mtd: spi-nor-core: Add support for DTR protocol

[platform/kernel/u-boot.git] / drivers / mtd / spi / spi-nor-core.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.
 *
 * Synced from Linux v4.19
 */

#include <common.h>
#include <log.h>
#include <watchdog.h>
#include <dm.h>
#include <dm/device_compat.h>
#include <dm/devres.h>
#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/log2.h>
#include <linux/math64.h>
#include <linux/sizes.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/spi-nor.h>
#include <spi-mem.h>
#include <spi.h>

#include "sf_internal.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 HZ                                      CONFIG_SYS_HZ

#define DEFAULT_READY_WAIT_JIFFIES              (40UL * HZ)

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_SST_ID             0x01bf  /* Manufacturer specific Table */

#define SFDP_SIGNATURE          0x50444653U
#define SFDP_JESD216_MAJOR      1
#define SFDP_JESD216_MINOR      0
#define SFDP_JESD216A_MINOR     5
#define SFDP_JESD216B_MINOR     6

struct sfdp_header {
        u32             signature; /* Ox50444653U <=> "SFDP" */
        u8              minor;
        u8              major;
        u8              nph; /* 0-base number of parameter headers */
        u8              unused;

        /* Basic Flash Parameter Table. */
        struct sfdp_parameter_header    bfpt_header;
};

/* Basic Flash Parameter Table */

/*
 * JESD216 rev B defines a Basic Flash Parameter Table of 16 DWORDs.
 * They are indexed from 1 but C arrays are indexed from 0.
 */
#define BFPT_DWORD(i)           ((i) - 1)
#define BFPT_DWORD_MAX          16

/* The first version of JESB216 defined only 9 DWORDs. */
#define BFPT_DWORD_MAX_JESD216                  9

/* 1st DWORD. */
#define BFPT_DWORD1_FAST_READ_1_1_2             BIT(16)
#define BFPT_DWORD1_ADDRESS_BYTES_MASK          GENMASK(18, 17)
#define BFPT_DWORD1_ADDRESS_BYTES_3_ONLY        (0x0UL << 17)
#define BFPT_DWORD1_ADDRESS_BYTES_3_OR_4        (0x1UL << 17)
#define BFPT_DWORD1_ADDRESS_BYTES_4_ONLY        (0x2UL << 17)
#define BFPT_DWORD1_DTR                         BIT(19)
#define BFPT_DWORD1_FAST_READ_1_2_2             BIT(20)
#define BFPT_DWORD1_FAST_READ_1_4_4             BIT(21)
#define BFPT_DWORD1_FAST_READ_1_1_4             BIT(22)

/* 5th DWORD. */
#define BFPT_DWORD5_FAST_READ_2_2_2             BIT(0)
#define BFPT_DWORD5_FAST_READ_4_4_4             BIT(4)

/* 11th DWORD. */
#define BFPT_DWORD11_PAGE_SIZE_SHIFT            4
#define BFPT_DWORD11_PAGE_SIZE_MASK             GENMASK(7, 4)

/* 15th DWORD. */

/*
 * (from JESD216 rev B)
 * Quad Enable Requirements (QER):
 * - 000b: Device does not have a QE bit. Device detects 1-1-4 and 1-4-4
 *         reads based on instruction. DQ3/HOLD# functions are hold during
 *         instruction phase.
 * - 001b: QE is bit 1 of status register 2. It is set via Write Status with
 *         two data bytes where bit 1 of the second byte is one.
 *         [...]
 *         Writing only one byte to the status register has the side-effect of
 *         clearing status register 2, including the QE bit. The 100b code is
 *         used if writing one byte to the status register does not modify
 *         status register 2.
 * - 010b: QE is bit 6 of status register 1. It is set via Write Status with
 *         one data byte where bit 6 is one.
 *         [...]
 * - 011b: QE is bit 7 of status register 2. It is set via Write status
 *         register 2 instruction 3Eh with one data byte where bit 7 is one.
 *         [...]
 *         The status register 2 is read using instruction 3Fh.
 * - 100b: QE is bit 1 of status register 2. It is set via Write Status with
 *         two data bytes where bit 1 of the second byte is one.
 *         [...]
 *         In contrast to the 001b code, writing one byte to the status
 *         register does not modify status register 2.
 * - 101b: QE is bit 1 of status register 2. Status register 1 is read using
 *         Read Status instruction 05h. Status register2 is read using
 *         instruction 35h. QE is set via Writ Status instruction 01h with
 *         two data bytes where bit 1 of the second byte is one.
 *         [...]
 */
#define BFPT_DWORD15_QER_MASK                   GENMASK(22, 20)
#define BFPT_DWORD15_QER_NONE                   (0x0UL << 20) /* Micron */
#define BFPT_DWORD15_QER_SR2_BIT1_BUGGY         (0x1UL << 20)
#define BFPT_DWORD15_QER_SR1_BIT6               (0x2UL << 20) /* Macronix */
#define BFPT_DWORD15_QER_SR2_BIT7               (0x3UL << 20)
#define BFPT_DWORD15_QER_SR2_BIT1_NO_RD         (0x4UL << 20)
#define BFPT_DWORD15_QER_SR2_BIT1               (0x5UL << 20) /* Spansion */

struct sfdp_bfpt {
        u32     dwords[BFPT_DWORD_MAX];
};

/**
 * 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 spi_nor_flash_parameter *params);
};

/**
 * spi_nor_get_cmd_ext() - Get the command opcode extension based on the
 *                         extension type.
 * @nor:                pointer to a 'struct spi_nor'
 * @op:                 pointer to the 'struct spi_mem_op' whose properties
 *                      need to be initialized.
 *
 * Right now, only "repeat" and "invert" are supported.
 *
 * Return: The opcode extension.
 */
static u8 spi_nor_get_cmd_ext(const struct spi_nor *nor,
                              const struct spi_mem_op *op)
{
        switch (nor->cmd_ext_type) {
        case SPI_NOR_EXT_INVERT:
                return ~op->cmd.opcode;

        case SPI_NOR_EXT_REPEAT:
                return op->cmd.opcode;

        default:
                dev_dbg(nor->dev, "Unknown command extension type\n");
                return 0;
        }
}

/**
 * spi_nor_setup_op() - Set up common properties of a spi-mem op.
 * @nor:                pointer to a 'struct spi_nor'
 * @op:                 pointer to the 'struct spi_mem_op' whose properties
 *                      need to be initialized.
 * @proto:              the protocol from which the properties need to be set.
 */
static void spi_nor_setup_op(const struct spi_nor *nor,
                             struct spi_mem_op *op,
                             const enum spi_nor_protocol proto)
{
        u8 ext;

        op->cmd.buswidth = spi_nor_get_protocol_inst_nbits(proto);

        if (op->addr.nbytes)
                op->addr.buswidth = spi_nor_get_protocol_addr_nbits(proto);

        if (op->dummy.nbytes)
                op->dummy.buswidth = spi_nor_get_protocol_addr_nbits(proto);

        if (op->data.nbytes)
                op->data.buswidth = spi_nor_get_protocol_data_nbits(proto);

        if (spi_nor_protocol_is_dtr(proto)) {
                /*
                 * spi-mem supports mixed DTR modes, but right now we can only
                 * have all phases either DTR or STR. IOW, spi-mem can have
                 * something like 4S-4D-4D, but spi-nor can't. So, set all 4
                 * phases to either DTR or STR.
                 */
                op->cmd.dtr = op->addr.dtr = op->dummy.dtr =
                        op->data.dtr = true;

