// SPDX-License-Identifier: GPL-2.0+

/*
 * Freescale QuadSPI driver.
 *
 * Copyright (C) 2013 Freescale Semiconductor, Inc.
 * Copyright (C) 2018 Bootlin
 * Copyright (C) 2018 exceet electronics GmbH
 * Copyright (C) 2018 Kontron Electronics GmbH
 *
 * Transition to SPI MEM interface:
 * Authors:
 *     Boris Brezillon <bbrezillon@kernel.org>
 *     Frieder Schrempf <frieder.schrempf@kontron.de>
 *     Yogesh Gaur <yogeshnarayan.gaur@nxp.com>
 *     Suresh Gupta <suresh.gupta@nxp.com>
 *
 * Based on the original fsl-quadspi.c spi-nor driver:
 * Author: Freescale Semiconductor, Inc.
 *
 */

#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_qos.h>
#include <linux/sizes.h>

#include <linux/spi/spi.h>
#include <linux/spi/spi-mem.h>

/*
 * The driver only uses one single LUT entry, that is updated on
 * each call of exec_op(). Index 0 is preset at boot with a basic
 * read operation, so let's use the last entry (15).
 */
#define SEQID_LUT                       15

/* Registers used by the driver */
#define QUADSPI_MCR                     0x00
#define QUADSPI_MCR_RESERVED_MASK       GENMASK(19, 16)
#define QUADSPI_MCR_MDIS_MASK           BIT(14)
#define QUADSPI_MCR_CLR_TXF_MASK        BIT(11)
#define QUADSPI_MCR_CLR_RXF_MASK        BIT(10)
#define QUADSPI_MCR_DDR_EN_MASK         BIT(7)
#define QUADSPI_MCR_END_CFG_MASK        GENMASK(3, 2)
#define QUADSPI_MCR_SWRSTHD_MASK        BIT(1)
#define QUADSPI_MCR_SWRSTSD_MASK        BIT(0)

#define QUADSPI_IPCR                    0x08
#define QUADSPI_IPCR_SEQID(x)           ((x) << 24)

#define QUADSPI_BUF3CR                  0x1c
#define QUADSPI_BUF3CR_ALLMST_MASK      BIT(31)
#define QUADSPI_BUF3CR_ADATSZ(x)        ((x) << 8)
#define QUADSPI_BUF3CR_ADATSZ_MASK      GENMASK(15, 8)

#define QUADSPI_BFGENCR                 0x20
#define QUADSPI_BFGENCR_SEQID(x)        ((x) << 12)

#define QUADSPI_BUF0IND                 0x30
#define QUADSPI_BUF1IND                 0x34
#define QUADSPI_BUF2IND                 0x38
#define QUADSPI_SFAR                    0x100

#define QUADSPI_SMPR                    0x108
#define QUADSPI_SMPR_DDRSMP_MASK        GENMASK(18, 16)
#define QUADSPI_SMPR_FSDLY_MASK         BIT(6)
#define QUADSPI_SMPR_FSPHS_MASK         BIT(5)
#define QUADSPI_SMPR_HSENA_MASK         BIT(0)

#define QUADSPI_RBCT                    0x110
#define QUADSPI_RBCT_WMRK_MASK          GENMASK(4, 0)
#define QUADSPI_RBCT_RXBRD_USEIPS       BIT(8)

#define QUADSPI_TBDR                    0x154

#define QUADSPI_SR                      0x15c
#define QUADSPI_SR_IP_ACC_MASK          BIT(1)
#define QUADSPI_SR_AHB_ACC_MASK         BIT(2)

#define QUADSPI_FR                      0x160
#define QUADSPI_FR_TFF_MASK             BIT(0)

#define QUADSPI_SPTRCLR                 0x16c
#define QUADSPI_SPTRCLR_IPPTRC          BIT(8)
#define QUADSPI_SPTRCLR_BFPTRC          BIT(0)

#define QUADSPI_SFA1AD                  0x180
#define QUADSPI_SFA2AD                  0x184
#define QUADSPI_SFB1AD                  0x188
#define QUADSPI_SFB2AD                  0x18c
#define QUADSPI_RBDR(x)                 (0x200 + ((x) * 4))

#define QUADSPI_LUTKEY                  0x300
#define QUADSPI_LUTKEY_VALUE            0x5AF05AF0

