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

/*
 * NXP FlexSPI(FSPI) controller driver.
 *
 * Copyright 2019-2020 NXP
 * Copyright 2020 Puresoftware Ltd.
 *
 * FlexSPI is a flexsible SPI host controller which supports two SPI
 * channels and up to 4 external devices. Each channel supports
 * Single/Dual/Quad/Octal mode data transfer (1/2/4/8 bidirectional
 * data lines).
 *
 * FlexSPI controller is driven by the LUT(Look-up Table) registers
 * LUT registers are a look-up-table for sequences of instructions.
 * A valid sequence consists of four LUT registers.
 * Maximum 32 LUT sequences can be programmed simultaneously.
 *
 * LUTs are being created at run-time based on the commands passed
 * from the spi-mem framework, thus using single LUT index.
 *
 * Software triggered Flash read/write access by IP Bus.
 *
 * Memory mapped read access by AHB Bus.
 *
 * Based on SPI MEM interface and spi-fsl-qspi.c driver.
 *
 * Author:
 *     Yogesh Narayan Gaur <yogeshnarayan.gaur@nxp.com>
 *     Boris Brezillon <bbrezillon@kernel.org>
 *     Frieder Schrempf <frieder.schrempf@kontron.de>
 */

#include <linux/acpi.h>
#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 (31).
 */
#define SEQID_LUT                       31

/* Registers used by the driver */
#define FSPI_MCR0                       0x00
#define FSPI_MCR0_AHB_TIMEOUT(x)        ((x) << 24)
#define FSPI_MCR0_IP_TIMEOUT(x)         ((x) << 16)
#define FSPI_MCR0_LEARN_EN              BIT(15)
#define FSPI_MCR0_SCRFRUN_EN            BIT(14)
#define FSPI_MCR0_OCTCOMB_EN            BIT(13)
#define FSPI_MCR0_DOZE_EN               BIT(12)
#define FSPI_MCR0_HSEN                  BIT(11)
#define FSPI_MCR0_SERCLKDIV             BIT(8)
#define FSPI_MCR0_ATDF_EN               BIT(7)
#define FSPI_MCR0_ARDF_EN               BIT(6)
#define FSPI_MCR0_RXCLKSRC(x)           ((x) << 4)
#define FSPI_MCR0_END_CFG(x)            ((x) << 2)
#define FSPI_MCR0_MDIS                  BIT(1)
#define FSPI_MCR0_SWRST                 BIT(0)

#define FSPI_MCR1                       0x04
#define FSPI_MCR1_SEQ_TIMEOUT(x)        ((x) << 16)
#define FSPI_MCR1_AHB_TIMEOUT(x)        (x)

#define FSPI_MCR2                       0x08
#define FSPI_MCR2_IDLE_WAIT(x)          ((x) << 24)
#define FSPI_MCR2_SAMEDEVICEEN          BIT(15)
#define FSPI_MCR2_CLRLRPHS              BIT(14)
#define FSPI_MCR2_ABRDATSZ              BIT(8)
#define FSPI_MCR2_ABRLEARN              BIT(7)
#define FSPI_MCR2_ABR_READ              BIT(6)
#define FSPI_MCR2_ABRWRITE              BIT(5)
#define FSPI_MCR2_ABRDUMMY              BIT(4)
#define FSPI_MCR2_ABR_MODE              BIT(3)
#define FSPI_MCR2_ABRCADDR              BIT(2)
#define FSPI_MCR2_ABRRADDR              BIT(1)
#define FSPI_MCR2_ABR_CMD               BIT(0)

#define FSPI_AHBCR                      0x0c
#define FSPI_AHBCR_RDADDROPT            BIT(6)
#define FSPI_AHBCR_PREF_EN              BIT(5)
#define FSPI_AHBCR_BUFF_EN              BIT(4)
#define FSPI_AHBCR_CACH_EN              BIT(3)
#define FSPI_AHBCR_CLRTXBUF             BIT(2)
#define FSPI_AHBCR_CLRRXBUF             BIT(1)
#define FSPI_AHBCR_PAR_EN               BIT(0)

#define FSPI_INTEN                      0x10
#define FSPI_INTEN_SCLKSBWR             BIT(9)
#define FSPI_INTEN_SCLKSBRD             BIT(8)
#define FSPI_INTEN_DATALRNFL            BIT(7)
#define FSPI_INTEN_IPTXWE               BIT(6)
#define FSPI_INTEN_IPRXWA               BIT(5)
#define FSPI_INTEN_AHBCMDERR            BIT(4)
#define FSPI_INTEN_IPCMDERR             BIT(3)
#define FSPI_INTEN_AHBCMDGE             BIT(2)
#define FSPI_INTEN_IPCMDGE              BIT(1)
#define FSPI_INTEN_IPCMDDONE            BIT(0)

