/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2009, Oleksandr Tymoshenko <gonzo@FreeBSD.org>
 * 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 unmodified, 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.
 */

/*
 * Watchdog driver for AR71xx 
 */

#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/eventhandler.h>
#include <sys/systm.h>
#include <sys/watchdog.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/sysctl.h>

#include <mips/atheros/ar71xxreg.h>
#include <mips/atheros/ar71xx_cpudef.h>

struct ar71xx_wdog_softc {
	device_t dev;
	int armed;
	int reboot_from_watchdog;
	int watchdog_nmi;
	int debug;
};

static void
ar71xx_wdog_watchdog_fn(void *private, u_int cmd, int *error)
{
	struct ar71xx_wdog_softc *sc = private;
	uint64_t timer_val;
	int action;

	action = RST_WDOG_ACTION_RESET;
	if (sc->watchdog_nmi != 0)
		action = RST_WDOG_ACTION_NMI;

	cmd &= WD_INTERVAL;
	if (sc->debug)
		device_printf(sc->dev, "%s: : cmd: %x\n", __func__, cmd);
	if (cmd > 0) {
		timer_val = (uint64_t)(1ULL << cmd) * ar71xx_ahb_freq() /
		    1000000000;

		/*
		 * Clamp the timer value in case we overflow.
		 */
		if (timer_val > 0xffffffff)
			timer_val = 0xffffffff;
		if (sc->debug)
			device_printf(sc->dev, "%s: programming timer: %jx\n",
			    __func__, (uintmax_t) timer_val);
		/*
		 * Make sure the watchdog is set to NOACTION and give it
		 * time to take.
		 */
		ATH_WRITE_REG(AR71XX_RST_WDOG_CONTROL, RST_WDOG_ACTION_NOACTION);
		wmb();
		DELAY(100);

		/*
		 * Update the timer value.  It's already clamped at this
		 * point so we don't have to wrap/clamp it here.
		 */
		ATH_WRITE_REG(AR71XX_RST_WDOG_TIMER, timer_val);
		wmb();
		DELAY(100);

		/*
		 * And now, arm.
		 */
		ATH_WRITE_REG(AR71XX_RST_WDOG_CONTROL, action);
		sc->armed = 1;
		*error = 0;
	} else {
		if (sc->debug)
			device_printf(sc->dev, "%s: disarming\n", __func__);
		if (sc->armed) {
			ATH_WRITE_REG(AR71XX_RST_WDOG_CONTROL,
			    RST_WDOG_ACTION_NOACTION);
			sc->armed = 0;
		}
	}
}

static int
ar71xx_wdog_probe(device_t dev)
{

	device_set_desc(dev, "Atheros AR71XX watchdog timer");
	return (BUS_PROBE_NOWILDCARD);
}

static void
ar71xx_wdog_sysctl(device_t dev)
{
	struct ar71xx_wdog_softc *sc = device_get_softc(dev);

        struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(sc->dev);
        struct sysctl_oid *tree = device_get_sysctl_tree(sc->dev);

        SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
                "debug", CTLFLAG_RW, &sc->debug, 0,
                "enable watchdog debugging");
        SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
                "nmi", CTLFLAG_RW, &sc->watchdog_nmi, 0,
                "watchdog triggers NMI instead of reset");
        SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
                "armed", CTLFLAG_RD, &sc->armed, 0,
                "whether the watchdog is armed");
        SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
                "reboot_from_watchdog", CTLFLAG_RD, &sc->reboot_from_watchdog, 0,
                "whether the system rebooted from the watchdog");
}

static int
ar71xx_wdog_attach(device_t dev)
{
	struct ar71xx_wdog_softc *sc = device_get_softc(dev);

	/* Initialise */
	sc->reboot_from_watchdog = 0;
	sc->armed = 0;
	sc->debug = 0;

	if (ATH_READ_REG(AR71XX_RST_WDOG_CONTROL) & RST_WDOG_LAST) {
		device_printf (dev, 
		    "Previous reset was due to watchdog timeout\n");
		sc->reboot_from_watchdog = 1;
	}

	ATH_WRITE_REG(AR71XX_RST_WDOG_CONTROL, RST_WDOG_ACTION_NOACTION);

	sc->dev = dev;
	EVENTHANDLER_REGISTER(watchdog_list, ar71xx_wdog_watchdog_fn, sc, 0);
	ar71xx_wdog_sysctl(dev);

	return (0);
}

static device_method_t ar71xx_wdog_methods[] = {
	DEVMETHOD(device_probe, ar71xx_wdog_probe),
	DEVMETHOD(device_attach, ar71xx_wdog_attach),
	{0, 0},
};

static driver_t ar71xx_wdog_driver = {
	"ar71xx_wdog",
	ar71xx_wdog_methods,
	sizeof(struct ar71xx_wdog_softc),
};
static devclass_t ar71xx_wdog_devclass;

DRIVER_MODULE(ar71xx_wdog, nexus, ar71xx_wdog_driver, ar71xx_wdog_devclass, 0, 0);