#define QUADSPI_LCKCR                   0x304
#define QUADSPI_LCKER_LOCK              BIT(0)
#define QUADSPI_LCKER_UNLOCK            BIT(1)

#define QUADSPI_RSER                    0x164
#define QUADSPI_RSER_TFIE               BIT(0)

#define QUADSPI_LUT_BASE                0x310
#define QUADSPI_LUT_OFFSET              (SEQID_LUT * 4 * 4)
#define QUADSPI_LUT_REG(idx) \
        (QUADSPI_LUT_BASE + QUADSPI_LUT_OFFSET + (idx) * 4)

/* Instruction set for the LUT register */
#define LUT_STOP                0
#define LUT_CMD                 1
#define LUT_ADDR                2
#define LUT_DUMMY               3
#define LUT_MODE                4
#define LUT_MODE2               5
#define LUT_MODE4               6
#define LUT_FSL_READ            7
#define LUT_FSL_WRITE           8
#define LUT_JMP_ON_CS           9
#define LUT_ADDR_DDR            10
#define LUT_MODE_DDR            11
#define LUT_MODE2_DDR           12
#define LUT_MODE4_DDR           13
#define LUT_FSL_READ_DDR        14
#define LUT_FSL_WRITE_DDR       15
#define LUT_DATA_LEARN          16

/*
 * The PAD definitions for LUT register.
 *
 * The pad stands for the number of IO lines [0:3].
 * For example, the quad read needs four IO lines,
 * so you should use LUT_PAD(4).
 */
#define LUT_PAD(x) (fls(x) - 1)

/*
 * Macro for constructing the LUT entries with the following
 * register layout:
 *
 *  ---------------------------------------------------
 *  | INSTR1 | PAD1 | OPRND1 | INSTR0 | PAD0 | OPRND0 |
 *  ---------------------------------------------------
 */
#define LUT_DEF(idx, ins, pad, opr)                                     \
        ((((ins) << 10) | ((pad) << 8) | (opr)) << (((idx) % 2) * 16))

/* Controller needs driver to swap endianness */
#define QUADSPI_QUIRK_SWAP_ENDIAN       BIT(0)

/* Controller needs 4x internal clock */
#define QUADSPI_QUIRK_4X_INT_CLK        BIT(1)

/*
 * TKT253890, the controller needs the driver to fill the txfifo with
 * 16 bytes at least to trigger a data transfer, even though the extra
 * data won't be transferred.
 */
#define QUADSPI_QUIRK_TKT253890         BIT(2)

/* TKT245618, the controller cannot wake up from wait mode */
#define QUADSPI_QUIRK_TKT245618         BIT(3)

/*
 * Controller adds QSPI_AMBA_BASE (base address of the mapped memory)
 * internally. No need to add it when setting SFXXAD and SFAR registers
 */
#define QUADSPI_QUIRK_BASE_INTERNAL     BIT(4)

struct fsl_qspi_devtype_data {
        unsigned int rxfifo;
        unsigned int txfifo;
        unsigned int ahb_buf_size;
        unsigned int quirks;
        bool little_endian;
};

static const struct fsl_qspi_devtype_data vybrid_data = {
        .rxfifo = SZ_128,
        .txfifo = SZ_64,
        .ahb_buf_size = SZ_1K,
        .quirks = QUADSPI_QUIRK_SWAP_ENDIAN,
        .little_endian = true,
};

static const struct fsl_qspi_devtype_data imx6sx_data = {
        .rxfifo = SZ_128,
        .txfifo = SZ_512,
        .ahb_buf_size = SZ_1K,
        .quirks = QUADSPI_QUIRK_4X_INT_CLK | QUADSPI_QUIRK_TKT245618,
        .little_endian = true,
};

static const struct fsl_qspi_devtype_data imx7d_data = {
        .rxfifo = SZ_128,
        .txfifo = SZ_512,
        .ahb_buf_size = SZ_1K,
        .quirks = QUADSPI_QUIRK_TKT253890 | QUADSPI_QUIRK_4X_INT_CLK,
        .little_endian = true,
};

static const struct fsl_qspi_devtype_data imx6ul_data = {
        .rxfifo = SZ_128,
        .txfifo = SZ_512,
        .ahb_buf_size = SZ_1K,
        .quirks = QUADSPI_QUIRK_TKT253890 | QUADSPI_QUIRK_4X_INT_CLK,
        .little_endian = true,
};

