root/drivers/spi/spi-ti-qspi.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * TI QSPI driver
 *
 * Copyright (C) 2013 Texas Instruments Incorporated - https://www.ti.com
 * Author: Sourav Poddar <sourav.poddar@ti.com>
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/omap-dma.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
#include <linux/pinctrl/consumer.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/sizes.h>

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

struct ti_qspi_regs {
        u32 clkctrl;
};

struct ti_qspi {
        struct completion       transfer_complete;

        /* list synchronization */
        struct mutex            list_lock;

        struct spi_controller   *host;
        void __iomem            *base;
        void __iomem            *mmap_base;
        size_t                  mmap_size;
        struct regmap           *ctrl_base;
        unsigned int            ctrl_reg;
        struct clk              *fclk;
        struct device           *dev;

        struct ti_qspi_regs     ctx_reg;

        dma_addr_t              mmap_phys_base;
        dma_addr_t              rx_bb_dma_addr;
        void                    *rx_bb_addr;
        struct dma_chan         *rx_chan;

        u32 cmd;
        u32 dc;

        bool mmap_enabled;
        int current_cs;
};

#define QSPI_PID                        (0x0)
#define QSPI_SYSCONFIG                  (0x10)
#define QSPI_SPI_CLOCK_CNTRL_REG        (0x40)
#define QSPI_SPI_DC_REG                 (0x44)
#define QSPI_SPI_CMD_REG                (0x48)
#define QSPI_SPI_STATUS_REG             (0x4c)
#define QSPI_SPI_DATA_REG               (0x50)
#define QSPI_SPI_SETUP_REG(n)           ((0x54 + 4 * n))
#define QSPI_SPI_SWITCH_REG             (0x64)
#define QSPI_SPI_DATA_REG_1             (0x68)
#define QSPI_SPI_DATA_REG_2             (0x6c)
#define QSPI_SPI_DATA_REG_3             (0x70)

#define QSPI_COMPLETION_TIMEOUT         msecs_to_jiffies(2000)

/* Clock Control */
#define QSPI_CLK_EN                     (1 << 31)
#define QSPI_CLK_DIV_MAX                0xffff

/* Command */
#define QSPI_EN_CS(n)                   (n << 28)
#define QSPI_WLEN(n)                    ((n - 1) << 19)
#define QSPI_3_PIN                      (1 << 18)
#define QSPI_RD_SNGL                    (1 << 16)
#define QSPI_WR_SNGL                    (2 << 16)
#define QSPI_RD_DUAL                    (3 << 16)
#define QSPI_RD_QUAD                    (7 << 16)
#define QSPI_INVAL                      (4 << 16)
#define QSPI_FLEN(n)                    ((n - 1) << 0)
#define QSPI_WLEN_MAX_BITS              128
#define QSPI_WLEN_MAX_BYTES             16
#define QSPI_WLEN_MASK                  QSPI_WLEN(QSPI_WLEN_MAX_BITS)

/* STATUS REGISTER */
#define BUSY                            0x01
#define WC                              0x02

/* Device Control */
#define QSPI_DD(m, n)                   (m << (3 + n * 8))
#define QSPI_CKPHA(n)                   (1 << (2 + n * 8))
#define QSPI_CSPOL(n)                   (1 << (1 + n * 8))
#define QSPI_CKPOL(n)                   (1 << (n * 8))

#define QSPI_FRAME                      4096

#define QSPI_AUTOSUSPEND_TIMEOUT         2000

#define MEM_CS_EN(n)                    ((n + 1) << 8)
#define MEM_CS_MASK                     (7 << 8)

#define MM_SWITCH                       0x1

#define QSPI_SETUP_RD_NORMAL            (0x0 << 12)
#define QSPI_SETUP_RD_DUAL              (0x1 << 12)
#define QSPI_SETUP_RD_QUAD              (0x3 << 12)
#define QSPI_SETUP_ADDR_SHIFT           8
#define QSPI_SETUP_DUMMY_SHIFT          10

