/*
 * (C) Copyright 2013 Xilinx, Inc.
 * (C) Copyright 2015 Jagan Teki <jteki@openedev.com>
 *
 * Xilinx Zynq Quad-SPI(QSPI) controller driver (master mode only)
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

#include <common.h>
#include <dm.h>
#include <malloc.h>
#include <spi.h>
#include <asm/io.h>

DECLARE_GLOBAL_DATA_PTR;

/* zynq qspi register bit masks ZYNQ_QSPI_<REG>_<BIT>_MASK */
#define ZYNQ_QSPI_CR_IFMODE_MASK        BIT(31) /* Flash intrface mode*/
#define ZYNQ_QSPI_CR_MSA_MASK           BIT(15) /* Manual start enb */
#define ZYNQ_QSPI_CR_MCS_MASK           BIT(14) /* Manual chip select */
#define ZYNQ_QSPI_CR_PCS_MASK           BIT(10) /* Peri chip select */
#define ZYNQ_QSPI_CR_FW_MASK            GENMASK(7, 6)   /* FIFO width */
#define ZYNQ_QSPI_CR_SS_MASK            GENMASK(13, 10) /* Slave Select */
#define ZYNQ_QSPI_CR_BAUD_MASK          GENMASK(5, 3)   /* Baud rate div */
#define ZYNQ_QSPI_CR_CPHA_MASK          BIT(2)  /* Clock phase */
#define ZYNQ_QSPI_CR_CPOL_MASK          BIT(1)  /* Clock polarity */
#define ZYNQ_QSPI_CR_MSTREN_MASK        BIT(0)  /* Mode select */
#define ZYNQ_QSPI_IXR_RXNEMPTY_MASK     BIT(4)  /* RX_FIFO_not_empty */
#define ZYNQ_QSPI_IXR_TXOW_MASK         BIT(2)  /* TX_FIFO_not_full */
#define ZYNQ_QSPI_IXR_ALL_MASK          GENMASK(6, 0)   /* All IXR bits */
#define ZYNQ_QSPI_ENR_SPI_EN_MASK       BIT(0)  /* SPI Enable */
#define ZYNQ_QSPI_LQSPICFG_LQMODE_MASK  BIT(31) /* Linear QSPI Mode */

/* zynq qspi Transmit Data Register */
#define ZYNQ_QSPI_TXD_00_00_OFFSET      0x1C    /* Transmit 4-byte inst */
#define ZYNQ_QSPI_TXD_00_01_OFFSET      0x80    /* Transmit 1-byte inst */
#define ZYNQ_QSPI_TXD_00_10_OFFSET      0x84    /* Transmit 2-byte inst */
#define ZYNQ_QSPI_TXD_00_11_OFFSET      0x88    /* Transmit 3-byte inst */

#define ZYNQ_QSPI_TXFIFO_THRESHOLD      1       /* Tx FIFO threshold level*/
#define ZYNQ_QSPI_RXFIFO_THRESHOLD      32      /* Rx FIFO threshold level */

#define ZYNQ_QSPI_CR_BAUD_MAX           8       /* Baud rate divisor max val */
#define ZYNQ_QSPI_CR_BAUD_SHIFT         3       /* Baud rate divisor shift */
#define ZYNQ_QSPI_CR_SS_SHIFT           10      /* Slave select shift */

#define ZYNQ_QSPI_FIFO_DEPTH            63
#ifndef CONFIG_SYS_ZYNQ_QSPI_WAIT
#define CONFIG_SYS_ZYNQ_QSPI_WAIT       CONFIG_SYS_HZ/100       /* 10 ms */
#endif