#define FSPI_INTR                       0x14
#define FSPI_INTR_SCLKSBWR              BIT(9)
#define FSPI_INTR_SCLKSBRD              BIT(8)
#define FSPI_INTR_DATALRNFL             BIT(7)
#define FSPI_INTR_IPTXWE                BIT(6)
#define FSPI_INTR_IPRXWA                BIT(5)
#define FSPI_INTR_AHBCMDERR             BIT(4)
#define FSPI_INTR_IPCMDERR              BIT(3)
#define FSPI_INTR_AHBCMDGE              BIT(2)
#define FSPI_INTR_IPCMDGE               BIT(1)
#define FSPI_INTR_IPCMDDONE             BIT(0)

#define FSPI_LUTKEY                     0x18
#define FSPI_LUTKEY_VALUE               0x5AF05AF0

#define FSPI_LCKCR                      0x1C

#define FSPI_LCKER_LOCK                 0x1
#define FSPI_LCKER_UNLOCK               0x2

#define FSPI_BUFXCR_INVALID_MSTRID      0xE
#define FSPI_AHBRX_BUF0CR0              0x20
#define FSPI_AHBRX_BUF1CR0              0x24
#define FSPI_AHBRX_BUF2CR0              0x28
#define FSPI_AHBRX_BUF3CR0              0x2C
#define FSPI_AHBRX_BUF4CR0              0x30
#define FSPI_AHBRX_BUF5CR0              0x34
#define FSPI_AHBRX_BUF6CR0              0x38
#define FSPI_AHBRX_BUF7CR0              0x3C
#define FSPI_AHBRXBUF0CR7_PREF          BIT(31)

#define FSPI_AHBRX_BUF0CR1              0x40
#define FSPI_AHBRX_BUF1CR1              0x44
#define FSPI_AHBRX_BUF2CR1              0x48
#define FSPI_AHBRX_BUF3CR1              0x4C
#define FSPI_AHBRX_BUF4CR1              0x50
#define FSPI_AHBRX_BUF5CR1              0x54
#define FSPI_AHBRX_BUF6CR1              0x58
#define FSPI_AHBRX_BUF7CR1              0x5C

#define FSPI_FLSHA1CR0                  0x60
#define FSPI_FLSHA2CR0                  0x64
#define FSPI_FLSHB1CR0                  0x68
#define FSPI_FLSHB2CR0                  0x6C
#define FSPI_FLSHXCR0_SZ_KB             10
#define FSPI_FLSHXCR0_SZ(x)             ((x) >> FSPI_FLSHXCR0_SZ_KB)

#define FSPI_FLSHA1CR1                  0x70
#define FSPI_FLSHA2CR1                  0x74
#define FSPI_FLSHB1CR1                  0x78
#define FSPI_FLSHB2CR1                  0x7C
#define FSPI_FLSHXCR1_CSINTR(x)         ((x) << 16)
#define FSPI_FLSHXCR1_CAS(x)            ((x) << 11)
#define FSPI_FLSHXCR1_WA                BIT(10)
#define FSPI_FLSHXCR1_TCSH(x)           ((x) << 5)
#define FSPI_FLSHXCR1_TCSS(x)           (x)

#define FSPI_FLSHA1CR2                  0x80
#define FSPI_FLSHA2CR2                  0x84
#define FSPI_FLSHB1CR2                  0x88
#define FSPI_FLSHB2CR2                  0x8C
#define FSPI_FLSHXCR2_CLRINSP           BIT(24)
#define FSPI_FLSHXCR2_AWRWAIT           BIT(16)
#define FSPI_FLSHXCR2_AWRSEQN_SHIFT     13
#define FSPI_FLSHXCR2_AWRSEQI_SHIFT     8
#define FSPI_FLSHXCR2_ARDSEQN_SHIFT     5
#define FSPI_FLSHXCR2_ARDSEQI_SHIFT     0

#define FSPI_IPCR0                      0xA0

#define FSPI_IPCR1                      0xA4
#define FSPI_IPCR1_IPAREN               BIT(31)
#define FSPI_IPCR1_SEQNUM_SHIFT         24
#define FSPI_IPCR1_SEQID_SHIFT          16
#define FSPI_IPCR1_IDATSZ(x)            (x)

#define FSPI_IPCMD                      0xB0
#define FSPI_IPCMD_TRG                  BIT(0)

#define FSPI_DLPR                       0xB4

#define FSPI_IPRXFCR                    0xB8
#define FSPI_IPRXFCR_CLR                BIT(0)
#define FSPI_IPRXFCR_DMA_EN             BIT(1)
#define FSPI_IPRXFCR_WMRK(x)            ((x) << 2)

#define FSPI_IPTXFCR                    0xBC
#define FSPI_IPTXFCR_CLR                BIT(0)
#define FSPI_IPTXFCR_DMA_EN             BIT(1)
#define FSPI_IPTXFCR_WMRK(x)            ((x) << 2)

#define FSPI_DLLACR                     0xC0
#define FSPI_DLLACR_OVRDEN              BIT(8)

#define FSPI_DLLBCR                     0xC4
#define FSPI_DLLBCR_OVRDEN              BIT(8)