#define QSPI_DMA_BUFFER_SIZE            SZ_64K

static inline unsigned long ti_qspi_read(struct ti_qspi *qspi,
                unsigned long reg)
{
        return readl(qspi->base + reg);
}

static inline void ti_qspi_write(struct ti_qspi *qspi,
                unsigned long val, unsigned long reg)
{
        writel(val, qspi->base + reg);
}

static int ti_qspi_setup(struct spi_device *spi)
{
        struct ti_qspi  *qspi = spi_controller_get_devdata(spi->controller);
        int ret;

        if (spi->controller->busy) {
                dev_dbg(qspi->dev, "host busy doing other transfers\n");
                return -EBUSY;
        }

        if (!qspi->host->max_speed_hz) {
                dev_err(qspi->dev, "spi max frequency not defined\n");
                return -EINVAL;
        }

        spi->max_speed_hz = min(spi->max_speed_hz, qspi->host->max_speed_hz);

        ret = pm_runtime_resume_and_get(qspi->dev);
        if (ret < 0) {
                dev_err(qspi->dev, "pm_runtime_get_sync() failed\n");
                return ret;
        }

        ret = pm_runtime_put_autosuspend(qspi->dev);
        if (ret < 0) {
                dev_err(qspi->dev, "pm_runtime_put_autosuspend() failed\n");
                return ret;
        }

        return 0;
}

static void ti_qspi_setup_clk(struct ti_qspi *qspi, u32 speed_hz)
{
        struct ti_qspi_regs *ctx_reg = &qspi->ctx_reg;
        int clk_div;
        u32 clk_ctrl_reg, clk_rate, clk_ctrl_new;

        clk_rate = clk_get_rate(qspi->fclk);
        clk_div = DIV_ROUND_UP(clk_rate, speed_hz) - 1;
        clk_div = clamp(clk_div, 0, QSPI_CLK_DIV_MAX);
        dev_dbg(qspi->dev, "hz: %d, clock divider %d\n", speed_hz, clk_div);

        pm_runtime_resume_and_get(qspi->dev);

        clk_ctrl_new = QSPI_CLK_EN | clk_div;
        if (ctx_reg->clkctrl != clk_ctrl_new) {
                clk_ctrl_reg = ti_qspi_read(qspi, QSPI_SPI_CLOCK_CNTRL_REG);

                clk_ctrl_reg &= ~QSPI_CLK_EN;

                /* disable SCLK */
                ti_qspi_write(qspi, clk_ctrl_reg, QSPI_SPI_CLOCK_CNTRL_REG);

                /* enable SCLK */
                ti_qspi_write(qspi, clk_ctrl_new, QSPI_SPI_CLOCK_CNTRL_REG);
                ctx_reg->clkctrl = clk_ctrl_new;
        }

        pm_runtime_put_autosuspend(qspi->dev);
}

static void ti_qspi_restore_ctx(struct ti_qspi *qspi)
{
        struct ti_qspi_regs *ctx_reg = &qspi->ctx_reg;

        ti_qspi_write(qspi, ctx_reg->clkctrl, QSPI_SPI_CLOCK_CNTRL_REG);
}

static inline u32 qspi_is_busy(struct ti_qspi *qspi)
{
        u32 stat;
        unsigned long timeout = jiffies + QSPI_COMPLETION_TIMEOUT;

        stat = ti_qspi_read(qspi, QSPI_SPI_STATUS_REG);
        while ((stat & BUSY) && time_after(timeout, jiffies)) {
                cpu_relax();
                stat = ti_qspi_read(qspi, QSPI_SPI_STATUS_REG);
        }

        WARN(stat & BUSY, "qspi busy\n");
        return stat & BUSY;
}

static inline int ti_qspi_poll_wc(struct ti_qspi *qspi)
{
        u32 stat;
        unsigned long timeout = jiffies + QSPI_COMPLETION_TIMEOUT;

        do {
                stat = ti_qspi_read(qspi, QSPI_SPI_STATUS_REG);
                if (stat & WC)
                        return 0;
                cpu_relax();
        } while (time_after(timeout, jiffies));

        stat = ti_qspi_read(qspi, QSPI_SPI_STATUS_REG);
        if (stat & WC)
                return 0;
        return  -ETIMEDOUT;
}

