mtd: spi-nor: Describe all the Reg Ops

[linux-2.6-microblaze.git] / drivers / mtd / spi-nor / spi-nor.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Based on m25p80.c, by Mike Lavender (mike@steroidmicros.com), with
 * influence from lart.c (Abraham Van Der Merwe) and mtd_dataflash.c
 *
 * Copyright (C) 2005, Intec Automation Inc.
 * Copyright (C) 2014, Freescale Semiconductor, Inc.
 */

#include <linux/err.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/math64.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/sort.h>

#include <linux/mtd/mtd.h>
#include <linux/of_platform.h>
#include <linux/sched/task_stack.h>
#include <linux/spi/flash.h>
#include <linux/mtd/spi-nor.h>

/* Define max times to check status register before we give up. */

/*
 * For everything but full-chip erase; probably could be much smaller, but kept
 * around for safety for now
 */
#define DEFAULT_READY_WAIT_JIFFIES              (40UL * HZ)

/*
 * For full-chip erase, calibrated to a 2MB flash (M25P16); should be scaled up
 * for larger flash
 */
#define CHIP_ERASE_2MB_READY_WAIT_JIFFIES       (40UL * HZ)

#define SPI_NOR_MAX_ID_LEN      6
#define SPI_NOR_MAX_ADDR_WIDTH  4

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_4BAIT_ID           0xff84  /* 4-byte Address Instruction 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 Write 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];
};

/**
 * struct spi_nor_fixups - SPI NOR fixup hooks
 * @default_init: called after default flash parameters init. Used to tweak
 *                flash parameters when information provided by the flash_info
 *                table is incomplete or wrong.
 * @post_bfpt: called after the BFPT table has been parsed
 * @post_sfdp: called after SFDP has been parsed (is also called for SPI NORs
 *             that do not support RDSFDP). Typically used to tweak various
 *             parameters that could not be extracted by other means (i.e.
 *             when information provided by the SFDP/flash_info tables are
 *             incomplete or wrong).
 *
 * Those hooks can be used to tweak the SPI NOR configuration when the SFDP
 * table is broken or not available.
 */
struct spi_nor_fixups {
        void (*default_init)(struct spi_nor *nor);
        int (*post_bfpt)(struct spi_nor *nor,
                         const struct sfdp_parameter_header *bfpt_header,
                         const struct sfdp_bfpt *bfpt,
                         struct spi_nor_flash_parameter *params);
        void (*post_sfdp)(struct spi_nor *nor);
};

struct flash_info {
        char            *name;

        /*
         * This array stores the ID bytes.
         * The first three bytes are the JEDIC ID.
         * JEDEC ID zero means "no ID" (mostly older chips).
         */
        u8              id[SPI_NOR_MAX_ID_LEN];
        u8              id_len;

        /* The size listed here is what works with SPINOR_OP_SE, which isn't
         * necessarily called a "sector" by the vendor.
         */
        unsigned        sector_size;
        u16             n_sectors;

        u16             page_size;
        u16             addr_width;

        u16             flags;
#define SECT_4K                 BIT(0)  /* SPINOR_OP_BE_4K works uniformly */
#define SPI_NOR_NO_ERASE        BIT(1)  /* No erase command needed */
#define SST_WRITE               BIT(2)  /* use SST byte programming */
#define SPI_NOR_NO_FR           BIT(3)  /* Can't do fastread */
#define SECT_4K_PMC             BIT(4)  /* SPINOR_OP_BE_4K_PMC works uniformly */
#define SPI_NOR_DUAL_READ       BIT(5)  /* Flash supports Dual Read */
#define SPI_NOR_QUAD_READ       BIT(6)  /* Flash supports Quad Read */
#define USE_FSR                 BIT(7)  /* use flag status register */
#define SPI_NOR_HAS_LOCK        BIT(8)  /* Flash supports lock/unlock via SR */
#define SPI_NOR_HAS_TB          BIT(9)  /*
                                         * Flash SR has Top/Bottom (TB) protect
                                         * bit. Must be used with
                                         * SPI_NOR_HAS_LOCK.
                                         */
#define SPI_NOR_XSR_RDY         BIT(10) /*
                                         * S3AN flashes have specific opcode to
                                         * read the status register.
                                         * Flags SPI_NOR_XSR_RDY and SPI_S3AN
                                         * use the same bit as one implies the
                                         * other, but we will get rid of
                                         * SPI_S3AN soon.
                                         */
#define SPI_S3AN                BIT(10) /*
                                         * Xilinx Spartan 3AN In-System Flash
                                         * (MFR cannot be used for probing
                                         * because it has the same value as
                                         * ATMEL flashes)
                                         */
#define SPI_NOR_4B_OPCODES      BIT(11) /*
                                         * Use dedicated 4byte address op codes
                                         * 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 USE_CLSR                BIT(14) /* use CLSR command */
#define SPI_NOR_OCTAL_READ      BIT(15) /* Flash supports Octal Read */

        /* Part specific fixup hooks. */
        const struct spi_nor_fixups *fixups;
};

#define JEDEC_MFR(info) ((info)->id[0])

/**
 * spi_nor_spimem_xfer_data() - helper function to read/write data to
 *                              flash's memory region
 * @nor:        pointer to 'struct spi_nor'
 * @op:         pointer to 'struct spi_mem_op' template for transfer
 *
 * Return: number of bytes transferred on success, -errno otherwise
 */
static ssize_t spi_nor_spimem_xfer_data(struct spi_nor *nor,
                                        struct spi_mem_op *op)
{
        bool usebouncebuf = false;
        void *rdbuf = NULL;
        const void *buf;
        int ret;

        if (op->data.dir == SPI_MEM_DATA_IN)
                buf = op->data.buf.in;
        else
                buf = op->data.buf.out;

        if (object_is_on_stack(buf) || !virt_addr_valid(buf))
                usebouncebuf = true;

        if (usebouncebuf) {
                if (op->data.nbytes > nor->bouncebuf_size)
                        op->data.nbytes = nor->bouncebuf_size;

                if (op->data.dir == SPI_MEM_DATA_IN) {
                        rdbuf = op->data.buf.in;
                        op->data.buf.in = nor->bouncebuf;
                } else {
                        op->data.buf.out = nor->bouncebuf;
                        memcpy(nor->bouncebuf, buf,
                               op->data.nbytes);
                }
        }

        ret = spi_mem_adjust_op_size(nor->spimem, op);
        if (ret)
                return ret;

        ret = spi_mem_exec_op(nor->spimem, op);
        if (ret)
                return ret;

        if (usebouncebuf && op->data.dir == SPI_MEM_DATA_IN)
                memcpy(rdbuf, nor->bouncebuf, op->data.nbytes);

        return op->data.nbytes;
}

/**
 * spi_nor_spimem_read_data() - read data from flash's memory region via
 *                              spi-mem
 * @nor:        pointer to 'struct spi_nor'
 * @from:       offset to read from
 * @len:        number of bytes to read
 * @buf:        pointer to dst buffer
 *
 * Return: number of bytes read successfully, -errno otherwise
 */
static ssize_t spi_nor_spimem_read_data(struct spi_nor *nor, loff_t from,
                                        size_t len, u8 *buf)
{
        struct spi_mem_op op =
                SPI_MEM_OP(SPI_MEM_OP_CMD(nor->read_opcode, 1),
                           SPI_MEM_OP_ADDR(nor->addr_width, from, 1),
                           SPI_MEM_OP_DUMMY(nor->read_dummy, 1),
                           SPI_MEM_OP_DATA_IN(len, buf, 1));

        /* get transfer protocols. */
        op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->read_proto);
        op.addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->read_proto);
        op.dummy.buswidth = op.addr.buswidth;
        op.data.buswidth = spi_nor_get_protocol_data_nbits(nor->read_proto);

        /* convert the dummy cycles to the number of bytes */
        op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;

        return spi_nor_spimem_xfer_data(nor, &op);
}

/**
 * spi_nor_read_data() - read data from flash memory
 * @nor:        pointer to 'struct spi_nor'
 * @from:       offset to read from
 * @len:        number of bytes to read
 * @buf:        pointer to dst buffer
 *
 * Return: number of bytes read successfully, -errno otherwise
 */
static ssize_t spi_nor_read_data(struct spi_nor *nor, loff_t from, size_t len,
                                 u8 *buf)
{
        if (nor->spimem)
                return spi_nor_spimem_read_data(nor, from, len, buf);

        return nor->controller_ops->read(nor, from, len, buf);
}

/**
 * spi_nor_spimem_write_data() - write data to flash memory via
 *                               spi-mem
 * @nor:        pointer to 'struct spi_nor'
 * @to:         offset to write to
 * @len:        number of bytes to write
 * @buf:        pointer to src buffer
 *
 * Return: number of bytes written successfully, -errno otherwise
 */
static ssize_t spi_nor_spimem_write_data(struct spi_nor *nor, loff_t to,
                                         size_t len, const u8 *buf)
{
        struct spi_mem_op op =
                SPI_MEM_OP(SPI_MEM_OP_CMD(nor->program_opcode, 1),
                           SPI_MEM_OP_ADDR(nor->addr_width, to, 1),
                           SPI_MEM_OP_NO_DUMMY,
                           SPI_MEM_OP_DATA_OUT(len, buf, 1));

        op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->write_proto);
        op.addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->write_proto);
        op.data.buswidth = spi_nor_get_protocol_data_nbits(nor->write_proto);

        if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second)
                op.addr.nbytes = 0;

        return spi_nor_spimem_xfer_data(nor, &op);
}

/**
 * spi_nor_write_data() - write data to flash memory
 * @nor:        pointer to 'struct spi_nor'
 * @to:         offset to write to
 * @len:        number of bytes to write
 * @buf:        pointer to src buffer
 *
 * Return: number of bytes written successfully, -errno otherwise
 */
static ssize_t spi_nor_write_data(struct spi_nor *nor, loff_t to, size_t len,
                                  const u8 *buf)
{
        if (nor->spimem)
                return spi_nor_spimem_write_data(nor, to, len, buf);

        return nor->controller_ops->write(nor, to, len, buf);
}

/**
 * spi_nor_write_enable() - Set write enable latch with Write Enable command.
 * @nor:        pointer to 'struct spi_nor'.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_write_enable(struct spi_nor *nor)
{
        int ret;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WREN, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_NO_DATA);

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->write_reg(nor, SPINOR_OP_WREN,
                                                     NULL, 0);
        }

        if (ret)
                dev_dbg(nor->dev, "error %d on Write Enable\n", ret);

        return ret;
}

/**
 * spi_nor_write_disable() - Send Write Disable instruction to the chip.
 * @nor:        pointer to 'struct spi_nor'.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_write_disable(struct spi_nor *nor)
{
        int ret;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WRDI, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_NO_DATA);

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->write_reg(nor, SPINOR_OP_WRDI,
                                                     NULL, 0);
        }

        if (ret)
                dev_dbg(nor->dev, "error %d on Write Disable\n", ret);

        return ret;
}

/**
 * spi_nor_read_sr() - Read the Status Register.
 * @nor:        pointer to 'struct spi_nor'.
 * @sr:         pointer to a DMA-able buffer where the value of the
 *              Status Register will be written.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
{
        int ret;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDSR, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_DATA_IN(1, sr, 1));

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->read_reg(nor, SPINOR_OP_RDSR,
                                                    sr, 1);
        }

        if (ret)
                dev_dbg(nor->dev, "error %d reading SR\n", ret);

        return ret;
}

/**
 * spi_nor_read_fsr() - Read the Flag Status Register.
 * @nor:        pointer to 'struct spi_nor'
 * @fsr:        pointer to a DMA-able buffer where the value of the
 *              Flag Status Register will be written.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_read_fsr(struct spi_nor *nor, u8 *fsr)
{
        int ret;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDFSR, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_DATA_IN(1, fsr, 1));

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->read_reg(nor, SPINOR_OP_RDFSR,
                                                    fsr, 1);
        }

        if (ret)
                dev_dbg(nor->dev, "error %d reading FSR\n", ret);

        return ret;
}

/**
 * spi_nor_read_cr() - Read the Configuration Register using the
 * SPINOR_OP_RDCR (35h) command.
 * @nor:        pointer to 'struct spi_nor'
 * @cr:         pointer to a DMA-able buffer where the value of the
 *              Configuration Register will be written.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_read_cr(struct spi_nor *nor, u8 *cr)
{
        int ret;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDCR, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_DATA_IN(1, cr, 1));

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->read_reg(nor, SPINOR_OP_RDCR, cr, 1);
        }

        if (ret)
                dev_dbg(nor->dev, "error %d reading CR\n", ret);

        return ret;
}

/**
 * macronix_set_4byte() - Set 4-byte address mode for Macronix flashes.
 * @nor:        pointer to 'struct spi_nor'.
 * @enable:     true to enter the 4-byte address mode, false to exit the 4-byte
 *              address mode.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int macronix_set_4byte(struct spi_nor *nor, bool enable)
{
        int ret;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(enable ?
                                                  SPINOR_OP_EN4B :
                                                  SPINOR_OP_EX4B,
                                                  1),
                                  SPI_MEM_OP_NO_ADDR,
                                  SPI_MEM_OP_NO_DUMMY,
                                  SPI_MEM_OP_NO_DATA);

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->write_reg(nor,
                                                     enable ? SPINOR_OP_EN4B :
                                                              SPINOR_OP_EX4B,
                                                     NULL, 0);
        }

        if (ret)
                dev_dbg(nor->dev, "error %d setting 4-byte mode\n", ret);

        return ret;
}

/**
 * st_micron_set_4byte() - Set 4-byte address mode for ST and Micron flashes.
 * @nor:        pointer to 'struct spi_nor'.
 * @enable:     true to enter the 4-byte address mode, false to exit the 4-byte
 *              address mode.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int st_micron_set_4byte(struct spi_nor *nor, bool enable)
{
        int ret;

        ret = spi_nor_write_enable(nor);
        if (ret)
                return ret;

        ret = macronix_set_4byte(nor, enable);
        if (ret)
                return ret;

        return spi_nor_write_disable(nor);
}

/**
 * spansion_set_4byte() - Set 4-byte address mode for Spansion flashes.
 * @nor:        pointer to 'struct spi_nor'.
 * @enable:     true to enter the 4-byte address mode, false to exit the 4-byte
 *              address mode.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spansion_set_4byte(struct spi_nor *nor, bool enable)
{
        int ret;

        nor->bouncebuf[0] = enable << 7;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_BRWR, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_DATA_OUT(1, nor->bouncebuf, 1));

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->write_reg(nor, SPINOR_OP_BRWR,
                                                     nor->bouncebuf, 1);
        }

        if (ret)
                dev_dbg(nor->dev, "error %d setting 4-byte mode\n", ret);

        return ret;
}

/**
 * spi_nor_write_ear() - Write Extended Address Register.
 * @nor:        pointer to 'struct spi_nor'.
 * @ear:        value to write to the Extended Address Register.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_write_ear(struct spi_nor *nor, u8 ear)
{
        int ret;

        nor->bouncebuf[0] = ear;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WREAR, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_DATA_OUT(1, nor->bouncebuf, 1));

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->write_reg(nor, SPINOR_OP_WREAR,
                                                     nor->bouncebuf, 1);
        }

        if (ret)
                dev_dbg(nor->dev, "error %d writing EAR\n", ret);

        return ret;
}

/**
 * winbond_set_4byte() - Set 4-byte address mode for Winbond flashes.
 * @nor:        pointer to 'struct spi_nor'.
 * @enable:     true to enter the 4-byte address mode, false to exit the 4-byte
 *              address mode.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int winbond_set_4byte(struct spi_nor *nor, bool enable)
{
        int ret;

        ret = macronix_set_4byte(nor, enable);
        if (ret || enable)
                return ret;

        /*
         * On Winbond W25Q256FV, leaving 4byte mode causes the Extended Address
         * Register to be set to 1, so all 3-byte-address reads come from the
         * second 16M. We must clear the register to enable normal behavior.
         */
        ret = spi_nor_write_enable(nor);
        if (ret)
                return ret;

        ret = spi_nor_write_ear(nor, 0);
        if (ret)
                return ret;

        return spi_nor_write_disable(nor);
}

/**
 * spi_nor_xread_sr() - Read the Status Register on S3AN flashes.
 * @nor:        pointer to 'struct spi_nor'.
 * @sr:         pointer to a DMA-able buffer where the value of the
 *              Status Register will be written.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_xread_sr(struct spi_nor *nor, u8 *sr)
{
        int ret;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_XRDSR, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_DATA_IN(1, sr, 1));

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->read_reg(nor, SPINOR_OP_XRDSR,
                                                    sr, 1);
        }

        if (ret)
                dev_dbg(nor->dev, "error %d reading XRDSR\n", ret);

        return ret;
}

/**
 * s3an_sr_ready() - Query the Status Register of the S3AN flash to see if the
 * flash is ready for new commands.
 * @nor:        pointer to 'struct spi_nor'.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int s3an_sr_ready(struct spi_nor *nor)
{
        int ret;

        ret = spi_nor_xread_sr(nor, nor->bouncebuf);
        if (ret)
                return ret;

        return !!(nor->bouncebuf[0] & XSR_RDY);
}

/**
 * spi_nor_clear_sr() - Clear the Status Register.
 * @nor:        pointer to 'struct spi_nor'.
 */
static void spi_nor_clear_sr(struct spi_nor *nor)
{
        int ret;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_CLSR, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_NO_DATA);