#define FSPI_STS0                       0xE0
#define FSPI_STS0_DLPHB(x)              ((x) << 8)
#define FSPI_STS0_DLPHA(x)              ((x) << 4)
#define FSPI_STS0_CMD_SRC(x)            ((x) << 2)
#define FSPI_STS0_ARB_IDLE              BIT(1)
#define FSPI_STS0_SEQ_IDLE              BIT(0)

#define FSPI_STS1                       0xE4
#define FSPI_STS1_IP_ERRCD(x)           ((x) << 24)
#define FSPI_STS1_IP_ERRID(x)           ((x) << 16)
#define FSPI_STS1_AHB_ERRCD(x)          ((x) << 8)
#define FSPI_STS1_AHB_ERRID(x)          (x)

#define FSPI_AHBSPNST                   0xEC
#define FSPI_AHBSPNST_DATLFT(x)         ((x) << 16)
#define FSPI_AHBSPNST_BUFID(x)          ((x) << 1)
#define FSPI_AHBSPNST_ACTIVE            BIT(0)

#define FSPI_IPRXFSTS                   0xF0
#define FSPI_IPRXFSTS_RDCNTR(x)         ((x) << 16)
#define FSPI_IPRXFSTS_FILL(x)           (x)

#define FSPI_IPTXFSTS                   0xF4
#define FSPI_IPTXFSTS_WRCNTR(x)         ((x) << 16)
#define FSPI_IPTXFSTS_FILL(x)           (x)

#define FSPI_RFDR                       0x100
#define FSPI_TFDR                       0x180

#define FSPI_LUT_BASE                   0x200
#define FSPI_LUT_OFFSET                 (SEQID_LUT * 4 * 4)
#define FSPI_LUT_REG(idx) \
        (FSPI_LUT_BASE + FSPI_LUT_OFFSET + (idx) * 4)

/* register map end */

/* Instruction set for the LUT register. */
#define LUT_STOP                        0x00
#define LUT_CMD                         0x01
#define LUT_ADDR                        0x02
#define LUT_CADDR_SDR                   0x03
#define LUT_MODE                        0x04
#define LUT_MODE2                       0x05
#define LUT_MODE4                       0x06
#define LUT_MODE8                       0x07
#define LUT_NXP_WRITE                   0x08
#define LUT_NXP_READ                    0x09
#define LUT_LEARN_SDR                   0x0A
#define LUT_DATSZ_SDR                   0x0B
#define LUT_DUMMY                       0x0C
#define LUT_DUMMY_RWDS_SDR              0x0D
#define LUT_JMP_ON_CS                   0x1F
#define LUT_CMD_DDR                     0x21
#define LUT_ADDR_DDR                    0x22
#define LUT_CADDR_DDR                   0x23
#define LUT_MODE_DDR                    0x24
#define LUT_MODE2_DDR                   0x25
#define LUT_MODE4_DDR                   0x26
#define LUT_MODE8_DDR                   0x27
#define LUT_WRITE_DDR                   0x28
#define LUT_READ_DDR                    0x29
#define LUT_LEARN_DDR                   0x2A
#define LUT_DATSZ_DDR                   0x2B
#define LUT_DUMMY_DDR                   0x2C
#define LUT_DUMMY_RWDS_DDR              0x2D

/*
 * Calculate number of required PAD bits for LUT register.
 *
 * The pad stands for the number of IO lines [0:7].
 * For example, the octal read needs eight IO lines,
 * so you should use LUT_PAD(8). This macro
 * returns 3 i.e. use eight (2^3) IP lines for read.
 */
#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 PAD_SHIFT               8
#define INSTR_SHIFT             10
#define OPRND_SHIFT             16

/* Macros for constructing the LUT register. */
#define LUT_DEF(idx, ins, pad, opr)                       \
        ((((ins) << INSTR_SHIFT) | ((pad) << PAD_SHIFT) | \
        (opr)) << (((idx) % 2) * OPRND_SHIFT))

#define POLL_TOUT               5000
#define NXP_FSPI_MAX_CHIPSELECT         4
#define NXP_FSPI_MIN_IOMAP      SZ_4M

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

static const struct nxp_fspi_devtype_data lx2160a_data = {
        .rxfifo = SZ_512,       /* (64  * 64 bits)  */
        .txfifo = SZ_1K,        /* (128 * 64 bits)  */
        .ahb_buf_size = SZ_2K,  /* (256 * 64 bits)  */
        .quirks = 0,
        .little_endian = true,  /* little-endian    */
};

static const struct nxp_fspi_devtype_data imx8mm_data = {
        .rxfifo = SZ_512,       /* (64  * 64 bits)  */
        .txfifo = SZ_1K,        /* (128 * 64 bits)  */
        .ahb_buf_size = SZ_2K,  /* (256 * 64 bits)  */
        .quirks = 0,
        .little_endian = true,  /* little-endian    */
};

static const struct nxp_fspi_devtype_data imx8qxp_data = {
        .rxfifo = SZ_512,       /* (64  * 64 bits)  */
        .txfifo = SZ_1K,        /* (128 * 64 bits)  */
        .ahb_buf_size = SZ_2K,  /* (256 * 64 bits)  */
        .quirks = 0,
        .little_endian = true,  /* little-endian    */
};

struct nxp_fspi {
        void __iomem *iobase;
        void __iomem *ahb_addr;
        u32 memmap_phy;
        u32 memmap_phy_size;
        u32 memmap_start;
        u32 memmap_len;
        struct clk *clk, *clk_en;
        struct device *dev;
        struct completion c;
        const struct nxp_fspi_devtype_data *devtype_data;
        struct mutex lock;
        struct pm_qos_request pm_qos_req;
        int selected;
};

