/*-
 * Copyright (c) 2013 Oleksandr Tymoshenko <gonzo@freebsd.org>
 * Copyright (c) 2016 Emmanuel Vadot <manu@freebsd.org>
 * Copyright (c) 2022 Julien Cassette <julien.cassette@gmail.com>
 * 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 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/eventhandler.h>
#include <sys/systm.h>
#include <sys/watchdog.h>
#include <sys/reboot.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/rman.h>

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

#include <machine/bus.h>

#include <arm/allwinner/aw_wdog.h>

#define READ(_sc, _r) bus_read_4((_sc)->res, (_r))
#define WRITE(_sc, _r, _v) bus_write_4((_sc)->res, (_r), (_v))

#define A10_WDOG_CTRL           0x00
#define A31_WDOG_CTRL           0x10
#define D1_WDOG_CTRL            0x10
#define H616_WDOG_CTRL          0xB0
#define  WDOG_CTRL_RESTART      (1 << 0)
#define  A31_WDOG_CTRL_KEY      (0xa57 << 1)
#define  D1_WDOG_CTRL_KEY       (0xa57 << 1)
#define  H616_WDOG_CTRL_KEY     (0xa57 << 1)
#define A10_WDOG_MODE           0x04
#define A31_WDOG_MODE           0x18
#define D1_WDOG_MODE            0x18
#define H616_WDOG_MODE          0xB8
#define  D1_WDOG_MODE_KEY       (0x16AA << 16)
#define  A10_WDOG_MODE_INTVL_SHIFT      3
#define  A31_WDOG_MODE_INTVL_SHIFT      4
#define  D1_WDOG_MODE_INTVL_SHIFT       4
#define  H616_WDOG_MODE_INTVL_SHIFT     4
#define  A10_WDOG_MODE_RST_EN   (1 << 1)
#define  WDOG_MODE_EN           (1 << 0)
#define A31_WDOG_CONFIG         0x14
#define D1_WDOG_CONFIG          0x14
#define H616_WDOG_CONFIG        0xB4
#define  A31_WDOG_CONFIG_RST_EN_SYSTEM  (1 << 0)
#define  A31_WDOG_CONFIG_RST_EN_INT     (2 << 0)
#define  D1_WDOG_CONFIG_KEY             (0x16AA << 16)
#define  D1_WDOG_CONFIG_RST_EN_SYSTEM   (1 << 0)
#define  D1_WDOG_CONFIG_RST_EN_INT      (2 << 0)
#define  H616_WDOG_CONFIG_RST_EN_SYSTEM (1 << 0)
#define  H616_WDOG_CONFIG_RST_EN_INT    (2 << 0)

struct aw_wdog_interval {
        uint64_t        milliseconds;
        unsigned int    value;
};

struct aw_wdog_interval wd_intervals[] = {
        {   500,         0 },
        {  1000,         1 },
        {  2000,         2 },
        {  3000,         3 },
        {  4000,         4 },
        {  5000,         5 },
        {  6000,         6 },
        {  8000,         7 },
        { 10000,         8 },
        { 12000,         9 },
        { 14000,        10 },
        { 16000,        11 },
        { 0,             0 } /* sentinel */
};

static struct aw_wdog_softc *aw_wdog_sc = NULL;

struct aw_wdog_softc {
        device_t                dev;
        struct resource *       res;
        struct mtx              mtx;
        uint8_t                 wdog_ctrl;
        uint32_t                wdog_ctrl_key;
        uint8_t                 wdog_mode;
        uint32_t                wdog_mode_key;
        uint8_t                 wdog_mode_intvl_shift;
        uint8_t                 wdog_mode_en;
        uint8_t                 wdog_config;
        uint32_t                wdog_config_value;
};

enum wdog_type {
        A10_WATCHDOG = 1,
        A31_WATCHDOG,
        D1_WATCHDOG,
        H616_WATCHDOG,
};

static struct ofw_compat_data compat_data[] = {
        {"allwinner,sun4i-a10-wdt", A10_WATCHDOG},
        {"allwinner,sun6i-a31-wdt", A31_WATCHDOG},
        {"allwinner,sun20i-d1-wdt", D1_WATCHDOG},
        {"allwinner,sun50i-h616-wdt", H616_WATCHDOG},
        {NULL,             0}
};

static void aw_wdog_watchdog_fn(void *, u_int, int *);
static void aw_wdog_shutdown_fn(void *, int);