static int qspi_write_msg(struct ti_qspi *qspi, struct spi_transfer *t,
                          int count)
{
        int wlen, xfer_len;
        unsigned int cmd;
        const u8 *txbuf;
        u32 data;

        txbuf = t->tx_buf;
        cmd = qspi->cmd | QSPI_WR_SNGL;
        wlen = t->bits_per_word >> 3;   /* in bytes */
        xfer_len = wlen;

        while (count) {
                if (qspi_is_busy(qspi))
                        return -EBUSY;

                switch (wlen) {
                case 1:
                        dev_dbg(qspi->dev, "tx cmd %08x dc %08x data %02x\n",
                                        cmd, qspi->dc, *txbuf);
                        if (count >= QSPI_WLEN_MAX_BYTES) {
                                u32 *txp = (u32 *)txbuf;

                                data = cpu_to_be32(*txp++);
                                writel(data, qspi->base +
                                       QSPI_SPI_DATA_REG_3);
                                data = cpu_to_be32(*txp++);
                                writel(data, qspi->base +
                                       QSPI_SPI_DATA_REG_2);
                                data = cpu_to_be32(*txp++);
                                writel(data, qspi->base +
                                       QSPI_SPI_DATA_REG_1);
                                data = cpu_to_be32(*txp++);
                                writel(data, qspi->base +
                                       QSPI_SPI_DATA_REG);
                                xfer_len = QSPI_WLEN_MAX_BYTES;
                                cmd |= QSPI_WLEN(QSPI_WLEN_MAX_BITS);
                        } else {
                                writeb(*txbuf, qspi->base + QSPI_SPI_DATA_REG);
                                cmd = qspi->cmd | QSPI_WR_SNGL;
                                xfer_len = wlen;
                                cmd |= QSPI_WLEN(wlen);
                        }
                        break;
                case 2:
                        dev_dbg(qspi->dev, "tx cmd %08x dc %08x data %04x\n",
                                        cmd, qspi->dc, *txbuf);
                        writew(*((u16 *)txbuf), qspi->base + QSPI_SPI_DATA_REG);
                        break;
                case 4:
                        dev_dbg(qspi->dev, "tx cmd %08x dc %08x data %08x\n",
                                        cmd, qspi->dc, *txbuf);
                        writel(*((u32 *)txbuf), qspi->base + QSPI_SPI_DATA_REG);
                        break;
                }

                ti_qspi_write(qspi, cmd, QSPI_SPI_CMD_REG);
                if (ti_qspi_poll_wc(qspi)) {
                        dev_err(qspi->dev, "write timed out\n");
                        return -ETIMEDOUT;
                }
                txbuf += xfer_len;
                count -= xfer_len;
        }

        return 0;
}

static int qspi_read_msg(struct ti_qspi *qspi, struct spi_transfer *t,
                         int count)
{
        int wlen;
        unsigned int cmd;
        u32 rx;
        u8 rxlen, rx_wlen;
        u8 *rxbuf;

        rxbuf = t->rx_buf;
        cmd = qspi->cmd;
        switch (t->rx_nbits) {
        case SPI_NBITS_DUAL:
                cmd |= QSPI_RD_DUAL;
                break;
        case SPI_NBITS_QUAD:
                cmd |= QSPI_RD_QUAD;
                break;
        default:
                cmd |= QSPI_RD_SNGL;
                break;
        }
        wlen = t->bits_per_word >> 3;   /* in bytes */
        rx_wlen = wlen;

        while (count) {
                dev_dbg(qspi->dev, "rx cmd %08x dc %08x\n", cmd, qspi->dc);
                if (qspi_is_busy(qspi))
                        return -EBUSY;

                switch (wlen) {
                case 1:
                        /*
                         * Optimize the 8-bit words transfers, as used by
                         * the SPI flash devices.
                         */
                        if (count >= QSPI_WLEN_MAX_BYTES) {
                                rxlen = QSPI_WLEN_MAX_BYTES;
                        } else {
                                rxlen = min(count, 4);
                        }
                        rx_wlen = rxlen << 3;
                        cmd &= ~QSPI_WLEN_MASK;
                        cmd |= QSPI_WLEN(rx_wlen);
                        break;
                default:
                        rxlen = wlen;
                        break;
                }