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

static u32 fspi_readl(struct nxp_fspi *f, void __iomem *addr)
{
        if (f->devtype_data->little_endian)
                return ioread32(addr);
        else
                return ioread32be(addr);
}

static irqreturn_t nxp_fspi_irq_handler(int irq, void *dev_id)
{
        struct nxp_fspi *f = dev_id;
        u32 reg;

        /* clear interrupt */
        reg = fspi_readl(f, f->iobase + FSPI_INTR);
        fspi_writel(f, FSPI_INTR_IPCMDDONE, f->iobase + FSPI_INTR);

        if (reg & FSPI_INTR_IPCMDDONE)
                complete(&f->c);

        return IRQ_HANDLED;
}

static int nxp_fspi_check_buswidth(struct nxp_fspi *f, u8 width)
{
        switch (width) {
        case 1:
        case 2:
        case 4:
        case 8:
                return 0;
        }

        return -ENOTSUPP;
}

static bool nxp_fspi_supports_op(struct spi_mem *mem,
                                 const struct spi_mem_op *op)
{
        struct nxp_fspi *f = spi_controller_get_devdata(mem->spi->master);
        int ret;

        ret = nxp_fspi_check_buswidth(f, op->cmd.buswidth);

        if (op->addr.nbytes)
                ret |= nxp_fspi_check_buswidth(f, op->addr.buswidth);

        if (op->dummy.nbytes)
                ret |= nxp_fspi_check_buswidth(f, op->dummy.buswidth);

        if (op->data.nbytes)
                ret |= nxp_fspi_check_buswidth(f, op->data.buswidth);

        if (ret)
                return false;

        /*
         * The number of address bytes should be equal to or less than 4 bytes.
         */
        if (op->addr.nbytes > 4)
                return false;

        /*
         * If requested address value is greater than controller assigned
         * memory mapped space, return error as it didn't fit in the range
         * of assigned address space.
         */
        if (op->addr.val >= f->memmap_phy_size)
                return false;

        /* Max 64 dummy clock cycles supported */
        if (op->dummy.buswidth &&
            (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 > f->devtype_data->ahb_buf_size ||
             (op->data.nbytes > f->devtype_data->rxfifo - 4 &&
              !IS_ALIGNED(op->data.nbytes, 8))))
                return false;

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

        return spi_mem_default_supports_op(mem, op);
}

/* Instead of busy looping invoke readl_poll_timeout functionality. */
static int fspi_readl_poll_tout(struct nxp_fspi *f, void __iomem *base,
                                u32 mask, u32 delay_us,
                                u32 timeout_us, bool c)
{
        u32 reg;

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

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

/*
 * If the slave device content being changed by Write/Erase, need to
 * invalidate the AHB buffer. This can be achieved by doing the reset
 * of controller after setting MCR0[SWRESET] bit.
 */
static inline void nxp_fspi_invalid(struct nxp_fspi *f)
{
        u32 reg;
        int ret;

        reg = fspi_readl(f, f->iobase + FSPI_MCR0);
        fspi_writel(f, reg | FSPI_MCR0_SWRST, f->iobase + FSPI_MCR0);

        /* w1c register, wait unit clear */
        ret = fspi_readl_poll_tout(f, f->iobase + FSPI_MCR0,
                                   FSPI_MCR0_SWRST, 0, POLL_TOUT, false);
        WARN_ON(ret);
}

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

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

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

        /* dummy bytes, if needed */
        if (op->dummy.nbytes) {
                lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_DUMMY,
                /*
                 * Due to FlexSPI controller limitation number of PAD for dummy
                 * buswidth needs to be programmed as equal to data buswidth.
                 */
                                              LUT_PAD(op->data.buswidth),
                                              op->dummy.nbytes * 8 /
                                              op->dummy.buswidth);
                lutidx++;
        }

        /* read/write data bytes */
        if (op->data.nbytes) {
                lutval[lutidx / 2] |= LUT_DEF(lutidx,
                                              op->data.dir == SPI_MEM_DATA_IN ?
                                              LUT_NXP_READ : LUT_NXP_WRITE,
                                              LUT_PAD(op->data.buswidth),
                                              0);
                lutidx++;
        }

        /* stop condition. */
        lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_STOP, 0, 0);

        /* unlock LUT */
        fspi_writel(f, FSPI_LUTKEY_VALUE, f->iobase + FSPI_LUTKEY);
        fspi_writel(f, FSPI_LCKER_UNLOCK, f->iobase + FSPI_LCKCR);

