/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2024 Bojan Novković <bnovkov@FreeBSD.org>
 *
 * 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.
 */

/*
 * Driver for cvitek's poweroff/restart controller.
 */

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/types.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/reboot.h>
#include <sys/rman.h>

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

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

#define RTC_CTRL0_UNLOCK        0x4
#define  RTC_CTRL0_UNLOCK_KEY   0xAB18

#define RTC_CTRL0                       0x8
#define  RTC_CTRL0_RESERVED_MASK        0xFFFF0800
#define  RTC_CTRL0_REQ_SHUTDOWN         0x01
#define  RTC_CTRL0_REQ_POWERCYCLE       0x08
#define  RTC_CTRL0_REQ_WARM_RESET       0x10

#define RTC_BASE_OFFSET         0x1000
#define RTC_EN_SHDN_REQ         (RTC_BASE_OFFSET + 0xC0)
#define RTC_EN_PWR_CYC_REQ      (RTC_BASE_OFFSET + 0xC8)
#define RTC_EN_WARM_RST_REQ     (RTC_BASE_OFFSET + 0xCC)

struct cvitek_restart_softc {
        int reg_rid;
        struct resource *reg;
        eventhandler_tag tag;
};

static void
cvitek_restart_shutdown_final(device_t dev, int howto)
{
        struct cvitek_restart_softc *sc;
        uint32_t val;

        sc = device_get_softc(dev);
        val = RTC_CTRL0_RESERVED_MASK;
        if ((howto & RB_POWEROFF) != 0)
                val |= RTC_CTRL0_REQ_SHUTDOWN;
        else if ((howto & RB_POWERCYCLE) != 0)
                val |= RTC_CTRL0_REQ_POWERCYCLE;
        else
                val |= RTC_CTRL0_REQ_WARM_RESET;

        /* Unlock writes to 'rtc_ctrl0'. */
        bus_write_4(sc->reg, RTC_CTRL0_UNLOCK, RTC_CTRL0_UNLOCK_KEY);
        bus_write_4(sc->reg, RTC_CTRL0, val);
        DELAY(1000);

        device_printf(dev, "Poweroff request failed\n");
}

static int
cvitek_restart_probe(device_t dev)
{

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

        if (ofw_bus_is_compatible(dev, "cvitek,restart")) {
                device_set_desc(dev, "Cvitek restart controller");
                return (BUS_PROBE_DEFAULT);
        }
        return (ENXIO);
}

static int
cvitek_restart_attach(device_t dev)
{
        struct cvitek_restart_softc *sc;

        sc = device_get_softc(dev);
        sc->reg = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->reg_rid,
            RF_ACTIVE);
        if (sc->reg == NULL) {
                device_printf(dev, "can't map RTC regs\n");
                return (ENXIO);
        }

        /* Enable requests for various poweroff methods. */
        bus_write_4(sc->reg, RTC_EN_SHDN_REQ, 0x1);
        bus_write_4(sc->reg, RTC_EN_PWR_CYC_REQ, 0x1);
        bus_write_4(sc->reg, RTC_EN_WARM_RST_REQ, 0x1);

        sc->tag = EVENTHANDLER_REGISTER(shutdown_final,
            cvitek_restart_shutdown_final, dev, SHUTDOWN_PRI_LAST);

        return (0);
}

static int
cvitek_restart_detach(device_t dev)
{
        struct cvitek_restart_softc *sc;

        sc = device_get_softc(dev);
        if (sc->reg == NULL)
                return (0);

        bus_write_4(sc->reg, RTC_EN_SHDN_REQ, 0x0);
        bus_write_4(sc->reg, RTC_EN_PWR_CYC_REQ, 0x0);
        bus_write_4(sc->reg, RTC_EN_WARM_RST_REQ, 0x0);

        bus_release_resource(dev, SYS_RES_MEMORY, sc->reg_rid, sc->reg);
        EVENTHANDLER_DEREGISTER(shutdown_final, sc->tag);

        return (0);
}

static device_method_t cvitek_restart_methods[] = {
        DEVMETHOD(device_probe,         cvitek_restart_probe),
        DEVMETHOD(device_attach,        cvitek_restart_attach),
        DEVMETHOD(device_detach,        cvitek_restart_detach),

        DEVMETHOD_END
};

DEFINE_CLASS_0(cvitek_restart, cvitek_restart_driver, cvitek_restart_methods,
    sizeof(struct cvitek_restart_softc));
DRIVER_MODULE(cvitek_restart, simplebus, cvitek_restart_driver, NULL, NULL);