/* $NetBSD: apple_wdog.c,v 1.3 2022/04/05 05:04:04 skrll Exp $ */

/*-
 * Copyright (c) 2021 Jared McNeill <jmcneill@invisible.ca>
 * All rights reserved.
 *
 * 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/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: apple_wdog.c,v 1.3 2022/04/05 05:04:04 skrll Exp $");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/device.h>
#include <sys/intr.h>
#include <sys/kernel.h>
#include <sys/lwp.h>
#include <sys/systm.h>

#include <dev/fdt/fdtvar.h>

#define WDOG_CHIP_CTL           0x000c
#define WDOG_SYS_TMR            0x0010
#define WDOG_SYS_RST            0x0014
#define WDOG_SYS_CTL            0x001c
#define  WDOG_SYS_CTL_ENABLE    __BIT(2)

static const struct device_compatible_entry compat_data[] = {
        { .compat = "apple,wdt" },
        { .compat = "apple,reboot-v0" },
        DEVICE_COMPAT_EOL
};

struct apple_wdog_softc {
        device_t sc_dev;
        bus_space_tag_t sc_bst;
        bus_space_handle_t sc_bsh;
};

#define WDOG_READ(sc, reg) \
        bus_space_read_4((sc)->sc_bst, (sc)->sc_bsh, (reg))
#define WDOG_WRITE(sc, reg, val) \
        bus_space_write_4((sc)->sc_bst, (sc)->sc_bsh, (reg), (val))

static void
apple_wdog_reset(device_t dev)
{
        struct apple_wdog_softc * const sc = device_private(dev);

        WDOG_WRITE(sc, WDOG_SYS_RST, 1);
        WDOG_WRITE(sc, WDOG_SYS_CTL, WDOG_SYS_CTL_ENABLE);
        WDOG_WRITE(sc, WDOG_SYS_TMR, 0);
}

static struct fdtbus_power_controller_func apple_wdog_power_funcs = {
        .reset = apple_wdog_reset,
};

static int
apple_wdog_match(device_t parent, cfdata_t cf, void *aux)
{
        struct fdt_attach_args * const faa = aux;

        return of_compatible_match(faa->faa_phandle, compat_data);
}

static void
apple_wdog_attach(device_t parent, device_t self, void *aux)
{
        struct apple_wdog_softc * const sc = device_private(self);
        struct fdt_attach_args * const faa = aux;
        const int phandle = faa->faa_phandle;
        bus_addr_t addr;
        bus_size_t size;

        if (fdtbus_get_reg(phandle, 0, &addr, &size) != 0) {
                aprint_error(": couldn't get registers\n");
                return;
        }

        sc->sc_dev = self;
        sc->sc_bst = faa->faa_bst;
        if (bus_space_map(sc->sc_bst, addr, size, 0, &sc->sc_bsh) != 0) {
                aprint_error(": couldn't map registers\n");
                return;
        }

        aprint_naive("\n");
        aprint_normal(": Apple Watchdog\n");

        WDOG_WRITE(sc, WDOG_CHIP_CTL, 0);
        WDOG_WRITE(sc, WDOG_SYS_CTL, 0);

        fdtbus_register_power_controller(self, phandle,
            &apple_wdog_power_funcs);
}

CFATTACH_DECL_NEW(apple_wdog, sizeof(struct apple_wdog_softc),
        apple_wdog_match, apple_wdog_attach, NULL, NULL);