'struct spi_nor'
 *
 * Used to detect if the flash supports the RDSFDP command as well as the
 * presence of a valid SFDP table.
 *
 * Return: 0 on success, -errno otherwise.
 */
int spi_nor_check_sfdp_signature(struct spi_nor *nor)
{
        u32 signature;
        int err;

        /* Get the SFDP header. */
        err = spi_nor_read_sfdp_dma_unsafe(nor, 0, sizeof(signature),
                                           &signature);
        if (err < 0)
                return err;

        /* Check the SFDP signature. */
        if (le32_to_cpu(signature) != SFDP_SIGNATURE)
                return -EINVAL;

        return 0;
}

/**
 * spi_nor_parse_sfdp() - parse the Serial Flash Discoverable Parameters.
 * @nor:                pointer to a 'struct spi_nor'
 *
 * 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.
 */
int spi_nor_parse_sfdp(struct spi_nor *nor)
{
        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;
        struct sfdp *sfdp;
        size_t sfdp_size;
        size_t psize;
        int i, err;

        /* Get the SFDP header. */
        err = spi_nor_read_sfdp_dma_unsafe(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)
                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;

        sfdp_size = SFDP_PARAM_HEADER_PTP(bfpt_header) +
                    SFDP_PARAM_HEADER_PARAM_LEN(bfpt_header);

        /*
         * 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_dbg(dev, "failed to read SFDP parameter headers\n");
                        goto exit;
                }
        }

        /*
         * Cache the complete SFDP data. It is not (easily) possible to fetch
         * SFDP after probe time and we need it for the sysfs access.
         */
        for (i = 0; i < header.nph; i++) {
                param_header = &param_headers[i];
                sfdp_size = max_t(size_t, sfdp_size,
                                  SFDP_PARAM_HEADER_PTP(param_header) +
                                  SFDP_PARAM_HEADER_PARAM_LEN(param_header));
        }

        /*
         * Limit the total size to a reasonable value to avoid allocating too
         * much memory just of because the flash returned some insane values.
         */
        if (sfdp_size > PAGE_SIZE) {
                dev_dbg(dev, "SFDP data (%zu) too big, truncating\n",
                        sfdp_size);
                sfdp_size = PAGE_SIZE;
        }

        sfdp = devm_kzalloc(dev, sizeof(*sfdp), GFP_KERNEL);
        if (!sfdp) {
                err = -ENOMEM;
                goto exit;
        }

        /*
         * The SFDP is organized in chunks of DWORDs. Thus, in theory, the
         * sfdp_size should be a multiple of DWORDs. But in case a flash
         * is not spec compliant, make sure that we have enough space to store
         * the complete SFDP data.
         */
        sfdp->num_dwords = DIV_ROUND_UP(sfdp_size, sizeof(*sfdp->dwords));
        sfdp->dwords = devm_kcalloc(dev, sfdp->num_dwords,
                                    sizeof(*sfdp->dwords), GFP_KERNEL);
        if (!sfdp->dwords) {
                err = -ENOMEM;
                devm_kfree(dev, sfdp);
                goto exit;
        }

        err = spi_nor_read_sfdp(nor, 0, sfdp_size, sfdp->dwords);
        if (err < 0) {
                dev_dbg(dev, "failed to read SFDP data\n");
                devm_kfree(dev, sfdp->dwords);
                devm_kfree(dev, sfdp);
                goto exit;
        }

        nor->sfdp = sfdp;

        /*
         * 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);
        if (err)
                goto exit;

        /* Parse optional parameter tables. */
        for (i = 0; i < header.nph; i++) {
                param_header = &param_headers[i];

                switch (SFDP_PARAM_HEADER_ID(param_header)) {
                case SFDP_SECTOR_MAP_ID:
                        err = spi_nor_parse_smpt(nor, param_header);
                        break;

                case SFDP_4BAIT_ID:
                        err = spi_nor_parse_4bait(nor, param_header);
                        break;

                case SFDP_PROFILE1_ID:
                        err = spi_nor_parse_profile1(nor, param_header);
                        break;

                case SFDP_SCCR_MAP_ID:
                        err = spi_nor_parse_sccr(nor, param_header);
                        break;

                case SFDP_SCCR_MAP_MC_ID:
                        err = spi_nor_parse_sccr_mc(nor, param_header);
                        break;

                default:
                        break;
                }

                if (err) {
                        dev_warn(dev, "Failed to parse optional parameter table: %04x\n",
                                 SFDP_PARAM_HEADER_ID(param_header));
                        /*
                         * Let's not drop all information we extracted so far
                         * if optional table parsers fail. In case of failing,
                         * each optional parser is responsible to roll back to
                         * the previously known spi_nor data.
                         */
                        err = 0;
                }
        }

        err = spi_nor_post_sfdp_fixups(nor);
exit:
        kfree(param_headers);
        return err;
}