static const struct fsl_qspi_devtype_data ls1021a_data = {
        .rxfifo = SZ_128,
        .txfifo = SZ_64,
        .ahb_buf_size = SZ_1K,
        .quirks = 0,
        .little_endian = false,
};

static const struct fsl_qspi_devtype_data ls2080a_data = {
        .rxfifo = SZ_128,
        .txfifo = SZ_64,
        .ahb_buf_size = SZ_1K,
        .quirks = QUADSPI_QUIRK_TKT253890 | QUADSPI_QUIRK_BASE_INTERNAL,
        .little_endian = true,
};

struct fsl_qspi {
        void __iomem *iobase;
        void __iomem *ahb_addr;
        u32 memmap_phy;
        struct clk *clk, *clk_en;
        struct device *dev;
        struct completion c;
        const struct fsl_qspi_devtype_data *devtype_data;
        struct mutex lock;
        struct pm_qos_request pm_qos_req;
        int selected;
};

static inline int needs_swap_endian(struct fsl_qspi *q)
{
        return q->devtype_data->quirks & QUADSPI_QUIRK_SWAP_ENDIAN;
}

static inline int needs_4x_clock(struct fsl_qspi *q)
{
        return q->devtype_data->quirks & QUADSPI_QUIRK_4X_INT_CLK;
}

static inline int needs_fill_txfifo(struct fsl_qspi *q)
{
        return q->devtype_data->quirks & QUADSPI_QUIRK_TKT253890;
}

static inline int needs_wakeup_wait_mode(struct fsl_qspi *q)
{
        return q->devtype_data->quirks & QUADSPI_QUIRK_TKT245618;
}

static inline int needs_amba_base_offset(struct fsl_qspi *q)
{
        return !(q->devtype_data->quirks & QUADSPI_QUIRK_BASE_INTERNAL);
}

/*
 * An IC bug makes it necessary to rearrange the 32-bit data.
 * Later chips, such as IMX6SLX, have fixed this bug.
 */
static inline u32 fsl_qspi_endian_xchg(struct fsl_qspi *q, u32 a)
{
        return needs_swap_endian(q) ? __swab32(a) : a;
}

/*
 * R/W functions for big- or little-endian registers:
 * The QSPI controller's endianness is independent of
 * the CPU core's endianness. So far, although the CPU
 * core is little-endian the QSPI controller can use
 * big-endian or little-endian.
 */
static void qspi_writel(struct fsl_qspi *q, u32 val, void __iomem *addr)
{
        if (q->devtype_data->little_endian)
                iowrite32(val, addr);
        else
                iowrite32be(val, addr);
}

static u32 qspi_readl(struct fsl_qspi *q, void __iomem *addr)
{
        if (q->devtype_data->little_endian)
                return ioread32(addr);

        return ioread32be(addr);
}

static irqreturn_t fsl_qspi_irq_handler(int irq, void *dev_id)
{
        struct fsl_qspi *q = dev_id;
        u32 reg;

        /* clear interrupt */
        reg = qspi_readl(q, q->iobase + QUADSPI_FR);
        qspi_writel(q, reg, q->iobase + QUADSPI_FR);

        if (reg & QUADSPI_FR_TFF_MASK)
                complete(&q->c);

        dev_dbg(q->dev, "QUADSPI_FR : 0x%.8x:0x%.8x\n", 0, reg);
        return IRQ_HANDLED;
}

static int fsl_qspi_check_buswidth(struct fsl_qspi *q, u8 width)
{
        switch (width) {
        case 1:
        case 2:
        case 4:
                return 0;
        }

        return -ENOTSUPP;
}

static bool fsl_qspi_supports_op(struct spi_mem *mem,
                                 const struct spi_mem_op *op)
{
        struct fsl_qspi *q = spi_controller_get_devdata(mem->spi->master);
        int ret;

        ret = fsl_qspi_check_buswidth(q, op->cmd.buswidth);

        if (op->addr.nbytes)
                ret |= fsl_qspi_check_buswidth(q, op->addr.buswidth);

        if (op->dummy.nbytes)
                ret |= fsl_qspi_check_buswidth(q, op->dummy.buswidth);

        if (op->data.nbytes)
                ret |= fsl_qspi_check_buswidth(q, op->data.buswidth);

        if (ret)
                return false;