                /* 2 bytes per clock cycle in DTR mode. */
                op->dummy.nbytes *= 2;

                ext = spi_nor_get_cmd_ext(nor, op);
                op->cmd.opcode = (op->cmd.opcode << 8) | ext;
                op->cmd.nbytes = 2;
        }
}

static int spi_nor_read_write_reg(struct spi_nor *nor, struct spi_mem_op
                *op, void *buf)
{
        if (op->data.dir == SPI_MEM_DATA_IN)
                op->data.buf.in = buf;
        else
                op->data.buf.out = buf;
        return spi_mem_exec_op(nor->spi, op);
}

static int spi_nor_read_reg(struct spi_nor *nor, u8 code, u8 *val, int len)
{
        struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(code, 0),
                                          SPI_MEM_OP_NO_ADDR,
                                          SPI_MEM_OP_NO_DUMMY,
                                          SPI_MEM_OP_DATA_IN(len, NULL, 0));
        int ret;

        spi_nor_setup_op(nor, &op, nor->reg_proto);

        ret = spi_nor_read_write_reg(nor, &op, val);
        if (ret < 0)
                dev_dbg(nor->dev, "error %d reading %x\n", ret, code);

        return ret;
}

static int spi_nor_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
{
        struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(opcode, 0),
                                          SPI_MEM_OP_NO_ADDR,
                                          SPI_MEM_OP_NO_DUMMY,
                                          SPI_MEM_OP_DATA_OUT(len, NULL, 0));

        spi_nor_setup_op(nor, &op, nor->reg_proto);

        if (len == 0)
                op.data.dir = SPI_MEM_NO_DATA;

        return spi_nor_read_write_reg(nor, &op, buf);
}

static ssize_t spi_nor_read_data(struct spi_nor *nor, loff_t from, size_t len,
                                 u_char *buf)
{
        struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(nor->read_opcode, 0),
                                   SPI_MEM_OP_ADDR(nor->addr_width, from, 0),
                                   SPI_MEM_OP_DUMMY(nor->read_dummy, 0),
                                   SPI_MEM_OP_DATA_IN(len, buf, 0));
        size_t remaining = len;
        int ret;

        spi_nor_setup_op(nor, &op, nor->read_proto);

        /* convert the dummy cycles to the number of bytes */
        op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
        if (spi_nor_protocol_is_dtr(nor->read_proto))
                op.dummy.nbytes *= 2;

        while (remaining) {
                op.data.nbytes = remaining < UINT_MAX ? remaining : UINT_MAX;
                ret = spi_mem_adjust_op_size(nor->spi, &op);
                if (ret)
                        return ret;

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

                op.addr.val += op.data.nbytes;
                remaining -= op.data.nbytes;
                op.data.buf.in += op.data.nbytes;
        }

        return len;
}

static ssize_t spi_nor_write_data(struct spi_nor *nor, loff_t to, size_t len,
                                  const u_char *buf)
{
        struct spi_mem_op op =
                        SPI_MEM_OP(SPI_MEM_OP_CMD(nor->program_opcode, 0),
                                   SPI_MEM_OP_ADDR(nor->addr_width, to, 0),
                                   SPI_MEM_OP_NO_DUMMY,
                                   SPI_MEM_OP_DATA_OUT(len, buf, 0));
        int ret;

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

        spi_nor_setup_op(nor, &op, nor->write_proto);

        ret = spi_mem_adjust_op_size(nor->spi, &op);
        if (ret)
                return ret;
        op.data.nbytes = len < op.data.nbytes ? len : op.data.nbytes;

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

        return op.data.nbytes;
}

/*
 * Read the status register, returning its value in the location
 * Return the status register value.
 * Returns negative if error occurred.
 */
static int read_sr(struct spi_nor *nor)
{
        int ret;
        u8 val;

        ret = nor->read_reg(nor, SPINOR_OP_RDSR, &val, 1);
        if (ret < 0) {
                pr_debug("error %d reading SR\n", (int)ret);
                return ret;
        }

        return val;
}

/*
 * Read the flag status register, returning its value in the location
 * Return the status register value.
 * Returns negative if error occurred.
 */
static int read_fsr(struct spi_nor *nor)
{
        int ret;
        u8 val;

        ret = nor->read_reg(nor, SPINOR_OP_RDFSR, &val, 1);
        if (ret < 0) {
                pr_debug("error %d reading FSR\n", ret);
                return ret;
        }

        return val;
}

/*
 * Read configuration register, returning its value in the
 * location. Return the configuration register value.
 * Returns negative if error occurred.
 */
#if defined(CONFIG_SPI_FLASH_SPANSION) || defined(CONFIG_SPI_FLASH_WINBOND)
static int read_cr(struct spi_nor *nor)
{
        int ret;
        u8 val;

        ret = nor->read_reg(nor, SPINOR_OP_RDCR, &val, 1);
        if (ret < 0) {
                dev_dbg(nor->dev, "error %d reading CR\n", ret);
                return ret;
        }

        return val;
}
#endif

/*
 * Write status register 1 byte
 * Returns negative if error occurred.
 */
static int write_sr(struct spi_nor *nor, u8 val)
{
        nor->cmd_buf[0] = val;
        return nor->write_reg(nor, SPINOR_OP_WRSR, nor->cmd_buf, 1);
}

/*
 * Set write enable latch with Write Enable command.
 * Returns negative if error occurred.
 */
static int write_enable(struct spi_nor *nor)
{
        return nor->write_reg(nor, SPINOR_OP_WREN, NULL, 0);
}

/*
 * Send write disable instruction to the chip.
 */
static int write_disable(struct spi_nor *nor)
{
        return nor->write_reg(nor, SPINOR_OP_WRDI, NULL, 0);
}

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

#ifndef CONFIG_SPI_FLASH_BAR
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,
                                      const struct flash_info *info)
{
        /* Do some manufacturer fixups first */
        switch (JEDEC_MFR(info)) {
        case SNOR_MFR_SPANSION:
                /* No small sector erase for 4-byte command set */
                nor->erase_opcode = SPINOR_OP_SE;
                nor->mtd.erasesize = info->sector_size;
                break;

        default:
                break;
        }

        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);
}
#endif /* !CONFIG_SPI_FLASH_BAR */

/* Enable/disable 4-byte addressing mode. */
static int set_4byte(struct spi_nor *nor, const struct flash_info *info,
                     int enable)
{
        int status;
        bool need_wren = false;
        u8 cmd;

        switch (JEDEC_MFR(info)) {
        case SNOR_MFR_ST:
        case SNOR_MFR_MICRON:
                /* Some Micron need WREN command; all will accept it */
                need_wren = true;
        case SNOR_MFR_ISSI:
        case SNOR_MFR_MACRONIX:
        case SNOR_MFR_WINBOND:
                if (need_wren)
                        write_enable(nor);

                cmd = enable ? SPINOR_OP_EN4B : SPINOR_OP_EX4B;
                status = nor->write_reg(nor, cmd, NULL, 0);
                if (need_wren)
                        write_disable(nor);

                if (!status && !enable &&
                    JEDEC_MFR(info) == SNOR_MFR_WINBOND) {
                        /*
                         * 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.
                         */
                        write_enable(nor);
                        nor->cmd_buf[0] = 0;
                        nor->write_reg(nor, SPINOR_OP_WREAR, nor->cmd_buf, 1);
                        write_disable(nor);
                }

                return status;
        default:
                /* Spansion style */
                nor->cmd_buf[0] = enable << 7;
                return nor->write_reg(nor, SPINOR_OP_BRWR, nor->cmd_buf, 1);
        }
}

static int spi_nor_sr_ready(struct spi_nor *nor)
{
        int sr = read_sr(nor);

        if (sr < 0)
                return sr;

        if (nor->flags & SNOR_F_USE_CLSR && sr & (SR_E_ERR | SR_P_ERR)) {
                if (sr & SR_E_ERR)
                        dev_dbg(nor->dev, "Erase Error occurred\n");
                else
                        dev_dbg(nor->dev, "Programming Error occurred\n");

                nor->write_reg(nor, SPINOR_OP_CLSR, NULL, 0);
                return -EIO;
        }

        return !(sr & SR_WIP);
}

static int spi_nor_fsr_ready(struct spi_nor *nor)
{
        int fsr = read_fsr(nor);

        if (fsr < 0)
                return fsr;