/* zynq qspi register set */
struct zynq_qspi_regs {
        u32 cr;         /* 0x00 */
        u32 isr;        /* 0x04 */
        u32 ier;        /* 0x08 */
        u32 idr;        /* 0x0C */
        u32 imr;        /* 0x10 */
        u32 enr;        /* 0x14 */
        u32 dr;         /* 0x18 */
        u32 txd0r;      /* 0x1C */
        u32 drxr;       /* 0x20 */
        u32 sicr;       /* 0x24 */
        u32 txftr;      /* 0x28 */
        u32 rxftr;      /* 0x2C */
        u32 gpior;      /* 0x30 */
        u32 reserved0[19];
        u32 txd1r;      /* 0x80 */
        u32 txd2r;      /* 0x84 */
        u32 txd3r;      /* 0x88 */
        u32 reserved1[5];
        u32 lqspicfg;   /* 0xA0 */
        u32 lqspists;   /* 0xA4 */
};

/* zynq qspi platform data */
struct zynq_qspi_platdata {
        struct zynq_qspi_regs *regs;
        u32 frequency;          /* input frequency */
        u32 speed_hz;
};

/* zynq qspi priv */
struct zynq_qspi_priv {
        struct zynq_qspi_regs *regs;
        u8 cs;
        u8 mode;
        u8 fifo_depth;
        u32 freq;               /* required frequency */
        const void *tx_buf;
        void *rx_buf;
        unsigned len;
        int bytes_to_transfer;
        int bytes_to_receive;
        unsigned int is_inst;
        unsigned cs_change:1;
};

static int zynq_qspi_ofdata_to_platdata(struct udevice *bus)
{
        struct zynq_qspi_platdata *plat = bus->platdata;
        const void *blob = gd->fdt_blob;
        int node = dev_of_offset(bus);

        plat->regs = (struct zynq_qspi_regs *)fdtdec_get_addr(blob,
                                                              node, "reg");

        /* FIXME: Use 166MHz as a suitable default */
        plat->frequency = fdtdec_get_int(blob, node, "spi-max-frequency",
                                        166666666);
        plat->speed_hz = plat->frequency / 2;

        debug("%s: regs=%p max-frequency=%d\n", __func__,
              plat->regs, plat->frequency);

        return 0;
}

static void zynq_qspi_init_hw(struct zynq_qspi_priv *priv)
{
        struct zynq_qspi_regs *regs = priv->regs;
        u32 confr;

        /* Disable QSPI */
        writel(~ZYNQ_QSPI_ENR_SPI_EN_MASK, &regs->enr);

        /* Disable Interrupts */
        writel(ZYNQ_QSPI_IXR_ALL_MASK, &regs->idr);

        /* Clear the TX and RX threshold reg */
        writel(ZYNQ_QSPI_TXFIFO_THRESHOLD, &regs->txftr);
        writel(ZYNQ_QSPI_RXFIFO_THRESHOLD, &regs->rxftr);

        /* Clear the RX FIFO */
        while (readl(&regs->isr) & ZYNQ_QSPI_IXR_RXNEMPTY_MASK)
                readl(&regs->drxr);

        /* Clear Interrupts */
        writel(ZYNQ_QSPI_IXR_ALL_MASK, &regs->isr);

        /* Manual slave select and Auto start */
        confr = readl(&regs->cr);
        confr &= ~ZYNQ_QSPI_CR_MSA_MASK;
        confr |= ZYNQ_QSPI_CR_IFMODE_MASK | ZYNQ_QSPI_CR_MCS_MASK |
                ZYNQ_QSPI_CR_PCS_MASK | ZYNQ_QSPI_CR_FW_MASK |
                ZYNQ_QSPI_CR_MSTREN_MASK;
        writel(confr, &regs->cr);

        /* Disable the LQSPI feature */
        confr = readl(&regs->lqspicfg);
        confr &= ~ZYNQ_QSPI_LQSPICFG_LQMODE_MASK;
        writel(confr, &regs->lqspicfg);

        /* Enable SPI */
        writel(ZYNQ_QSPI_ENR_SPI_EN_MASK, &regs->enr);
}

static int zynq_qspi_probe(struct udevice *bus)
{
        struct zynq_qspi_platdata *plat = dev_get_platdata(bus);
        struct zynq_qspi_priv *priv = dev_get_priv(bus);

        priv->regs = plat->regs;
        priv->fifo_depth = ZYNQ_QSPI_FIFO_DEPTH;