        /*
         * The number of instructions needed for the op, needs
         * to fit into a single LUT entry.
         */
        if (op->addr.nbytes +
           (op->dummy.nbytes ? 1:0) +
           (op->data.nbytes ? 1:0) > 6)
                return false;

        /* Max 64 dummy clock cycles supported */
        if (op->dummy.nbytes &&
            (op->dummy.nbytes * 8 / op->dummy.buswidth > 64))
                return false;

        /* Max data length, check controller limits and alignment */
        if (op->data.dir == SPI_MEM_DATA_IN &&
            (op->data.nbytes > q->devtype_data->ahb_buf_size ||
             (op->data.nbytes > q->devtype_data->rxfifo - 4 &&
              !IS_ALIGNED(op->data.nbytes, 8))))
                return false;

        if (op->data.dir == SPI_MEM_DATA_OUT &&
            op->data.nbytes > q->devtype_data->txfifo)
                return false;

        return true;
}

static void fsl_qspi_prepare_lut(struct fsl_qspi *q,
                                 const struct spi_mem_op *op)
{
        void __iomem *base = q->iobase;
        u32 lutval[4] = {};
        int lutidx = 1, i;

        lutval[0] |= LUT_DEF(0, LUT_CMD, LUT_PAD(op->cmd.buswidth),
                             op->cmd.opcode);

        /*
         * For some unknown reason, using LUT_ADDR doesn't work in some
         * cases (at least with only one byte long addresses), so
         * let's use LUT_MODE to write the address bytes one by one
         */
        for (i = 0; i < op->addr.nbytes; i++) {
                u8 addrbyte = op->addr.val >> (8 * (op->addr.nbytes - i - 1));

                lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_MODE,
                                              LUT_PAD(op->addr.buswidth),
                                              addrbyte);
                lutidx++;
        }

        if (op->dummy.nbytes) {
                lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_DUMMY,
                                              LUT_PAD(op->dummy.buswidth),
                                              op->dummy.nbytes * 8 /
                                              op->dummy.buswidth);
                lutidx++;
        }

        if (op->data.nbytes) {
                lutval[lutidx / 2] |= LUT_DEF(lutidx,
                                              op->data.dir == SPI_MEM_DATA_IN ?
                                              LUT_FSL_READ : LUT_FSL_WRITE,
                                              LUT_PAD(op->data.buswidth),
                                              0);
                lutidx++;
        }

        lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_STOP, 0, 0);

        /* unlock LUT */
        qspi_writel(q, QUADSPI_LUTKEY_VALUE, q->iobase + QUADSPI_LUTKEY);
        qspi_writel(q, QUADSPI_LCKER_UNLOCK, q->iobase + QUADSPI_LCKCR);

        /* fill LUT */
        for (i = 0; i < ARRAY_SIZE(lutval); i++)
                qspi_writel(q, lutval[i], base + QUADSPI_LUT_REG(i));

        /* lock LUT */
        qspi_writel(q, QUADSPI_LUTKEY_VALUE, q->iobase + QUADSPI_LUTKEY);
        qspi_writel(q, QUADSPI_LCKER_LOCK, q->iobase + QUADSPI_LCKCR);
}

static int fsl_qspi_clk_prep_enable(struct fsl_qspi *q)
{
        int ret;

        ret = clk_prepare_enable(q->clk_en);
        if (ret)
                return ret;

        ret = clk_prepare_enable(q->clk);
        if (ret) {
                clk_disable_unprepare(q->clk_en);
                return ret;
        }

        if (needs_wakeup_wait_mode(q))
                pm_qos_add_request(&q->pm_qos_req, PM_QOS_CPU_DMA_LATENCY, 0);

        return 0;
}

static void fsl_qspi_clk_disable_unprep(struct fsl_qspi *q)
{
        if (needs_wakeup_wait_mode(q))
                pm_qos_remove_request(&q->pm_qos_req);

        clk_disable_unprepare(q->clk);
        clk_disable_unprepare(q->clk_en);
}

/*
 * If we have changed the content of the flash by writing or erasing, or if we
 * read from flash with a different offset into the page buffer, we need to
 * invalidate the AHB buffer. If we do not do so, we may read out the wrong
 * data. The spec tells us reset the AHB domain and Serial Flash domain at
 * the same time.
 */
static void fsl_qspi_invalidate(struct fsl_qspi *q)
{
        u32 reg;

        reg = qspi_readl(q, q->iobase + QUADSPI_MCR);
        reg |= QUADSPI_MCR_SWRSTHD_MASK | QUADSPI_MCR_SWRSTSD_MASK;
        qspi_writel(q, reg, q->iobase + QUADSPI_MCR);