        /* fill LUT */
        for (i = 0; i < ARRAY_SIZE(lutval); i++)
                fspi_writel(f, lutval[i], base + FSPI_LUT_REG(i));

        dev_dbg(f->dev, "CMD[%x] lutval[0:%x \t 1:%x \t 2:%x \t 3:%x]\n",
                op->cmd.opcode, lutval[0], lutval[1], lutval[2], lutval[3]);

        /* lock LUT */
        fspi_writel(f, FSPI_LUTKEY_VALUE, f->iobase + FSPI_LUTKEY);
        fspi_writel(f, FSPI_LCKER_LOCK, f->iobase + FSPI_LCKCR);
}

static int nxp_fspi_clk_prep_enable(struct nxp_fspi *f)
{
        int ret;

        if (is_acpi_node(f->dev->fwnode))
                return 0;

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

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

        return 0;
}

static int nxp_fspi_clk_disable_unprep(struct nxp_fspi *f)
{
        if (is_acpi_node(f->dev->fwnode))
                return 0;

        clk_disable_unprepare(f->clk);
        clk_disable_unprepare(f->clk_en);

        return 0;
}

/*
 * In FlexSPI controller, flash access is based on value of FSPI_FLSHXXCR0
 * register and start base address of the slave device.
 *
 *                                                          (Higher address)
 *                              --------    <-- FLSHB2CR0
 *                              |  B2  |
 *                              |      |
 *      B2 start address -->    --------    <-- FLSHB1CR0
 *                              |  B1  |
 *                              |      |
 *      B1 start address -->    --------    <-- FLSHA2CR0
 *                              |  A2  |
 *                              |      |
 *      A2 start address -->    --------    <-- FLSHA1CR0
 *                              |  A1  |
 *                              |      |
 *      A1 start address -->    --------                    (Lower address)
 *
 *
 * Start base address defines the starting address range for given CS and
 * FSPI_FLSHXXCR0 defines the size of the slave device connected at given CS.
 *
 * But, different targets are having different combinations of number of CS,
 * some targets only have single CS or two CS covering controller's full
 * memory mapped space area.
 * Thus, implementation is being done as independent of the size and number
 * of the connected slave device.
 * Assign controller memory mapped space size as the size to the connected
 * slave device.
 * Mark FLSHxxCR0 as zero initially and then assign value only to the selected
 * chip-select Flash configuration register.
 *
 * For e.g. to access CS2 (B1), FLSHB1CR0 register would be equal to the
 * memory mapped size of the controller.
 * Value for rest of the CS FLSHxxCR0 register would be zero.
 *
 */
static void nxp_fspi_select_mem(struct nxp_fspi *f, struct spi_device *spi)
{
        unsigned long rate = spi->max_speed_hz;
        int ret;
        uint64_t size_kb;

        /*
         * Return, if previously selected slave device is same as current
         * requested slave device.
         */
        if (f->selected == spi->chip_select)
                return;

        /* Reset FLSHxxCR0 registers */
        fspi_writel(f, 0, f->iobase + FSPI_FLSHA1CR0);
        fspi_writel(f, 0, f->iobase + FSPI_FLSHA2CR0);
        fspi_writel(f, 0, f->iobase + FSPI_FLSHB1CR0);
        fspi_writel(f, 0, f->iobase + FSPI_FLSHB2CR0);

        /* Assign controller memory mapped space as size, KBytes, of flash. */
        size_kb = FSPI_FLSHXCR0_SZ(f->memmap_phy_size);

        fspi_writel(f, size_kb, f->iobase + FSPI_FLSHA1CR0 +
                    4 * spi->chip_select);

        dev_dbg(f->dev, "Slave device [CS:%x] selected\n", spi->chip_select);

        nxp_fspi_clk_disable_unprep(f);

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

        ret = nxp_fspi_clk_prep_enable(f);
        if (ret)
                return;

        f->selected = spi->chip_select;
}

static int nxp_fspi_read_ahb(struct nxp_fspi *f, const struct spi_mem_op *op)
{
        u32 start = op->addr.val;
        u32 len = op->data.nbytes;

        /* if necessary, ioremap before AHB read */
        if ((!f->ahb_addr) || start < f->memmap_start ||
             start + len > f->memmap_start + f->memmap_len) {
                if (f->ahb_addr)
                        iounmap(f->ahb_addr);

                f->memmap_start = start;
                f->memmap_len = len > NXP_FSPI_MIN_IOMAP ?
                                len : NXP_FSPI_MIN_IOMAP;

                f->ahb_addr = ioremap_wc(f->memmap_phy + f->memmap_start,
                                         f->memmap_len);

                if (!f->ahb_addr) {
                        dev_err(f->dev, "failed to alloc memory\n");
                        return -ENOMEM;
                }
        }