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->write_reg(nor, SPINOR_OP_CLSR,
                                                     NULL, 0);
        }

        if (ret)
                dev_dbg(nor->dev, "error %d clearing SR\n", ret);
}

/**
 * spi_nor_sr_ready() - Query the Status Register to see if the flash is ready
 * for new commands.
 * @nor:        pointer to 'struct spi_nor'.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_sr_ready(struct spi_nor *nor)
{
        int ret = spi_nor_read_sr(nor, nor->bouncebuf);

        if (ret)
                return ret;

        if (nor->flags & SNOR_F_USE_CLSR &&
            nor->bouncebuf[0] & (SR_E_ERR | SR_P_ERR)) {
                if (nor->bouncebuf[0] & SR_E_ERR)
                        dev_err(nor->dev, "Erase Error occurred\n");
                else
                        dev_err(nor->dev, "Programming Error occurred\n");

                spi_nor_clear_sr(nor);
                return -EIO;
        }

        return !(nor->bouncebuf[0] & SR_WIP);
}

/**
 * spi_nor_clear_fsr() - Clear the Flag Status Register.
 * @nor:        pointer to 'struct spi_nor'.
 */
static void spi_nor_clear_fsr(struct spi_nor *nor)
{
        int ret;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_CLFSR, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_NO_DATA);

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->write_reg(nor, SPINOR_OP_CLFSR,
                                                     NULL, 0);
        }

        if (ret)
                dev_dbg(nor->dev, "error %d clearing FSR\n", ret);
}

/**
 * spi_nor_fsr_ready() - Query the Flag Status Register to see if the flash is
 * ready for new commands.
 * @nor:        pointer to 'struct spi_nor'.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_fsr_ready(struct spi_nor *nor)
{
        int ret = spi_nor_read_fsr(nor, nor->bouncebuf);

        if (ret)
                return ret;

        if (nor->bouncebuf[0] & (FSR_E_ERR | FSR_P_ERR)) {
                if (nor->bouncebuf[0] & FSR_E_ERR)
                        dev_err(nor->dev, "Erase operation failed.\n");
                else
                        dev_err(nor->dev, "Program operation failed.\n");

                if (nor->bouncebuf[0] & FSR_PT_ERR)
                        dev_err(nor->dev,
                        "Attempted to modify a protected sector.\n");

                spi_nor_clear_fsr(nor);
                return -EIO;
        }

        return nor->bouncebuf[0] & FSR_READY;
}

/**
 * spi_nor_ready() - Query the flash to see if it is ready for new commands.
 * @nor:        pointer to 'struct spi_nor'.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_ready(struct spi_nor *nor)
{
        int sr, fsr;

        if (nor->flags & SNOR_F_READY_XSR_RDY)
                sr = s3an_sr_ready(nor);
        else
                sr = spi_nor_sr_ready(nor);
        if (sr < 0)
                return sr;
        fsr = nor->flags & SNOR_F_USE_FSR ? spi_nor_fsr_ready(nor) : 1;
        if (fsr < 0)
                return fsr;
        return sr && fsr;
}

/**
 * spi_nor_wait_till_ready_with_timeout() - Service routine to read the
 * Status Register until ready, or timeout occurs.
 * @nor:                pointer to "struct spi_nor".
 * @timeout_jiffies:    jiffies to wait until timeout.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_wait_till_ready_with_timeout(struct spi_nor *nor,
                                                unsigned long timeout_jiffies)
{
        unsigned long deadline;
        int timeout = 0, ret;

        deadline = jiffies + timeout_jiffies;

        while (!timeout) {
                if (time_after_eq(jiffies, deadline))
                        timeout = 1;

                ret = spi_nor_ready(nor);
                if (ret < 0)
                        return ret;
                if (ret)
                        return 0;

                cond_resched();
        }

        dev_dbg(nor->dev, "flash operation timed out\n");

        return -ETIMEDOUT;
}

/**
 * spi_nor_wait_till_ready() - Wait for a predefined amount of time for the
 * flash to be ready, or timeout occurs.
 * @nor:        pointer to "struct spi_nor".
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_wait_till_ready(struct spi_nor *nor)
{
        return spi_nor_wait_till_ready_with_timeout(nor,
                                                    DEFAULT_READY_WAIT_JIFFIES);
}

/**
 * spi_nor_write_sr() - Write the Status Register.
 * @nor:        pointer to 'struct spi_nor'.
 * @sr:         pointer to DMA-able buffer to write to the Status Register.
 * @len:        number of bytes to write to the Status Register.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_write_sr(struct spi_nor *nor, const u8 *sr, size_t len)
{
        int ret;

        ret = spi_nor_write_enable(nor);
        if (ret)
                return ret;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WRSR, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_DATA_OUT(len, sr, 1));

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->write_reg(nor, SPINOR_OP_WRSR,
                                                     sr, len);
        }

        if (ret) {
                dev_dbg(nor->dev, "error %d writing SR\n", ret);
                return ret;
        }

        return spi_nor_wait_till_ready(nor);
}

/* Write status register and ensure bits in mask match written values */
static int spi_nor_write_sr_and_check(struct spi_nor *nor, u8 status_new,
                                      u8 mask)
{
        int ret;

        nor->bouncebuf[0] = status_new;

        ret = spi_nor_write_sr(nor, nor->bouncebuf, 1);
        if (ret)
                return ret;

        ret = spi_nor_read_sr(nor, nor->bouncebuf);
        if (ret)
                return ret;

        return ((nor->bouncebuf[0] & mask) != (status_new & mask)) ? -EIO : 0;
}

/**
 * spi_nor_write_sr2() - Write the Status Register 2 using the
 * SPINOR_OP_WRSR2 (3eh) command.
 * @nor:        pointer to 'struct spi_nor'.
 * @sr2:        pointer to DMA-able buffer to write to the Status Register 2.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_write_sr2(struct spi_nor *nor, const u8 *sr2)
{
        int ret;

        ret = spi_nor_write_enable(nor);
        if (ret)
                return ret;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WRSR2, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_DATA_OUT(1, sr2, 1));

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->write_reg(nor, SPINOR_OP_WRSR2,
                                                     sr2, 1);
        }

        if (ret) {
                dev_dbg(nor->dev, "error %d writing SR2\n", ret);
                return ret;
        }

        return spi_nor_wait_till_ready(nor);
}

/**
 * spi_nor_read_sr2() - Read the Status Register 2 using the
 * SPINOR_OP_RDSR2 (3fh) command.
 * @nor:        pointer to 'struct spi_nor'.
 * @sr2:        pointer to DMA-able buffer where the value of the
 *              Status Register 2 will be written.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_read_sr2(struct spi_nor *nor, u8 *sr2)
{
        int ret;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDSR2, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_DATA_IN(1, sr2, 1));

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->read_reg(nor, SPINOR_OP_RDSR2,
                                                    sr2, 1);
        }

        if (ret)
                dev_dbg(nor->dev, "error %d reading SR2\n", ret);

        return ret;
}

/**
 * spi_nor_erase_chip() - Erase the entire flash memory.
 * @nor:        pointer to 'struct spi_nor'.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_erase_chip(struct spi_nor *nor)
{
        int ret;

        dev_dbg(nor->dev, " %lldKiB\n", (long long)(nor->mtd.size >> 10));

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_CHIP_ERASE, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_NO_DATA);

                ret = spi_mem_exec_op(nor->spimem, &op);
        } else {
                ret = nor->controller_ops->write_reg(nor, SPINOR_OP_CHIP_ERASE,
                                                     NULL, 0);
        }

        if (ret)
                dev_dbg(nor->dev, "error %d erasing chip\n", ret);

        return ret;
}

static struct spi_nor *mtd_to_spi_nor(struct mtd_info *mtd)
{
        return mtd->priv;
}

static u8 spi_nor_convert_opcode(u8 opcode, const u8 table[][2], size_t size)
{
        size_t i;

        for (i = 0; i < size; i++)
                if (table[i][0] == opcode)
                        return table[i][1];

        /* No conversion found, keep input op code. */
        return opcode;
}

static u8 spi_nor_convert_3to4_read(u8 opcode)
{
        static const u8 spi_nor_3to4_read[][2] = {
                { SPINOR_OP_READ,       SPINOR_OP_READ_4B },
                { SPINOR_OP_READ_FAST,  SPINOR_OP_READ_FAST_4B },
                { SPINOR_OP_READ_1_1_2, SPINOR_OP_READ_1_1_2_4B },
                { SPINOR_OP_READ_1_2_2, SPINOR_OP_READ_1_2_2_4B },
                { SPINOR_OP_READ_1_1_4, SPINOR_OP_READ_1_1_4_4B },
                { SPINOR_OP_READ_1_4_4, SPINOR_OP_READ_1_4_4_4B },
                { SPINOR_OP_READ_1_1_8, SPINOR_OP_READ_1_1_8_4B },
                { SPINOR_OP_READ_1_8_8, SPINOR_OP_READ_1_8_8_4B },

                { SPINOR_OP_READ_1_1_1_DTR,     SPINOR_OP_READ_1_1_1_DTR_4B },
                { SPINOR_OP_READ_1_2_2_DTR,     SPINOR_OP_READ_1_2_2_DTR_4B },
                { SPINOR_OP_READ_1_4_4_DTR,     SPINOR_OP_READ_1_4_4_DTR_4B },
        };

        return spi_nor_convert_opcode(opcode, spi_nor_3to4_read,
                                      ARRAY_SIZE(spi_nor_3to4_read));
}

static u8 spi_nor_convert_3to4_program(u8 opcode)
{
        static const u8 spi_nor_3to4_program[][2] = {
                { SPINOR_OP_PP,         SPINOR_OP_PP_4B },
                { SPINOR_OP_PP_1_1_4,   SPINOR_OP_PP_1_1_4_4B },
                { SPINOR_OP_PP_1_4_4,   SPINOR_OP_PP_1_4_4_4B },
                { SPINOR_OP_PP_1_1_8,   SPINOR_OP_PP_1_1_8_4B },
                { SPINOR_OP_PP_1_8_8,   SPINOR_OP_PP_1_8_8_4B },
        };

        return spi_nor_convert_opcode(opcode, spi_nor_3to4_program,
                                      ARRAY_SIZE(spi_nor_3to4_program));
}

static u8 spi_nor_convert_3to4_erase(u8 opcode)
{
        static const u8 spi_nor_3to4_erase[][2] = {
                { SPINOR_OP_BE_4K,      SPINOR_OP_BE_4K_4B },
                { SPINOR_OP_BE_32K,     SPINOR_OP_BE_32K_4B },
                { SPINOR_OP_SE,         SPINOR_OP_SE_4B },
        };

        return spi_nor_convert_opcode(opcode, spi_nor_3to4_erase,
                                      ARRAY_SIZE(spi_nor_3to4_erase));
}

static void spi_nor_set_4byte_opcodes(struct spi_nor *nor)
{
        nor->read_opcode = spi_nor_convert_3to4_read(nor->read_opcode);
        nor->program_opcode = spi_nor_convert_3to4_program(nor->program_opcode);
        nor->erase_opcode = spi_nor_convert_3to4_erase(nor->erase_opcode);

        if (!spi_nor_has_uniform_erase(nor)) {
                struct spi_nor_erase_map *map = &nor->params.erase_map;
                struct spi_nor_erase_type *erase;
                int i;

                for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++) {
                        erase = &map->erase_type[i];
                        erase->opcode =
                                spi_nor_convert_3to4_erase(erase->opcode);
                }
        }
}

static int spi_nor_lock_and_prep(struct spi_nor *nor, enum spi_nor_ops ops)
{
        int ret = 0;

        mutex_lock(&nor->lock);

        if (nor->controller_ops &&  nor->controller_ops->prepare) {
                ret = nor->controller_ops->prepare(nor, ops);
                if (ret) {
                        mutex_unlock(&nor->lock);
                        return ret;
                }
        }
        return ret;
}

static void spi_nor_unlock_and_unprep(struct spi_nor *nor, enum spi_nor_ops ops)
{
        if (nor->controller_ops && nor->controller_ops->unprepare)
                nor->controller_ops->unprepare(nor, ops);
        mutex_unlock(&nor->lock);
}

/*
 * This code converts an address to the Default Address Mode, that has non
 * power of two page sizes. We must support this mode because it is the default
 * mode supported by Xilinx tools, it can access the whole flash area and
 * changing over to the Power-of-two mode is irreversible and corrupts the
 * original data.
 * Addr can safely be unsigned int, the biggest S3AN device is smaller than
 * 4 MiB.
 */
static u32 s3an_convert_addr(struct spi_nor *nor, u32 addr)
{
        u32 offset, page;

        offset = addr % nor->page_size;
        page = addr / nor->page_size;
        page <<= (nor->page_size > 512) ? 10 : 9;

        return page | offset;
}

static u32 spi_nor_convert_addr(struct spi_nor *nor, loff_t addr)
{
        if (!nor->params.convert_addr)
                return addr;

        return nor->params.convert_addr(nor, addr);
}

/*
 * Initiate the erasure of a single sector
 */
static int spi_nor_erase_sector(struct spi_nor *nor, u32 addr)
{
        int i;

        addr = spi_nor_convert_addr(nor, addr);

        if (nor->controller_ops && nor->controller_ops->erase)
                return nor->controller_ops->erase(nor, addr);

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(nor->erase_opcode, 1),
                                   SPI_MEM_OP_ADDR(nor->addr_width, addr, 1),
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_NO_DATA);

                return spi_mem_exec_op(nor->spimem, &op);
        }

        /*
         * Default implementation, if driver doesn't have a specialized HW
         * control
         */
        for (i = nor->addr_width - 1; i >= 0; i--) {
                nor->bouncebuf[i] = addr & 0xff;
                addr >>= 8;
        }

        return nor->controller_ops->write_reg(nor, nor->erase_opcode,
                                              nor->bouncebuf, nor->addr_width);
}

/**
 * spi_nor_div_by_erase_size() - calculate remainder and update new dividend
 * @erase:      pointer to a structure that describes a SPI NOR erase type
 * @dividend:   dividend value
 * @remainder:  pointer to u32 remainder (will be updated)
 *
 * Return: the result of the division
 */
static u64 spi_nor_div_by_erase_size(const struct spi_nor_erase_type *erase,
                                     u64 dividend, u32 *remainder)
{
        /* JEDEC JESD216B Standard imposes erase sizes to be power of 2. */
        *remainder = (u32)dividend & erase->size_mask;
        return dividend >> erase->size_shift;
}

/**
 * spi_nor_find_best_erase_type() - find the best erase type for the given
 *                                  offset in the serial flash memory and the
 *                                  number of bytes to erase. The region in
 *                                  which the address fits is expected to be
 *                                  provided.
 * @map:        the erase map of the SPI NOR
 * @region:     pointer to a structure that describes a SPI NOR erase region
 * @addr:       offset in the serial flash memory
 * @len:        number of bytes to erase
 *
 * Return: a pointer to the best fitted erase type, NULL otherwise.
 */
static const struct spi_nor_erase_type *
spi_nor_find_best_erase_type(const struct spi_nor_erase_map *map,
                             const struct spi_nor_erase_region *region,
                             u64 addr, u32 len)
{
        const struct spi_nor_erase_type *erase;
        u32 rem;
        int i;
        u8 erase_mask = region->offset & SNOR_ERASE_TYPE_MASK;

        /*
         * Erase types are ordered by size, with the smallest erase type at
         * index 0.
         */
        for (i = SNOR_ERASE_TYPE_MAX - 1; i >= 0; i--) {
                /* Does the erase region support the tested erase type? */
                if (!(erase_mask & BIT(i)))
                        continue;

                erase = &map->erase_type[i];

                /* Don't erase more than what the user has asked for. */
                if (erase->size > len)
                        continue;

                /* Alignment is not mandatory for overlaid regions */
                if (region->offset & SNOR_OVERLAID_REGION)
                        return erase;

                spi_nor_div_by_erase_size(erase, addr, &rem);
                if (rem)
                        continue;
                else
                        return erase;
        }

        return NULL;
}

/**
 * spi_nor_region_next() - get the next spi nor region
 * @region:     pointer to a structure that describes a SPI NOR erase region
 *
 * Return: the next spi nor region or NULL if last region.
 */
static struct spi_nor_erase_region *
spi_nor_region_next(struct spi_nor_erase_region *region)
{
        if (spi_nor_region_is_last(region))
                return NULL;
        region++;
        return region;
}

/**
 * spi_nor_find_erase_region() - find the region of the serial flash memory in
 *                               which the offset fits
 * @map:        the erase map of the SPI NOR
 * @addr:       offset in the serial flash memory
 *
 * Return: a pointer to the spi_nor_erase_region struct, ERR_PTR(-errno)
 *         otherwise.
 */
static struct spi_nor_erase_region *
spi_nor_find_erase_region(const struct spi_nor_erase_map *map, u64 addr)
{
        struct spi_nor_erase_region *region = map->regions;
        u64 region_start = region->offset & ~SNOR_ERASE_FLAGS_MASK;
        u64 region_end = region_start + region->size;

        while (addr < region_start || addr >= region_end) {
                region = spi_nor_region_next(region);
                if (!region)
                        return ERR_PTR(-EINVAL);

                region_start = region->offset & ~SNOR_ERASE_FLAGS_MASK;
                region_end = region_start + region->size;
        }

        return region;
}

/**
 * spi_nor_init_erase_cmd() - initialize an erase command
 * @region:     pointer to a structure that describes a SPI NOR erase region
 * @erase:      pointer to a structure that describes a SPI NOR erase type
 *
 * Return: the pointer to the allocated erase command, ERR_PTR(-errno)
 *         otherwise.
 */
static struct spi_nor_erase_command *
spi_nor_init_erase_cmd(const struct spi_nor_erase_region *region,
                       const struct spi_nor_erase_type *erase)
{
        struct spi_nor_erase_command *cmd;

        cmd = kmalloc(sizeof(*cmd), GFP_KERNEL);
        if (!cmd)
                return ERR_PTR(-ENOMEM);