                ti_qspi_write(qspi, cmd, QSPI_SPI_CMD_REG);
                if (ti_qspi_poll_wc(qspi)) {
                        dev_err(qspi->dev, "read timed out\n");
                        return -ETIMEDOUT;
                }

                switch (wlen) {
                case 1:
                        /*
                         * Optimize the 8-bit words transfers, as used by
                         * the SPI flash devices.
                         */
                        if (count >= QSPI_WLEN_MAX_BYTES) {
                                u32 *rxp = (u32 *) rxbuf;
                                rx = readl(qspi->base + QSPI_SPI_DATA_REG_3);
                                *rxp++ = be32_to_cpu(rx);
                                rx = readl(qspi->base + QSPI_SPI_DATA_REG_2);
                                *rxp++ = be32_to_cpu(rx);
                                rx = readl(qspi->base + QSPI_SPI_DATA_REG_1);
                                *rxp++ = be32_to_cpu(rx);
                                rx = readl(qspi->base + QSPI_SPI_DATA_REG);
                                *rxp++ = be32_to_cpu(rx);
                        } else {
                                u8 *rxp = rxbuf;
                                rx = readl(qspi->base + QSPI_SPI_DATA_REG);
                                if (rx_wlen >= 8)
                                        *rxp++ = rx >> (rx_wlen - 8);
                                if (rx_wlen >= 16)
                                        *rxp++ = rx >> (rx_wlen - 16);
                                if (rx_wlen >= 24)
                                        *rxp++ = rx >> (rx_wlen - 24);
                                if (rx_wlen >= 32)
                                        *rxp++ = rx;
                        }
                        break;
                case 2:
                        *((u16 *)rxbuf) = readw(qspi->base + QSPI_SPI_DATA_REG);
                        break;
                case 4:
                        *((u32 *)rxbuf) = readl(qspi->base + QSPI_SPI_DATA_REG);
                        break;
                }
                rxbuf += rxlen;
                count -= rxlen;
        }

        return 0;
}

static int qspi_transfer_msg(struct ti_qspi *qspi, struct spi_transfer *t,
                             int count)
{
        int ret;

        if (t->tx_buf) {
                ret = qspi_write_msg(qspi, t, count);
                if (ret) {
                        dev_dbg(qspi->dev, "Error while writing\n");
                        return ret;
                }
        }

        if (t->rx_buf) {
                ret = qspi_read_msg(qspi, t, count);
                if (ret) {
                        dev_dbg(qspi->dev, "Error while reading\n");
                        return ret;
                }
        }

        return 0;
}

static void ti_qspi_dma_callback(void *param)
{
        struct ti_qspi *qspi = param;

        complete(&qspi->transfer_complete);
}

static int ti_qspi_dma_xfer(struct ti_qspi *qspi, dma_addr_t dma_dst,
                            dma_addr_t dma_src, size_t len)
{
        struct dma_chan *chan = qspi->rx_chan;
        dma_cookie_t cookie;
        enum dma_ctrl_flags flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
        struct dma_async_tx_descriptor *tx;
        int ret;
        unsigned long time_left;

        tx = dmaengine_prep_dma_memcpy(chan, dma_dst, dma_src, len, flags);
        if (!tx) {
                dev_err(qspi->dev, "device_prep_dma_memcpy error\n");
                return -EIO;
        }

        tx->callback = ti_qspi_dma_callback;
        tx->callback_param = qspi;
        cookie = tx->tx_submit(tx);
        reinit_completion(&qspi->transfer_complete);

        ret = dma_submit_error(cookie);
        if (ret) {
                dev_err(qspi->dev, "dma_submit_error %d\n", cookie);
                return -EIO;
        }

        dma_async_issue_pending(chan);
        time_left = wait_for_completion_timeout(&qspi->transfer_complete,
                                          msecs_to_jiffies(len));
        if (time_left == 0) {
                dmaengine_terminate_sync(chan);
                dev_err(qspi->dev, "DMA wait_for_completion_timeout\n");
                return -ETIMEDOUT;
        }

        return 0;
}

static int ti_qspi_dma_bounce_buffer(struct ti_qspi *qspi, loff_t offs,
                                     void *to, size_t readsize)
{
        dma_addr_t dma_src = qspi->mmap_phys_base + offs;
        int ret = 0;

