/*-
 * Copyright (c) 2016 Jared McNeill <jmcneill@invisible.ca>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <machine/bus.h>

#include <dev/uart/uart.h>
#include <dev/uart/uart_bus.h>
#include <dev/uart/uart_cpu_fdt.h>
#include <dev/uart/uart_dev_ns8250.h>

#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>

#include <dev/clk/clk.h>
#include <dev/hwreset/hwreset.h>

#include "uart_if.h"

struct snps_softc {
        struct ns8250_softc     ns8250;

        clk_t                   baudclk;
        clk_t                   apb_pclk;
        hwreset_t               reset;
};

/*
 * To use early printf on 64 bits Allwinner SoC, add to kernel config
 * options SOCDEV_PA=0x0
 * options EARLY_PRINTF=snps
 *
 * To use early printf on 32 bits Allwinner SoC, add to kernel config
 * options SOCDEV_PA=0x01C00000
 * options SOCDEV_VA=0x10000000
 * options EARLY_PRINTF=snps
 *
 * remove the if 0
*/
#if CHECK_EARLY_PRINTF(snps)
static void
uart_snps_early_putc(int c)
{
        volatile uint32_t *stat;
        volatile uint32_t *tx;

#ifdef ALLWINNER_64
        stat = (uint32_t *) (socdev_va + 0x1C2807C);
        tx = (uint32_t *) (socdev_va + 0x1C28000);
#endif
#ifdef ALLWINNER_32
        stat = (uint32_t *) (socdev_va + 0x2807C);
        tx = (uint32_t *) (socdev_va + 0x28000);
#endif

        while ((*stat & (1 << 2)) == 0)
                continue;
        *tx = c;
}
early_putc_t *early_putc = uart_snps_early_putc;
#endif /* CHECK_EARLY_PRINTF */

static kobj_method_t snps_methods[] = {
        KOBJMETHOD(uart_probe,          ns8250_bus_probe),
        KOBJMETHOD(uart_attach,         ns8250_bus_attach),
        KOBJMETHOD(uart_detach,         ns8250_bus_detach),
        KOBJMETHOD(uart_flush,          ns8250_bus_flush),
        KOBJMETHOD(uart_getsig,         ns8250_bus_getsig),
        KOBJMETHOD(uart_ioctl,          ns8250_bus_ioctl),
        KOBJMETHOD(uart_ipend,          ns8250_bus_ipend),
        KOBJMETHOD(uart_param,          ns8250_bus_param),
        KOBJMETHOD(uart_receive,        ns8250_bus_receive),
        KOBJMETHOD(uart_setsig,         ns8250_bus_setsig),
        KOBJMETHOD(uart_transmit,       ns8250_bus_transmit),
        KOBJMETHOD(uart_txbusy,         ns8250_bus_txbusy),
        KOBJMETHOD(uart_grab,           ns8250_bus_grab),
        KOBJMETHOD(uart_ungrab,         ns8250_bus_ungrab),
        KOBJMETHOD_END
};

struct uart_class uart_snps_class = {
        "snps",
        snps_methods,
        sizeof(struct snps_softc),
        .uc_ops = &uart_ns8250_ops,
        .uc_range = 8,
        .uc_rclk = 0,
};

struct uart_class uart_snps_jh7110_class = {
        "snps",
        snps_methods,
        sizeof(struct snps_softc),
        .uc_ops = &uart_ns8250_ops,
        .uc_range = 8,
        .uc_rclk = 24000000,
};

static struct ofw_compat_data compat_data[] = {
        { "starfive,jh7110-uart",       (uintptr_t)&uart_snps_jh7110_class },
        { "snps,dw-apb-uart",           (uintptr_t)&uart_snps_class },
        { "marvell,armada-38x-uart",    (uintptr_t)&uart_snps_class },
        { NULL,                         (uintptr_t)NULL }
};
UART_FDT_CLASS(compat_data);

static int
snps_get_clocks(device_t dev, clk_t *baudclk, clk_t *apb_pclk)
{

        *baudclk = NULL;
        *apb_pclk = NULL;

        /* Baud clock is either named "baudclk", or there is a single
         * unnamed clock.
         */
        if (clk_get_by_ofw_name(dev, 0, "baudclk", baudclk) != 0 &&
            clk_get_by_ofw_index(dev, 0, 0, baudclk) != 0)
                return (ENOENT);