        INIT_LIST_HEAD(&cmd->list);
        cmd->opcode = erase->opcode;
        cmd->count = 1;

        if (region->offset & SNOR_OVERLAID_REGION)
                cmd->size = region->size;
        else
                cmd->size = erase->size;

        return cmd;
}

/**
 * spi_nor_destroy_erase_cmd_list() - destroy erase command list
 * @erase_list: list of erase commands
 */
static void spi_nor_destroy_erase_cmd_list(struct list_head *erase_list)
{
        struct spi_nor_erase_command *cmd, *next;

        list_for_each_entry_safe(cmd, next, erase_list, list) {
                list_del(&cmd->list);
                kfree(cmd);
        }
}

/**
 * spi_nor_init_erase_cmd_list() - initialize erase command list
 * @nor:        pointer to a 'struct spi_nor'
 * @erase_list: list of erase commands to be executed once we validate that the
 *              erase can be performed
 * @addr:       offset in the serial flash memory
 * @len:        number of bytes to erase
 *
 * Builds the list of best fitted erase commands and verifies if the erase can
 * be performed.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_init_erase_cmd_list(struct spi_nor *nor,
                                       struct list_head *erase_list,
                                       u64 addr, u32 len)
{
        const struct spi_nor_erase_map *map = &nor->params.erase_map;
        const struct spi_nor_erase_type *erase, *prev_erase = NULL;
        struct spi_nor_erase_region *region;
        struct spi_nor_erase_command *cmd = NULL;
        u64 region_end;
        int ret = -EINVAL;

        region = spi_nor_find_erase_region(map, addr);
        if (IS_ERR(region))
                return PTR_ERR(region);

        region_end = spi_nor_region_end(region);

        while (len) {
                erase = spi_nor_find_best_erase_type(map, region, addr, len);
                if (!erase)
                        goto destroy_erase_cmd_list;

                if (prev_erase != erase ||
                    region->offset & SNOR_OVERLAID_REGION) {
                        cmd = spi_nor_init_erase_cmd(region, erase);
                        if (IS_ERR(cmd)) {
                                ret = PTR_ERR(cmd);
                                goto destroy_erase_cmd_list;
                        }

                        list_add_tail(&cmd->list, erase_list);
                } else {
                        cmd->count++;
                }

                addr += cmd->size;
                len -= cmd->size;

                if (len && addr >= region_end) {
                        region = spi_nor_region_next(region);
                        if (!region)
                                goto destroy_erase_cmd_list;
                        region_end = spi_nor_region_end(region);
                }

                prev_erase = erase;
        }

        return 0;

destroy_erase_cmd_list:
        spi_nor_destroy_erase_cmd_list(erase_list);
        return ret;
}

/**
 * spi_nor_erase_multi_sectors() - perform a non-uniform erase
 * @nor:        pointer to a 'struct spi_nor'
 * @addr:       offset in the serial flash memory
 * @len:        number of bytes to erase
 *
 * Build a list of best fitted erase commands and execute it once we validate
 * that the erase can be performed.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_erase_multi_sectors(struct spi_nor *nor, u64 addr, u32 len)
{
        LIST_HEAD(erase_list);
        struct spi_nor_erase_command *cmd, *next;
        int ret;

        ret = spi_nor_init_erase_cmd_list(nor, &erase_list, addr, len);
        if (ret)
                return ret;

        list_for_each_entry_safe(cmd, next, &erase_list, list) {
                nor->erase_opcode = cmd->opcode;
                while (cmd->count) {
                        ret = spi_nor_write_enable(nor);
                        if (ret)
                                goto destroy_erase_cmd_list;

                        ret = spi_nor_erase_sector(nor, addr);
                        if (ret)
                                goto destroy_erase_cmd_list;

                        addr += cmd->size;
                        cmd->count--;

                        ret = spi_nor_wait_till_ready(nor);
                        if (ret)
                                goto destroy_erase_cmd_list;
                }
                list_del(&cmd->list);
                kfree(cmd);
        }

        return 0;

destroy_erase_cmd_list:
        spi_nor_destroy_erase_cmd_list(&erase_list);
        return ret;
}

/*
 * Erase an address range on the nor chip.  The address range may extend
 * one or more erase sectors.  Return an error is there is a problem erasing.
 */
static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
{
        struct spi_nor *nor = mtd_to_spi_nor(mtd);
        u32 addr, len;
        uint32_t rem;
        int ret;

        dev_dbg(nor->dev, "at 0x%llx, len %lld\n", (long long)instr->addr,
                        (long long)instr->len);

        if (spi_nor_has_uniform_erase(nor)) {
                div_u64_rem(instr->len, mtd->erasesize, &rem);
                if (rem)
                        return -EINVAL;
        }

        addr = instr->addr;
        len = instr->len;

        ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_ERASE);
        if (ret)
                return ret;

        /* whole-chip erase? */
        if (len == mtd->size && !(nor->flags & SNOR_F_NO_OP_CHIP_ERASE)) {
                unsigned long timeout;

                ret = spi_nor_write_enable(nor);
                if (ret)
                        goto erase_err;

                ret = spi_nor_erase_chip(nor);
                if (ret)
                        goto erase_err;

                /*
                 * Scale the timeout linearly with the size of the flash, with
                 * a minimum calibrated to an old 2MB flash. We could try to
                 * pull these from CFI/SFDP, but these values should be good
                 * enough for now.
                 */
                timeout = max(CHIP_ERASE_2MB_READY_WAIT_JIFFIES,
                              CHIP_ERASE_2MB_READY_WAIT_JIFFIES *
                              (unsigned long)(mtd->size / SZ_2M));
                ret = spi_nor_wait_till_ready_with_timeout(nor, timeout);
                if (ret)
                        goto erase_err;

        /* REVISIT in some cases we could speed up erasing large regions
         * by using SPINOR_OP_SE instead of SPINOR_OP_BE_4K.  We may have set up
         * to use "small sector erase", but that's not always optimal.
         */

        /* "sector"-at-a-time erase */
        } else if (spi_nor_has_uniform_erase(nor)) {
                while (len) {
                        ret = spi_nor_write_enable(nor);
                        if (ret)
                                goto erase_err;

                        ret = spi_nor_erase_sector(nor, addr);
                        if (ret)
                                goto erase_err;

                        addr += mtd->erasesize;
                        len -= mtd->erasesize;

                        ret = spi_nor_wait_till_ready(nor);
                        if (ret)
                                goto erase_err;
                }

        /* erase multiple sectors */
        } else {
                ret = spi_nor_erase_multi_sectors(nor, addr, len);
                if (ret)
                        goto erase_err;
        }

        ret = spi_nor_write_disable(nor);

erase_err:
        spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_ERASE);

        return ret;
}

static void stm_get_locked_range(struct spi_nor *nor, u8 sr, loff_t *ofs,
                                 uint64_t *len)
{
        struct mtd_info *mtd = &nor->mtd;
        u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
        int shift = ffs(mask) - 1;
        int pow;

        if (!(sr & mask)) {
                /* No protection */
                *ofs = 0;
                *len = 0;
        } else {
                pow = ((sr & mask) ^ mask) >> shift;
                *len = mtd->size >> pow;
                if (nor->flags & SNOR_F_HAS_SR_TB && sr & SR_TB)
                        *ofs = 0;
                else
                        *ofs = mtd->size - *len;
        }
}

/*
 * Return 1 if the entire region is locked (if @locked is true) or unlocked (if
 * @locked is false); 0 otherwise
 */
static int stm_check_lock_status_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
                                    u8 sr, bool locked)
{
        loff_t lock_offs;
        uint64_t lock_len;

        if (!len)
                return 1;

        stm_get_locked_range(nor, sr, &lock_offs, &lock_len);

        if (locked)
                /* Requested range is a sub-range of locked range */
                return (ofs + len <= lock_offs + lock_len) && (ofs >= lock_offs);
        else
                /* Requested range does not overlap with locked range */
                return (ofs >= lock_offs + lock_len) || (ofs + len <= lock_offs);
}

static int stm_is_locked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
                            u8 sr)
{
        return stm_check_lock_status_sr(nor, ofs, len, sr, true);
}

static int stm_is_unlocked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
                              u8 sr)
{
        return stm_check_lock_status_sr(nor, ofs, len, sr, false);
}

/*
 * Lock a region of the flash. Compatible with ST Micro and similar flash.
 * Supports the block protection bits BP{0,1,2} in the status register
 * (SR). Does not support these features found in newer SR bitfields:
 *   - SEC: sector/block protect - only handle SEC=0 (block protect)
 *   - CMP: complement protect - only support CMP=0 (range is not complemented)
 *
 * Support for the following is provided conditionally for some flash:
 *   - TB: top/bottom protect
 *
 * Sample table portion for 8MB flash (Winbond w25q64fw):
 *
 *   SEC  |  TB   |  BP2  |  BP1  |  BP0  |  Prot Length  | Protected Portion
 *  --------------------------------------------------------------------------
 *    X   |   X   |   0   |   0   |   0   |  NONE         | NONE
 *    0   |   0   |   0   |   0   |   1   |  128 KB       | Upper 1/64
 *    0   |   0   |   0   |   1   |   0   |  256 KB       | Upper 1/32
 *    0   |   0   |   0   |   1   |   1   |  512 KB       | Upper 1/16
 *    0   |   0   |   1   |   0   |   0   |  1 MB         | Upper 1/8
 *    0   |   0   |   1   |   0   |   1   |  2 MB         | Upper 1/4
 *    0   |   0   |   1   |   1   |   0   |  4 MB         | Upper 1/2
 *    X   |   X   |   1   |   1   |   1   |  8 MB         | ALL
 *  ------|-------|-------|-------|-------|---------------|-------------------
 *    0   |   1   |   0   |   0   |   1   |  128 KB       | Lower 1/64
 *    0   |   1   |   0   |   1   |   0   |  256 KB       | Lower 1/32
 *    0   |   1   |   0   |   1   |   1   |  512 KB       | Lower 1/16
 *    0   |   1   |   1   |   0   |   0   |  1 MB         | Lower 1/8
 *    0   |   1   |   1   |   0   |   1   |  2 MB         | Lower 1/4
 *    0   |   1   |   1   |   1   |   0   |  4 MB         | Lower 1/2
 *
 * Returns negative on errors, 0 on success.
 */
static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
        struct mtd_info *mtd = &nor->mtd;
        int ret, status_old, status_new;
        u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
        u8 shift = ffs(mask) - 1, pow, val;
        loff_t lock_len;
        bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
        bool use_top;

        ret = spi_nor_read_sr(nor, nor->bouncebuf);
        if (ret)
                return ret;

        status_old = nor->bouncebuf[0];

        /* If nothing in our range is unlocked, we don't need to do anything */
        if (stm_is_locked_sr(nor, ofs, len, status_old))
                return 0;

        /* If anything below us is unlocked, we can't use 'bottom' protection */
        if (!stm_is_locked_sr(nor, 0, ofs, status_old))
                can_be_bottom = false;

        /* If anything above us is unlocked, we can't use 'top' protection */
        if (!stm_is_locked_sr(nor, ofs + len, mtd->size - (ofs + len),
                                status_old))
                can_be_top = false;

        if (!can_be_bottom && !can_be_top)
                return -EINVAL;

        /* Prefer top, if both are valid */
        use_top = can_be_top;

        /* lock_len: length of region that should end up locked */
        if (use_top)
                lock_len = mtd->size - ofs;
        else
                lock_len = ofs + len;

        /*
         * Need smallest pow such that:
         *
         *   1 / (2^pow) <= (len / size)
         *
         * so (assuming power-of-2 size) we do:
         *
         *   pow = ceil(log2(size / len)) = log2(size) - floor(log2(len))
         */
        pow = ilog2(mtd->size) - ilog2(lock_len);
        val = mask - (pow << shift);
        if (val & ~mask)
                return -EINVAL;
        /* Don't "lock" with no region! */
        if (!(val & mask))
                return -EINVAL;

        status_new = (status_old & ~mask & ~SR_TB) | val;

        /* Disallow further writes if WP pin is asserted */
        status_new |= SR_SRWD;

        if (!use_top)
                status_new |= SR_TB;

        /* Don't bother if they're the same */
        if (status_new == status_old)
                return 0;

        /* Only modify protection if it will not unlock other areas */
        if ((status_new & mask) < (status_old & mask))
                return -EINVAL;

        return spi_nor_write_sr_and_check(nor, status_new, mask);
}

/*
 * Unlock a region of the flash. See stm_lock() for more info
 *
 * Returns negative on errors, 0 on success.
 */
static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
        struct mtd_info *mtd = &nor->mtd;
        int ret, status_old, status_new;
        u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
        u8 shift = ffs(mask) - 1, pow, val;
        loff_t lock_len;
        bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
        bool use_top;

        ret = spi_nor_read_sr(nor, nor->bouncebuf);
        if (ret)
                return ret;

        status_old = nor->bouncebuf[0];

        /* If nothing in our range is locked, we don't need to do anything */
        if (stm_is_unlocked_sr(nor, ofs, len, status_old))
                return 0;

        /* If anything below us is locked, we can't use 'top' protection */
        if (!stm_is_unlocked_sr(nor, 0, ofs, status_old))
                can_be_top = false;

        /* If anything above us is locked, we can't use 'bottom' protection */
        if (!stm_is_unlocked_sr(nor, ofs + len, mtd->size - (ofs + len),
                                status_old))
                can_be_bottom = false;

        if (!can_be_bottom && !can_be_top)
                return -EINVAL;

        /* Prefer top, if both are valid */
        use_top = can_be_top;

        /* lock_len: length of region that should remain locked */
        if (use_top)
                lock_len = mtd->size - (ofs + len);
        else
                lock_len = ofs;

        /*
         * Need largest pow such that:
         *
         *   1 / (2^pow) >= (len / size)
         *
         * so (assuming power-of-2 size) we do:
         *
         *   pow = floor(log2(size / len)) = log2(size) - ceil(log2(len))
         */
        pow = ilog2(mtd->size) - order_base_2(lock_len);
        if (lock_len == 0) {
                val = 0; /* fully unlocked */
        } else {
                val = mask - (pow << shift);
                /* Some power-of-two sizes are not supported */
                if (val & ~mask)
                        return -EINVAL;
        }

        status_new = (status_old & ~mask & ~SR_TB) | val;

        /* Don't protect status register if we're fully unlocked */
        if (lock_len == 0)
                status_new &= ~SR_SRWD;

        if (!use_top)
                status_new |= SR_TB;

        /* Don't bother if they're the same */
        if (status_new == status_old)
                return 0;

        /* Only modify protection if it will not lock other areas */
        if ((status_new & mask) > (status_old & mask))
                return -EINVAL;

        return spi_nor_write_sr_and_check(nor, status_new, mask);
}

/*
 * Check if a region of the flash is (completely) locked. See stm_lock() for
 * more info.
 *
 * Returns 1 if entire region is locked, 0 if any portion is unlocked, and
 * negative on errors.
 */
static int stm_is_locked(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
        int ret;

        ret = spi_nor_read_sr(nor, nor->bouncebuf);
        if (ret)
                return ret;

        return stm_is_locked_sr(nor, ofs, len, nor->bouncebuf[0]);
}

static const struct spi_nor_locking_ops stm_locking_ops = {
        .lock = stm_lock,
        .unlock = stm_unlock,
        .is_locked = stm_is_locked,
};

static int spi_nor_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
        struct spi_nor *nor = mtd_to_spi_nor(mtd);
        int ret;

        ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_LOCK);
        if (ret)
                return ret;

        ret = nor->params.locking_ops->lock(nor, ofs, len);

        spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_UNLOCK);
        return ret;
}

static int spi_nor_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
        struct spi_nor *nor = mtd_to_spi_nor(mtd);
        int ret;

        ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_UNLOCK);
        if (ret)
                return ret;

        ret = nor->params.locking_ops->unlock(nor, ofs, len);

        spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
        return ret;
}

static int spi_nor_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
        struct spi_nor *nor = mtd_to_spi_nor(mtd);
        int ret;

        ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_UNLOCK);
        if (ret)
                return ret;

        ret = nor->params.locking_ops->is_locked(nor, ofs, len);

        spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
        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;

        ret = spi_nor_read_sr(nor, nor->bouncebuf);
        if (ret)
                return ret;

        if (nor->bouncebuf[0] & SR_QUAD_EN_MX)
                return 0;

        nor->bouncebuf[0] |= SR_QUAD_EN_MX;

        ret = spi_nor_write_sr(nor, nor->bouncebuf, 1);
        if (ret)
                return ret;

        ret = spi_nor_read_sr(nor, nor->bouncebuf);
        if (ret)
                return ret;

        if (!(nor->bouncebuf[0] & SR_QUAD_EN_MX)) {
                dev_dbg(nor->dev, "Macronix Quad bit not set\n");
                return -EINVAL;
        }

        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 spi_nor_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 = nor->bouncebuf;
        int ret;

        sr_cr[0] = 0;
        sr_cr[1] = CR_QUAD_EN_SPAN;
        ret = spi_nor_write_sr(nor, sr_cr, 2);
        if (ret)
                return ret;

        /* read back and check it */
        ret = spi_nor_read_cr(nor, nor->bouncebuf);
        if (ret)
                return ret;

        if (!(nor->bouncebuf[0] & CR_QUAD_EN_SPAN)) {
                dev_dbg(nor->dev, "Spansion Quad bit not set\n");
                return -EINVAL;
        }

        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 = nor->bouncebuf;
        int ret;

        /* Keep the current value of the Status Register. */
        ret = spi_nor_read_sr(nor, sr_cr);
        if (ret)
                return ret;

        sr_cr[1] = CR_QUAD_EN_SPAN;

        return spi_nor_write_sr(nor, sr_cr, 2);
}

/**
 * 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)
{
        u8 *sr_cr = nor->bouncebuf;
        int ret;

