/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2020 Poul-Henning Kamp
 *
 * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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/kernel.h>
#include <sys/bus.h>
#include <sys/eventhandler.h>
#include <sys/module.h>
#include <sys/rman.h>
#include <sys/systm.h>
#include <sys/watchdog.h>

#include <dev/superio/superio.h>

#include <machine/bus.h>
#include <machine/resource.h>

struct ftwd_softc {
        eventhandler_tag        wd_ev;
};

static void
ftwd_func(void *priv, u_int cmd, int *error)
{
        device_t dev = priv;
        uint64_t timeout;
        uint8_t val = 0;
        uint8_t minutes = 0;

        if (cmd != 0) {
                cmd &= WD_INTERVAL;

                /* Convert the requested timeout to seconds. */
                if (cmd >= WD_TO_1SEC)
                        timeout = (uint64_t)1 << (cmd - WD_TO_1SEC);
                else
                        timeout = 1;

                if (timeout <= UINT8_MAX) {
                        val = timeout;
                        *error = 0;
                } else if ((timeout / 60) <= UINT8_MAX) {
                        val = timeout / 60;
                        minutes = 1;
                        *error = 0;
                }
        }
        if (bootverbose) {
                if (val == 0) {
                        device_printf(dev, "disabling watchdog\n");
                } else {
                        device_printf(dev,
                            "arm watchdog to %d %s%s (Was: 0x%02x)\n",
                            val, minutes ? "minute" : "second",
                            val == 1 ? "" : "s",
                            superio_read(dev, 0xf6)
                        );
                }
        }
        superio_write(dev, 0xf0, 0x00);         // Disable WDTRST#
        superio_write(dev, 0xf6, val);          // Set Counter

        if (minutes)
                superio_write(dev, 0xf5, 0x7d); // minutes, act high, 125ms
        else
                superio_write(dev, 0xf5, 0x75); // seconds, act high, 125ms

        if (val)
                superio_write(dev, 0xf7, 0x01); // Disable PME
        if (val)
                superio_write(dev, 0xf0, 0x81); // Enable WDTRST#
        else
                superio_write(dev, 0xf0, 0x00); // Disable WDTRST
}

static int
ftwd_probe(device_t dev)
{

        if (superio_vendor(dev) != SUPERIO_VENDOR_FINTEK ||
            superio_get_type(dev) != SUPERIO_DEV_WDT)
                return (ENXIO);
        device_set_desc(dev, "Watchdog Timer on Fintek SuperIO");
        return (BUS_PROBE_DEFAULT);
}

static int
ftwd_attach(device_t dev)
{
        struct ftwd_softc *sc = device_get_softc(dev);

        /*
         * We do not touch the watchdog at this time, it might be armed
         * by firmware to protect the full boot sequence.
         */

        sc->wd_ev = EVENTHANDLER_REGISTER(watchdog_list, ftwd_func, dev, 0);
        return (0);
}

static int
ftwd_detach(device_t dev)
{
        struct ftwd_softc *sc = device_get_softc(dev);
        int dummy;

        if (sc->wd_ev != NULL)
                EVENTHANDLER_DEREGISTER(watchdog_list, sc->wd_ev);
        ftwd_func(dev, 0, &dummy);
        return (0);
}

static device_method_t ftwd_methods[] = {
        DEVMETHOD(device_probe,         ftwd_probe),
        DEVMETHOD(device_attach,        ftwd_attach),
        DEVMETHOD(device_detach,        ftwd_detach),
        DEVMETHOD_END
};

static driver_t ftwd_driver = {
        "ftwd",
        ftwd_methods,
        sizeof (struct ftwd_softc)
};

DRIVER_MODULE(ftwd, superio, ftwd_driver, NULL, NULL);
MODULE_DEPEND(ftwd, superio, 1, 1, 1);
MODULE_VERSION(ftwd, 1);