        /* init the zynq spi hw */
        zynq_qspi_init_hw(priv);

        return 0;
}

/*
 * zynq_qspi_read_data - Copy data to RX buffer
 * @zqspi:      Pointer to the zynq_qspi structure
 * @data:       The 32 bit variable where data is stored
 * @size:       Number of bytes to be copied from data to RX buffer
 */
static void zynq_qspi_read_data(struct zynq_qspi_priv *priv, u32 data, u8 size)
{
        u8 byte3;

        debug("%s: data 0x%04x rx_buf addr: 0x%08x size %d\n", __func__ ,
              data, (unsigned)(priv->rx_buf), size);

        if (priv->rx_buf) {
                switch (size) {
                case 1:
                        *((u8 *)priv->rx_buf) = data;
                        priv->rx_buf += 1;
                        break;
                case 2:
                        *((u16 *)priv->rx_buf) = data;
                        priv->rx_buf += 2;
                        break;
                case 3:
                        *((u16 *)priv->rx_buf) = data;
                        priv->rx_buf += 2;
                        byte3 = (u8)(data >> 16);
                        *((u8 *)priv->rx_buf) = byte3;
                        priv->rx_buf += 1;
                        break;
                case 4:
                        /* Can not assume word aligned buffer */
                        memcpy(priv->rx_buf, &data, size);
                        priv->rx_buf += 4;
                        break;
                default:
                        /* This will never execute */
                        break;
                }
        }
        priv->bytes_to_receive -= size;
        if (priv->bytes_to_receive < 0)
                priv->bytes_to_receive = 0;
}

/*
 * zynq_qspi_write_data - Copy data from TX buffer
 * @zqspi:      Pointer to the zynq_qspi structure
 * @data:       Pointer to the 32 bit variable where data is to be copied
 * @size:       Number of bytes to be copied from TX buffer to data
 */
static void zynq_qspi_write_data(struct  zynq_qspi_priv *priv,
                u32 *data, u8 size)
{
        if (priv->tx_buf) {
                switch (size) {
                case 1:
                        *data = *((u8 *)priv->tx_buf);
                        priv->tx_buf += 1;
                        *data |= 0xFFFFFF00;
                        break;
                case 2:
                        *data = *((u16 *)priv->tx_buf);
                        priv->tx_buf += 2;
                        *data |= 0xFFFF0000;
                        break;
                case 3:
                        *data = *((u16 *)priv->tx_buf);
                        priv->tx_buf += 2;
                        *data |= (*((u8 *)priv->tx_buf) << 16);
                        priv->tx_buf += 1;
                        *data |= 0xFF000000;
                        break;
                case 4:
                        /* Can not assume word aligned buffer */
                        memcpy(data, priv->tx_buf, size);
                        priv->tx_buf += 4;
                        break;
                default:
                        /* This will never execute */
                        break;
                }
        } else {
                *data = 0;
        }

        debug("%s: data 0x%08x tx_buf addr: 0x%08x size %d\n", __func__,
              *data, (u32)priv->tx_buf, size);

        priv->bytes_to_transfer -= size;
        if (priv->bytes_to_transfer < 0)
                priv->bytes_to_transfer = 0;
}

static void zynq_qspi_chipselect(struct  zynq_qspi_priv *priv, int is_on)
{
        u32 confr;
        struct zynq_qspi_regs *regs = priv->regs;

        confr = readl(&regs->cr);

        if (is_on) {
                /* Select the slave */
                confr &= ~ZYNQ_QSPI_CR_SS_MASK;
                confr |= (~(1 << priv->cs) << ZYNQ_QSPI_CR_SS_SHIFT) &
                                        ZYNQ_QSPI_CR_SS_MASK;
        } else
                /* Deselect the slave */
                confr |= ZYNQ_QSPI_CR_SS_MASK;