        /*
         * The minimum delay : 1 AHB + 2 SFCK clocks.
         * Delay 1 us is enough.
         */
        udelay(1);

        reg &= ~(QUADSPI_MCR_SWRSTHD_MASK | QUADSPI_MCR_SWRSTSD_MASK);
        qspi_writel(q, reg, q->iobase + QUADSPI_MCR);
}

static void fsl_qspi_select_mem(struct fsl_qspi *q, struct spi_device *spi)
{
        unsigned long rate = spi->max_speed_hz;
        int ret;

        if (q->selected == spi->chip_select)
                return;

        if (needs_4x_clock(q))
                rate *= 4;

        fsl_qspi_clk_disable_unprep(q);

        ret = clk_set_rate(q->clk, rate);
        if (ret)
                return;

        ret = fsl_qspi_clk_prep_enable(q);
        if (ret)
                return;

        q->selected = spi->chip_select;

        fsl_qspi_invalidate(q);
}

static void fsl_qspi_read_ahb(struct fsl_qspi *q, const struct spi_mem_op *op)
{
        memcpy_fromio(op->data.buf.in,
                      q->ahb_addr + q->selected * q->devtype_data->ahb_buf_size,
                      op->data.nbytes);
}

static void fsl_qspi_fill_txfifo(struct fsl_qspi *q,
                                 const struct spi_mem_op *op)
{
        void __iomem *base = q->iobase;
        int i;
        u32 val;

        for (i = 0; i < ALIGN_DOWN(op->data.nbytes, 4); i += 4) {
                memcpy(&val, op->data.buf.out + i, 4);
                val = fsl_qspi_endian_xchg(q, val);
                qspi_writel(q, val, base + QUADSPI_TBDR);
        }

        if (i < op->data.nbytes) {
                memcpy(&val, op->data.buf.out + i, op->data.nbytes - i);
                val = fsl_qspi_endian_xchg(q, val);
                qspi_writel(q, val, base + QUADSPI_TBDR);
        }

        if (needs_fill_txfifo(q)) {
                for (i = op->data.nbytes; i < 16; i += 4)
                        qspi_writel(q, 0, base + QUADSPI_TBDR);
        }
}

static void fsl_qspi_read_rxfifo(struct fsl_qspi *q,
                          const struct spi_mem_op *op)
{
        void __iomem *base = q->iobase;
        int i;
        u8 *buf = op->data.buf.in;
        u32 val;

        for (i = 0; i < ALIGN_DOWN(op->data.nbytes, 4); i += 4) {
                val = qspi_readl(q, base + QUADSPI_RBDR(i / 4));
                val = fsl_qspi_endian_xchg(q, val);
                memcpy(buf + i, &val, 4);
        }

        if (i < op->data.nbytes) {
                val = qspi_readl(q, base + QUADSPI_RBDR(i / 4));
                val = fsl_qspi_endian_xchg(q, val);
                memcpy(buf + i, &val, op->data.nbytes - i);
        }
}

static int fsl_qspi_do_op(struct fsl_qspi *q, const struct spi_mem_op *op)
{
        void __iomem *base = q->iobase;
        int err = 0;

        init_completion(&q->c);

        /*
         * Always start the sequence at the same index since we update
         * the LUT at each exec_op() call. And also specify the DATA
         * length, since it's has not been specified in the LUT.
         */
        qspi_writel(q, op->data.nbytes | QUADSPI_IPCR_SEQID(SEQID_LUT),
                    base + QUADSPI_IPCR);

        /* Wait for the interrupt. */
        if (!wait_for_completion_timeout(&q->c, msecs_to_jiffies(1000)))
                err = -ETIMEDOUT;

        if (!err && op->data.nbytes && op->data.dir == SPI_MEM_DATA_IN)
                fsl_qspi_read_rxfifo(q, op);

        return err;
}

static int fsl_qspi_readl_poll_tout(struct fsl_qspi *q, void __iomem *base,
                                    u32 mask, u32 delay_us, u32 timeout_us)
{
        u32 reg;

        if (!q->devtype_data->little_endian)
                mask = (u32)cpu_to_be32(mask);

        return readl_poll_timeout(base, reg, !(reg & mask), delay_us,
                                  timeout_us);
}

static int fsl_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
{
        struct fsl_qspi *q = spi_controller_get_devdata(mem->spi->master);
        void __iomem *base = q->iobase;
        u32 addr_offset = 0;
        int err = 0;

        mutex_lock(&q->lock);