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

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

                nor->write_reg(nor, SPINOR_OP_CLFSR, NULL, 0);
                return -EIO;
        }

        return fsr & FSR_READY;
}

static int spi_nor_ready(struct spi_nor *nor)
{
        int sr, fsr;

        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;
}

/*
 * Service routine to read status register until ready, or timeout occurs.
 * Returns non-zero if error.
 */
static int spi_nor_wait_till_ready_with_timeout(struct spi_nor *nor,
                                                unsigned long timeout)
{
        unsigned long timebase;
        int ret;

        timebase = get_timer(0);

        while (get_timer(timebase) < timeout) {
                ret = spi_nor_ready(nor);
                if (ret < 0)
                        return ret;
                if (ret)
                        return 0;
        }

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

        return -ETIMEDOUT;
}

static int spi_nor_wait_till_ready(struct spi_nor *nor)
{
        return spi_nor_wait_till_ready_with_timeout(nor,
                                                    DEFAULT_READY_WAIT_JIFFIES);
}

#ifdef CONFIG_SPI_FLASH_BAR
/*
 * This "clean_bar" is necessary in a situation when one was accessing
 * spi flash memory > 16 MiB by using Bank Address Register's BA24 bit.
 *
 * After it the BA24 bit shall be cleared to allow access to correct
 * memory region after SW reset (by calling "reset" command).
 *
 * Otherwise, the BA24 bit may be left set and then after reset, the
 * ROM would read/write/erase SPL from 16 MiB * bank_sel address.
 */
static int clean_bar(struct spi_nor *nor)
{
        u8 cmd, bank_sel = 0;

        if (nor->bank_curr == 0)
                return 0;
        cmd = nor->bank_write_cmd;
        nor->bank_curr = 0;
        write_enable(nor);

        return nor->write_reg(nor, cmd, &bank_sel, 1);
}

static int write_bar(struct spi_nor *nor, u32 offset)
{
        u8 cmd, bank_sel;
        int ret;

        bank_sel = offset / SZ_16M;
        if (bank_sel == nor->bank_curr)
                goto bar_end;

        cmd = nor->bank_write_cmd;
        write_enable(nor);
        ret = nor->write_reg(nor, cmd, &bank_sel, 1);
        if (ret < 0) {
                debug("SF: fail to write bank register\n");
                return ret;
        }

bar_end:
        nor->bank_curr = bank_sel;
        return nor->bank_curr;
}

static int read_bar(struct spi_nor *nor, const struct flash_info *info)
{
        u8 curr_bank = 0;
        int ret;

        switch (JEDEC_MFR(info)) {
        case SNOR_MFR_SPANSION:
                nor->bank_read_cmd = SPINOR_OP_BRRD;
                nor->bank_write_cmd = SPINOR_OP_BRWR;
                break;
        default:
                nor->bank_read_cmd = SPINOR_OP_RDEAR;
                nor->bank_write_cmd = SPINOR_OP_WREAR;
        }

        ret = nor->read_reg(nor, nor->bank_read_cmd,
                                    &curr_bank, 1);
        if (ret) {
                debug("SF: fail to read bank addr register\n");
                return ret;
        }
        nor->bank_curr = curr_bank;

        return 0;
}
#endif

/*
 * Initiate the erasure of a single sector
 */
static int spi_nor_erase_sector(struct spi_nor *nor, u32 addr)
{
        struct spi_mem_op op =
                SPI_MEM_OP(SPI_MEM_OP_CMD(nor->erase_opcode, 0),
                           SPI_MEM_OP_ADDR(nor->addr_width, addr, 0),
                           SPI_MEM_OP_NO_DUMMY,
                           SPI_MEM_OP_NO_DATA);

        spi_nor_setup_op(nor, &op, nor->write_proto);

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

        /*
         * Default implementation, if driver doesn't have a specialized HW
         * control
         */
        return spi_mem_exec_op(nor->spi, &op);
}

/*
 * 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, rem;
        int ret;

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

        if (!instr->len)
                return 0;

        div_u64_rem(instr->len, mtd->erasesize, &rem);
        if (rem)
                return -EINVAL;

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

        while (len) {
                WATCHDOG_RESET();
#ifdef CONFIG_SPI_FLASH_BAR
                ret = write_bar(nor, addr);
                if (ret < 0)
                        return ret;
#endif
                write_enable(nor);

                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_err:
#ifdef CONFIG_SPI_FLASH_BAR
        ret = clean_bar(nor);
#endif
        write_disable(nor);

        return ret;
}

#if defined(CONFIG_SPI_FLASH_STMICRO) || defined(CONFIG_SPI_FLASH_SST)
/* Write status register and ensure bits in mask match written values */
static int write_sr_and_check(struct spi_nor *nor, u8 status_new, u8 mask)
{
        int ret;

        write_enable(nor);
        ret = write_sr(nor, status_new);
        if (ret)
                return ret;

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

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

        return ((ret & mask) != (status_new & mask)) ? -EIO : 0;
}

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, u64 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 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;

        status_old = read_sr(nor);
        if (status_old < 0)
                return status_old;

        /* 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 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 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;

        status_old = read_sr(nor);
        if (status_old < 0)
                return status_old;

        /* 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 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 status;

        status = read_sr(nor);
        if (status < 0)
                return status;

        return stm_is_locked_sr(nor, ofs, len, status);
}
#endif /* CONFIG_SPI_FLASH_STMICRO */

static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
{
        int                     tmp;
        u8                      id[SPI_NOR_MAX_ID_LEN];
        const struct flash_info *info;

        tmp = nor->read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
        if (tmp < 0) {
                dev_dbg(nor->dev, "error %d reading JEDEC ID\n", tmp);
                return ERR_PTR(tmp);
        }

        info = spi_nor_ids;
        for (; info->name; info++) {
                if (info->id_len) {
                        if (!memcmp(info->id, id, info->id_len))
                                return info;
                }
        }

        dev_err(nor->dev, "unrecognized JEDEC id bytes: %02x, %02x, %02x\n",
                id[0], id[1], id[2]);
        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);
        int ret;

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

        while (len) {
                loff_t addr = from;
                size_t read_len = len;

#ifdef CONFIG_SPI_FLASH_BAR
                u32 remain_len;

                ret = write_bar(nor, addr);
                if (ret < 0)
                        return log_ret(ret);
                remain_len = (SZ_16M * (nor->bank_curr + 1)) - addr;

                if (len < remain_len)
                        read_len = len;
                else
                        read_len = remain_len;
#endif