        writel(confr, &regs->cr);
}

/*
 * zynq_qspi_fill_tx_fifo - Fills the TX FIFO with as many bytes as possible
 * @zqspi:      Pointer to the zynq_qspi structure
 */
static void zynq_qspi_fill_tx_fifo(struct zynq_qspi_priv *priv, u32 size)
{
        u32 data = 0;
        u32 fifocount = 0;
        unsigned len, offset;
        struct zynq_qspi_regs *regs = priv->regs;
        static const unsigned offsets[4] = {
                ZYNQ_QSPI_TXD_00_00_OFFSET, ZYNQ_QSPI_TXD_00_01_OFFSET,
                ZYNQ_QSPI_TXD_00_10_OFFSET, ZYNQ_QSPI_TXD_00_11_OFFSET };

        while ((fifocount < size) &&
                        (priv->bytes_to_transfer > 0)) {
                if (priv->bytes_to_transfer >= 4) {
                        if (priv->tx_buf) {
                                memcpy(&data, priv->tx_buf, 4);
                                priv->tx_buf += 4;
                        } else {
                                data = 0;
                        }
                        writel(data, &regs->txd0r);
                        priv->bytes_to_transfer -= 4;
                        fifocount++;
                } else {
                        /* Write TXD1, TXD2, TXD3 only if TxFIFO is empty. */
                        if (!(readl(&regs->isr)
                                        & ZYNQ_QSPI_IXR_TXOW_MASK) &&
                                        !priv->rx_buf)
                                return;
                        len = priv->bytes_to_transfer;
                        zynq_qspi_write_data(priv, &data, len);
                        offset = (priv->rx_buf) ? offsets[0] : offsets[len];
                        writel(data, &regs->cr + (offset / 4));
                }
        }
}

/*
 * zynq_qspi_irq_poll - Interrupt service routine of the QSPI controller
 * @zqspi:      Pointer to the zynq_qspi structure
 *
 * This function handles TX empty and Mode Fault interrupts only.
 * On TX empty interrupt this function reads the received data from RX FIFO and
 * fills the TX FIFO if there is any data remaining to be transferred.
 * On Mode Fault interrupt this function indicates that transfer is completed,
 * the SPI subsystem will identify the error as the remaining bytes to be
 * transferred is non-zero.
 *
 * returns:     0 for poll timeout
 *              1 transfer operation complete
 */
static int zynq_qspi_irq_poll(struct zynq_qspi_priv *priv)
{
        struct zynq_qspi_regs *regs = priv->regs;
        u32 rxindex = 0;
        u32 rxcount;
        u32 status, timeout;

        /* Poll until any of the interrupt status bits are set */
        timeout = get_timer(0);
        do {
                status = readl(&regs->isr);
        } while ((status == 0) &&
                (get_timer(timeout) < CONFIG_SYS_ZYNQ_QSPI_WAIT));

        if (status == 0) {
                printf("zynq_qspi_irq_poll: Timeout!\n");
                return -ETIMEDOUT;
        }

        writel(status, &regs->isr);

        /* Disable all interrupts */
        writel(ZYNQ_QSPI_IXR_ALL_MASK, &regs->idr);
        if ((status & ZYNQ_QSPI_IXR_TXOW_MASK) ||
            (status & ZYNQ_QSPI_IXR_RXNEMPTY_MASK)) {
                /*
                 * This bit is set when Tx FIFO has < THRESHOLD entries. We have
                 * the THRESHOLD value set to 1, so this bit indicates Tx FIFO
                 * is empty
                 */
                rxcount = priv->bytes_to_receive - priv->bytes_to_transfer;
                rxcount = (rxcount % 4) ? ((rxcount/4)+1) : (rxcount/4);
                while ((rxindex < rxcount) &&
                                (rxindex < ZYNQ_QSPI_RXFIFO_THRESHOLD)) {
                        /* Read out the data from the RX FIFO */
                        u32 data;
                        data = readl(&regs->drxr);