        /* wait for the controller being ready */
        fsl_qspi_readl_poll_tout(q, base + QUADSPI_SR, (QUADSPI_SR_IP_ACC_MASK |
                                 QUADSPI_SR_AHB_ACC_MASK), 10, 1000);

        fsl_qspi_select_mem(q, mem->spi);

        if (needs_amba_base_offset(q))
                addr_offset = q->memmap_phy;

        qspi_writel(q,
                    q->selected * q->devtype_data->ahb_buf_size + addr_offset,
                    base + QUADSPI_SFAR);

        qspi_writel(q, qspi_readl(q, base + QUADSPI_MCR) |
                    QUADSPI_MCR_CLR_RXF_MASK | QUADSPI_MCR_CLR_TXF_MASK,
                    base + QUADSPI_MCR);

        qspi_writel(q, QUADSPI_SPTRCLR_BFPTRC | QUADSPI_SPTRCLR_IPPTRC,
                    base + QUADSPI_SPTRCLR);

        fsl_qspi_prepare_lut(q, op);

        /*
         * If we have large chunks of data, we read them through the AHB bus
         * by accessing the mapped memory. In all other cases we use
         * IP commands to access the flash.
         */
        if (op->data.nbytes > (q->devtype_data->rxfifo - 4) &&
            op->data.dir == SPI_MEM_DATA_IN) {
                fsl_qspi_read_ahb(q, op);
        } else {
                qspi_writel(q, QUADSPI_RBCT_WMRK_MASK |
                            QUADSPI_RBCT_RXBRD_USEIPS, base + QUADSPI_RBCT);

                if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_OUT)
                        fsl_qspi_fill_txfifo(q, op);

                err = fsl_qspi_do_op(q, op);
        }

        /* Invalidate the data in the AHB buffer. */
        fsl_qspi_invalidate(q);

        mutex_unlock(&q->lock);

        return err;
}

static int fsl_qspi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
{
        struct fsl_qspi *q = spi_controller_get_devdata(mem->spi->master);

        if (op->data.dir == SPI_MEM_DATA_OUT) {
                if (op->data.nbytes > q->devtype_data->txfifo)
                        op->data.nbytes = q->devtype_data->txfifo;
        } else {
                if (op->data.nbytes > q->devtype_data->ahb_buf_size)
                        op->data.nbytes = q->devtype_data->ahb_buf_size;
                else if (op->data.nbytes > (q->devtype_data->rxfifo - 4))
                        op->data.nbytes = ALIGN_DOWN(op->data.nbytes, 8);
        }

        return 0;
}

static int fsl_qspi_default_setup(struct fsl_qspi *q)
{
        void __iomem *base = q->iobase;
        u32 reg, addr_offset = 0;
        int ret;

        /* disable and unprepare clock to avoid glitch pass to controller */
        fsl_qspi_clk_disable_unprep(q);

        /* the default frequency, we will change it later if necessary. */
        ret = clk_set_rate(q->clk, 66000000);
        if (ret)
                return ret;

        ret = fsl_qspi_clk_prep_enable(q);
        if (ret)
                return ret;

        /* Reset the module */
        qspi_writel(q, QUADSPI_MCR_SWRSTSD_MASK | QUADSPI_MCR_SWRSTHD_MASK,
                    base + QUADSPI_MCR);
        udelay(1);

        /* Disable the module */
        qspi_writel(q, QUADSPI_MCR_MDIS_MASK | QUADSPI_MCR_RESERVED_MASK,
                    base + QUADSPI_MCR);

        reg = qspi_readl(q, base + QUADSPI_SMPR);
        qspi_writel(q, reg & ~(QUADSPI_SMPR_FSDLY_MASK
                        | QUADSPI_SMPR_FSPHS_MASK
                        | QUADSPI_SMPR_HSENA_MASK
                        | QUADSPI_SMPR_DDRSMP_MASK), base + QUADSPI_SMPR);