        /*
         * Use bounce buffer as FS like jffs2, ubifs may pass
         * buffers that does not belong to kernel lowmem region.
         */
        while (readsize != 0) {
                size_t xfer_len = min_t(size_t, QSPI_DMA_BUFFER_SIZE,
                                        readsize);

                ret = ti_qspi_dma_xfer(qspi, qspi->rx_bb_dma_addr,
                                       dma_src, xfer_len);
                if (ret != 0)
                        return ret;
                memcpy(to, qspi->rx_bb_addr, xfer_len);
                readsize -= xfer_len;
                dma_src += xfer_len;
                to += xfer_len;
        }

        return ret;
}

static int ti_qspi_dma_xfer_sg(struct ti_qspi *qspi, struct sg_table rx_sg,
                               loff_t from)
{
        struct scatterlist *sg;
        dma_addr_t dma_src = qspi->mmap_phys_base + from;
        dma_addr_t dma_dst;
        int i, len, ret;

        for_each_sg(rx_sg.sgl, sg, rx_sg.nents, i) {
                dma_dst = sg_dma_address(sg);
                len = sg_dma_len(sg);
                ret = ti_qspi_dma_xfer(qspi, dma_dst, dma_src, len);
                if (ret)
                        return ret;
                dma_src += len;
        }

        return 0;
}

static void ti_qspi_enable_memory_map(struct spi_device *spi)
{
        struct ti_qspi  *qspi = spi_controller_get_devdata(spi->controller);

        ti_qspi_write(qspi, MM_SWITCH, QSPI_SPI_SWITCH_REG);
        if (qspi->ctrl_base) {
                regmap_update_bits(qspi->ctrl_base, qspi->ctrl_reg,
                                   MEM_CS_MASK,
                                   MEM_CS_EN(spi_get_chipselect(spi, 0)));
        }
        qspi->mmap_enabled = true;
        qspi->current_cs = spi_get_chipselect(spi, 0);
}

static void ti_qspi_disable_memory_map(struct spi_device *spi)
{
        struct ti_qspi  *qspi = spi_controller_get_devdata(spi->controller);

        ti_qspi_write(qspi, 0, QSPI_SPI_SWITCH_REG);
        if (qspi->ctrl_base)
                regmap_update_bits(qspi->ctrl_base, qspi->ctrl_reg,
                                   MEM_CS_MASK, 0);
        qspi->mmap_enabled = false;
        qspi->current_cs = -1;
}

static void ti_qspi_setup_mmap_read(struct spi_device *spi, u8 opcode,
                                    u8 data_nbits, u8 addr_width,
                                    u8 dummy_bytes)
{
        struct ti_qspi  *qspi = spi_controller_get_devdata(spi->controller);
        u32 memval = opcode;

        switch (data_nbits) {
        case SPI_NBITS_QUAD:
                memval |= QSPI_SETUP_RD_QUAD;
                break;
        case SPI_NBITS_DUAL:
                memval |= QSPI_SETUP_RD_DUAL;
                break;
        default:
                memval |= QSPI_SETUP_RD_NORMAL;
                break;
        }
        memval |= ((addr_width - 1) << QSPI_SETUP_ADDR_SHIFT |
                   dummy_bytes << QSPI_SETUP_DUMMY_SHIFT);
        ti_qspi_write(qspi, memval,
                      QSPI_SPI_SETUP_REG(spi_get_chipselect(spi, 0)));
}

static int ti_qspi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
{
        struct ti_qspi *qspi = spi_controller_get_devdata(mem->spi->controller);
        size_t max_len;

        if (op->data.dir == SPI_MEM_DATA_IN) {
                if (op->addr.val < qspi->mmap_size) {
                        /* Limit MMIO to the mmaped region */
                        if (op->addr.val + op->data.nbytes > qspi->mmap_size) {
                                max_len = qspi->mmap_size - op->addr.val;
                                op->data.nbytes = min((size_t) op->data.nbytes,
                                                      max_len);
                        }
                } else {
                        /*
                         * Use fallback mode (SW generated transfers) above the
                         * mmaped region.
                         * Adjust size to comply with the QSPI max frame length.
                         */
                        max_len = QSPI_FRAME;
                        max_len -= 1 + op->addr.nbytes + op->dummy.nbytes;
                        op->data.nbytes = min((size_t) op->data.nbytes,
                                              max_len);
                }
        }

        return 0;
}

static int ti_qspi_exec_mem_op(struct spi_mem *mem,
                               const struct spi_mem_op *op)
{
        struct ti_qspi *qspi = spi_controller_get_devdata(mem->spi->controller);
        u32 from = 0;
        int ret = 0;