        /* APB peripheral clock is optional */
        (void)clk_get_by_ofw_name(dev, 0, "apb_pclk", apb_pclk);

        return (0);
}

static int
snps_probe(device_t dev)
{
        struct snps_softc *sc;
        struct uart_class *uart_class;
        phandle_t node;
        uint32_t shift, iowidth, clock;
        uint64_t freq;
        int error;
        clk_t baudclk, apb_pclk;
        hwreset_t reset;

        if (!ofw_bus_status_okay(dev))
                return (ENXIO);

        uart_class = (struct uart_class *)ofw_bus_search_compatible(dev,
            compat_data)->ocd_data;
        if (uart_class == NULL)
                return (ENXIO);

        freq = 0;
        sc = device_get_softc(dev);
        sc->ns8250.base.sc_class = uart_class;

        node = ofw_bus_get_node(dev);
        if (OF_getencprop(node, "reg-shift", &shift, sizeof(shift)) <= 0)
                shift = 0;
        if (OF_getencprop(node, "reg-io-width", &iowidth, sizeof(iowidth)) <= 0)
                iowidth = 1;
        if (OF_getencprop(node, "clock-frequency", &clock, sizeof(clock)) <= 0)
                clock = 0;

        if (hwreset_get_by_ofw_idx(dev, 0, 0, &reset) == 0) {
                error = hwreset_deassert(reset);
                if (error != 0) {
                        device_printf(dev, "cannot de-assert reset\n");
                        return (error);
                }
        }

        if (snps_get_clocks(dev, &baudclk, &apb_pclk) == 0) {
                error = clk_enable(baudclk);
                if (error != 0) {
                        device_printf(dev, "cannot enable baud clock\n");
                        return (error);
                }
                if (apb_pclk != NULL) {
                        error = clk_enable(apb_pclk);
                        if (error != 0) {
                                device_printf(dev,
                                    "cannot enable peripheral clock\n");
                                return (error);
                        }
                }

                if (clock == 0) {
                        error = clk_get_freq(baudclk, &freq);
                        if (error != 0) {
                                device_printf(dev, "cannot get frequency\n");
                                return (error);
                        }
                        clock = (uint32_t)freq;
                }
        }

        if (bootverbose && clock == 0)
                device_printf(dev, "could not determine frequency\n");

        error = uart_bus_probe(dev, (int)shift, (int)iowidth, (int)clock, 0, 0, UART_F_BUSY_DETECT);
        if (error > 0)
                return (error);

        /* XXX uart_bus_probe has changed the softc, so refresh it */
        sc = device_get_softc(dev);

        /* Store clock and reset handles for detach */
        sc->baudclk = baudclk;
        sc->apb_pclk = apb_pclk;
        sc->reset = reset;

        return (BUS_PROBE_VENDOR);
}

static int
snps_attach(device_t dev)
{
        phandle_t node;
        int ret;

        ret = uart_bus_attach(dev);
        if (ret == 0) {
                node = ofw_bus_get_node(dev);
                /* Set up phandle to dev mapping */
                OF_device_register_xref(OF_xref_from_node(node), dev);
        }

        return (ret);
}

static int
snps_detach(device_t dev)
{
        struct snps_softc *sc;
        clk_t baudclk, apb_pclk;
        hwreset_t reset;
        int error;

        sc = device_get_softc(dev);
        baudclk = sc->baudclk;
        apb_pclk = sc->apb_pclk;
        reset = sc->reset;

        error = uart_bus_detach(dev);
        if (error != 0)
                return (error);

        if (reset != NULL) {
                error = hwreset_assert(reset);
                if (error != 0) {
                        device_printf(dev, "cannot assert reset\n");
                        return (error);
                }
                hwreset_release(reset);
        }
        if (apb_pclk != NULL) {
                error = clk_release(apb_pclk);
                if (error != 0) {
                        device_printf(dev, "cannot release peripheral clock\n");
                        return (error);
                }
        }
        if (baudclk != NULL) {
                error = clk_release(baudclk);
                if (error != 0) {
                        device_printf(dev, "cannot release baud clock\n");
                        return (error);
                }
        }

        return (0);
}

static device_method_t snps_bus_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         snps_probe),
        DEVMETHOD(device_attach,        snps_attach),
        DEVMETHOD(device_detach,        snps_detach),
        DEVMETHOD_END
};

static driver_t snps_uart_driver = {
        uart_driver_name,
        snps_bus_methods,
        sizeof(struct snps_softc)
};

DRIVER_MODULE(uart_snps, simplebus, snps_uart_driver, 0, 0);