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

                *retlen += ret;
                buf += ret;
                from += ret;
                len -= ret;
        }
        ret = 0;

read_err:
#ifdef CONFIG_SPI_FLASH_BAR
        ret = clean_bar(nor);
#endif
        return ret;
}

#ifdef CONFIG_SPI_FLASH_SST
/*
 * sst26 flash series has its own block protection implementation:
 * 4x   - 8  KByte blocks - read & write protection bits - upper addresses
 * 1x   - 32 KByte blocks - write protection bits
 * rest - 64 KByte blocks - write protection bits
 * 1x   - 32 KByte blocks - write protection bits
 * 4x   - 8  KByte blocks - read & write protection bits - lower addresses
 *
 * We'll support only per 64k lock/unlock so lower and upper 64 KByte region
 * will be treated as single block.
 */
#define SST26_BPR_8K_NUM                4
#define SST26_MAX_BPR_REG_LEN           (18 + 1)
#define SST26_BOUND_REG_SIZE            ((32 + SST26_BPR_8K_NUM * 8) * SZ_1K)

enum lock_ctl {
        SST26_CTL_LOCK,
        SST26_CTL_UNLOCK,
        SST26_CTL_CHECK
};

static bool sst26_process_bpr(u32 bpr_size, u8 *cmd, u32 bit, enum lock_ctl ctl)
{
        switch (ctl) {
        case SST26_CTL_LOCK:
                cmd[bpr_size - (bit / 8) - 1] |= BIT(bit % 8);
                break;
        case SST26_CTL_UNLOCK:
                cmd[bpr_size - (bit / 8) - 1] &= ~BIT(bit % 8);
                break;
        case SST26_CTL_CHECK:
                return !!(cmd[bpr_size - (bit / 8) - 1] & BIT(bit % 8));
        }

        return false;
}

/*
 * Lock, unlock or check lock status of the flash region of the flash (depending
 * on the lock_ctl value)
 */
static int sst26_lock_ctl(struct spi_nor *nor, loff_t ofs, uint64_t len, enum lock_ctl ctl)
{
        struct mtd_info *mtd = &nor->mtd;
        u32 i, bpr_ptr, rptr_64k, lptr_64k, bpr_size;
        bool lower_64k = false, upper_64k = false;
        u8 bpr_buff[SST26_MAX_BPR_REG_LEN] = {};
        int ret;

        /* Check length and offset for 64k alignment */
        if ((ofs & (SZ_64K - 1)) || (len & (SZ_64K - 1))) {
                dev_err(nor->dev, "length or offset is not 64KiB allighned\n");
                return -EINVAL;
        }

        if (ofs + len > mtd->size) {
                dev_err(nor->dev, "range is more than device size: %#llx + %#llx > %#llx\n",
                        ofs, len, mtd->size);
                return -EINVAL;
        }

        /* SST26 family has only 16 Mbit, 32 Mbit and 64 Mbit IC */
        if (mtd->size != SZ_2M &&
            mtd->size != SZ_4M &&
            mtd->size != SZ_8M)
                return -EINVAL;

        bpr_size = 2 + (mtd->size / SZ_64K / 8);

        ret = nor->read_reg(nor, SPINOR_OP_READ_BPR, bpr_buff, bpr_size);
        if (ret < 0) {
                dev_err(nor->dev, "fail to read block-protection register\n");
                return ret;
        }

        rptr_64k = min_t(u32, ofs + len, mtd->size - SST26_BOUND_REG_SIZE);
        lptr_64k = max_t(u32, ofs, SST26_BOUND_REG_SIZE);

        upper_64k = ((ofs + len) > (mtd->size - SST26_BOUND_REG_SIZE));
        lower_64k = (ofs < SST26_BOUND_REG_SIZE);

        /* Lower bits in block-protection register are about 64k region */
        bpr_ptr = lptr_64k / SZ_64K - 1;

        /* Process 64K blocks region */
        while (lptr_64k < rptr_64k) {
                if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
                        return EACCES;

                bpr_ptr++;
                lptr_64k += SZ_64K;
        }

        /* 32K and 8K region bits in BPR are after 64k region bits */
        bpr_ptr = (mtd->size - 2 * SST26_BOUND_REG_SIZE) / SZ_64K;

        /* Process lower 32K block region */
        if (lower_64k)
                if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
                        return EACCES;

        bpr_ptr++;

        /* Process upper 32K block region */
        if (upper_64k)
                if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
                        return EACCES;

        bpr_ptr++;

        /* Process lower 8K block regions */
        for (i = 0; i < SST26_BPR_8K_NUM; i++) {
                if (lower_64k)
                        if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
                                return EACCES;

                /* In 8K area BPR has both read and write protection bits */
                bpr_ptr += 2;
        }

        /* Process upper 8K block regions */
        for (i = 0; i < SST26_BPR_8K_NUM; i++) {
                if (upper_64k)
                        if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
                                return EACCES;

                /* In 8K area BPR has both read and write protection bits */
                bpr_ptr += 2;
        }

        /* If we check region status we don't need to write BPR back */
        if (ctl == SST26_CTL_CHECK)
                return 0;

        ret = nor->write_reg(nor, SPINOR_OP_WRITE_BPR, bpr_buff, bpr_size);
        if (ret < 0) {
                dev_err(nor->dev, "fail to write block-protection register\n");
                return ret;
        }

        return 0;
}

static int sst26_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
        return sst26_lock_ctl(nor, ofs, len, SST26_CTL_UNLOCK);
}

static int sst26_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
        return sst26_lock_ctl(nor, ofs, len, SST26_CTL_LOCK);
}

/*
 * Returns EACCES (positive value) if region is locked, 0 if region is unlocked,
 * and negative on errors.
 */
static int sst26_is_locked(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
        /*
         * is_locked function is used for check before reading or erasing flash
         * region, so offset and length might be not 64k allighned, so adjust
         * them to be 64k allighned as sst26_lock_ctl works only with 64k
         * allighned regions.
         */
        ofs -= ofs & (SZ_64K - 1);
        len = len & (SZ_64K - 1) ? (len & ~(SZ_64K - 1)) + SZ_64K : len;

        return sst26_lock_ctl(nor, ofs, len, SST26_CTL_CHECK);
}

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

        for (actual = 0; actual < len; actual++) {
                nor->program_opcode = SPINOR_OP_BP;

                write_enable(nor);
                /* write one byte. */
                ret = nor->write(nor, to, 1, buf + actual);
                if (ret < 0)
                        goto sst_write_err;
                ret = spi_nor_wait_till_ready(nor);
                if (ret)
                        goto sst_write_err;
                to++;
        }

sst_write_err:
        write_disable(nor);
        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);
        struct spi_slave *spi = nor->spi;
        size_t actual;
        int ret;

        dev_dbg(nor->dev, "to 0x%08x, len %zd\n", (u32)to, len);
        if (spi->mode & SPI_TX_BYTE)
                return sst_write_byteprogram(nor, to, len, retlen, buf);

        write_enable(nor);

        nor->sst_write_second = false;

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

                /* write one byte. */
                ret = nor->write(nor, to, 1, buf);
                if (ret < 0)
                        goto sst_write_err;
                ret = spi_nor_wait_till_ready(nor);
                if (ret)
                        goto sst_write_err;
        }
        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 = nor->write(nor, to, 2, buf + actual);
                if (ret < 0)
                        goto sst_write_err;
                ret = spi_nor_wait_till_ready(nor);
                if (ret)
                        goto sst_write_err;
                to += 2;
                nor->sst_write_second = true;
        }
        nor->sst_write_second = false;

        write_disable(nor);
        ret = spi_nor_wait_till_ready(nor);
        if (ret)
                goto sst_write_err;