        /* Check current Quad Enable bit value. */
        ret = spi_nor_read_cr(nor, &sr_cr[1]);
        if (ret)
                return ret;

        if (sr_cr[1] & CR_QUAD_EN_SPAN)
                return 0;

        sr_cr[1] |= CR_QUAD_EN_SPAN;

        /* Keep the current value of the Status Register. */
        ret = spi_nor_read_sr(nor, sr_cr);
        if (ret)
                return ret;

        ret = spi_nor_write_sr(nor, sr_cr, 2);
        if (ret)
                return ret;

        /* Read back and check it. */
        ret = spi_nor_read_cr(nor, &sr_cr[1]);
        if (ret)
                return ret;

        if (!(sr_cr[1] & CR_QUAD_EN_SPAN)) {
                dev_dbg(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 = nor->bouncebuf;
        int ret;

        /* Check current Quad Enable bit value. */
        ret = spi_nor_read_sr2(nor, sr2);
        if (ret)
                return ret;
        if (*sr2 & SR2_QUAD_EN_BIT7)
                return 0;

        /* Update the Quad Enable bit. */
        *sr2 |= SR2_QUAD_EN_BIT7;

        ret = spi_nor_write_sr2(nor, sr2);
        if (ret)
                return ret;

        /* Read back and check it. */
        ret = spi_nor_read_sr2(nor, sr2);
        if (ret)
                return ret;

        if (!(*sr2 & SR2_QUAD_EN_BIT7)) {
                dev_dbg(nor->dev, "SR2 Quad bit not set\n");
                return -EINVAL;
        }

        return 0;
}

/**
 * spi_nor_clear_sr_bp() - clear the Status Register Block Protection bits.
 * @nor:        pointer to a 'struct spi_nor'
 *
 * Read-modify-write function that clears the Block Protection bits from the
 * Status Register without affecting other bits.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_clear_sr_bp(struct spi_nor *nor)
{
        int ret;
        u8 mask = SR_BP2 | SR_BP1 | SR_BP0;

        ret = spi_nor_read_sr(nor, nor->bouncebuf);
        if (ret)
                return ret;

        nor->bouncebuf[0] &= ~mask;

        return spi_nor_write_sr(nor, nor->bouncebuf, 1);
}

/**
 * spi_nor_spansion_clear_sr_bp() - clear the Status Register Block Protection
 * bits on spansion flashes.
 * @nor:        pointer to a 'struct spi_nor'
 *
 * Read-modify-write function that clears the Block Protection bits from the
 * Status Register without affecting other bits. The function is tightly
 * coupled with the spansion_quad_enable() function. Both assume that the Write
 * Register with 16 bits, together with the Read Configuration Register (35h)
 * instructions are supported.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_spansion_clear_sr_bp(struct spi_nor *nor)
{
        int ret;
        u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
        u8 *sr_cr =  nor->bouncebuf;

        /* Check current Quad Enable bit value. */
        ret = spi_nor_read_cr(nor, &sr_cr[1]);
        if (ret)
                return ret;

        /*
         * When the configuration register Quad Enable bit is one, only the
         * Write Status (01h) command with two data bytes may be used.
         */
        if (sr_cr[1] & CR_QUAD_EN_SPAN) {
                ret = spi_nor_read_sr(nor, sr_cr);
                if (ret)
                        return ret;

                sr_cr[0] &= ~mask;

                return spi_nor_write_sr(nor, sr_cr, 2);
        }

        /*
         * If the Quad Enable bit is zero, use the Write Status (01h) command
         * with one data byte.
         */
        return spi_nor_clear_sr_bp(nor);
}

/* Used when the "_ext_id" is two bytes at most */
#define INFO(_jedec_id, _ext_id, _sector_size, _n_sectors, _flags)      \
                .id = {                                                 \
                        ((_jedec_id) >> 16) & 0xff,                     \
                        ((_jedec_id) >> 8) & 0xff,                      \
                        (_jedec_id) & 0xff,                             \
                        ((_ext_id) >> 8) & 0xff,                        \
                        (_ext_id) & 0xff,                               \
                        },                                              \
                .id_len = (!(_jedec_id) ? 0 : (3 + ((_ext_id) ? 2 : 0))),       \
                .sector_size = (_sector_size),                          \
                .n_sectors = (_n_sectors),                              \
                .page_size = 256,                                       \
                .flags = (_flags),

#define INFO6(_jedec_id, _ext_id, _sector_size, _n_sectors, _flags)     \
                .id = {                                                 \
                        ((_jedec_id) >> 16) & 0xff,                     \
                        ((_jedec_id) >> 8) & 0xff,                      \
                        (_jedec_id) & 0xff,                             \
                        ((_ext_id) >> 16) & 0xff,                       \
                        ((_ext_id) >> 8) & 0xff,                        \
                        (_ext_id) & 0xff,                               \
                        },                                              \
                .id_len = 6,                                            \
                .sector_size = (_sector_size),                          \
                .n_sectors = (_n_sectors),                              \
                .page_size = 256,                                       \
                .flags = (_flags),

#define CAT25_INFO(_sector_size, _n_sectors, _page_size, _addr_width, _flags)   \
                .sector_size = (_sector_size),                          \
                .n_sectors = (_n_sectors),                              \
                .page_size = (_page_size),                              \
                .addr_width = (_addr_width),                            \
                .flags = (_flags),

#define S3AN_INFO(_jedec_id, _n_sectors, _page_size)                    \
                .id = {                                                 \
                        ((_jedec_id) >> 16) & 0xff,                     \
                        ((_jedec_id) >> 8) & 0xff,                      \
                        (_jedec_id) & 0xff                              \
                        },                                              \
                .id_len = 3,                                            \
                .sector_size = (8*_page_size),                          \
                .n_sectors = (_n_sectors),                              \
                .page_size = _page_size,                                \
                .addr_width = 3,                                        \
                .flags = SPI_NOR_NO_FR | SPI_S3AN,

static int
is25lp256_post_bfpt_fixups(struct spi_nor *nor,
                           const struct sfdp_parameter_header *bfpt_header,
                           const struct sfdp_bfpt *bfpt,
                           struct spi_nor_flash_parameter *params)
{
        /*
         * IS25LP256 supports 4B opcodes, but the BFPT advertises a
         * BFPT_DWORD1_ADDRESS_BYTES_3_ONLY address width.
         * Overwrite the address width advertised by the BFPT.
         */
        if ((bfpt->dwords[BFPT_DWORD(1)] & BFPT_DWORD1_ADDRESS_BYTES_MASK) ==
                BFPT_DWORD1_ADDRESS_BYTES_3_ONLY)
                nor->addr_width = 4;

        return 0;
}

static struct spi_nor_fixups is25lp256_fixups = {
        .post_bfpt = is25lp256_post_bfpt_fixups,
};

static int
mx25l25635_post_bfpt_fixups(struct spi_nor *nor,
                            const struct sfdp_parameter_header *bfpt_header,
                            const struct sfdp_bfpt *bfpt,
                            struct spi_nor_flash_parameter *params)
{
        /*
         * MX25L25635F supports 4B opcodes but MX25L25635E does not.
         * Unfortunately, Macronix has re-used the same JEDEC ID for both
         * variants which prevents us from defining a new entry in the parts
         * table.
         * We need a way to differentiate MX25L25635E and MX25L25635F, and it
         * seems that the F version advertises support for Fast Read 4-4-4 in
         * its BFPT table.
         */
        if (bfpt->dwords[BFPT_DWORD(5)] & BFPT_DWORD5_FAST_READ_4_4_4)
                nor->flags |= SNOR_F_4B_OPCODES;

        return 0;
}

static struct spi_nor_fixups mx25l25635_fixups = {
        .post_bfpt = mx25l25635_post_bfpt_fixups,
};

static void gd25q256_default_init(struct spi_nor *nor)
{
        /*
         * Some manufacturer like GigaDevice may use different
         * bit to set QE on different memories, so the MFR can't
         * indicate the quad_enable method for this case, we need
         * to set it in the default_init fixup hook.
         */
        nor->params.quad_enable = macronix_quad_enable;
}

static struct spi_nor_fixups gd25q256_fixups = {
        .default_init = gd25q256_default_init,
};

/* NOTE: double check command sets and memory organization when you add
 * more nor chips.  This current list focusses on newer chips, which
 * have been converging on command sets which including JEDEC ID.
 *
 * All newly added entries should describe *hardware* and should use SECT_4K
 * (or SECT_4K_PMC) if hardware supports erasing 4 KiB sectors. For usage
 * scenarios excluding small sectors there is config option that can be
 * disabled: CONFIG_MTD_SPI_NOR_USE_4K_SECTORS.
 * For historical (and compatibility) reasons (before we got above config) some
 * old entries may be missing 4K flag.
 */
static const struct flash_info spi_nor_ids[] = {
        /* Atmel -- some are (confusingly) marketed as "DataFlash" */
        { "at25fs010",  INFO(0x1f6601, 0, 32 * 1024,   4, SECT_4K) },
        { "at25fs040",  INFO(0x1f6604, 0, 64 * 1024,   8, SECT_4K) },

        { "at25df041a", INFO(0x1f4401, 0, 64 * 1024,   8, SECT_4K) },
        { "at25df321",  INFO(0x1f4700, 0, 64 * 1024,  64, SECT_4K) },
        { "at25df321a", INFO(0x1f4701, 0, 64 * 1024,  64, SECT_4K) },
        { "at25df641",  INFO(0x1f4800, 0, 64 * 1024, 128, SECT_4K) },

        { "at26f004",   INFO(0x1f0400, 0, 64 * 1024,  8, SECT_4K) },
        { "at26df081a", INFO(0x1f4501, 0, 64 * 1024, 16, SECT_4K) },
        { "at26df161a", INFO(0x1f4601, 0, 64 * 1024, 32, SECT_4K) },
        { "at26df321",  INFO(0x1f4700, 0, 64 * 1024, 64, SECT_4K) },

        { "at45db081d", INFO(0x1f2500, 0, 64 * 1024, 16, SECT_4K) },

        /* EON -- en25xxx */
        { "en25f32",    INFO(0x1c3116, 0, 64 * 1024,   64, SECT_4K) },
        { "en25p32",    INFO(0x1c2016, 0, 64 * 1024,   64, 0) },
        { "en25q32b",   INFO(0x1c3016, 0, 64 * 1024,   64, 0) },
        { "en25p64",    INFO(0x1c2017, 0, 64 * 1024,  128, 0) },
        { "en25q64",    INFO(0x1c3017, 0, 64 * 1024,  128, SECT_4K) },
        { "en25q80a",   INFO(0x1c3014, 0, 64 * 1024,   16,
                        SECT_4K | SPI_NOR_DUAL_READ) },
        { "en25qh16",   INFO(0x1c7015, 0, 64 * 1024,   32,
                        SECT_4K | SPI_NOR_DUAL_READ) },
        { "en25qh32",   INFO(0x1c7016, 0, 64 * 1024,   64, 0) },
        { "en25qh64",   INFO(0x1c7017, 0, 64 * 1024,  128,
                        SECT_4K | SPI_NOR_DUAL_READ) },
        { "en25qh128",  INFO(0x1c7018, 0, 64 * 1024,  256, 0) },
        { "en25qh256",  INFO(0x1c7019, 0, 64 * 1024,  512, 0) },
        { "en25s64",    INFO(0x1c3817, 0, 64 * 1024,  128, SECT_4K) },

        /* ESMT */
        { "f25l32pa", INFO(0x8c2016, 0, 64 * 1024, 64, SECT_4K | SPI_NOR_HAS_LOCK) },
        { "f25l32qa", INFO(0x8c4116, 0, 64 * 1024, 64, SECT_4K | SPI_NOR_HAS_LOCK) },
        { "f25l64qa", INFO(0x8c4117, 0, 64 * 1024, 128, SECT_4K | SPI_NOR_HAS_LOCK) },

        /* Everspin */
        { "mr25h128", CAT25_INFO( 16 * 1024, 1, 256, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
        { "mr25h256", CAT25_INFO( 32 * 1024, 1, 256, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
        { "mr25h10",  CAT25_INFO(128 * 1024, 1, 256, 3, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
        { "mr25h40",  CAT25_INFO(512 * 1024, 1, 256, 3, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },

        /* Fujitsu */
        { "mb85rs1mt", INFO(0x047f27, 0, 128 * 1024, 1, SPI_NOR_NO_ERASE) },

        /* GigaDevice */
        {
                "gd25q16", INFO(0xc84015, 0, 64 * 1024,  32,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
        },
        {
                "gd25q32", INFO(0xc84016, 0, 64 * 1024,  64,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
        },
        {
                "gd25lq32", INFO(0xc86016, 0, 64 * 1024, 64,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
        },
        {
                "gd25q64", INFO(0xc84017, 0, 64 * 1024, 128,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
        },
        {
                "gd25lq64c", INFO(0xc86017, 0, 64 * 1024, 128,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
        },
        {
                "gd25q128", INFO(0xc84018, 0, 64 * 1024, 256,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
        },
        {
                "gd25q256", INFO(0xc84019, 0, 64 * 1024, 512,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_4B_OPCODES | SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
                        .fixups = &gd25q256_fixups,
        },

        /* Intel/Numonyx -- xxxs33b */
        { "160s33b",  INFO(0x898911, 0, 64 * 1024,  32, 0) },
        { "320s33b",  INFO(0x898912, 0, 64 * 1024,  64, 0) },
        { "640s33b",  INFO(0x898913, 0, 64 * 1024, 128, 0) },

        /* ISSI */
        { "is25cd512",  INFO(0x7f9d20, 0, 32 * 1024,   2, SECT_4K) },
        { "is25lq040b", INFO(0x9d4013, 0, 64 * 1024,   8,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "is25lp016d", INFO(0x9d6015, 0, 64 * 1024,  32,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "is25lp080d", INFO(0x9d6014, 0, 64 * 1024,  16,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "is25lp032",  INFO(0x9d6016, 0, 64 * 1024,  64,
                        SECT_4K | SPI_NOR_DUAL_READ) },
        { "is25lp064",  INFO(0x9d6017, 0, 64 * 1024, 128,
                        SECT_4K | SPI_NOR_DUAL_READ) },
        { "is25lp128",  INFO(0x9d6018, 0, 64 * 1024, 256,
                        SECT_4K | SPI_NOR_DUAL_READ) },
        { "is25lp256",  INFO(0x9d6019, 0, 64 * 1024, 512,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_4B_OPCODES)
                        .fixups = &is25lp256_fixups },
        { "is25wp032",  INFO(0x9d7016, 0, 64 * 1024,  64,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "is25wp064",  INFO(0x9d7017, 0, 64 * 1024, 128,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "is25wp128",  INFO(0x9d7018, 0, 64 * 1024, 256,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },

        /* Macronix */
        { "mx25l512e",   INFO(0xc22010, 0, 64 * 1024,   1, SECT_4K) },
        { "mx25l2005a",  INFO(0xc22012, 0, 64 * 1024,   4, SECT_4K) },
        { "mx25l4005a",  INFO(0xc22013, 0, 64 * 1024,   8, SECT_4K) },
        { "mx25l8005",   INFO(0xc22014, 0, 64 * 1024,  16, 0) },
        { "mx25l1606e",  INFO(0xc22015, 0, 64 * 1024,  32, SECT_4K) },
        { "mx25l3205d",  INFO(0xc22016, 0, 64 * 1024,  64, SECT_4K) },
        { "mx25l3255e",  INFO(0xc29e16, 0, 64 * 1024,  64, SECT_4K) },
        { "mx25l6405d",  INFO(0xc22017, 0, 64 * 1024, 128, SECT_4K) },
        { "mx25u2033e",  INFO(0xc22532, 0, 64 * 1024,   4, SECT_4K) },
        { "mx25u3235f",  INFO(0xc22536, 0, 64 * 1024,  64,
                         SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "mx25u4035",   INFO(0xc22533, 0, 64 * 1024,   8, SECT_4K) },
        { "mx25u8035",   INFO(0xc22534, 0, 64 * 1024,  16, SECT_4K) },
        { "mx25u6435f",  INFO(0xc22537, 0, 64 * 1024, 128, SECT_4K) },
        { "mx25l12805d", INFO(0xc22018, 0, 64 * 1024, 256, 0) },
        { "mx25l12855e", INFO(0xc22618, 0, 64 * 1024, 256, 0) },
        { "mx25u12835f", INFO(0xc22538, 0, 64 * 1024, 256,
                         SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "mx25l25635e", INFO(0xc22019, 0, 64 * 1024, 512,
                         SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)
                         .fixups = &mx25l25635_fixups },
        { "mx25u25635f", INFO(0xc22539, 0, 64 * 1024, 512, SECT_4K | SPI_NOR_4B_OPCODES) },
        { "mx25v8035f",  INFO(0xc22314, 0, 64 * 1024,  16,
                         SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "mx25l25655e", INFO(0xc22619, 0, 64 * 1024, 512, 0) },
        { "mx66l51235l", INFO(0xc2201a, 0, 64 * 1024, 1024, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
        { "mx66u51235f", INFO(0xc2253a, 0, 64 * 1024, 1024, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
        { "mx66l1g45g",  INFO(0xc2201b, 0, 64 * 1024, 2048, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "mx66l1g55g",  INFO(0xc2261b, 0, 64 * 1024, 2048, SPI_NOR_QUAD_READ) },