        /* Only optimize read path. */
        if (!op->data.nbytes || op->data.dir != SPI_MEM_DATA_IN ||
            !op->addr.nbytes || op->addr.nbytes > 4)
                return -EOPNOTSUPP;

        /* Address exceeds MMIO window size, fall back to regular mode. */
        from = op->addr.val;
        if (from + op->data.nbytes > qspi->mmap_size)
                return -EOPNOTSUPP;

        mutex_lock(&qspi->list_lock);

        if (!qspi->mmap_enabled || qspi->current_cs != spi_get_chipselect(mem->spi, 0)) {
                ti_qspi_setup_clk(qspi, op->max_freq);
                ti_qspi_enable_memory_map(mem->spi);
        }
        ti_qspi_setup_mmap_read(mem->spi, op->cmd.opcode, op->data.buswidth,
                                op->addr.nbytes, op->dummy.nbytes);

        if (qspi->rx_chan) {
                struct sg_table sgt;

                if (virt_addr_valid(op->data.buf.in) &&
                    !spi_controller_dma_map_mem_op_data(mem->spi->controller, op,
                                                        &sgt)) {
                        ret = ti_qspi_dma_xfer_sg(qspi, sgt, from);
                        spi_controller_dma_unmap_mem_op_data(mem->spi->controller,
                                                             op, &sgt);
                } else {
                        ret = ti_qspi_dma_bounce_buffer(qspi, from,
                                                        op->data.buf.in,
                                                        op->data.nbytes);
                }
        } else {
                memcpy_fromio(op->data.buf.in, qspi->mmap_base + from,
                              op->data.nbytes);
        }

        mutex_unlock(&qspi->list_lock);

        return ret;
}

static const struct spi_controller_mem_ops ti_qspi_mem_ops = {
        .exec_op = ti_qspi_exec_mem_op,
        .adjust_op_size = ti_qspi_adjust_op_size,
};

static const struct spi_controller_mem_caps ti_qspi_mem_caps = {
        .per_op_freq = true,
};

static int ti_qspi_start_transfer_one(struct spi_controller *host,
                struct spi_message *m)
{
        struct ti_qspi *qspi = spi_controller_get_devdata(host);
        struct spi_device *spi = m->spi;
        struct spi_transfer *t;
        int status = 0, ret;
        unsigned int frame_len_words, transfer_len_words;
        int wlen;

        /* setup device control reg */
        qspi->dc = 0;

        if (spi->mode & SPI_CPHA)
                qspi->dc |= QSPI_CKPHA(spi_get_chipselect(spi, 0));
        if (spi->mode & SPI_CPOL)
                qspi->dc |= QSPI_CKPOL(spi_get_chipselect(spi, 0));
        if (spi->mode & SPI_CS_HIGH)
                qspi->dc |= QSPI_CSPOL(spi_get_chipselect(spi, 0));

        frame_len_words = 0;
        list_for_each_entry(t, &m->transfers, transfer_list)
                frame_len_words += t->len / (t->bits_per_word >> 3);
        frame_len_words = min_t(unsigned int, frame_len_words, QSPI_FRAME);