                        if (priv->bytes_to_receive >= 4) {
                                if (priv->rx_buf) {
                                        memcpy(priv->rx_buf, &data, 4);
                                        priv->rx_buf += 4;
                                }
                                priv->bytes_to_receive -= 4;
                        } else {
                                zynq_qspi_read_data(priv, data,
                                                    priv->bytes_to_receive);
                        }
                        rxindex++;
                }

                if (priv->bytes_to_transfer) {
                        /* There is more data to send */
                        zynq_qspi_fill_tx_fifo(priv,
                                               ZYNQ_QSPI_RXFIFO_THRESHOLD);

                        writel(ZYNQ_QSPI_IXR_ALL_MASK, &regs->ier);
                } else {
                        /*
                         * If transfer and receive is completed then only send
                         * complete signal
                         */
                        if (!priv->bytes_to_receive) {
                                /* return operation complete */
                                writel(ZYNQ_QSPI_IXR_ALL_MASK,
                                       &regs->idr);
                                return 1;
                        }
                }
        }

        return 0;
}

/*
 * zynq_qspi_start_transfer - Initiates the QSPI transfer
 * @qspi:       Pointer to the spi_device structure
 * @transfer:   Pointer to the spi_transfer structure which provide information
 *              about next transfer parameters
 *
 * This function fills the TX FIFO, starts the QSPI transfer, and waits for the
 * transfer to be completed.
 *
 * returns:     Number of bytes transferred in the last transfer
 */
static int zynq_qspi_start_transfer(struct zynq_qspi_priv *priv)
{
        u32 data = 0;
        struct zynq_qspi_regs *regs = priv->regs;

        debug("%s: qspi: 0x%08x transfer: 0x%08x len: %d\n", __func__,
              (u32)priv, (u32)priv, priv->len);

        priv->bytes_to_transfer = priv->len;
        priv->bytes_to_receive = priv->len;

        if (priv->len < 4)
                zynq_qspi_fill_tx_fifo(priv, priv->len);
        else
                zynq_qspi_fill_tx_fifo(priv, priv->fifo_depth);

        writel(ZYNQ_QSPI_IXR_ALL_MASK, &regs->ier);

        /* wait for completion */
        do {
                data = zynq_qspi_irq_poll(priv);
        } while (data == 0);

        return (priv->len) - (priv->bytes_to_transfer);
}

static int zynq_qspi_transfer(struct zynq_qspi_priv *priv)
{
        unsigned cs_change = 1;
        int status = 0;

        while (1) {
                /* Select the chip if required */
                if (cs_change)
                        zynq_qspi_chipselect(priv, 1);

                cs_change = priv->cs_change;

                if (!priv->tx_buf && !priv->rx_buf && priv->len) {
                        status = -1;
                        break;
                }

                /* Request the transfer */
                if (priv->len) {
                        status = zynq_qspi_start_transfer(priv);
                        priv->is_inst = 0;
                }

                if (status != priv->len) {
                        if (status > 0)
                                status = -EMSGSIZE;
                        debug("zynq_qspi_transfer:%d len:%d\n",
                              status, priv->len);
                        break;
                }
                status = 0;

                if (cs_change)
                        /* Deselect the chip */
                        zynq_qspi_chipselect(priv, 0);

                break;
        }

        return 0;
}

static int zynq_qspi_claim_bus(struct udevice *dev)
{
        struct udevice *bus = dev->parent;
        struct zynq_qspi_priv *priv = dev_get_priv(bus);
        struct zynq_qspi_regs *regs = priv->regs;

        writel(ZYNQ_QSPI_ENR_SPI_EN_MASK, &regs->enr);

        return 0;
}

static int zynq_qspi_release_bus(struct udevice *dev)
{
        struct udevice *bus = dev->parent;
        struct zynq_qspi_priv *priv = dev_get_priv(bus);
        struct zynq_qspi_regs *regs = priv->regs;

        writel(~ZYNQ_QSPI_ENR_SPI_EN_MASK, &regs->enr);

        return 0;
}

static int zynq_qspi_xfer(struct udevice *dev, unsigned int bitlen,
                const void *dout, void *din, unsigned long flags)
{
        struct udevice *bus = dev->parent;
        struct zynq_qspi_priv *priv = dev_get_priv(bus);
        struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);

        priv->cs = slave_plat->cs;
        priv->tx_buf = dout;
        priv->rx_buf = din;
        priv->len = bitlen / 8;

        debug("zynq_qspi_xfer: bus:%i cs:%i bitlen:%i len:%i flags:%lx\n",
              bus->seq, slave_plat->cs, bitlen, priv->len, flags);