        /* Micron <--> ST Micro */
        { "n25q016a",    INFO(0x20bb15, 0, 64 * 1024,   32, SECT_4K | SPI_NOR_QUAD_READ) },
        { "n25q032",     INFO(0x20ba16, 0, 64 * 1024,   64, SPI_NOR_QUAD_READ) },
        { "n25q032a",    INFO(0x20bb16, 0, 64 * 1024,   64, SPI_NOR_QUAD_READ) },
        { "n25q064",     INFO(0x20ba17, 0, 64 * 1024,  128, SECT_4K | SPI_NOR_QUAD_READ) },
        { "n25q064a",    INFO(0x20bb17, 0, 64 * 1024,  128, SECT_4K | SPI_NOR_QUAD_READ) },
        { "n25q128a11",  INFO(0x20bb18, 0, 64 * 1024,  256, SECT_4K | SPI_NOR_QUAD_READ) },
        { "n25q128a13",  INFO(0x20ba18, 0, 64 * 1024,  256, SECT_4K | SPI_NOR_QUAD_READ) },
        { "n25q256a",    INFO(0x20ba19, 0, 64 * 1024,  512, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "n25q256ax1",  INFO(0x20bb19, 0, 64 * 1024,  512, SECT_4K | SPI_NOR_QUAD_READ) },
        { "n25q512ax3",  INFO(0x20ba20, 0, 64 * 1024, 1024, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ) },
        { "n25q00",      INFO(0x20ba21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
        { "n25q00a",     INFO(0x20bb21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
        { "mt25ql02g",   INFO(0x20ba22, 0, 64 * 1024, 4096,
                              SECT_4K | USE_FSR | SPI_NOR_QUAD_READ |
                              NO_CHIP_ERASE) },
        { "mt25qu512a (n25q512a)", INFO(0x20bb20, 0, 64 * 1024, 1024,
                                        SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
                                        SPI_NOR_QUAD_READ |
                                        SPI_NOR_4B_OPCODES) },
        { "mt25qu02g",   INFO(0x20bb22, 0, 64 * 1024, 4096, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },

        /* Micron */
        {
                "mt35xu512aba", INFO(0x2c5b1a, 0, 128 * 1024, 512,
                        SECT_4K | USE_FSR | SPI_NOR_OCTAL_READ |
                        SPI_NOR_4B_OPCODES)
        },
        { "mt35xu02g",  INFO(0x2c5b1c, 0, 128 * 1024, 2048,
                             SECT_4K | USE_FSR | SPI_NOR_OCTAL_READ |
                             SPI_NOR_4B_OPCODES) },

        /* PMC */
        { "pm25lv512",   INFO(0,        0, 32 * 1024,    2, SECT_4K_PMC) },
        { "pm25lv010",   INFO(0,        0, 32 * 1024,    4, SECT_4K_PMC) },
        { "pm25lq032",   INFO(0x7f9d46, 0, 64 * 1024,   64, SECT_4K) },

        /* Spansion/Cypress -- single (large) sector size only, at least
         * for the chips listed here (without boot sectors).
         */
        { "s25sl032p",  INFO(0x010215, 0x4d00,  64 * 1024,  64, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "s25sl064p",  INFO(0x010216, 0x4d00,  64 * 1024, 128, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "s25fl128s0", INFO6(0x012018, 0x4d0080, 256 * 1024, 64,
                        SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | USE_CLSR) },
        { "s25fl128s1", INFO6(0x012018, 0x4d0180, 64 * 1024, 256,
                        SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | USE_CLSR) },
        { "s25fl256s0", INFO(0x010219, 0x4d00, 256 * 1024, 128, USE_CLSR) },
        { "s25fl256s1", INFO(0x010219, 0x4d01,  64 * 1024, 512, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | USE_CLSR) },
        { "s25fl512s",  INFO6(0x010220, 0x4d0080, 256 * 1024, 256,
                        SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_HAS_LOCK | USE_CLSR) },
        { "s25fs512s",  INFO6(0x010220, 0x4d0081, 256 * 1024, 256, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | USE_CLSR) },
        { "s70fl01gs",  INFO(0x010221, 0x4d00, 256 * 1024, 256, 0) },
        { "s25sl12800", INFO(0x012018, 0x0300, 256 * 1024,  64, 0) },
        { "s25sl12801", INFO(0x012018, 0x0301,  64 * 1024, 256, 0) },
        { "s25fl129p0", INFO(0x012018, 0x4d00, 256 * 1024,  64, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | USE_CLSR) },
        { "s25fl129p1", INFO(0x012018, 0x4d01,  64 * 1024, 256, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | USE_CLSR) },
        { "s25sl004a",  INFO(0x010212,      0,  64 * 1024,   8, 0) },
        { "s25sl008a",  INFO(0x010213,      0,  64 * 1024,  16, 0) },
        { "s25sl016a",  INFO(0x010214,      0,  64 * 1024,  32, 0) },
        { "s25sl032a",  INFO(0x010215,      0,  64 * 1024,  64, 0) },
        { "s25sl064a",  INFO(0x010216,      0,  64 * 1024, 128, 0) },
        { "s25fl004k",  INFO(0xef4013,      0,  64 * 1024,   8, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "s25fl008k",  INFO(0xef4014,      0,  64 * 1024,  16, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "s25fl016k",  INFO(0xef4015,      0,  64 * 1024,  32, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "s25fl064k",  INFO(0xef4017,      0,  64 * 1024, 128, SECT_4K) },
        { "s25fl116k",  INFO(0x014015,      0,  64 * 1024,  32, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "s25fl132k",  INFO(0x014016,      0,  64 * 1024,  64, SECT_4K) },
        { "s25fl164k",  INFO(0x014017,      0,  64 * 1024, 128, SECT_4K) },
        { "s25fl204k",  INFO(0x014013,      0,  64 * 1024,   8, SECT_4K | SPI_NOR_DUAL_READ) },
        { "s25fl208k",  INFO(0x014014,      0,  64 * 1024,  16, SECT_4K | SPI_NOR_DUAL_READ) },
        { "s25fl064l",  INFO(0x016017,      0,  64 * 1024, 128, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
        { "s25fl128l",  INFO(0x016018,      0,  64 * 1024, 256, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
        { "s25fl256l",  INFO(0x016019,      0,  64 * 1024, 512, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },

        /* SST -- large erase sizes are "overlays", "sectors" are 4K */
        { "sst25vf040b", INFO(0xbf258d, 0, 64 * 1024,  8, SECT_4K | SST_WRITE) },
        { "sst25vf080b", INFO(0xbf258e, 0, 64 * 1024, 16, SECT_4K | SST_WRITE) },
        { "sst25vf016b", INFO(0xbf2541, 0, 64 * 1024, 32, SECT_4K | SST_WRITE) },
        { "sst25vf032b", INFO(0xbf254a, 0, 64 * 1024, 64, SECT_4K | SST_WRITE) },
        { "sst25vf064c", INFO(0xbf254b, 0, 64 * 1024, 128, SECT_4K) },
        { "sst25wf512",  INFO(0xbf2501, 0, 64 * 1024,  1, SECT_4K | SST_WRITE) },
        { "sst25wf010",  INFO(0xbf2502, 0, 64 * 1024,  2, SECT_4K | SST_WRITE) },
        { "sst25wf020",  INFO(0xbf2503, 0, 64 * 1024,  4, SECT_4K | SST_WRITE) },
        { "sst25wf020a", INFO(0x621612, 0, 64 * 1024,  4, SECT_4K) },
        { "sst25wf040b", INFO(0x621613, 0, 64 * 1024,  8, SECT_4K) },
        { "sst25wf040",  INFO(0xbf2504, 0, 64 * 1024,  8, SECT_4K | SST_WRITE) },
        { "sst25wf080",  INFO(0xbf2505, 0, 64 * 1024, 16, SECT_4K | SST_WRITE) },
        { "sst26wf016b", INFO(0xbf2651, 0, 64 * 1024, 32, SECT_4K |
                              SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "sst26vf064b", INFO(0xbf2643, 0, 64 * 1024, 128, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },

        /* ST Microelectronics -- newer production may have feature updates */
        { "m25p05",  INFO(0x202010,  0,  32 * 1024,   2, 0) },
        { "m25p10",  INFO(0x202011,  0,  32 * 1024,   4, 0) },
        { "m25p20",  INFO(0x202012,  0,  64 * 1024,   4, 0) },
        { "m25p40",  INFO(0x202013,  0,  64 * 1024,   8, 0) },
        { "m25p80",  INFO(0x202014,  0,  64 * 1024,  16, 0) },
        { "m25p16",  INFO(0x202015,  0,  64 * 1024,  32, 0) },
        { "m25p32",  INFO(0x202016,  0,  64 * 1024,  64, 0) },
        { "m25p64",  INFO(0x202017,  0,  64 * 1024, 128, 0) },
        { "m25p128", INFO(0x202018,  0, 256 * 1024,  64, 0) },

        { "m25p05-nonjedec",  INFO(0, 0,  32 * 1024,   2, 0) },
        { "m25p10-nonjedec",  INFO(0, 0,  32 * 1024,   4, 0) },
        { "m25p20-nonjedec",  INFO(0, 0,  64 * 1024,   4, 0) },
        { "m25p40-nonjedec",  INFO(0, 0,  64 * 1024,   8, 0) },
        { "m25p80-nonjedec",  INFO(0, 0,  64 * 1024,  16, 0) },
        { "m25p16-nonjedec",  INFO(0, 0,  64 * 1024,  32, 0) },
        { "m25p32-nonjedec",  INFO(0, 0,  64 * 1024,  64, 0) },
        { "m25p64-nonjedec",  INFO(0, 0,  64 * 1024, 128, 0) },
        { "m25p128-nonjedec", INFO(0, 0, 256 * 1024,  64, 0) },

        { "m45pe10", INFO(0x204011,  0, 64 * 1024,    2, 0) },
        { "m45pe80", INFO(0x204014,  0, 64 * 1024,   16, 0) },
        { "m45pe16", INFO(0x204015,  0, 64 * 1024,   32, 0) },

        { "m25pe20", INFO(0x208012,  0, 64 * 1024,  4,       0) },
        { "m25pe80", INFO(0x208014,  0, 64 * 1024, 16,       0) },
        { "m25pe16", INFO(0x208015,  0, 64 * 1024, 32, SECT_4K) },

        { "m25px16",    INFO(0x207115,  0, 64 * 1024, 32, SECT_4K) },
        { "m25px32",    INFO(0x207116,  0, 64 * 1024, 64, SECT_4K) },
        { "m25px32-s0", INFO(0x207316,  0, 64 * 1024, 64, SECT_4K) },
        { "m25px32-s1", INFO(0x206316,  0, 64 * 1024, 64, SECT_4K) },
        { "m25px64",    INFO(0x207117,  0, 64 * 1024, 128, 0) },
        { "m25px80",    INFO(0x207114,  0, 64 * 1024, 16, 0) },

        /* Winbond -- w25x "blocks" are 64K, "sectors" are 4KiB */
        { "w25x05", INFO(0xef3010, 0, 64 * 1024,  1,  SECT_4K) },
        { "w25x10", INFO(0xef3011, 0, 64 * 1024,  2,  SECT_4K) },
        { "w25x20", INFO(0xef3012, 0, 64 * 1024,  4,  SECT_4K) },
        { "w25x40", INFO(0xef3013, 0, 64 * 1024,  8,  SECT_4K) },
        { "w25x80", INFO(0xef3014, 0, 64 * 1024,  16, SECT_4K) },
        { "w25x16", INFO(0xef3015, 0, 64 * 1024,  32, SECT_4K) },
        {
                "w25q16dw", INFO(0xef6015, 0, 64 * 1024,  32,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
        },
        { "w25x32", INFO(0xef3016, 0, 64 * 1024,  64, SECT_4K) },
        {
                "w25q16jv-im/jm", INFO(0xef7015, 0, 64 * 1024,  32,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
        },
        { "w25q20cl", INFO(0xef4012, 0, 64 * 1024,  4, SECT_4K) },
        { "w25q20bw", INFO(0xef5012, 0, 64 * 1024,  4, SECT_4K) },
        { "w25q20ew", INFO(0xef6012, 0, 64 * 1024,  4, SECT_4K) },
        { "w25q32", INFO(0xef4016, 0, 64 * 1024,  64, SECT_4K) },
        {
                "w25q32dw", INFO(0xef6016, 0, 64 * 1024,  64,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
        },
        {
                "w25q32jv", INFO(0xef7016, 0, 64 * 1024,  64,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
        },
        { "w25x64", INFO(0xef3017, 0, 64 * 1024, 128, SECT_4K) },
        { "w25q64", INFO(0xef4017, 0, 64 * 1024, 128, SECT_4K) },
        {
                "w25q64dw", INFO(0xef6017, 0, 64 * 1024, 128,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
        },
        {
                "w25q128fw", INFO(0xef6018, 0, 64 * 1024, 256,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
        },
        {
                "w25q128jv", INFO(0xef7018, 0, 64 * 1024, 256,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
                        SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
        },
        { "w25q80", INFO(0xef5014, 0, 64 * 1024,  16, SECT_4K) },
        { "w25q80bl", INFO(0xef4014, 0, 64 * 1024,  16, SECT_4K) },
        { "w25q128", INFO(0xef4018, 0, 64 * 1024, 256, SECT_4K) },
        { "w25q256", INFO(0xef4019, 0, 64 * 1024, 512, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "w25q256jvm", INFO(0xef7019, 0, 64 * 1024, 512,
                             SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "w25m512jv", INFO(0xef7119, 0, 64 * 1024, 1024,
                        SECT_4K | SPI_NOR_QUAD_READ | SPI_NOR_DUAL_READ) },

        /* Catalyst / On Semiconductor -- non-JEDEC */
        { "cat25c11", CAT25_INFO(  16, 8, 16, 1, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
        { "cat25c03", CAT25_INFO(  32, 8, 16, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
        { "cat25c09", CAT25_INFO( 128, 8, 32, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
        { "cat25c17", CAT25_INFO( 256, 8, 32, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
        { "cat25128", CAT25_INFO(2048, 8, 64, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },

        /* Xilinx S3AN Internal Flash */
        { "3S50AN", S3AN_INFO(0x1f2200, 64, 264) },
        { "3S200AN", S3AN_INFO(0x1f2400, 256, 264) },
        { "3S400AN", S3AN_INFO(0x1f2400, 256, 264) },
        { "3S700AN", S3AN_INFO(0x1f2500, 512, 264) },
        { "3S1400AN", S3AN_INFO(0x1f2600, 512, 528) },

        /* XMC (Wuhan Xinxin Semiconductor Manufacturing Corp.) */
        { "XM25QH64A", INFO(0x207017, 0, 64 * 1024, 128, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "XM25QH128A", INFO(0x207018, 0, 64 * 1024, 256, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { },
};

static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
{
        int                     tmp;
        u8                      *id = nor->bouncebuf;
        const struct flash_info *info;

        if (nor->spimem) {
                struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDID, 1),
                                   SPI_MEM_OP_NO_ADDR,
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_DATA_IN(SPI_NOR_MAX_ID_LEN, id, 1));

                tmp = spi_mem_exec_op(nor->spimem, &op);
        } else {
                tmp = nor->controller_ops->read_reg(nor, SPINOR_OP_RDID, id,
                                                    SPI_NOR_MAX_ID_LEN);
        }
        if (tmp) {
                dev_dbg(nor->dev, "error %d reading JEDEC ID\n", tmp);
                return ERR_PTR(tmp);
        }

        for (tmp = 0; tmp < ARRAY_SIZE(spi_nor_ids) - 1; tmp++) {
                info = &spi_nor_ids[tmp];
                if (info->id_len) {
                        if (!memcmp(info->id, id, info->id_len))
                                return &spi_nor_ids[tmp];
                }
        }
        dev_err(nor->dev, "unrecognized JEDEC id bytes: %*ph\n",
                SPI_NOR_MAX_ID_LEN, id);
        return ERR_PTR(-ENODEV);
}

static int spi_nor_read(struct mtd_info *mtd, loff_t from, size_t len,
                        size_t *retlen, u_char *buf)
{
        struct spi_nor *nor = mtd_to_spi_nor(mtd);
        ssize_t ret;

        dev_dbg(nor->dev, "from 0x%08x, len %zd\n", (u32)from, len);

        ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_READ);
        if (ret)
                return ret;

        while (len) {
                loff_t addr = from;

                addr = spi_nor_convert_addr(nor, addr);

                ret = spi_nor_read_data(nor, addr, len, buf);
                if (ret == 0) {
                        /* We shouldn't see 0-length reads */
                        ret = -EIO;
                        goto read_err;
                }
                if (ret < 0)
                        goto read_err;

                WARN_ON(ret > len);
                *retlen += ret;
                buf += ret;
                from += ret;
                len -= ret;
        }
        ret = 0;

read_err:
        spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_READ);
        return ret;
}

static int sst_write(struct mtd_info *mtd, loff_t to, size_t len,
                size_t *retlen, const u_char *buf)
{
        struct spi_nor *nor = mtd_to_spi_nor(mtd);
        size_t actual = 0;
        int ret;

        dev_dbg(nor->dev, "to 0x%08x, len %zd\n", (u32)to, len);

        ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_WRITE);
        if (ret)
                return ret;

        ret = spi_nor_write_enable(nor);
        if (ret)
                goto out;

        nor->sst_write_second = false;

        /* Start write from odd address. */
        if (to % 2) {
                nor->program_opcode = SPINOR_OP_BP;

                /* write one byte. */
                ret = spi_nor_write_data(nor, to, 1, buf);
                if (ret < 0)
                        goto out;
                WARN(ret != 1, "While writing 1 byte written %i bytes\n", ret);
                ret = spi_nor_wait_till_ready(nor);
                if (ret)
                        goto out;

                to++;
                actual++;
        }

        /* Write out most of the data here. */
        for (; actual < len - 1; actual += 2) {
                nor->program_opcode = SPINOR_OP_AAI_WP;