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

                nor->program_opcode = SPINOR_OP_BP;
                ret = nor->write(nor, to, 1, buf + actual);
                if (ret < 0)
                        goto sst_write_err;
                ret = spi_nor_wait_till_ready(nor);
                if (ret)
                        goto sst_write_err;
                write_disable(nor);
                actual += 1;
        }
sst_write_err:
        *retlen += actual;
        return ret;
}
#endif
/*
 * 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;

#ifdef CONFIG_SPI_FLASH_SST
        /* sst nor chips use AAI word program */
        if (nor->info->flags & SST_WRITE)
                return sst_write(mtd, to, len, retlen, buf);
#endif

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

        if (!len)
                return 0;

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

                /*
                 * 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).
                 */
                if (is_power_of_2(nor->page_size)) {
                        page_offset = addr & (nor->page_size - 1);
                } else {
                        u64 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);

#ifdef CONFIG_SPI_FLASH_BAR
                ret = write_bar(nor, addr);
                if (ret < 0)
                        return ret;
#endif
                write_enable(nor);
                ret = nor->write(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:
#ifdef CONFIG_SPI_FLASH_BAR
        ret = clean_bar(nor);
#endif
        return ret;
}

#if defined(CONFIG_SPI_FLASH_MACRONIX) || defined(CONFIG_SPI_FLASH_ISSI)
/**
 * macronix_quad_enable() - set QE bit in Status Register.
 * @nor:        pointer to a 'struct spi_nor'
 *
 * Set the Quad Enable (QE) bit in the Status Register.
 *
 * bit 6 of the Status Register is the QE bit for Macronix like QSPI memories.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int macronix_quad_enable(struct spi_nor *nor)
{
        int ret, val;

        val = read_sr(nor);
        if (val < 0)
                return val;
        if (val & SR_QUAD_EN_MX)
                return 0;

        write_enable(nor);

        write_sr(nor, val | SR_QUAD_EN_MX);

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

        ret = read_sr(nor);
        if (!(ret > 0 && (ret & SR_QUAD_EN_MX))) {
                dev_err(nor->dev, "Macronix Quad bit not set\n");
                return -EINVAL;
        }

        return 0;
}
#endif

#if defined(CONFIG_SPI_FLASH_SPANSION) || defined(CONFIG_SPI_FLASH_WINBOND)
/*
 * Write status Register and configuration register with 2 bytes
 * The first byte will be written to the status register, while the
 * second byte will be written to the configuration register.
 * Return negative if error occurred.
 */
static int write_sr_cr(struct spi_nor *nor, u8 *sr_cr)
{
        int ret;

        write_enable(nor);

        ret = nor->write_reg(nor, SPINOR_OP_WRSR, sr_cr, 2);
        if (ret < 0) {
                dev_dbg(nor->dev,
                        "error while writing configuration register\n");
                return -EINVAL;
        }

        ret = spi_nor_wait_till_ready(nor);
        if (ret) {
                dev_dbg(nor->dev,
                        "timeout while writing configuration register\n");
                return ret;
        }

        return 0;
}

/**
 * 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[2];
        int ret;

        /* Check current Quad Enable bit value. */
        ret = read_cr(nor);
        if (ret < 0) {
                dev_dbg(nor->dev,
                        "error while reading configuration register\n");
                return -EINVAL;
        }

        if (ret & CR_QUAD_EN_SPAN)
                return 0;

        sr_cr[1] = ret | CR_QUAD_EN_SPAN;

        /* Keep the current value of the Status Register. */
        ret = read_sr(nor);
        if (ret < 0) {
                dev_dbg(nor->dev, "error while reading status register\n");
                return -EINVAL;
        }
        sr_cr[0] = ret;

        ret = write_sr_cr(nor, sr_cr);
        if (ret)
                return ret;

        /* Read back and check it. */
        ret = read_cr(nor);
        if (!(ret > 0 && (ret & CR_QUAD_EN_SPAN))) {
                dev_dbg(nor->dev, "Spansion Quad bit not set\n");
                return -EINVAL;
        }

        return 0;
}

#if CONFIG_IS_ENABLED(SPI_FLASH_SFDP_SUPPORT)
/**
 * spansion_no_read_cr_quad_enable() - set QE bit in Configuration Register.
 * @nor:        pointer to a 'struct spi_nor'
 *
 * Set the Quad Enable (QE) bit in the Configuration Register.
 * This function should be used with QSPI memories not supporting the Read
 * Configuration Register (35h) instruction.
 *
 * bit 1 of the Configuration Register is the QE bit for Spansion like QSPI
 * memories.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spansion_no_read_cr_quad_enable(struct spi_nor *nor)
{
        u8 sr_cr[2];
        int ret;

        /* Keep the current value of the Status Register. */
        ret = read_sr(nor);
        if (ret < 0) {
                dev_dbg(nor->dev, "error while reading status register\n");
                return -EINVAL;
        }
        sr_cr[0] = ret;
        sr_cr[1] = CR_QUAD_EN_SPAN;

        return write_sr_cr(nor, sr_cr);
}

#endif /* CONFIG_SPI_FLASH_SFDP_SUPPORT */
#endif /* CONFIG_SPI_FLASH_SPANSION */

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;
}

#if CONFIG_IS_ENABLED(SPI_FLASH_SFDP_SUPPORT)
/*
 * Serial Flash Discoverable Parameters (SFDP) parsing.
 */

/**
 * spi_nor_read_sfdp() - read Serial Flash Discoverable Parameters.
 * @nor:        pointer to a 'struct spi_nor'
 * @addr:       offset in the SFDP area to start reading data from
 * @len:        number of bytes to read
 * @buf:        buffer where the SFDP data are copied into (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;

        while (len) {
                ret = nor->read(nor, addr, len, (u8 *)buf);
                if (!ret || ret > len) {
                        ret = -EIO;
                        goto read_err;
                }
                if (ret < 0)
                        goto read_err;

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

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

        return ret;
}

/* 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},
};

static int spi_nor_hwcaps_read2cmd(u32 hwcaps);

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->fixups && nor->fixups->post_bfpt)
                return nor->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 mtd_info *mtd = &nor->mtd;
        struct sfdp_bfpt bfpt;
        size_t len;
        int i, cmd, err;
        u32 addr;
        u16 half;

        /* JESD216 Basic Flash Parameter Table length is at least 9 DWORDs. */
        if (bfpt_header->length < BFPT_DWORD_MAX_JESD216)
                return -EINVAL;

        /* Read the Basic Flash Parameter Table. */
        len = min_t(size_t, sizeof(bfpt),
                    bfpt_header->length * sizeof(u32));
        addr = SFDP_PARAM_HEADER_PTP(bfpt_header);
        memset(&bfpt, 0, sizeof(bfpt));
        err = spi_nor_read_sfdp(nor,  addr, len, &bfpt);
        if (err < 0)
                return err;

        /* Fix endianness of the BFPT DWORDs. */
        for (i = 0; i < BFPT_DWORD_MAX; i++)
                bfpt.dwords[i] = le32_to_cpu(bfpt.dwords[i]);