        /*
         * Festering sore.
         * Assume that the beginning of a transfer with bits to
         * transmit must contain a device command.
         */
        if (dout && flags & SPI_XFER_BEGIN)
                priv->is_inst = 1;
        else
                priv->is_inst = 0;

        if (flags & SPI_XFER_END)
                priv->cs_change = 1;
        else
                priv->cs_change = 0;

        zynq_qspi_transfer(priv);

        return 0;
}

static int zynq_qspi_set_speed(struct udevice *bus, uint speed)
{
        struct zynq_qspi_platdata *plat = bus->platdata;
        struct zynq_qspi_priv *priv = dev_get_priv(bus);
        struct zynq_qspi_regs *regs = priv->regs;
        uint32_t confr;
        u8 baud_rate_val = 0;

        if (speed > plat->frequency)
                speed = plat->frequency;

        /* Set the clock frequency */
        confr = readl(&regs->cr);
        if (speed == 0) {
                /* Set baudrate x8, if the freq is 0 */
                baud_rate_val = 0x2;
        } else if (plat->speed_hz != speed) {
                while ((baud_rate_val < ZYNQ_QSPI_CR_BAUD_MAX) &&
                       ((plat->frequency /
                       (2 << baud_rate_val)) > speed))
                        baud_rate_val++;

                plat->speed_hz = speed / (2 << baud_rate_val);
        }
        confr &= ~ZYNQ_QSPI_CR_BAUD_MASK;
        confr |= (baud_rate_val << ZYNQ_QSPI_CR_BAUD_SHIFT);

        writel(confr, &regs->cr);
        priv->freq = speed;

        debug("%s: regs=%p, speed=%d\n", __func__, priv->regs, priv->freq);

        return 0;
}

static int zynq_qspi_set_mode(struct udevice *bus, uint mode)
{
        struct zynq_qspi_priv *priv = dev_get_priv(bus);
        struct zynq_qspi_regs *regs = priv->regs;
        uint32_t confr;

        /* Set the SPI Clock phase and polarities */
        confr = readl(&regs->cr);
        confr &= ~(ZYNQ_QSPI_CR_CPHA_MASK | ZYNQ_QSPI_CR_CPOL_MASK);

        if (mode & SPI_CPHA)
                confr |= ZYNQ_QSPI_CR_CPHA_MASK;
        if (mode & SPI_CPOL)
                confr |= ZYNQ_QSPI_CR_CPOL_MASK;

        writel(confr, &regs->cr);
        priv->mode = mode;

        debug("%s: regs=%p, mode=%d\n", __func__, priv->regs, priv->mode);

        return 0;
}

static const struct dm_spi_ops zynq_qspi_ops = {
        .claim_bus      = zynq_qspi_claim_bus,
        .release_bus    = zynq_qspi_release_bus,
        .xfer           = zynq_qspi_xfer,
        .set_speed      = zynq_qspi_set_speed,
        .set_mode       = zynq_qspi_set_mode,
};

static const struct udevice_id zynq_qspi_ids[] = {
        { .compatible = "xlnx,zynq-qspi-1.0" },
        { }
};

U_BOOT_DRIVER(zynq_qspi) = {
        .name   = "zynq_qspi",
        .id     = UCLASS_SPI,
        .of_match = zynq_qspi_ids,
        .ops    = &zynq_qspi_ops,
        .ofdata_to_platdata = zynq_qspi_ofdata_to_platdata,
        .platdata_auto_alloc_size = sizeof(struct zynq_qspi_platdata),
        .priv_auto_alloc_size = sizeof(struct zynq_qspi_priv),
        .probe  = zynq_qspi_probe,
};