                /* write two bytes. */
                ret = spi_nor_write_data(nor, to, 2, buf + actual);
                if (ret < 0)
                        goto out;
                WARN(ret != 2, "While writing 2 bytes written %i bytes\n", ret);
                ret = spi_nor_wait_till_ready(nor);
                if (ret)
                        goto out;
                to += 2;
                nor->sst_write_second = true;
        }
        nor->sst_write_second = false;

        ret = spi_nor_write_disable(nor);
        if (ret)
                goto out;

        ret = spi_nor_wait_till_ready(nor);
        if (ret)
                goto out;

        /* Write out trailing byte if it exists. */
        if (actual != len) {
                ret = spi_nor_write_enable(nor);
                if (ret)
                        goto out;

                nor->program_opcode = SPINOR_OP_BP;
                ret = spi_nor_write_data(nor, to, 1, buf + actual);
                if (ret < 0)
                        goto out;
                WARN(ret != 1, "While writing 1 byte written %i bytes\n", ret);
                ret = spi_nor_wait_till_ready(nor);
                if (ret)
                        goto out;

                actual += 1;

                ret = spi_nor_write_disable(nor);
        }
out:
        *retlen += actual;
        spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_WRITE);
        return ret;
}

/*
 * Write an address range to the nor chip.  Data must be written in
 * FLASH_PAGESIZE chunks.  The address range may be any size provided
 * it is within the physical boundaries.
 */
static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
        size_t *retlen, const u_char *buf)
{
        struct spi_nor *nor = mtd_to_spi_nor(mtd);
        size_t page_offset, page_remain, i;
        ssize_t ret;

        dev_dbg(nor->dev, "to 0x%08x, len %zd\n", (u32)to, len);

        ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_WRITE);
        if (ret)
                return ret;

        for (i = 0; i < len; ) {
                ssize_t written;
                loff_t addr = to + i;

                /*
                 * If page_size is a power of two, the offset can be quickly
                 * calculated with an AND operation. On the other cases we
                 * need to do a modulus operation (more expensive).
                 * Power of two numbers have only one bit set and we can use
                 * the instruction hweight32 to detect if we need to do a
                 * modulus (do_div()) or not.
                 */
                if (hweight32(nor->page_size) == 1) {
                        page_offset = addr & (nor->page_size - 1);
                } else {
                        uint64_t aux = addr;

                        page_offset = do_div(aux, nor->page_size);
                }
                /* the size of data remaining on the first page */
                page_remain = min_t(size_t,
                                    nor->page_size - page_offset, len - i);

                addr = spi_nor_convert_addr(nor, addr);

                ret = spi_nor_write_enable(nor);
                if (ret)
                        goto write_err;

                ret = spi_nor_write_data(nor, addr, page_remain, buf + i);
                if (ret < 0)
                        goto write_err;
                written = ret;

                ret = spi_nor_wait_till_ready(nor);
                if (ret)
                        goto write_err;
                *retlen += written;
                i += written;
        }

write_err:
        spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_WRITE);
        return ret;
}

static int spi_nor_check(struct spi_nor *nor)
{
        if (!nor->dev ||
            (!nor->spimem && nor->controller_ops &&
            (!nor->controller_ops->read ||
             !nor->controller_ops->write ||
             !nor->controller_ops->read_reg ||
             !nor->controller_ops->write_reg))) {
                pr_err("spi-nor: please fill all the necessary fields!\n");
                return -EINVAL;
        }

        return 0;
}

static int s3an_nor_setup(struct spi_nor *nor,
                          const struct spi_nor_hwcaps *hwcaps)
{
        int ret;

        ret = spi_nor_xread_sr(nor, nor->bouncebuf);
        if (ret)
                return ret;

        nor->erase_opcode = SPINOR_OP_XSE;
        nor->program_opcode = SPINOR_OP_XPP;
        nor->read_opcode = SPINOR_OP_READ;
        nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;

        /*
         * This flashes have a page size of 264 or 528 bytes (known as
         * Default addressing mode). It can be changed to a more standard
         * Power of two mode where the page size is 256/512. This comes
         * with a price: there is 3% less of space, the data is corrupted
         * and the page size cannot be changed back to default addressing
         * mode.
         *
         * The current addressing mode can be read from the XRDSR register
         * and should not be changed, because is a destructive operation.
         */
        if (nor->bouncebuf[0] & XSR_PAGESIZE) {
                /* Flash in Power of 2 mode */
                nor->page_size = (nor->page_size == 264) ? 256 : 512;
                nor->mtd.writebufsize = nor->page_size;
                nor->mtd.size = 8 * nor->page_size * nor->info->n_sectors;
                nor->mtd.erasesize = 8 * nor->page_size;
        } else {
                /* Flash in Default addressing mode */
                nor->params.convert_addr = s3an_convert_addr;
                nor->mtd.erasesize = nor->info->sector_size;
        }

        return 0;
}

static void
spi_nor_set_read_settings(struct spi_nor_read_command *read,
                          u8 num_mode_clocks,
                          u8 num_wait_states,
                          u8 opcode,
                          enum spi_nor_protocol proto)
{
        read->num_mode_clocks = num_mode_clocks;
        read->num_wait_states = num_wait_states;
        read->opcode = opcode;
        read->proto = proto;
}

static void
spi_nor_set_pp_settings(struct spi_nor_pp_command *pp,
                        u8 opcode,
                        enum spi_nor_protocol proto)
{
        pp->opcode = opcode;
        pp->proto = proto;
}

static int spi_nor_hwcaps2cmd(u32 hwcaps, const int table[][2], size_t size)
{
        size_t i;

        for (i = 0; i < size; i++)
                if (table[i][0] == (int)hwcaps)
                        return table[i][1];

        return -EINVAL;
}

static int spi_nor_hwcaps_read2cmd(u32 hwcaps)
{
        static const int hwcaps_read2cmd[][2] = {
                { SNOR_HWCAPS_READ,             SNOR_CMD_READ },
                { SNOR_HWCAPS_READ_FAST,        SNOR_CMD_READ_FAST },
                { SNOR_HWCAPS_READ_1_1_1_DTR,   SNOR_CMD_READ_1_1_1_DTR },
                { SNOR_HWCAPS_READ_1_1_2,       SNOR_CMD_READ_1_1_2 },
                { SNOR_HWCAPS_READ_1_2_2,       SNOR_CMD_READ_1_2_2 },
                { SNOR_HWCAPS_READ_2_2_2,       SNOR_CMD_READ_2_2_2 },
                { SNOR_HWCAPS_READ_1_2_2_DTR,   SNOR_CMD_READ_1_2_2_DTR },
                { SNOR_HWCAPS_READ_1_1_4,       SNOR_CMD_READ_1_1_4 },
                { SNOR_HWCAPS_READ_1_4_4,       SNOR_CMD_READ_1_4_4 },
                { SNOR_HWCAPS_READ_4_4_4,       SNOR_CMD_READ_4_4_4 },
                { SNOR_HWCAPS_READ_1_4_4_DTR,   SNOR_CMD_READ_1_4_4_DTR },
                { SNOR_HWCAPS_READ_1_1_8,       SNOR_CMD_READ_1_1_8 },
                { SNOR_HWCAPS_READ_1_8_8,       SNOR_CMD_READ_1_8_8 },
                { SNOR_HWCAPS_READ_8_8_8,       SNOR_CMD_READ_8_8_8 },
                { SNOR_HWCAPS_READ_1_8_8_DTR,   SNOR_CMD_READ_1_8_8_DTR },
        };

        return spi_nor_hwcaps2cmd(hwcaps, hwcaps_read2cmd,
                                  ARRAY_SIZE(hwcaps_read2cmd));
}

static int spi_nor_hwcaps_pp2cmd(u32 hwcaps)
{
        static const int hwcaps_pp2cmd[][2] = {
                { SNOR_HWCAPS_PP,               SNOR_CMD_PP },
                { SNOR_HWCAPS_PP_1_1_4,         SNOR_CMD_PP_1_1_4 },
                { SNOR_HWCAPS_PP_1_4_4,         SNOR_CMD_PP_1_4_4 },
                { SNOR_HWCAPS_PP_4_4_4,         SNOR_CMD_PP_4_4_4 },
                { SNOR_HWCAPS_PP_1_1_8,         SNOR_CMD_PP_1_1_8 },
                { SNOR_HWCAPS_PP_1_8_8,         SNOR_CMD_PP_1_8_8 },
                { SNOR_HWCAPS_PP_8_8_8,         SNOR_CMD_PP_8_8_8 },
        };

        return spi_nor_hwcaps2cmd(hwcaps, hwcaps_pp2cmd,
                                  ARRAY_SIZE(hwcaps_pp2cmd));
}

/*
 * Serial Flash Discoverable Parameters (SFDP) parsing.
 */

/**
 * spi_nor_read_raw() - raw read of serial flash memory. read_opcode,
 *                      addr_width 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_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 = spi_nor_read_raw(nor, addr, len, buf);

        nor->read_opcode = read_opcode;
        nor->addr_width = addr_width;
        nor->read_dummy = read_dummy;

        return ret;
}

/**
 * spi_nor_spimem_check_op - check if the operation is supported
 *                           by controller
 *@nor:        pointer to a 'struct spi_nor'
 *@op:         pointer to op template to be checked
 *
 * Returns 0 if operation is supported, -ENOTSUPP otherwise.
 */
static int spi_nor_spimem_check_op(struct spi_nor *nor,
                                   struct spi_mem_op *op)
{
        /*
         * First test with 4 address bytes. The opcode itself might
         * be a 3B addressing opcode but we don't care, because
         * SPI controller implementation should not check the opcode,
         * but just the sequence.
         */
        op->addr.nbytes = 4;
        if (!spi_mem_supports_op(nor->spimem, op)) {
                if (nor->mtd.size > SZ_16M)
                        return -ENOTSUPP;

                /* If flash size <= 16MB, 3 address bytes are sufficient */
                op->addr.nbytes = 3;
                if (!spi_mem_supports_op(nor->spimem, op))
                        return -ENOTSUPP;
        }

        return 0;
}

/**
 * spi_nor_spimem_check_readop - check if the read op is supported
 *                               by controller
 *@nor:         pointer to a 'struct spi_nor'
 *@read:        pointer to op template to be checked
 *
 * Returns 0 if operation is supported, -ENOTSUPP otherwise.
 */
static int spi_nor_spimem_check_readop(struct spi_nor *nor,
                                       const struct spi_nor_read_command *read)
{
        struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(read->opcode, 1),
                                          SPI_MEM_OP_ADDR(3, 0, 1),
                                          SPI_MEM_OP_DUMMY(0, 1),
                                          SPI_MEM_OP_DATA_IN(0, NULL, 1));

        op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(read->proto);
        op.addr.buswidth = spi_nor_get_protocol_addr_nbits(read->proto);
        op.data.buswidth = spi_nor_get_protocol_data_nbits(read->proto);
        op.dummy.buswidth = op.addr.buswidth;
        op.dummy.nbytes = (read->num_mode_clocks + read->num_wait_states) *
                          op.dummy.buswidth / 8;

        return spi_nor_spimem_check_op(nor, &op);
}

/**
 * spi_nor_spimem_check_pp - check if the page program op is supported
 *                           by controller
 *@nor:         pointer to a 'struct spi_nor'
 *@pp:          pointer to op template to be checked
 *
 * Returns 0 if operation is supported, -ENOTSUPP otherwise.
 */
static int spi_nor_spimem_check_pp(struct spi_nor *nor,
                                   const struct spi_nor_pp_command *pp)
{
        struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(pp->opcode, 1),
                                          SPI_MEM_OP_ADDR(3, 0, 1),
                                          SPI_MEM_OP_NO_DUMMY,
                                          SPI_MEM_OP_DATA_OUT(0, NULL, 1));

        op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(pp->proto);
        op.addr.buswidth = spi_nor_get_protocol_addr_nbits(pp->proto);
        op.data.buswidth = spi_nor_get_protocol_data_nbits(pp->proto);

        return spi_nor_spimem_check_op(nor, &op);
}

/**
 * spi_nor_spimem_adjust_hwcaps - Find optimal Read/Write protocol
 *                                based on SPI controller capabilities
 * @nor:        pointer to a 'struct spi_nor'
 * @hwcaps:     pointer to resulting capabilities after adjusting
 *              according to controller and flash's capability
 */
static void
spi_nor_spimem_adjust_hwcaps(struct spi_nor *nor, u32 *hwcaps)
{
        struct spi_nor_flash_parameter *params =  &nor->params;
        unsigned int cap;

        /* DTR modes are not supported yet, mask them all. */
        *hwcaps &= ~SNOR_HWCAPS_DTR;

        /* X-X-X modes are not supported yet, mask them all. */
        *hwcaps &= ~SNOR_HWCAPS_X_X_X;

        for (cap = 0; cap < sizeof(*hwcaps) * BITS_PER_BYTE; cap++) {
                int rdidx, ppidx;

                if (!(*hwcaps & BIT(cap)))
                        continue;

                rdidx = spi_nor_hwcaps_read2cmd(BIT(cap));
                if (rdidx >= 0 &&
                    spi_nor_spimem_check_readop(nor, &params->reads[rdidx]))
                        *hwcaps &= ~BIT(cap);

                ppidx = spi_nor_hwcaps_pp2cmd(BIT(cap));
                if (ppidx < 0)
                        continue;

                if (spi_nor_spimem_check_pp(nor,
                                            &params->page_programs[ppidx]))
                        *hwcaps &= ~BIT(cap);
        }
}

/**
 * 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;
}

/* Fast Read settings. */

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;
}

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},
};

/**
 * spi_nor_set_erase_type() - set a SPI NOR erase type
 * @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
 */
static void spi_nor_set_erase_type(struct spi_nor_erase_type *erase,
                                   u32 size, u8 opcode)
{
        erase->size = size;
        erase->opcode = opcode;
        /* JEDEC JESD216B Standard imposes erase sizes to be power of 2. */
        erase->size_shift = ffs(erase->size) - 1;
        erase->size_mask = (1 << erase->size_shift) - 1;
}

/**
 * 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 region_erase_mask, sorted_erase_mask;

        while (region) {
                region_erase_mask = region->offset & SNOR_ERASE_TYPE_MASK;

                sorted_erase_mask = spi_nor_sort_erase_mask(map,
                                                            region_erase_mask);

                /* Overwrite erase mask. */
                region->offset = (region->offset & ~SNOR_ERASE_TYPE_MASK) |
                                 sorted_erase_mask;

                region = spi_nor_region_next(region);
        }
}

/**
 * spi_nor_init_uniform_erase_map() - Initialize uniform erase map
 * @map:                the erase map of the SPI NOR
 * @erase_mask:         bitmask encoding erase types that can erase the entire
 *                      flash memory
 * @flash_size:         the spi nor flash memory size
 */
static void spi_nor_init_uniform_erase_map(struct spi_nor_erase_map *map,
                                           u8 erase_mask, u64 flash_size)
{
        /* Offset 0 with erase_mask and SNOR_LAST_REGION bit set */
        map->uniform_region.offset = (erase_mask & SNOR_ERASE_TYPE_MASK) |
                                     SNOR_LAST_REGION;
        map->uniform_region.size = flash_size;
        map->regions = &map->uniform_region;
        map->uniform_erase_type = erase_mask;
}

static int
spi_nor_post_bfpt_fixups(struct spi_nor *nor,
                         const struct sfdp_parameter_header *bfpt_header,
                         const struct sfdp_bfpt *bfpt,
                         struct spi_nor_flash_parameter *params)
{
        if (nor->info->fixups && nor->info->fixups->post_bfpt)
                return nor->info->fixups->post_bfpt(nor, bfpt_header, bfpt,
                                                    params);

        return 0;
}

/**
 * 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 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;
        u16 half;
        u8 erase_mask;

        /* 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. */
        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);

                /*
                 * 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 (params->size > 63)
                        return -EINVAL;

                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. 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);
        map->uniform_erase_type = map->uniform_region.offset &
                                  SNOR_ERASE_TYPE_MASK;

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

        /* 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 spi_nor_post_bfpt_fixups(nor, bfpt_header, &bfpt, params);
}

#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)

/**
 * spi_nor_smpt_addr_width() - return the address width 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_width(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:
                /* fall through */
        default:
                return nor->addr_width;
        }
}

/**
 * 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_width, 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_width = nor->addr_width;
        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_width = spi_nor_smpt_addr_width(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_width = addr_width;
        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_type & BIT(i)))
                        continue;
                if (region->size & erase[i].size_mask) {
                        spi_nor_region_mark_overlay(region);
                        return;
                }
        }
}

/**
 * spi_nor_init_non_uniform_erase_map() - initialize the non-uniform erase map
 * @nor:        pointer to a 'struct spi_nor'
 * @params:     pointer to a duplicate 'struct spi_nor_flash_parameter' that is
 *              used for storing SFDP parsed data
 * @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,
                                   struct spi_nor_flash_parameter *params,
                                   const u32 *smpt)
{
        struct spi_nor_erase_map *map = &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;

        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].size = SMPT_MAP_REGION_SIZE(smpt[j]);
                erase_type = SMPT_MAP_REGION_ERASE_TYPE(smpt[j]);
                region[i].offset = offset | 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 & ~SNOR_ERASE_FLAGS_MASK) +
                         region[i].size;
        }

        save_uniform_erase_type = map->uniform_erase_type;
        map->uniform_erase_type = 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_erase_type = 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_set_erase_type(&erase[i], 0, 0xFF);

        spi_nor_region_mark_end(&region[i - 1]);

        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
 * @params:             pointer to a duplicate 'struct spi_nor_flash_parameter'
 *                      that is used for storing SFDP parsed data
 *
 * 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,
                              struct spi_nor_flash_parameter *params)
{
        const u32 *sector_map;
        u32 *smpt;
        size_t len;
        u32 addr;
        int i, 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. */
        for (i = 0; i < smpt_header->length; i++)
                smpt[i] = le32_to_cpu(smpt[i]);