        /* Read out the data directly from the AHB buffer. */
        memcpy_fromio(op->data.buf.in,
                      f->ahb_addr + start - f->memmap_start, len);

        return 0;
}

static void nxp_fspi_fill_txfifo(struct nxp_fspi *f,
                                 const struct spi_mem_op *op)
{
        void __iomem *base = f->iobase;
        int i, ret;
        u8 *buf = (u8 *) op->data.buf.out;

        /* clear the TX FIFO. */
        fspi_writel(f, FSPI_IPTXFCR_CLR, base + FSPI_IPTXFCR);

        /*
         * Default value of water mark level is 8 bytes, hence in single
         * write request controller can write max 8 bytes of data.
         */

        for (i = 0; i < ALIGN_DOWN(op->data.nbytes, 8); i += 8) {
                /* Wait for TXFIFO empty */
                ret = fspi_readl_poll_tout(f, f->iobase + FSPI_INTR,
                                           FSPI_INTR_IPTXWE, 0,
                                           POLL_TOUT, true);
                WARN_ON(ret);

                fspi_writel(f, *(u32 *) (buf + i), base + FSPI_TFDR);
                fspi_writel(f, *(u32 *) (buf + i + 4), base + FSPI_TFDR + 4);
                fspi_writel(f, FSPI_INTR_IPTXWE, base + FSPI_INTR);
        }

        if (i < op->data.nbytes) {
                u32 data = 0;
                int j;
                /* Wait for TXFIFO empty */
                ret = fspi_readl_poll_tout(f, f->iobase + FSPI_INTR,
                                           FSPI_INTR_IPTXWE, 0,
                                           POLL_TOUT, true);
                WARN_ON(ret);

                for (j = 0; j < ALIGN(op->data.nbytes - i, 4); j += 4) {
                        memcpy(&data, buf + i + j, 4);
                        fspi_writel(f, data, base + FSPI_TFDR + j);
                }
                fspi_writel(f, FSPI_INTR_IPTXWE, base + FSPI_INTR);
        }
}

static void nxp_fspi_read_rxfifo(struct nxp_fspi *f,
                          const struct spi_mem_op *op)
{
        void __iomem *base = f->iobase;
        int i, ret;
        int len = op->data.nbytes;
        u8 *buf = (u8 *) op->data.buf.in;

        /*
         * Default value of water mark level is 8 bytes, hence in single
         * read request controller can read max 8 bytes of data.
         */
        for (i = 0; i < ALIGN_DOWN(len, 8); i += 8) {
                /* Wait for RXFIFO available */
                ret = fspi_readl_poll_tout(f, f->iobase + FSPI_INTR,
                                           FSPI_INTR_IPRXWA, 0,
                                           POLL_TOUT, true);
                WARN_ON(ret);

                *(u32 *)(buf + i) = fspi_readl(f, base + FSPI_RFDR);
                *(u32 *)(buf + i + 4) = fspi_readl(f, base + FSPI_RFDR + 4);
                /* move the FIFO pointer */
                fspi_writel(f, FSPI_INTR_IPRXWA, base + FSPI_INTR);
        }

        if (i < len) {
                u32 tmp;
                int size, j;

                buf = op->data.buf.in + i;
                /* Wait for RXFIFO available */
                ret = fspi_readl_poll_tout(f, f->iobase + FSPI_INTR,
                                           FSPI_INTR_IPRXWA, 0,
                                           POLL_TOUT, true);
                WARN_ON(ret);

                len = op->data.nbytes - i;
                for (j = 0; j < op->data.nbytes - i; j += 4) {
                        tmp = fspi_readl(f, base + FSPI_RFDR + j);
                        size = min(len, 4);
                        memcpy(buf + j, &tmp, size);
                        len -= size;
                }
        }

        /* invalid the RXFIFO */
        fspi_writel(f, FSPI_IPRXFCR_CLR, base + FSPI_IPRXFCR);
        /* move the FIFO pointer */
        fspi_writel(f, FSPI_INTR_IPRXWA, base + FSPI_INTR);
}

static int nxp_fspi_do_op(struct nxp_fspi *f, const struct spi_mem_op *op)
{
        void __iomem *base = f->iobase;
        int seqnum = 0;
        int err = 0;
        u32 reg;

        reg = fspi_readl(f, base + FSPI_IPRXFCR);
        /* invalid RXFIFO first */
        reg &= ~FSPI_IPRXFCR_DMA_EN;
        reg = reg | FSPI_IPRXFCR_CLR;
        fspi_writel(f, reg, base + FSPI_IPRXFCR);

        init_completion(&f->c);

        fspi_writel(f, op->addr.val, base + FSPI_IPCR0);
        /*
         * 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.
         */
        fspi_writel(f, op->data.nbytes |
                 (SEQID_LUT << FSPI_IPCR1_SEQID_SHIFT) |
                 (seqnum << FSPI_IPCR1_SEQNUM_SHIFT),
                 base + FSPI_IPCR1);

        /* Trigger the LUT now. */
        fspi_writel(f, FSPI_IPCMD_TRG, base + FSPI_IPCMD);