        /* We only use the buffer3 for AHB read */
        qspi_writel(q, 0, base + QUADSPI_BUF0IND);
        qspi_writel(q, 0, base + QUADSPI_BUF1IND);
        qspi_writel(q, 0, base + QUADSPI_BUF2IND);

        qspi_writel(q, QUADSPI_BFGENCR_SEQID(SEQID_LUT),
                    q->iobase + QUADSPI_BFGENCR);
        qspi_writel(q, QUADSPI_RBCT_WMRK_MASK, base + QUADSPI_RBCT);
        qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
                    QUADSPI_BUF3CR_ADATSZ(q->devtype_data->ahb_buf_size / 8),
                    base + QUADSPI_BUF3CR);

        if (needs_amba_base_offset(q))
                addr_offset = q->memmap_phy;

        /*
         * In HW there can be a maximum of four chips on two buses with
         * two chip selects on each bus. We use four chip selects in SW
         * to differentiate between the four chips.
         * We use ahb_buf_size for each chip and set SFA1AD, SFA2AD, SFB1AD,
         * SFB2AD accordingly.
         */
        qspi_writel(q, q->devtype_data->ahb_buf_size + addr_offset,
                    base + QUADSPI_SFA1AD);
        qspi_writel(q, q->devtype_data->ahb_buf_size * 2 + addr_offset,
                    base + QUADSPI_SFA2AD);
        qspi_writel(q, q->devtype_data->ahb_buf_size * 3 + addr_offset,
                    base + QUADSPI_SFB1AD);
        qspi_writel(q, q->devtype_data->ahb_buf_size * 4 + addr_offset,
                    base + QUADSPI_SFB2AD);

        q->selected = -1;

        /* Enable the module */
        qspi_writel(q, QUADSPI_MCR_RESERVED_MASK | QUADSPI_MCR_END_CFG_MASK,
                    base + QUADSPI_MCR);

        /* clear all interrupt status */
        qspi_writel(q, 0xffffffff, q->iobase + QUADSPI_FR);

        /* enable the interrupt */
        qspi_writel(q, QUADSPI_RSER_TFIE, q->iobase + QUADSPI_RSER);

        return 0;
}

static const char *fsl_qspi_get_name(struct spi_mem *mem)
{
        struct fsl_qspi *q = spi_controller_get_devdata(mem->spi->master);
        struct device *dev = &mem->spi->dev;
        const char *name;

        /*
         * In order to keep mtdparts compatible with the old MTD driver at
         * mtd/spi-nor/fsl-quadspi.c, we set a custom name derived from the
         * platform_device of the controller.
         */
        if (of_get_available_child_count(q->dev->of_node) == 1)
                return dev_name(q->dev);

        name = devm_kasprintf(dev, GFP_KERNEL,
                              "%s-%d", dev_name(q->dev),
                              mem->spi->chip_select);

        if (!name) {
                dev_err(dev, "failed to get memory for custom flash name\n");
                return ERR_PTR(-ENOMEM);
        }

        return name;
}

static const struct spi_controller_mem_ops fsl_qspi_mem_ops = {
        .adjust_op_size = fsl_qspi_adjust_op_size,
        .supports_op = fsl_qspi_supports_op,
        .exec_op = fsl_qspi_exec_op,
        .get_name = fsl_qspi_get_name,
};

static int fsl_qspi_probe(struct platform_device *pdev)
{
        struct spi_controller *ctlr;
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        struct resource *res;
        struct fsl_qspi *q;
        int ret;

        ctlr = spi_alloc_master(&pdev->dev, sizeof(*q));
        if (!ctlr)
                return -ENOMEM;

        ctlr->mode_bits = SPI_RX_DUAL | SPI_RX_QUAD |
                          SPI_TX_DUAL | SPI_TX_QUAD;

        q = spi_controller_get_devdata(ctlr);
        q->dev = dev;
        q->devtype_data = of_device_get_match_data(dev);
        if (!q->devtype_data) {
                ret = -ENODEV;
                goto err_put_ctrl;
        }

        platform_set_drvdata(pdev, q);

        /* find the resources */
        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "QuadSPI");
        q->iobase = devm_ioremap_resource(dev, res);
        if (IS_ERR(q->iobase)) {
                ret = PTR_ERR(q->iobase);
                goto err_put_ctrl;
        }

        res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
                                        "QuadSPI-memory");
        q->ahb_addr = devm_ioremap_resource(dev, res);
        if (IS_ERR(q->ahb_addr)) {
                ret = PTR_ERR(q->ahb_addr);
                goto err_put_ctrl;
        }

        q->memmap_phy = res->start;