        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, params, sector_map);
        if (ret)
                goto out;

        spi_nor_regions_sort_erase_types(&params->erase_map);
        /* fall through */
out:
        kfree(smpt);
        return ret;
}

#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_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.
 * @params:             pointer to the 'struct spi_nor_flash_parameter' to be.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_parse_4bait(struct spi_nor *nor,
                               const struct sfdp_parameter_header *param_header,
                               struct spi_nor_flash_parameter *params)
{
        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) },
        };
        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_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. */
        for (i = 0; i < SFDP_4BAIT_DWORD_MAX; i++)
                dwords[i] = le32_to_cpu(dwords[i]);

        /*
         * 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[0] & 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[0] & 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[0] & 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_width 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);
        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[1] >>
                                                erase_type[i].idx * 8) & 0xFF;
                else
                        spi_nor_set_erase_type(&erase_type[i], 0u, 0xFF);
        }

        /*
         * 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.
         */
        nor->addr_width = 4;
        nor->flags |= SNOR_F_4B_OPCODES | SNOR_F_HAS_4BAIT;

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

/**
 * 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_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;

        /*
         * 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;
                }
        }

        /*
         * 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 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, params);
                        break;

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

exit:
        kfree(param_headers);
        return err;
}

static int spi_nor_select_read(struct spi_nor *nor,
                               u32 shared_hwcaps)
{
        int cmd, best_match = fls(shared_hwcaps & SNOR_HWCAPS_READ_MASK) - 1;
        const struct spi_nor_read_command *read;

        if (best_match < 0)
                return -EINVAL;

        cmd = spi_nor_hwcaps_read2cmd(BIT(best_match));
        if (cmd < 0)
                return -EINVAL;

        read = &nor->params.reads[cmd];
        nor->read_opcode = read->opcode;
        nor->read_proto = read->proto;

        /*
         * In the spi-nor framework, we don't need to make the difference
         * between mode clock cycles and wait state clock cycles.
         * Indeed, the value of the mode clock cycles is used by a QSPI
         * flash memory to know whether it should enter or leave its 0-4-4
         * (Continuous Read / XIP) mode.
         * eXecution In Place is out of the scope of the mtd sub-system.
         * Hence we choose to merge both mode and wait state clock cycles
         * into the so called dummy clock cycles.
         */
        nor->read_dummy = read->num_mode_clocks + read->num_wait_states;
        return 0;
}

static int spi_nor_select_pp(struct spi_nor *nor,
                             u32 shared_hwcaps)
{
        int cmd, best_match = fls(shared_hwcaps & SNOR_HWCAPS_PP_MASK) - 1;
        const struct spi_nor_pp_command *pp;

        if (best_match < 0)
                return -EINVAL;

        cmd = spi_nor_hwcaps_pp2cmd(BIT(best_match));
        if (cmd < 0)
                return -EINVAL;

        pp = &nor->params.page_programs[cmd];
        nor->program_opcode = pp->opcode;
        nor->write_proto = pp->proto;
        return 0;
}

/**
 * spi_nor_select_uniform_erase() - select optimum uniform erase type
 * @map:                the erase map of the SPI NOR
 * @wanted_size:        the erase type size to search for. Contains the value of
 *                      info->sector_size or of the "small sector" size in case
 *                      CONFIG_MTD_SPI_NOR_USE_4K_SECTORS is defined.
 *
 * Once the optimum uniform sector erase command is found, disable all the
 * other.
 *
 * Return: pointer to erase type on success, NULL otherwise.
 */
static const struct spi_nor_erase_type *
spi_nor_select_uniform_erase(struct spi_nor_erase_map *map,
                             const u32 wanted_size)
{
        const struct spi_nor_erase_type *tested_erase, *erase = NULL;
        int i;
        u8 uniform_erase_type = map->uniform_erase_type;

        for (i = SNOR_ERASE_TYPE_MAX - 1; i >= 0; i--) {
                if (!(uniform_erase_type & BIT(i)))
                        continue;

                tested_erase = &map->erase_type[i];

                /*
                 * If the current erase size is the one, stop here:
                 * we have found the right uniform Sector Erase command.
                 */
                if (tested_erase->size == wanted_size) {
                        erase = tested_erase;
                        break;
                }

                /*
                 * Otherwise, the current erase size is still a valid canditate.
                 * Select the biggest valid candidate.
                 */
                if (!erase && tested_erase->size)
                        erase = tested_erase;
                        /* keep iterating to find the wanted_size */
        }

        if (!erase)
                return NULL;

        /* Disable all other Sector Erase commands. */
        map->uniform_erase_type &= ~SNOR_ERASE_TYPE_MASK;
        map->uniform_erase_type |= BIT(erase - map->erase_type);
        return erase;
}

static int spi_nor_select_erase(struct spi_nor *nor)
{
        struct spi_nor_erase_map *map = &nor->params.erase_map;
        const struct spi_nor_erase_type *erase = NULL;
        struct mtd_info *mtd = &nor->mtd;
        u32 wanted_size = nor->info->sector_size;
        int i;

        /*
         * The previous implementation handling Sector Erase commands assumed
         * that the SPI flash memory has an uniform layout then used only one
         * of the supported erase sizes for all Sector Erase commands.
         * So to be backward compatible, the new implementation also tries to
         * manage the SPI flash memory as uniform with a single erase sector
         * size, when possible.
         */
#ifdef CONFIG_MTD_SPI_NOR_USE_4K_SECTORS
        /* prefer "small sector" erase if possible */
        wanted_size = 4096u;
#endif

        if (spi_nor_has_uniform_erase(nor)) {
                erase = spi_nor_select_uniform_erase(map, wanted_size);
                if (!erase)
                        return -EINVAL;
                nor->erase_opcode = erase->opcode;
                mtd->erasesize = erase->size;
                return 0;
        }

        /*
         * For non-uniform SPI flash memory, set mtd->erasesize to the
         * maximum erase sector size. No need to set nor->erase_opcode.
         */
        for (i = SNOR_ERASE_TYPE_MAX - 1; i >= 0; i--) {
                if (map->erase_type[i].size) {
                        erase = &map->erase_type[i];
                        break;
                }
        }

        if (!erase)
                return -EINVAL;

        mtd->erasesize = erase->size;
        return 0;
}

static int spi_nor_default_setup(struct spi_nor *nor,
                                 const struct spi_nor_hwcaps *hwcaps)
{
        struct spi_nor_flash_parameter *params = &nor->params;
        u32 ignored_mask, shared_mask;
        int err;

        /*
         * Keep only the hardware capabilities supported by both the SPI
         * controller and the SPI flash memory.
         */
        shared_mask = hwcaps->mask & params->hwcaps.mask;

        if (nor->spimem) {
                /*
                 * When called from spi_nor_probe(), all caps are set and we
                 * need to discard some of them based on what the SPI
                 * controller actually supports (using spi_mem_supports_op()).
                 */
                spi_nor_spimem_adjust_hwcaps(nor, &shared_mask);
        } else {
                /*
                 * SPI n-n-n protocols are not supported when the SPI
                 * controller directly implements the spi_nor interface.
                 * Yet another reason to switch to spi-mem.
                 */
                ignored_mask = SNOR_HWCAPS_X_X_X;
                if (shared_mask & ignored_mask) {
                        dev_dbg(nor->dev,
                                "SPI n-n-n protocols are not supported.\n");
                        shared_mask &= ~ignored_mask;
                }
        }

        /* Select the (Fast) Read command. */
        err = spi_nor_select_read(nor, shared_mask);
        if (err) {
                dev_dbg(nor->dev,
                        "can't select read settings supported by both the SPI controller and memory.\n");
                return err;
        }

        /* Select the Page Program command. */
        err = spi_nor_select_pp(nor, shared_mask);
        if (err) {
                dev_dbg(nor->dev,
                        "can't select write settings supported by both the SPI controller and memory.\n");
                return err;
        }

        /* Select the Sector Erase command. */
        err = spi_nor_select_erase(nor);
        if (err) {
                dev_dbg(nor->dev,
                        "can't select erase settings supported by both the SPI controller and memory.\n");
                return err;
        }

        return 0;
}

static int spi_nor_setup(struct spi_nor *nor,
                         const struct spi_nor_hwcaps *hwcaps)
{
        if (!nor->params.setup)
                return 0;

        return nor->params.setup(nor, hwcaps);
}

static void macronix_set_default_init(struct spi_nor *nor)
{
        nor->params.quad_enable = macronix_quad_enable;
        nor->params.set_4byte = macronix_set_4byte;
}

static void st_micron_set_default_init(struct spi_nor *nor)
{
        nor->flags |= SNOR_F_HAS_LOCK;
        nor->params.quad_enable = NULL;
        nor->params.set_4byte = st_micron_set_4byte;
}

static void winbond_set_default_init(struct spi_nor *nor)
{
        nor->params.set_4byte = winbond_set_4byte;
}

/**
 * spi_nor_manufacturer_init_params() - Initialize the flash's parameters and
 * settings based on MFR register and ->default_init() hook.
 * @nor:        pointer to a 'struct spi-nor'.
 */
static void spi_nor_manufacturer_init_params(struct spi_nor *nor)
{
        /* Init flash parameters based on MFR */
        switch (JEDEC_MFR(nor->info)) {
        case SNOR_MFR_MACRONIX:
                macronix_set_default_init(nor);
                break;

        case SNOR_MFR_ST:
        case SNOR_MFR_MICRON:
                st_micron_set_default_init(nor);
                break;

        case SNOR_MFR_WINBOND:
                winbond_set_default_init(nor);
                break;

        default:
                break;
        }

        if (nor->info->fixups && nor->info->fixups->default_init)
                nor->info->fixups->default_init(nor);
}

/**
 * spi_nor_sfdp_init_params() - Initialize the flash's parameters and settings
 * based on JESD216 SFDP standard.
 * @nor:        pointer to a 'struct spi-nor'.
 *
 * The method has a roll-back mechanism: in case the SFDP parsing fails, the
 * legacy flash parameters and settings will be restored.
 */
static void spi_nor_sfdp_init_params(struct spi_nor *nor)
{
        struct spi_nor_flash_parameter sfdp_params;

        memcpy(&sfdp_params, &nor->params, sizeof(sfdp_params));

        if (spi_nor_parse_sfdp(nor, &sfdp_params)) {
                nor->addr_width = 0;
                nor->flags &= ~SNOR_F_4B_OPCODES;
        } else {
                memcpy(&nor->params, &sfdp_params, sizeof(nor->params));
        }
}

/**
 * spi_nor_info_init_params() - Initialize the flash's parameters and settings
 * based on nor->info data.
 * @nor:        pointer to a 'struct spi-nor'.
 */
static void spi_nor_info_init_params(struct spi_nor *nor)
{
        struct spi_nor_flash_parameter *params = &nor->params;
        struct spi_nor_erase_map *map = &params->erase_map;
        const struct flash_info *info = nor->info;
        struct device_node *np = spi_nor_get_flash_node(nor);
        u8 i, erase_mask;

        /* Initialize legacy flash parameters and settings. */
        params->quad_enable = spansion_quad_enable;
        params->set_4byte = spansion_set_4byte;
        params->setup = spi_nor_default_setup;

        /* Set SPI NOR sizes. */
        params->size = (u64)info->sector_size * info->n_sectors;
        params->page_size = info->page_size;

        if (!(info->flags & SPI_NOR_NO_FR)) {
                /* Default to Fast Read for DT and non-DT platform devices. */
                params->hwcaps.mask |= SNOR_HWCAPS_READ_FAST;

                /* Mask out Fast Read if not requested at DT instantiation. */
                if (np && !of_property_read_bool(np, "m25p,fast-read"))
                        params->hwcaps.mask &= ~SNOR_HWCAPS_READ_FAST;
        }

        /* (Fast) Read settings. */
        params->hwcaps.mask |= SNOR_HWCAPS_READ;
        spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ],
                                  0, 0, SPINOR_OP_READ,
                                  SNOR_PROTO_1_1_1);

        if (params->hwcaps.mask & SNOR_HWCAPS_READ_FAST)
                spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ_FAST],
                                          0, 8, SPINOR_OP_READ_FAST,
                                          SNOR_PROTO_1_1_1);

        if (info->flags & SPI_NOR_DUAL_READ) {
                params->hwcaps.mask |= SNOR_HWCAPS_READ_1_1_2;
                spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ_1_1_2],
                                          0, 8, SPINOR_OP_READ_1_1_2,
                                          SNOR_PROTO_1_1_2);
        }

        if (info->flags & SPI_NOR_QUAD_READ) {
                params->hwcaps.mask |= SNOR_HWCAPS_READ_1_1_4;
                spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ_1_1_4],
                                          0, 8, SPINOR_OP_READ_1_1_4,
                                          SNOR_PROTO_1_1_4);
        }

        if (info->flags & SPI_NOR_OCTAL_READ) {
                params->hwcaps.mask |= SNOR_HWCAPS_READ_1_1_8;
                spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ_1_1_8],
                                          0, 8, SPINOR_OP_READ_1_1_8,
                                          SNOR_PROTO_1_1_8);
        }

        /* Page Program settings. */
        params->hwcaps.mask |= SNOR_HWCAPS_PP;
        spi_nor_set_pp_settings(&params->page_programs[SNOR_CMD_PP],
                                SPINOR_OP_PP, SNOR_PROTO_1_1_1);

        /*
         * Sector Erase settings. Sort Erase Types in ascending order, with the
         * smallest erase size starting at BIT(0).
         */
        erase_mask = 0;
        i = 0;
        if (info->flags & SECT_4K_PMC) {
                erase_mask |= BIT(i);
                spi_nor_set_erase_type(&map->erase_type[i], 4096u,
                                       SPINOR_OP_BE_4K_PMC);
                i++;
        } else if (info->flags & SECT_4K) {
                erase_mask |= BIT(i);
                spi_nor_set_erase_type(&map->erase_type[i], 4096u,
                                       SPINOR_OP_BE_4K);
                i++;
        }
        erase_mask |= BIT(i);
        spi_nor_set_erase_type(&map->erase_type[i], info->sector_size,
                               SPINOR_OP_SE);
        spi_nor_init_uniform_erase_map(map, erase_mask, params->size);
}

static void spansion_post_sfdp_fixups(struct spi_nor *nor)
{
        struct mtd_info *mtd = &nor->mtd;

        if (mtd->size <= SZ_16M)
                return;

        nor->flags |= SNOR_F_4B_OPCODES;
        /* No small sector erase for 4-byte command set */
        nor->erase_opcode = SPINOR_OP_SE;
        nor->mtd.erasesize = nor->info->sector_size;
}

static void s3an_post_sfdp_fixups(struct spi_nor *nor)
{
        nor->params.setup = s3an_nor_setup;
}

/**
 * spi_nor_post_sfdp_fixups() - Updates the flash's parameters and settings
 * after SFDP has been parsed (is also called for SPI NORs that do not
 * support RDSFDP).
 * @nor:        pointer to a 'struct spi_nor'
 *
 * Typically used to tweak various parameters that could not be extracted by
 * other means (i.e. when information provided by the SFDP/flash_info tables
 * are incomplete or wrong).
 */
static void spi_nor_post_sfdp_fixups(struct spi_nor *nor)
{
        switch (JEDEC_MFR(nor->info)) {
        case SNOR_MFR_SPANSION:
                spansion_post_sfdp_fixups(nor);
                break;

        default:
                break;
        }

        if (nor->info->flags & SPI_S3AN)
                s3an_post_sfdp_fixups(nor);

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

/**
 * spi_nor_late_init_params() - Late initialization of default flash parameters.
 * @nor:        pointer to a 'struct spi_nor'
 *
 * Used to set default flash parameters and settings when the ->default_init()
 * hook or the SFDP parser let voids.
 */
static void spi_nor_late_init_params(struct spi_nor *nor)
{
        /*
         * NOR protection support. When locking_ops are not provided, we pick
         * the default ones.
         */
        if (nor->flags & SNOR_F_HAS_LOCK && !nor->params.locking_ops)
                nor->params.locking_ops = &stm_locking_ops;
}