        /* setup command reg */
        qspi->cmd = 0;
        qspi->cmd |= QSPI_EN_CS(spi_get_chipselect(spi, 0));
        qspi->cmd |= QSPI_FLEN(frame_len_words);

        ti_qspi_write(qspi, qspi->dc, QSPI_SPI_DC_REG);

        mutex_lock(&qspi->list_lock);

        if (qspi->mmap_enabled)
                ti_qspi_disable_memory_map(spi);

        list_for_each_entry(t, &m->transfers, transfer_list) {
                qspi->cmd = ((qspi->cmd & ~QSPI_WLEN_MASK) |
                             QSPI_WLEN(t->bits_per_word));

                wlen = t->bits_per_word >> 3;
                transfer_len_words = min(t->len / wlen, frame_len_words);

                ti_qspi_setup_clk(qspi, t->speed_hz);
                ret = qspi_transfer_msg(qspi, t, transfer_len_words * wlen);
                if (ret) {
                        dev_dbg(qspi->dev, "transfer message failed\n");
                        mutex_unlock(&qspi->list_lock);
                        return -EINVAL;
                }

                m->actual_length += transfer_len_words * wlen;
                frame_len_words -= transfer_len_words;
                if (frame_len_words == 0)
                        break;
        }

        mutex_unlock(&qspi->list_lock);

        ti_qspi_write(qspi, qspi->cmd | QSPI_INVAL, QSPI_SPI_CMD_REG);
        m->status = status;
        spi_finalize_current_message(host);

        return status;
}

static int ti_qspi_runtime_resume(struct device *dev)
{
        struct ti_qspi      *qspi;

        qspi = dev_get_drvdata(dev);
        ti_qspi_restore_ctx(qspi);

        return 0;
}

static void ti_qspi_dma_cleanup(struct ti_qspi *qspi)
{
        if (qspi->rx_bb_addr)
                dma_free_coherent(qspi->dev, QSPI_DMA_BUFFER_SIZE,
                                  qspi->rx_bb_addr,
                                  qspi->rx_bb_dma_addr);

        if (qspi->rx_chan)
                dma_release_channel(qspi->rx_chan);
}

static const struct of_device_id ti_qspi_match[] = {
        {.compatible = "ti,dra7xxx-qspi" },
        {.compatible = "ti,am4372-qspi" },
        {},
};
MODULE_DEVICE_TABLE(of, ti_qspi_match);

static int ti_qspi_probe(struct platform_device *pdev)
{
        struct  ti_qspi *qspi;
        struct spi_controller *host;
        struct resource         *r, *res_mmap;
        struct device_node *np = pdev->dev.of_node;
        u32 max_freq;
        int ret = 0, num_cs, irq;
        dma_cap_mask_t mask;

        host = spi_alloc_host(&pdev->dev, sizeof(*qspi));
        if (!host)
                return -ENOMEM;

        host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_RX_DUAL | SPI_RX_QUAD;

        host->flags = SPI_CONTROLLER_HALF_DUPLEX;
        host->setup = ti_qspi_setup;
        host->auto_runtime_pm = true;
        host->transfer_one_message = ti_qspi_start_transfer_one;
        host->bits_per_word_mask = SPI_BPW_MASK(32) | SPI_BPW_MASK(16) |
                                   SPI_BPW_MASK(8);
        host->mem_ops = &ti_qspi_mem_ops;
        host->mem_caps = &ti_qspi_mem_caps;

        if (!of_property_read_u32(np, "num-cs", &num_cs))
                host->num_chipselect = num_cs;

        qspi = spi_controller_get_devdata(host);
        qspi->host = host;
        qspi->dev = &pdev->dev;
        platform_set_drvdata(pdev, qspi);

        r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi_base");
        if (r == NULL) {
                r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
                if (r == NULL) {
                        dev_err(&pdev->dev, "missing platform data\n");
                        ret = -ENODEV;
                        goto free_host;
                }
        }

        res_mmap = platform_get_resource_byname(pdev,
                        IORESOURCE_MEM, "qspi_mmap");
        if (res_mmap == NULL) {
                res_mmap = platform_get_resource(pdev, IORESOURCE_MEM, 1);
                if (res_mmap == NULL) {
                        dev_err(&pdev->dev,
                                "memory mapped resource not required\n");
                }
        }

        if (res_mmap)
                qspi->mmap_size = resource_size(res_mmap);