        /* Number of address bytes. */
        switch (bfpt.dwords[BFPT_DWORD(1)] & BFPT_DWORD1_ADDRESS_BYTES_MASK) {
        case BFPT_DWORD1_ADDRESS_BYTES_3_ONLY:
                nor->addr_width = 3;
                break;

        case BFPT_DWORD1_ADDRESS_BYTES_4_ONLY:
                nor->addr_width = 4;
                break;

        default:
                break;
        }

        /* Flash Memory Density (in bits). */
        params->size = bfpt.dwords[BFPT_DWORD(2)];
        if (params->size & BIT(31)) {
                params->size &= ~BIT(31);

                /*
                 * 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. */
        for (i = 0; i < ARRAY_SIZE(sfdp_bfpt_erases); i++) {
                const struct sfdp_bfpt_erase *er = &sfdp_bfpt_erases[i];
                u32 erasesize;
                u8 opcode;

                half = bfpt.dwords[er->dword] >> er->shift;
                erasesize = half & 0xff;

                /* erasesize == 0 means this Erase Type is not supported. */
                if (!erasesize)
                        continue;

                erasesize = 1U << erasesize;
                opcode = (half >> 8) & 0xff;
#ifdef CONFIG_SPI_FLASH_USE_4K_SECTORS
                if (erasesize == SZ_4K) {
                        nor->erase_opcode = opcode;
                        mtd->erasesize = erasesize;
                        break;
                }
#endif
                if (!mtd->erasesize || mtd->erasesize < erasesize) {
                        nor->erase_opcode = opcode;
                        mtd->erasesize = erasesize;
                }
        }

        /* Stop here if not JESD216 rev A or later. */
        if (bfpt_header->length < BFPT_DWORD_MAX)
                return 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;
#if defined(CONFIG_SPI_FLASH_SPANSION) || defined(CONFIG_SPI_FLASH_WINBOND)
        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;
#endif
#if defined(CONFIG_SPI_FLASH_MACRONIX) || defined(CONFIG_SPI_FLASH_ISSI)
        case BFPT_DWORD15_QER_SR1_BIT6:
                params->quad_enable = macronix_quad_enable;
                break;
#endif
#if defined(CONFIG_SPI_FLASH_SPANSION) || defined(CONFIG_SPI_FLASH_WINBOND)
        case BFPT_DWORD15_QER_SR2_BIT1:
                params->quad_enable = spansion_read_cr_quad_enable;
                break;
#endif
        default:
                return -EINVAL;
        }

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

/**
 * spi_nor_parse_microchip_sfdp() - parse the Microchip manufacturer specific
 * SFDP table.
 * @nor:                pointer to a 'struct spi_nor'.
 * @param_header:       pointer to the SFDP parameter header.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int
spi_nor_parse_microchip_sfdp(struct spi_nor *nor,
                             const struct sfdp_parameter_header *param_header)
{
        size_t size;
        u32 addr;
        int ret;

        size = param_header->length * sizeof(u32);
        addr = SFDP_PARAM_HEADER_PTP(param_header);

        nor->manufacturer_sfdp = devm_kmalloc(nor->dev, size, GFP_KERNEL);
        if (!nor->manufacturer_sfdp)
                return -ENOMEM;

        ret = spi_nor_read_sfdp(nor, addr, size, nor->manufacturer_sfdp);

        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;
        size_t psize;
        int i, err;

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

        /* Check the SFDP header version. */
        if (le32_to_cpu(header.signature) != SFDP_SIGNATURE ||
            header.major != SFDP_JESD216_MAJOR)
                return -EINVAL;

        /*
         * Verify that the first and only mandatory parameter header is a
         * Basic Flash Parameter Table header as specified in JESD216.
         */
        bfpt_header = &header.bfpt_header;
        if (SFDP_PARAM_HEADER_ID(bfpt_header) != SFDP_BFPT_ID ||
            bfpt_header->major != SFDP_JESD216_MAJOR)
                return -EINVAL;

        /*
         * Allocate memory then read all parameter headers with a single
         * Read SFDP command. These parameter headers will actually be parsed
         * twice: a first time to get the latest revision of the basic flash
         * parameter table, then a second time to handle the supported optional
         * tables.
         * Hence we read the parameter headers once for all to reduce the
         * processing time. Also we use kmalloc() instead of devm_kmalloc()
         * because we don't need to keep these parameter headers: the allocated
         * memory is always released with kfree() before exiting this function.
         */
        if (header.nph) {
                psize = header.nph * sizeof(*param_headers);

                param_headers = kmalloc(psize, GFP_KERNEL);
                if (!param_headers)
                        return -ENOMEM;

                err = spi_nor_read_sfdp(nor, sizeof(header),
                                        psize, param_headers);
                if (err < 0) {
                        dev_err(nor->dev,
                                "failed to read SFDP parameter headers\n");
                        goto exit;
                }
        }

        /*
         * Check other parameter headers to get the latest revision of
         * the basic flash parameter table.
         */
        for (i = 0; i < header.nph; i++) {
                param_header = &param_headers[i];

                if (SFDP_PARAM_HEADER_ID(param_header) == SFDP_BFPT_ID &&
                    param_header->major == SFDP_JESD216_MAJOR &&
                    (param_header->minor > bfpt_header->minor ||
                     (param_header->minor == bfpt_header->minor &&
                      param_header->length > bfpt_header->length)))
                        bfpt_header = param_header;
        }

        err = spi_nor_parse_bfpt(nor, bfpt_header, params);
        if (err)
                goto exit;

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

                switch (SFDP_PARAM_HEADER_ID(param_header)) {
                case SFDP_SECTOR_MAP_ID:
                        dev_info(nor->dev,
                                 "non-uniform erase sector maps are not supported yet.\n");
                        break;

                case SFDP_SST_ID:
                        err = spi_nor_parse_microchip_sfdp(nor, param_header);
                        break;

                default:
                        break;
                }

                if (err) {
                        dev_warn(nor->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;
}
#else
static int spi_nor_parse_sfdp(struct spi_nor *nor,
                              struct spi_nor_flash_parameter *params)
{
        return -EINVAL;
}
#endif /* SPI_FLASH_SFDP_SUPPORT */

/**
 * 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,
                                     struct spi_nor_flash_parameter *params)
{
        if (nor->fixups && nor->fixups->post_sfdp)
                nor->fixups->post_sfdp(nor, params);
}

static void spi_nor_default_init_fixups(struct spi_nor *nor)
{
        if (nor->fixups && nor->fixups->default_init)
                nor->fixups->default_init(nor);
}

static int spi_nor_init_params(struct spi_nor *nor,
                               const struct flash_info *info,
                               struct spi_nor_flash_parameter *params)
{
        /* Set legacy flash parameters as default. */
        memset(params, 0, sizeof(*params));

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

        /* (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 (!(info->flags & SPI_NOR_NO_FR)) {
                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);
        }

        if (info->flags & SPI_NOR_OCTAL_DTR_READ) {
                params->hwcaps.mask |= SNOR_HWCAPS_READ_8_8_8_DTR;
                spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ_8_8_8_DTR],
                                          0, 20, SPINOR_OP_READ_FAST,
                                          SNOR_PROTO_8_8_8_DTR);
        }

        /* 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);