/**
 * spi_nor_init_params() - Initialize the flash's parameters and settings.
 * @nor:        pointer to a 'struct spi-nor'.
 *
 * The flash parameters and settings are initialized based on a sequence of
 * calls that are ordered by priority:
 *
 * 1/ Default flash parameters initialization. The initializations are done
 *    based on nor->info data:
 *              spi_nor_info_init_params()
 *
 * which can be overwritten by:
 * 2/ Manufacturer flash parameters initialization. The initializations are
 *    done based on MFR register, or when the decisions can not be done solely
 *    based on MFR, by using specific flash_info tweeks, ->default_init():
 *              spi_nor_manufacturer_init_params()
 *
 * which can be overwritten by:
 * 3/ SFDP flash parameters initialization. JESD216 SFDP is a standard and
 *    should be more accurate that the above.
 *              spi_nor_sfdp_init_params()
 *
 *    Please note that there is a ->post_bfpt() fixup hook that can overwrite
 *    the flash parameters and settings immediately after parsing the Basic
 *    Flash Parameter Table.
 *
 * which can be overwritten by:
 * 4/ Post SFDP flash parameters initialization. Used to tweak various
 *    parameters that could not be extracted by other means (i.e. when
 *    information provided by the SFDP/flash_info tables are incomplete or
 *    wrong).
 *              spi_nor_post_sfdp_fixups()
 *
 * 5/ Late default flash parameters initialization, used when the
 * ->default_init() hook or the SFDP parser do not set specific params.
 *              spi_nor_late_init_params()
 */
static void spi_nor_init_params(struct spi_nor *nor)
{
        spi_nor_info_init_params(nor);

        spi_nor_manufacturer_init_params(nor);

        if ((nor->info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)) &&
            !(nor->info->flags & SPI_NOR_SKIP_SFDP))
                spi_nor_sfdp_init_params(nor);

        spi_nor_post_sfdp_fixups(nor);

        spi_nor_late_init_params(nor);
}

/**
 * spi_nor_quad_enable() - enable Quad I/O if needed.
 * @nor:                pointer to a 'struct spi_nor'
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_quad_enable(struct spi_nor *nor)
{
        if (!nor->params.quad_enable)
                return 0;

        if (!(spi_nor_get_protocol_width(nor->read_proto) == 4 ||
              spi_nor_get_protocol_width(nor->write_proto) == 4))
                return 0;

        return nor->params.quad_enable(nor);
}

static int spi_nor_init(struct spi_nor *nor)
{
        int err;

        if (nor->clear_sr_bp) {
                if (nor->params.quad_enable == spansion_quad_enable)
                        nor->clear_sr_bp = spi_nor_spansion_clear_sr_bp;

                err = nor->clear_sr_bp(nor);
                if (err) {
                        dev_dbg(nor->dev,
                                "fail to clear block protection bits\n");
                        return err;
                }
        }

        err = spi_nor_quad_enable(nor);
        if (err) {
                dev_dbg(nor->dev, "quad mode not supported\n");
                return err;
        }

        if (nor->addr_width == 4 && !(nor->flags & SNOR_F_4B_OPCODES)) {
                /*
                 * If the RESET# pin isn't hooked up properly, or the system
                 * otherwise doesn't perform a reset command in the boot
                 * sequence, it's impossible to 100% protect against unexpected
                 * reboots (e.g., crashes). Warn the user (or hopefully, system
                 * designer) that this is bad.
                 */
                WARN_ONCE(nor->flags & SNOR_F_BROKEN_RESET,
                          "enabling reset hack; may not recover from unexpected reboots\n");
                nor->params.set_4byte(nor, true);
        }

        return 0;
}

/* mtd resume handler */
static void spi_nor_resume(struct mtd_info *mtd)
{
        struct spi_nor *nor = mtd_to_spi_nor(mtd);
        struct device *dev = nor->dev;
        int ret;

        /* re-initialize the nor chip */
        ret = spi_nor_init(nor);
        if (ret)
                dev_err(dev, "resume() failed\n");
}

void spi_nor_restore(struct spi_nor *nor)
{
        /* restore the addressing mode */
        if (nor->addr_width == 4 && !(nor->flags & SNOR_F_4B_OPCODES) &&
            nor->flags & SNOR_F_BROKEN_RESET)
                nor->params.set_4byte(nor, false);
}
EXPORT_SYMBOL_GPL(spi_nor_restore);

static const struct flash_info *spi_nor_match_id(const char *name)
{
        const struct flash_info *id = spi_nor_ids;

        while (id->name) {
                if (!strcmp(name, id->name))
                        return id;
                id++;
        }
        return NULL;
}

static int spi_nor_set_addr_width(struct spi_nor *nor)
{
        if (nor->addr_width) {
                /* already configured from SFDP */
        } else if (nor->info->addr_width) {
                nor->addr_width = nor->info->addr_width;
        } else if (nor->mtd.size > 0x1000000) {
                /* enable 4-byte addressing if the device exceeds 16MiB */
                nor->addr_width = 4;
        } else {
                nor->addr_width = 3;
        }

        if (nor->addr_width > SPI_NOR_MAX_ADDR_WIDTH) {
                dev_dbg(nor->dev, "address width is too large: %u\n",
                        nor->addr_width);
                return -EINVAL;
        }

        /* Set 4byte opcodes when possible. */
        if (nor->addr_width == 4 && nor->flags & SNOR_F_4B_OPCODES &&
            !(nor->flags & SNOR_F_HAS_4BAIT))
                spi_nor_set_4byte_opcodes(nor);

        return 0;
}

static void spi_nor_debugfs_init(struct spi_nor *nor,
                                 const struct flash_info *info)
{
        struct mtd_info *mtd = &nor->mtd;

        mtd->dbg.partname = info->name;
        mtd->dbg.partid = devm_kasprintf(nor->dev, GFP_KERNEL, "spi-nor:%*phN",
                                         info->id_len, info->id);
}

static const struct flash_info *spi_nor_get_flash_info(struct spi_nor *nor,
                                                       const char *name)
{
        const struct flash_info *info = NULL;

        if (name)
                info = spi_nor_match_id(name);
        /* Try to auto-detect if chip name wasn't specified or not found */
        if (!info)
                info = spi_nor_read_id(nor);
        if (IS_ERR_OR_NULL(info))
                return ERR_PTR(-ENOENT);

        /*
         * If caller has specified name of flash model that can normally be
         * detected using JEDEC, let's verify it.
         */
        if (name && info->id_len) {
                const struct flash_info *jinfo;

                jinfo = spi_nor_read_id(nor);
                if (IS_ERR(jinfo)) {
                        return jinfo;
                } else if (jinfo != info) {
                        /*
                         * JEDEC knows better, so overwrite platform ID. We
                         * can't trust partitions any longer, but we'll let
                         * mtd apply them anyway, since some partitions may be
                         * marked read-only, and we don't want to lose that
                         * information, even if it's not 100% accurate.
                         */
                        dev_warn(nor->dev, "found %s, expected %s\n",
                                 jinfo->name, info->name);
                        info = jinfo;
                }
        }

        return info;
}

int spi_nor_scan(struct spi_nor *nor, const char *name,
                 const struct spi_nor_hwcaps *hwcaps)
{
        const struct flash_info *info;
        struct device *dev = nor->dev;
        struct mtd_info *mtd = &nor->mtd;
        struct device_node *np = spi_nor_get_flash_node(nor);
        struct spi_nor_flash_parameter *params = &nor->params;
        int ret;
        int i;

        ret = spi_nor_check(nor);
        if (ret)
                return ret;

        /* Reset SPI protocol for all commands. */
        nor->reg_proto = SNOR_PROTO_1_1_1;
        nor->read_proto = SNOR_PROTO_1_1_1;
        nor->write_proto = SNOR_PROTO_1_1_1;

        /*
         * We need the bounce buffer early to read/write registers when going
         * through the spi-mem layer (buffers have to be DMA-able).
         * For spi-mem drivers, we'll reallocate a new buffer if
         * nor->page_size turns out to be greater than PAGE_SIZE (which
         * shouldn't happen before long since NOR pages are usually less
         * than 1KB) after spi_nor_scan() returns.
         */
        nor->bouncebuf_size = PAGE_SIZE;
        nor->bouncebuf = devm_kmalloc(dev, nor->bouncebuf_size,
                                      GFP_KERNEL);
        if (!nor->bouncebuf)
                return -ENOMEM;

        info = spi_nor_get_flash_info(nor, name);
        if (IS_ERR(info))
                return PTR_ERR(info);

        nor->info = info;

        spi_nor_debugfs_init(nor, info);

        mutex_init(&nor->lock);

        /*
         * Make sure the XSR_RDY flag is set before calling
         * spi_nor_wait_till_ready(). Xilinx S3AN share MFR
         * with Atmel spi-nor
         */
        if (info->flags & SPI_NOR_XSR_RDY)
                nor->flags |=  SNOR_F_READY_XSR_RDY;

        if (info->flags & SPI_NOR_HAS_LOCK)
                nor->flags |= SNOR_F_HAS_LOCK;

        /*
         * Atmel, SST, Intel/Numonyx, and others serial NOR tend to power up
         * with the software protection bits set.
         */
        if (JEDEC_MFR(nor->info) == SNOR_MFR_ATMEL ||
            JEDEC_MFR(nor->info) == SNOR_MFR_INTEL ||
            JEDEC_MFR(nor->info) == SNOR_MFR_SST ||
            nor->info->flags & SPI_NOR_HAS_LOCK)
                nor->clear_sr_bp = spi_nor_clear_sr_bp;

        /* Init flash parameters based on flash_info struct and SFDP */
        spi_nor_init_params(nor);

        if (!mtd->name)
                mtd->name = dev_name(dev);
        mtd->priv = nor;
        mtd->type = MTD_NORFLASH;
        mtd->writesize = 1;
        mtd->flags = MTD_CAP_NORFLASH;
        mtd->size = params->size;
        mtd->_erase = spi_nor_erase;
        mtd->_read = spi_nor_read;
        mtd->_resume = spi_nor_resume;

        if (nor->params.locking_ops) {
                mtd->_lock = spi_nor_lock;
                mtd->_unlock = spi_nor_unlock;
                mtd->_is_locked = spi_nor_is_locked;
        }

        /* sst nor chips use AAI word program */
        if (info->flags & SST_WRITE)
                mtd->_write = sst_write;
        else
                mtd->_write = spi_nor_write;

        if (info->flags & USE_FSR)
                nor->flags |= SNOR_F_USE_FSR;
        if (info->flags & SPI_NOR_HAS_TB)
                nor->flags |= SNOR_F_HAS_SR_TB;
        if (info->flags & NO_CHIP_ERASE)
                nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
        if (info->flags & USE_CLSR)
                nor->flags |= SNOR_F_USE_CLSR;

        if (info->flags & SPI_NOR_NO_ERASE)
                mtd->flags |= MTD_NO_ERASE;

        mtd->dev.parent = dev;
        nor->page_size = params->page_size;
        mtd->writebufsize = nor->page_size;

        if (of_property_read_bool(np, "broken-flash-reset"))
                nor->flags |= SNOR_F_BROKEN_RESET;

        /*
         * Configure the SPI memory:
         * - select op codes for (Fast) Read, Page Program and Sector Erase.
         * - set the number of dummy cycles (mode cycles + wait states).
         * - set the SPI protocols for register and memory accesses.
         */
        ret = spi_nor_setup(nor, hwcaps);
        if (ret)
                return ret;

        if (info->flags & SPI_NOR_4B_OPCODES)
                nor->flags |= SNOR_F_4B_OPCODES;

        ret = spi_nor_set_addr_width(nor);
        if (ret)
                return ret;

        /* Send all the required SPI flash commands to initialize device */
        ret = spi_nor_init(nor);
        if (ret)
                return ret;

        dev_info(dev, "%s (%lld Kbytes)\n", info->name,
                        (long long)mtd->size >> 10);

        dev_dbg(dev,
                "mtd .name = %s, .size = 0x%llx (%lldMiB), "
                ".erasesize = 0x%.8x (%uKiB) .numeraseregions = %d\n",
                mtd->name, (long long)mtd->size, (long long)(mtd->size >> 20),
                mtd->erasesize, mtd->erasesize / 1024, mtd->numeraseregions);

        if (mtd->numeraseregions)
                for (i = 0; i < mtd->numeraseregions; i++)
                        dev_dbg(dev,
                                "mtd.eraseregions[%d] = { .offset = 0x%llx, "
                                ".erasesize = 0x%.8x (%uKiB), "
                                ".numblocks = %d }\n",
                                i, (long long)mtd->eraseregions[i].offset,
                                mtd->eraseregions[i].erasesize,
                                mtd->eraseregions[i].erasesize / 1024,
                                mtd->eraseregions[i].numblocks);
        return 0;
}
EXPORT_SYMBOL_GPL(spi_nor_scan);

static int spi_nor_probe(struct spi_mem *spimem)
{
        struct spi_device *spi = spimem->spi;
        struct flash_platform_data *data = dev_get_platdata(&spi->dev);
        struct spi_nor *nor;
        /*
         * Enable all caps by default. The core will mask them after
         * checking what's really supported using spi_mem_supports_op().
         */
        const struct spi_nor_hwcaps hwcaps = { .mask = SNOR_HWCAPS_ALL };
        char *flash_name;
        int ret;

        nor = devm_kzalloc(&spi->dev, sizeof(*nor), GFP_KERNEL);
        if (!nor)
                return -ENOMEM;

        nor->spimem = spimem;
        nor->dev = &spi->dev;
        spi_nor_set_flash_node(nor, spi->dev.of_node);

        spi_mem_set_drvdata(spimem, nor);

        if (data && data->name)
                nor->mtd.name = data->name;

        if (!nor->mtd.name)
                nor->mtd.name = spi_mem_get_name(spimem);

        /*
         * For some (historical?) reason many platforms provide two different
         * names in flash_platform_data: "name" and "type". Quite often name is
         * set to "m25p80" and then "type" provides a real chip name.
         * If that's the case, respect "type" and ignore a "name".
         */
        if (data && data->type)
                flash_name = data->type;
        else if (!strcmp(spi->modalias, "spi-nor"))
                flash_name = NULL; /* auto-detect */
        else
                flash_name = spi->modalias;

        ret = spi_nor_scan(nor, flash_name, &hwcaps);
        if (ret)
                return ret;

        /*
         * None of the existing parts have > 512B pages, but let's play safe
         * and add this logic so that if anyone ever adds support for such
         * a NOR we don't end up with buffer overflows.
         */
        if (nor->page_size > PAGE_SIZE) {
                nor->bouncebuf_size = nor->page_size;
                devm_kfree(nor->dev, nor->bouncebuf);
                nor->bouncebuf = devm_kmalloc(nor->dev,
                                              nor->bouncebuf_size,
                                              GFP_KERNEL);
                if (!nor->bouncebuf)
                        return -ENOMEM;
        }

        return mtd_device_register(&nor->mtd, data ? data->parts : NULL,
                                   data ? data->nr_parts : 0);
}

static int spi_nor_remove(struct spi_mem *spimem)
{
        struct spi_nor *nor = spi_mem_get_drvdata(spimem);

        spi_nor_restore(nor);

        /* Clean up MTD stuff. */
        return mtd_device_unregister(&nor->mtd);
}

static void spi_nor_shutdown(struct spi_mem *spimem)
{
        struct spi_nor *nor = spi_mem_get_drvdata(spimem);

        spi_nor_restore(nor);
}

/*
 * Do NOT add to this array without reading the following:
 *
 * Historically, many flash devices are bound to this driver by their name. But
 * since most of these flash are compatible to some extent, and their
 * differences can often be differentiated by the JEDEC read-ID command, we
 * encourage new users to add support to the spi-nor library, and simply bind
 * against a generic string here (e.g., "jedec,spi-nor").
 *
 * Many flash names are kept here in this list (as well as in spi-nor.c) to
 * keep them available as module aliases for existing platforms.
 */
static const struct spi_device_id spi_nor_dev_ids[] = {
        /*
         * Allow non-DT platform devices to bind to the "spi-nor" modalias, and
         * hack around the fact that the SPI core does not provide uevent
         * matching for .of_match_table
         */
        {"spi-nor"},

        /*
         * Entries not used in DTs that should be safe to drop after replacing
         * them with "spi-nor" in platform data.
         */
        {"s25sl064a"},  {"w25x16"},     {"m25p10"},     {"m25px64"},

        /*
         * Entries that were used in DTs without "jedec,spi-nor" fallback and
         * should be kept for backward compatibility.
         */
        {"at25df321a"}, {"at25df641"},  {"at26df081a"},
        {"mx25l4005a"}, {"mx25l1606e"}, {"mx25l6405d"}, {"mx25l12805d"},
        {"mx25l25635e"},{"mx66l51235l"},
        {"n25q064"},    {"n25q128a11"}, {"n25q128a13"}, {"n25q512a"},
        {"s25fl256s1"}, {"s25fl512s"},  {"s25sl12801"}, {"s25fl008k"},
        {"s25fl064k"},
        {"sst25vf040b"},{"sst25vf016b"},{"sst25vf032b"},{"sst25wf040"},
        {"m25p40"},     {"m25p80"},     {"m25p16"},     {"m25p32"},
        {"m25p64"},     {"m25p128"},
        {"w25x80"},     {"w25x32"},     {"w25q32"},     {"w25q32dw"},
        {"w25q80bl"},   {"w25q128"},    {"w25q256"},

        /* Flashes that can't be detected using JEDEC */
        {"m25p05-nonjedec"},    {"m25p10-nonjedec"},    {"m25p20-nonjedec"},
        {"m25p40-nonjedec"},    {"m25p80-nonjedec"},    {"m25p16-nonjedec"},
        {"m25p32-nonjedec"},    {"m25p64-nonjedec"},    {"m25p128-nonjedec"},

        /* Everspin MRAMs (non-JEDEC) */
        { "mr25h128" }, /* 128 Kib, 40 MHz */
        { "mr25h256" }, /* 256 Kib, 40 MHz */
        { "mr25h10" },  /*   1 Mib, 40 MHz */
        { "mr25h40" },  /*   4 Mib, 40 MHz */

        { },
};
MODULE_DEVICE_TABLE(spi, spi_nor_dev_ids);

static const struct of_device_id spi_nor_of_table[] = {
        /*
         * Generic compatibility for SPI NOR that can be identified by the
         * JEDEC READ ID opcode (0x9F). Use this, if possible.
         */
        { .compatible = "jedec,spi-nor" },
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, spi_nor_of_table);

/*
 * REVISIT: many of these chips have deep power-down modes, which
 * should clearly be entered on suspend() to minimize power use.
 * And also when they're otherwise idle...
 */
static struct spi_mem_driver spi_nor_driver = {
        .spidrv = {
                .driver = {
                        .name = "spi-nor",
                        .of_match_table = spi_nor_of_table,
                },
                .id_table = spi_nor_dev_ids,
        },
        .probe = spi_nor_probe,
        .remove = spi_nor_remove,
        .shutdown = spi_nor_shutdown,
};
module_spi_mem_driver(spi_nor_driver);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Huang Shijie <shijie8@gmail.com>");
MODULE_AUTHOR("Mike Lavender");
MODULE_DESCRIPTION("framework for SPI NOR");