/*
 * Altera SPI driver
 *
 * based on bfin_spi.c
 * Copyright (c) 2005-2008 Analog Devices Inc.
 * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <malloc.h>
#include <fdtdec.h>
#include <spi.h>
#include <asm/io.h>

DECLARE_GLOBAL_DATA_PTR;

#define ALTERA_SPI_STATUS_RRDY_MSK      BIT(7)
#define ALTERA_SPI_CONTROL_SSO_MSK      BIT(10)

#ifndef CONFIG_ALTERA_SPI_IDLE_VAL
#define CONFIG_ALTERA_SPI_IDLE_VAL      0xff
#endif

struct altera_spi_regs {
        u32     rxdata;
        u32     txdata;
        u32     status;
        u32     control;
        u32     _reserved;
        u32     slave_sel;
};

struct altera_spi_platdata {
        struct altera_spi_regs *regs;
};

struct altera_spi_priv {
        struct altera_spi_regs *regs;
};

static void spi_cs_activate(struct udevice *dev, uint cs)
{
        struct udevice *bus = dev->parent;
        struct altera_spi_priv *priv = dev_get_priv(bus);
        struct altera_spi_regs *const regs = priv->regs;

        writel(1 << cs, &regs->slave_sel);
        writel(ALTERA_SPI_CONTROL_SSO_MSK, &regs->control);
}

static void spi_cs_deactivate(struct udevice *dev)
{
        struct udevice *bus = dev->parent;
        struct altera_spi_priv *priv = dev_get_priv(bus);
        struct altera_spi_regs *const regs = priv->regs;

        writel(0, &regs->control);
        writel(0, &regs->slave_sel);
}

static int altera_spi_claim_bus(struct udevice *dev)
{
        struct udevice *bus = dev->parent;
        struct altera_spi_priv *priv = dev_get_priv(bus);
        struct altera_spi_regs *const regs = priv->regs;

        writel(0, &regs->control);
        writel(0, &regs->slave_sel);

        return 0;
}

static int altera_spi_release_bus(struct udevice *dev)
{
        struct udevice *bus = dev->parent;
        struct altera_spi_priv *priv = dev_get_priv(bus);
        struct altera_spi_regs *const regs = priv->regs;

        writel(0, &regs->slave_sel);

        return 0;
}

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

        /* assume spi core configured to do 8 bit transfers */
        unsigned int bytes = bitlen / 8;
        const unsigned char *txp = dout;
        unsigned char *rxp = din;
        uint32_t reg, data, start;

        debug("%s: bus:%i cs:%i bitlen:%i bytes:%i flags:%lx\n", __func__,
              bus->seq, slave_plat->cs, bitlen, bytes, flags);

        if (bitlen == 0)
                goto done;

        if (bitlen % 8) {
                flags |= SPI_XFER_END;
                goto done;
        }

        /* empty read buffer */
        if (readl(&regs->status) & ALTERA_SPI_STATUS_RRDY_MSK)
                readl(&regs->rxdata);

        if (flags & SPI_XFER_BEGIN)
                spi_cs_activate(dev, slave_plat->cs);

        while (bytes--) {
                if (txp)
                        data = *txp++;
                else
                        data = CONFIG_ALTERA_SPI_IDLE_VAL;

                debug("%s: tx:%x ", __func__, data);
                writel(data, &regs->txdata);

                start = get_timer(0);
                while (1) {
                        reg = readl(&regs->status);
                        if (reg & ALTERA_SPI_STATUS_RRDY_MSK)
                                break;
                        if (get_timer(start) > (CONFIG_SYS_HZ / 1000)) {
                                debug("%s: Transmission timed out!\n", __func__);
                                return -1;
                        }
                }

                data = readl(&regs->rxdata);
                if (rxp)
                        *rxp++ = data & 0xff;

                debug("rx:%x\n", data);
        }

done:
        if (flags & SPI_XFER_END)
                spi_cs_deactivate(dev);

        return 0;
}

static int altera_spi_set_speed(struct udevice *bus, uint speed)
{
        return 0;
}

static int altera_spi_set_mode(struct udevice *bus, uint mode)
{
        return 0;
}

static int altera_spi_probe(struct udevice *bus)
{
        struct altera_spi_platdata *plat = dev_get_platdata(bus);
        struct altera_spi_priv *priv = dev_get_priv(bus);

        priv->regs = plat->regs;

        return 0;
}

static int altera_spi_ofdata_to_platdata(struct udevice *bus)
{
        struct altera_spi_platdata *plat = dev_get_platdata(bus);

        plat->regs = map_physmem(dev_get_addr(bus),
                                 sizeof(struct altera_spi_regs),
                                 MAP_NOCACHE);

        return 0;
}

static const struct dm_spi_ops altera_spi_ops = {
        .claim_bus      = altera_spi_claim_bus,
        .release_bus    = altera_spi_release_bus,
        .xfer           = altera_spi_xfer,
        .set_speed      = altera_spi_set_speed,
        .set_mode       = altera_spi_set_mode,
        /*
         * cs_info is not needed, since we require all chip selects to be
         * in the device tree explicitly
         */
};

static const struct udevice_id altera_spi_ids[] = {
        { .compatible = "altr,spi-1.0" },
        {}
};

U_BOOT_DRIVER(altera_spi) = {
        .name   = "altera_spi",
        .id     = UCLASS_SPI,
        .of_match = altera_spi_ids,
        .ops    = &altera_spi_ops,
        .ofdata_to_platdata = altera_spi_ofdata_to_platdata,
        .platdata_auto_alloc_size = sizeof(struct altera_spi_platdata),
        .priv_auto_alloc_size = sizeof(struct altera_spi_priv),
        .probe  = altera_spi_probe,
};