        /*
         * Since xSPI Page Program opcode is backward compatible with
         * Legacy SPI, use Legacy SPI opcode there as well.
         */
        spi_nor_set_pp_settings(&params->page_programs[SNOR_CMD_PP_8_8_8_DTR],
                                SPINOR_OP_PP, SNOR_PROTO_8_8_8_DTR);

        if (info->flags & SPI_NOR_QUAD_READ) {
                params->hwcaps.mask |= SNOR_HWCAPS_PP_1_1_4;
                spi_nor_set_pp_settings(&params->page_programs[SNOR_CMD_PP_1_1_4],
                                        SPINOR_OP_PP_1_1_4, SNOR_PROTO_1_1_4);
        }

        /* Select the procedure to set the Quad Enable bit. */
        if (params->hwcaps.mask & (SNOR_HWCAPS_READ_QUAD |
                                   SNOR_HWCAPS_PP_QUAD)) {
                switch (JEDEC_MFR(info)) {
#if defined(CONFIG_SPI_FLASH_MACRONIX) || defined(CONFIG_SPI_FLASH_ISSI)
                case SNOR_MFR_MACRONIX:
                case SNOR_MFR_ISSI:
                        params->quad_enable = macronix_quad_enable;
                        break;
#endif
                case SNOR_MFR_ST:
                case SNOR_MFR_MICRON:
                        break;

                default:
#if defined(CONFIG_SPI_FLASH_SPANSION) || defined(CONFIG_SPI_FLASH_WINBOND)
                        /* Kept only for backward compatibility purpose. */
                        params->quad_enable = spansion_read_cr_quad_enable;
#endif
                        break;
                }
        }

        spi_nor_default_init_fixups(nor);

        /* Override the parameters with data read from SFDP tables. */
        nor->addr_width = 0;
        nor->mtd.erasesize = 0;
        if ((info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
             SPI_NOR_OCTAL_DTR_READ)) &&
            !(info->flags & SPI_NOR_SKIP_SFDP)) {
                struct spi_nor_flash_parameter sfdp_params;

                memcpy(&sfdp_params, params, sizeof(sfdp_params));
                if (spi_nor_parse_sfdp(nor, &sfdp_params)) {
                        nor->addr_width = 0;
                        nor->mtd.erasesize = 0;
                } else {
                        memcpy(params, &sfdp_params, sizeof(*params));
                }
        }

        spi_nor_post_sfdp_fixups(nor, params);

        return 0;
}

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 },
                { SNOR_HWCAPS_READ_8_8_8_DTR,   SNOR_CMD_READ_8_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 },
                { SNOR_HWCAPS_PP_8_8_8_DTR,     SNOR_CMD_PP_8_8_8_DTR },
        };

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

#ifdef CONFIG_SPI_FLASH_SMART_HWCAPS
/**
 * spi_nor_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_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->spi, 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->spi, op))
                        return -ENOTSUPP;
        }

        return 0;
}

/**
 * spi_nor_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_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, 0),
                                          SPI_MEM_OP_ADDR(3, 0, 0),
                                          SPI_MEM_OP_DUMMY(1, 0),
                                          SPI_MEM_OP_DATA_IN(2, NULL, 0));

        spi_nor_setup_op(nor, &op, read->proto);

        op.dummy.nbytes = (read->num_mode_clocks + read->num_wait_states) *
                          op.dummy.buswidth / 8;
        if (spi_nor_protocol_is_dtr(nor->read_proto))
                op.dummy.nbytes *= 2;

        return spi_nor_check_op(nor, &op);
}

/**
 * spi_nor_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_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, 0),
                                          SPI_MEM_OP_ADDR(3, 0, 0),
                                          SPI_MEM_OP_NO_DUMMY,
                                          SPI_MEM_OP_DATA_OUT(2, NULL, 0));

        spi_nor_setup_op(nor, &op, pp->proto);

        return spi_nor_check_op(nor, &op);
}

/**
 * spi_nor_adjust_hwcaps - Find optimal Read/Write protocol based on SPI
 *                         controller capabilities
 * @nor:        pointer to a 'struct spi_nor'
 * @params:     pointer to the 'struct spi_nor_flash_parameter'
 *              representing SPI NOR flash capabilities
 * @hwcaps:     pointer to resulting capabilities after adjusting
 *              according to controller and flash's capability
 *
 * Discard caps based on what the SPI controller actually supports (using
 * spi_mem_supports_op()).
 */
static void
spi_nor_adjust_hwcaps(struct spi_nor *nor,
                      const struct spi_nor_flash_parameter *params,
                      u32 *hwcaps)
{
        unsigned int cap;

        /*
         * Enable all caps by default. We will mask them after checking what's
         * really supported using spi_mem_supports_op().
         */
        *hwcaps = SNOR_HWCAPS_ALL;

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

        /*
         * If the reset line is broken, we do not want to enter a stateful
         * mode.
         */
        if (nor->flags & SNOR_F_BROKEN_RESET)
                *hwcaps &= ~(SNOR_HWCAPS_X_X_X | SNOR_HWCAPS_X_X_X_DTR);

        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_check_readop(nor, &params->reads[rdidx]))
                        *hwcaps &= ~BIT(cap);

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

                if (spi_nor_check_pp(nor, &params->page_programs[ppidx]))
                        *hwcaps &= ~BIT(cap);
        }
}
#else
/**
 * spi_nor_adjust_hwcaps - Find optimal Read/Write protocol based on SPI
 *                         controller capabilities
 * @nor:        pointer to a 'struct spi_nor'
 * @params:     pointer to the 'struct spi_nor_flash_parameter'
 *              representing SPI NOR flash capabilities
 * @hwcaps:     pointer to resulting capabilities after adjusting
 *              according to controller and flash's capability
 *
 * Select caps based on what the SPI controller and SPI flash both support.
 */
static void
spi_nor_adjust_hwcaps(struct spi_nor *nor,
                      const struct spi_nor_flash_parameter *params,
                      u32 *hwcaps)
{
        struct spi_slave *spi = nor->spi;
        u32 ignored_mask = (SNOR_HWCAPS_READ_2_2_2 |
                            SNOR_HWCAPS_READ_4_4_4 |
                            SNOR_HWCAPS_READ_8_8_8 |
                            SNOR_HWCAPS_PP_4_4_4   |
                            SNOR_HWCAPS_PP_8_8_8);
        u32 spi_hwcaps = (SNOR_HWCAPS_READ | SNOR_HWCAPS_READ_FAST |
                          SNOR_HWCAPS_PP);

        /* Get the hardware capabilities the SPI controller supports. */
        if (spi->mode & SPI_RX_OCTAL) {
                spi_hwcaps |= SNOR_HWCAPS_READ_1_1_8;

                if (spi->mode & SPI_TX_OCTAL)
                        spi_hwcaps |= (SNOR_HWCAPS_READ_1_8_8 |
                                        SNOR_HWCAPS_PP_1_1_8 |
                                        SNOR_HWCAPS_PP_1_8_8);
        } else if (spi->mode & SPI_RX_QUAD) {
                spi_hwcaps |= SNOR_HWCAPS_READ_1_1_4;

                if (spi->mode & SPI_TX_QUAD)
                        spi_hwcaps |= (SNOR_HWCAPS_READ_1_4_4 |
                                        SNOR_HWCAPS_PP_1_1_4 |
                                        SNOR_HWCAPS_PP_1_4_4);
        } else if (spi->mode & SPI_RX_DUAL) {
                spi_hwcaps |= SNOR_HWCAPS_READ_1_1_2;

                if (spi->mode & SPI_TX_DUAL)
                        spi_hwcaps |= SNOR_HWCAPS_READ_1_2_2;
        }