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

        /* Invoke IP data read, if request is of data read. */
        if (!err && op->data.nbytes && op->data.dir == SPI_MEM_DATA_IN)
                nxp_fspi_read_rxfifo(f, op);

        return err;
}

static int nxp_fspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
{
        struct nxp_fspi *f = spi_controller_get_devdata(mem->spi->master);
        int err = 0;

        mutex_lock(&f->lock);

        /* Wait for controller being ready. */
        err = fspi_readl_poll_tout(f, f->iobase + FSPI_STS0,
                                   FSPI_STS0_ARB_IDLE, 1, POLL_TOUT, true);
        WARN_ON(err);

        nxp_fspi_select_mem(f, mem->spi);

        nxp_fspi_prepare_lut(f, 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 > (f->devtype_data->rxfifo - 4) &&
            op->data.dir == SPI_MEM_DATA_IN) {
                err = nxp_fspi_read_ahb(f, op);
        } else {
                if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_OUT)
                        nxp_fspi_fill_txfifo(f, op);

                err = nxp_fspi_do_op(f, op);
        }

        /* Invalidate the data in the AHB buffer. */
        nxp_fspi_invalid(f);

        mutex_unlock(&f->lock);

        return err;
}

static int nxp_fspi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
{
        struct nxp_fspi *f = spi_controller_get_devdata(mem->spi->master);

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

        return 0;
}

static int nxp_fspi_default_setup(struct nxp_fspi *f)
{
        void __iomem *base = f->iobase;
        int ret, i;
        u32 reg;

        /* disable and unprepare clock to avoid glitch pass to controller */
        nxp_fspi_clk_disable_unprep(f);

        /* the default frequency, we will change it later if necessary. */
        ret = clk_set_rate(f->clk, 20000000);
        if (ret)
                return ret;

        ret = nxp_fspi_clk_prep_enable(f);
        if (ret)
                return ret;

        /* Reset the module */
        /* w1c register, wait unit clear */
        ret = fspi_readl_poll_tout(f, f->iobase + FSPI_MCR0,
                                   FSPI_MCR0_SWRST, 0, POLL_TOUT, false);
        WARN_ON(ret);

        /* Disable the module */
        fspi_writel(f, FSPI_MCR0_MDIS, base + FSPI_MCR0);

        /* Reset the DLL register to default value */
        fspi_writel(f, FSPI_DLLACR_OVRDEN, base + FSPI_DLLACR);
        fspi_writel(f, FSPI_DLLBCR_OVRDEN, base + FSPI_DLLBCR);

        /* enable module */
        fspi_writel(f, FSPI_MCR0_AHB_TIMEOUT(0xFF) |
                    FSPI_MCR0_IP_TIMEOUT(0xFF) | (u32) FSPI_MCR0_OCTCOMB_EN,
                    base + FSPI_MCR0);

        /*
         * Disable same device enable bit and configure all slave devices
         * independently.
         */
        reg = fspi_readl(f, f->iobase + FSPI_MCR2);
        reg = reg & ~(FSPI_MCR2_SAMEDEVICEEN);
        fspi_writel(f, reg, base + FSPI_MCR2);

        /* AHB configuration for access buffer 0~7. */
        for (i = 0; i < 7; i++)
                fspi_writel(f, 0, base + FSPI_AHBRX_BUF0CR0 + 4 * i);

        /*
         * Set ADATSZ with the maximum AHB buffer size to improve the read
         * performance.
         */
        fspi_writel(f, (f->devtype_data->ahb_buf_size / 8 |
                  FSPI_AHBRXBUF0CR7_PREF), base + FSPI_AHBRX_BUF7CR0);

        /* prefetch and no start address alignment limitation */
        fspi_writel(f, FSPI_AHBCR_PREF_EN | FSPI_AHBCR_RDADDROPT,
                 base + FSPI_AHBCR);

        /* AHB Read - Set lut sequence ID for all CS. */
        fspi_writel(f, SEQID_LUT, base + FSPI_FLSHA1CR2);
        fspi_writel(f, SEQID_LUT, base + FSPI_FLSHA2CR2);
        fspi_writel(f, SEQID_LUT, base + FSPI_FLSHB1CR2);
        fspi_writel(f, SEQID_LUT, base + FSPI_FLSHB2CR2);

        f->selected = -1;

        /* enable the interrupt */
        fspi_writel(f, FSPI_INTEN_IPCMDDONE, base + FSPI_INTEN);

        return 0;
}

static const char *nxp_fspi_get_name(struct spi_mem *mem)
{
        struct nxp_fspi *f = spi_controller_get_devdata(mem->spi->master);
        struct device *dev = &mem->spi->dev;
        const char *name;

        // Set custom name derived from the platform_device of the controller.
        if (of_get_available_child_count(f->dev->of_node) == 1)
                return dev_name(f->dev);

        name = devm_kasprintf(dev, GFP_KERNEL,
                              "%s-%d", dev_name(f->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 nxp_fspi_mem_ops = {
        .adjust_op_size = nxp_fspi_adjust_op_size,
        .supports_op = nxp_fspi_supports_op,
        .exec_op = nxp_fspi_exec_op,
        .get_name = nxp_fspi_get_name,
};

static int nxp_fspi_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 nxp_fspi *f;
        int ret;
        u32 reg;