        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                ret = irq;
                goto free_host;
        }

        mutex_init(&qspi->list_lock);

        qspi->base = devm_ioremap_resource(&pdev->dev, r);
        if (IS_ERR(qspi->base)) {
                ret = PTR_ERR(qspi->base);
                goto free_host;
        }


        if (of_property_present(np, "syscon-chipselects")) {
                qspi->ctrl_base =
                        syscon_regmap_lookup_by_phandle_args(np, "syscon-chipselects",
                                                             1, &qspi->ctrl_reg);
                if (IS_ERR(qspi->ctrl_base)) {
                        ret = PTR_ERR(qspi->ctrl_base);
                        goto free_host;
                }
        }

        qspi->fclk = devm_clk_get(&pdev->dev, "fck");
        if (IS_ERR(qspi->fclk)) {
                ret = PTR_ERR(qspi->fclk);
                dev_err(&pdev->dev, "could not get clk: %d\n", ret);
        }

        pm_runtime_use_autosuspend(&pdev->dev);
        pm_runtime_set_autosuspend_delay(&pdev->dev, QSPI_AUTOSUSPEND_TIMEOUT);
        pm_runtime_enable(&pdev->dev);

        if (!of_property_read_u32(np, "spi-max-frequency", &max_freq))
                host->max_speed_hz = max_freq;

        dma_cap_zero(mask);
        dma_cap_set(DMA_MEMCPY, mask);

        qspi->rx_chan = dma_request_chan_by_mask(&mask);
        if (IS_ERR(qspi->rx_chan)) {
                dev_err(qspi->dev,
                        "No Rx DMA available, trying mmap mode\n");
                qspi->rx_chan = NULL;
                goto no_dma;
        }
        qspi->rx_bb_addr = dma_alloc_coherent(qspi->dev,
                                              QSPI_DMA_BUFFER_SIZE,
                                              &qspi->rx_bb_dma_addr,
                                              GFP_KERNEL | GFP_DMA);
        if (!qspi->rx_bb_addr) {
                dev_err(qspi->dev,
                        "dma_alloc_coherent failed, using PIO mode\n");
                dma_release_channel(qspi->rx_chan);
                goto no_dma;
        }
        host->dma_rx = qspi->rx_chan;
        init_completion(&qspi->transfer_complete);
        if (res_mmap)
                qspi->mmap_phys_base = (dma_addr_t)res_mmap->start;

no_dma:
        if (!qspi->rx_chan && res_mmap) {
                qspi->mmap_base = devm_ioremap_resource(&pdev->dev, res_mmap);
                if (IS_ERR(qspi->mmap_base)) {
                        dev_info(&pdev->dev,
                                 "mmap failed with error %ld using PIO mode\n",
                                 PTR_ERR(qspi->mmap_base));
                        qspi->mmap_base = NULL;
                        host->mem_ops = NULL;
                }
        }
        qspi->mmap_enabled = false;
        qspi->current_cs = -1;

        ret = devm_spi_register_controller(&pdev->dev, host);
        if (!ret)
                return 0;

        ti_qspi_dma_cleanup(qspi);

        pm_runtime_disable(&pdev->dev);
free_host:
        spi_controller_put(host);
        return ret;
}

static void ti_qspi_remove(struct platform_device *pdev)
{
        struct ti_qspi *qspi = platform_get_drvdata(pdev);
        int rc;

        rc = spi_controller_suspend(qspi->host);
        if (rc) {
                dev_alert(&pdev->dev, "spi_controller_suspend() failed (%pe)\n",
                          ERR_PTR(rc));
                return;
        }

        pm_runtime_put_sync(&pdev->dev);
        pm_runtime_disable(&pdev->dev);

        ti_qspi_dma_cleanup(qspi);
}

static const struct dev_pm_ops ti_qspi_pm_ops = {
        .runtime_resume = ti_qspi_runtime_resume,
};

static struct platform_driver ti_qspi_driver = {
        .probe  = ti_qspi_probe,
        .remove = ti_qspi_remove,
        .driver = {
                .name   = "ti-qspi",
                .pm =   &ti_qspi_pm_ops,
                .of_match_table = ti_qspi_match,
        }
};

module_platform_driver(ti_qspi_driver);

MODULE_AUTHOR("Sourav Poddar <sourav.poddar@ti.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("TI QSPI controller driver");
MODULE_ALIAS("platform:ti-qspi");