        /*
         * Keep only the hardware capabilities supported by both the SPI
         * controller and the SPI flash memory.
         */
        *hwcaps = spi_hwcaps & params->hwcaps.mask;
        if (*hwcaps & ignored_mask) {
                dev_dbg(nor->dev,
                        "SPI n-n-n protocols are not supported yet.\n");
                *hwcaps &= ~ignored_mask;
        }
}
#endif /* CONFIG_SPI_FLASH_SMART_HWCAPS */

static int spi_nor_select_read(struct spi_nor *nor,
                               const struct spi_nor_flash_parameter *params,
                               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 = &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,
                             const struct spi_nor_flash_parameter *params,
                             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 = &params->page_programs[cmd];
        nor->program_opcode = pp->opcode;
        nor->write_proto = pp->proto;
        return 0;
}

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

        /* Do nothing if already configured from SFDP. */
        if (mtd->erasesize)
                return 0;

#ifdef CONFIG_SPI_FLASH_USE_4K_SECTORS
        /* prefer "small sector" erase if possible */
        if (info->flags & SECT_4K) {
                nor->erase_opcode = SPINOR_OP_BE_4K;
                mtd->erasesize = 4096;
        } else if (info->flags & SECT_4K_PMC) {
                nor->erase_opcode = SPINOR_OP_BE_4K_PMC;
                mtd->erasesize = 4096;
        } else
#endif
        {
                nor->erase_opcode = SPINOR_OP_SE;
                mtd->erasesize = info->sector_size;
        }
        return 0;
}

static int spi_nor_default_setup(struct spi_nor *nor,
                                 const struct flash_info *info,
                                 const struct spi_nor_flash_parameter *params)
{
        u32 shared_mask;
        bool enable_quad_io;
        int err;

        spi_nor_adjust_hwcaps(nor, params, &shared_mask);

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

        /* Enable Quad I/O if needed. */
        enable_quad_io = (spi_nor_get_protocol_width(nor->read_proto) == 4 ||
                          spi_nor_get_protocol_width(nor->write_proto) == 4);
        if (enable_quad_io && params->quad_enable)
                nor->quad_enable = params->quad_enable;
        else
                nor->quad_enable = NULL;

        return 0;
}

static int spi_nor_setup(struct spi_nor *nor, const struct flash_info *info,
                         const struct spi_nor_flash_parameter *params)
{
        if (!nor->setup)
                return 0;

        return nor->setup(nor, info, params);
}

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

        /*
         * Atmel, SST, Intel/Numonyx, and others serial NOR tend to power up
         * with the software protection bits set
         */
        if (IS_ENABLED(CONFIG_SPI_FLASH_UNLOCK_ALL) &&
            (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)) {
                write_enable(nor);
                write_sr(nor, 0);
                spi_nor_wait_till_ready(nor);
        }

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

        if (nor->addr_width == 4 &&
            !(nor->info->flags & SPI_NOR_OCTAL_DTR_READ) &&
            (JEDEC_MFR(nor->info) != SNOR_MFR_SPANSION) &&
            !(nor->info->flags & SPI_NOR_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.
                 */
                if (nor->flags & SNOR_F_BROKEN_RESET)
                        debug("enabling reset hack; may not recover from unexpected reboots\n");
                set_4byte(nor, nor->info, 1);
        }

        return 0;
}

void spi_nor_set_fixups(struct spi_nor *nor)
{
}

int spi_nor_scan(struct spi_nor *nor)
{
        struct spi_nor_flash_parameter params;
        const struct flash_info *info = NULL;
        struct mtd_info *mtd = &nor->mtd;
        struct spi_slave *spi = nor->spi;
        int 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;
        nor->read = spi_nor_read_data;
        nor->write = spi_nor_write_data;
        nor->read_reg = spi_nor_read_reg;
        nor->write_reg = spi_nor_write_reg;

        nor->setup = spi_nor_default_setup;

        info = spi_nor_read_id(nor);
        if (IS_ERR_OR_NULL(info))
                return -ENOENT;
        nor->info = info;

        spi_nor_set_fixups(nor);

        /* Parse the Serial Flash Discoverable Parameters table. */
        ret = spi_nor_init_params(nor, info, &params);
        if (ret)
                return ret;

        if (!mtd->name)
                mtd->name = info->name;
        mtd->dev = nor->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->_write = spi_nor_write;

#if defined(CONFIG_SPI_FLASH_STMICRO) || defined(CONFIG_SPI_FLASH_SST)
        /* NOR protection support for STmicro/Micron chips and similar */
        if (JEDEC_MFR(info) == SNOR_MFR_ST ||
            JEDEC_MFR(info) == SNOR_MFR_MICRON ||
            JEDEC_MFR(info) == SNOR_MFR_SST ||
                        info->flags & SPI_NOR_HAS_LOCK) {
                nor->flash_lock = stm_lock;
                nor->flash_unlock = stm_unlock;
                nor->flash_is_locked = stm_is_locked;
        }
#endif

#ifdef CONFIG_SPI_FLASH_SST
        /*
         * sst26 series block protection implementation differs from other
         * series.
         */
        if (info->flags & SPI_NOR_HAS_SST26LOCK) {
                nor->flash_lock = sst26_lock;
                nor->flash_unlock = sst26_unlock;
                nor->flash_is_locked = sst26_is_locked;
        }
#endif

        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;

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

        /* Some devices cannot do fast-read, no matter what DT tells us */
        if ((info->flags & SPI_NOR_NO_FR) || (spi->mode & SPI_RX_SLOW))
                params.hwcaps.mask &= ~SNOR_HWCAPS_READ_FAST;

        /*
         * 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.
         * - set the Quad Enable bit if needed (required by SPI x-y-4 protos).
         */
        ret = spi_nor_setup(nor, info, &params);
        if (ret)
                return ret;

        if (spi_nor_protocol_is_dtr(nor->read_proto)) {
                 /* Always use 4-byte addresses in DTR mode. */
                nor->addr_width = 4;
        } else if (nor->addr_width) {
                /* already configured from SFDP */
        } else if (info->addr_width) {
                nor->addr_width = info->addr_width;
        } else {
                nor->addr_width = 3;
        }

        if (nor->addr_width == 3 && mtd->size > SZ_16M) {
#ifndef CONFIG_SPI_FLASH_BAR
                /* enable 4-byte addressing if the device exceeds 16MiB */
                nor->addr_width = 4;
                if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
                    info->flags & SPI_NOR_4B_OPCODES)
                        spi_nor_set_4byte_opcodes(nor, info);
#else
        /* Configure the BAR - discover bank cmds and read current bank */
        nor->addr_width = 3;
        ret = read_bar(nor, info);
        if (ret < 0)
                return ret;
#endif
        }

        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;
        }

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

        nor->name = mtd->name;
        nor->size = mtd->size;
        nor->erase_size = mtd->erasesize;
        nor->sector_size = mtd->erasesize;

#ifndef CONFIG_SPL_BUILD
        printf("SF: Detected %s with page size ", nor->name);
        print_size(nor->page_size, ", erase size ");
        print_size(nor->erase_size, ", total ");
        print_size(nor->size, "");
        puts("\n");
#endif

        return 0;
}

/* U-Boot specific functions, need to extend MTD to support these */
int spi_flash_cmd_get_sw_write_prot(struct spi_nor *nor)
{
        int sr = read_sr(nor);

        if (sr < 0)
                return sr;

        return (sr >> 2) & 7;
}