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

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

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

        platform_set_drvdata(pdev, f);

        /* find the resources - configuration register address space */
        if (is_acpi_node(f->dev->fwnode))
                res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        else
                res = platform_get_resource_byname(pdev,
                                IORESOURCE_MEM, "fspi_base");

        f->iobase = devm_ioremap_resource(dev, res);
        if (IS_ERR(f->iobase)) {
                ret = PTR_ERR(f->iobase);
                goto err_put_ctrl;
        }

        /* Clear potential interrupts */
        reg = fspi_readl(f, f->iobase + FSPI_INTR);
        if (reg)
                fspi_writel(f, reg, f->iobase + FSPI_INTR);


        /* find the resources - controller memory mapped space */
        if (is_acpi_node(f->dev->fwnode))
                res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
        else
                res = platform_get_resource_byname(pdev,
                                IORESOURCE_MEM, "fspi_mmap");

        if (!res) {
                ret = -ENODEV;
                goto err_put_ctrl;
        }

        /* assign memory mapped starting address and mapped size. */
        f->memmap_phy = res->start;
        f->memmap_phy_size = resource_size(res);

        /* find the clocks */
        if (dev_of_node(&pdev->dev)) {
                f->clk_en = devm_clk_get(dev, "fspi_en");
                if (IS_ERR(f->clk_en)) {
                        ret = PTR_ERR(f->clk_en);
                        goto err_put_ctrl;
                }

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

                ret = nxp_fspi_clk_prep_enable(f);
                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)
                goto err_disable_clk;

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

        mutex_init(&f->lock);

        ctlr->bus_num = -1;
        ctlr->num_chipselect = NXP_FSPI_MAX_CHIPSELECT;
        ctlr->mem_ops = &nxp_fspi_mem_ops;

        nxp_fspi_default_setup(f);

        ctlr->dev.of_node = np;

        ret = devm_spi_register_controller(&pdev->dev, ctlr);
        if (ret)
                goto err_destroy_mutex;

        return 0;

err_destroy_mutex:
        mutex_destroy(&f->lock);

err_disable_clk:
        nxp_fspi_clk_disable_unprep(f);

err_put_ctrl:
        spi_controller_put(ctlr);

        dev_err(dev, "NXP FSPI probe failed\n");
        return ret;
}

static int nxp_fspi_remove(struct platform_device *pdev)
{
        struct nxp_fspi *f = platform_get_drvdata(pdev);

        /* disable the hardware */
        fspi_writel(f, FSPI_MCR0_MDIS, f->iobase + FSPI_MCR0);

        nxp_fspi_clk_disable_unprep(f);

        mutex_destroy(&f->lock);

        if (f->ahb_addr)
                iounmap(f->ahb_addr);

        return 0;
}

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

static int nxp_fspi_resume(struct device *dev)
{
        struct nxp_fspi *f = dev_get_drvdata(dev);

        nxp_fspi_default_setup(f);

        return 0;
}

static const struct of_device_id nxp_fspi_dt_ids[] = {
        { .compatible = "nxp,lx2160a-fspi", .data = (void *)&lx2160a_data, },
        { .compatible = "nxp,imx8mm-fspi", .data = (void *)&imx8mm_data, },
        { .compatible = "nxp,imx8qxp-fspi", .data = (void *)&imx8qxp_data, },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, nxp_fspi_dt_ids);

#ifdef CONFIG_ACPI
static const struct acpi_device_id nxp_fspi_acpi_ids[] = {
        { "NXP0009", .driver_data = (kernel_ulong_t)&lx2160a_data, },
        {}
};
MODULE_DEVICE_TABLE(acpi, nxp_fspi_acpi_ids);
#endif

static const struct dev_pm_ops nxp_fspi_pm_ops = {
        .suspend        = nxp_fspi_suspend,
        .resume         = nxp_fspi_resume,
};

static struct platform_driver nxp_fspi_driver = {
        .driver = {
                .name   = "nxp-fspi",
                .of_match_table = nxp_fspi_dt_ids,
                .acpi_match_table = ACPI_PTR(nxp_fspi_acpi_ids),
                .pm =   &nxp_fspi_pm_ops,
        },
        .probe          = nxp_fspi_probe,
        .remove         = nxp_fspi_remove,
};
module_platform_driver(nxp_fspi_driver);

MODULE_DESCRIPTION("NXP FSPI Controller Driver");
MODULE_AUTHOR("NXP Semiconductor");
MODULE_AUTHOR("Yogesh Narayan Gaur <yogeshnarayan.gaur@nxp.com>");
MODULE_AUTHOR("Boris Brezillon <bbrezillon@kernel.org>");
MODULE_AUTHOR("Frieder Schrempf <frieder.schrempf@kontron.de>");
MODULE_LICENSE("GPL v2");