        /* find the clocks */
        q->clk_en = devm_clk_get(dev, "qspi_en");
        if (IS_ERR(q->clk_en)) {
                ret = PTR_ERR(q->clk_en);
                goto err_put_ctrl;
        }

        q->clk = devm_clk_get(dev, "qspi");
        if (IS_ERR(q->clk)) {
                ret = PTR_ERR(q->clk);
                goto err_put_ctrl;
        }

        ret = fsl_qspi_clk_prep_enable(q);
        if (ret) {
                dev_err(dev, "can not enable the clock\n");
                goto err_put_ctrl;
        }

        /* find the irq */
        ret = platform_get_irq(pdev, 0);
        if (ret < 0) {
                dev_err(dev, "failed to get the irq: %d\n", ret);
                goto err_disable_clk;
        }

        ret = devm_request_irq(dev, ret,
                        fsl_qspi_irq_handler, 0, pdev->name, q);
        if (ret) {
                dev_err(dev, "failed to request irq: %d\n", ret);
                goto err_disable_clk;
        }

        mutex_init(&q->lock);

        ctlr->bus_num = -1;
        ctlr->num_chipselect = 4;
        ctlr->mem_ops = &fsl_qspi_mem_ops;

        fsl_qspi_default_setup(q);

        ctlr->dev.of_node = np;

        ret = devm_spi_register_controller(dev, ctlr);
        if (ret)
                goto err_destroy_mutex;

        return 0;

err_destroy_mutex:
        mutex_destroy(&q->lock);

err_disable_clk:
        fsl_qspi_clk_disable_unprep(q);

err_put_ctrl:
        spi_controller_put(ctlr);

        dev_err(dev, "Freescale QuadSPI probe failed\n");
        return ret;
}

static int fsl_qspi_remove(struct platform_device *pdev)
{
        struct fsl_qspi *q = platform_get_drvdata(pdev);

        /* disable the hardware */
        qspi_writel(q, QUADSPI_MCR_MDIS_MASK, q->iobase + QUADSPI_MCR);
        qspi_writel(q, 0x0, q->iobase + QUADSPI_RSER);

        fsl_qspi_clk_disable_unprep(q);

        mutex_destroy(&q->lock);

        return 0;
}

static int fsl_qspi_suspend(struct device *dev)
{
        return 0;
}

static int fsl_qspi_resume(struct device *dev)
{
        struct fsl_qspi *q = dev_get_drvdata(dev);

        fsl_qspi_default_setup(q);

        return 0;
}

static const struct of_device_id fsl_qspi_dt_ids[] = {
        { .compatible = "fsl,vf610-qspi", .data = &vybrid_data, },
        { .compatible = "fsl,imx6sx-qspi", .data = &imx6sx_data, },
        { .compatible = "fsl,imx7d-qspi", .data = &imx7d_data, },
        { .compatible = "fsl,imx6ul-qspi", .data = &imx6ul_data, },
        { .compatible = "fsl,ls1021a-qspi", .data = &ls1021a_data, },
        { .compatible = "fsl,ls2080a-qspi", .data = &ls2080a_data, },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, fsl_qspi_dt_ids);

static const struct dev_pm_ops fsl_qspi_pm_ops = {
        .suspend        = fsl_qspi_suspend,
        .resume         = fsl_qspi_resume,
};

static struct platform_driver fsl_qspi_driver = {
        .driver = {
                .name   = "fsl-quadspi",
                .of_match_table = fsl_qspi_dt_ids,
                .pm =   &fsl_qspi_pm_ops,
        },
        .probe          = fsl_qspi_probe,
        .remove         = fsl_qspi_remove,
};
module_platform_driver(fsl_qspi_driver);

MODULE_DESCRIPTION("Freescale QuadSPI Controller Driver");
MODULE_AUTHOR("Freescale Semiconductor Inc.");
MODULE_AUTHOR("Boris Brezillon <bbrezillon@kernel.org>");
MODULE_AUTHOR("Frieder Schrempf <frieder.schrempf@kontron.de>");
MODULE_AUTHOR("Yogesh Gaur <yogeshnarayan.gaur@nxp.com>");
MODULE_AUTHOR("Suresh Gupta <suresh.gupta@nxp.com>");
MODULE_LICENSE("GPL v2");