static int
aw_wdog_probe(device_t dev)
{

        if (!ofw_bus_status_okay(dev))
                return (ENXIO);
        switch (ofw_bus_search_compatible(dev, compat_data)->ocd_data) {
        case A10_WATCHDOG:
                device_set_desc(dev, "Allwinner A10 Watchdog");
                return (BUS_PROBE_DEFAULT);
        case A31_WATCHDOG:
                device_set_desc(dev, "Allwinner A31 Watchdog");
                return (BUS_PROBE_DEFAULT);
        case D1_WATCHDOG:
                device_set_desc(dev, "Allwinner D1 Watchdog");
                return (BUS_PROBE_DEFAULT);
        case H616_WATCHDOG:
                device_set_desc(dev, "Allwinner H616 Watchdog");
                return (BUS_PROBE_DEFAULT);
        }
        return (ENXIO);
}

static int
aw_wdog_attach(device_t dev)
{
        struct aw_wdog_softc *sc;
        int rid;

        if (aw_wdog_sc != NULL)
                return (ENXIO);

        sc = device_get_softc(dev);
        sc->dev = dev;

        rid = 0;
        sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
        if (sc->res == NULL) {
                device_printf(dev, "could not allocate memory resource\n");
                return (ENXIO);
        }

        aw_wdog_sc = sc;

        switch (ofw_bus_search_compatible(dev, compat_data)->ocd_data) {
        case A10_WATCHDOG:
                sc->wdog_ctrl = A10_WDOG_CTRL;
                sc->wdog_mode = A10_WDOG_MODE;
                sc->wdog_mode_key = 0;
                sc->wdog_mode_intvl_shift = A10_WDOG_MODE_INTVL_SHIFT;
                sc->wdog_mode_en = A10_WDOG_MODE_RST_EN | WDOG_MODE_EN;
                break;
        case A31_WATCHDOG:
                sc->wdog_ctrl = A31_WDOG_CTRL;
                sc->wdog_ctrl_key = A31_WDOG_CTRL_KEY;
                sc->wdog_mode = A31_WDOG_MODE;
                sc->wdog_mode_key = 0;
                sc->wdog_mode_intvl_shift = A31_WDOG_MODE_INTVL_SHIFT;
                sc->wdog_mode_en = WDOG_MODE_EN;
                sc->wdog_config = A31_WDOG_CONFIG;
                sc->wdog_config_value = A31_WDOG_CONFIG_RST_EN_SYSTEM;
                break;
        case D1_WATCHDOG:
                sc->wdog_ctrl = D1_WDOG_CTRL;
                sc->wdog_ctrl_key = D1_WDOG_CTRL_KEY;
                sc->wdog_mode = D1_WDOG_MODE;
                sc->wdog_mode_key = D1_WDOG_MODE_KEY;
                sc->wdog_mode_intvl_shift = D1_WDOG_MODE_INTVL_SHIFT;
                sc->wdog_mode_en = WDOG_MODE_EN;
                sc->wdog_config = D1_WDOG_CONFIG;
                sc->wdog_config_value = D1_WDOG_CONFIG_KEY | D1_WDOG_CONFIG_RST_EN_SYSTEM;
                break;
        case H616_WATCHDOG:
                sc->wdog_ctrl = H616_WDOG_CTRL;
                sc->wdog_ctrl_key = H616_WDOG_CTRL_KEY;
                sc->wdog_mode = H616_WDOG_MODE;
                sc->wdog_mode_key = 0;
                sc->wdog_mode_intvl_shift = H616_WDOG_MODE_INTVL_SHIFT;
                sc->wdog_mode_en = WDOG_MODE_EN;
                sc->wdog_config = H616_WDOG_CONFIG;
                sc->wdog_config_value = H616_WDOG_CONFIG_RST_EN_SYSTEM;
                break;
        default:
                bus_release_resource(dev, SYS_RES_MEMORY, rid, sc->res);
                return (ENXIO);
        }

        mtx_init(&sc->mtx, "AW Watchdog", "aw_wdog", MTX_DEF);
        EVENTHANDLER_REGISTER(watchdog_list, aw_wdog_watchdog_fn, sc, 0);
        EVENTHANDLER_REGISTER(shutdown_final, aw_wdog_shutdown_fn, sc,
            SHUTDOWN_PRI_LAST - 1);

        /* Disable watchdog for now. */
        WRITE(sc, sc->wdog_mode, sc->wdog_mode_key);

        return (0);
}

static void
aw_wdog_watchdog_fn(void *private, u_int cmd, int *error)
{
        struct aw_wdog_softc *sc;
        uint64_t ms;
        int i;

        sc = private;
        mtx_lock(&sc->mtx);

        cmd &= WD_INTERVAL;

        if (cmd > 0) {
                ms = ((uint64_t)1 << (cmd & WD_INTERVAL)) / 1000000;
                i = 0;
                while (wd_intervals[i].milliseconds &&
                    (ms > wd_intervals[i].milliseconds))
                        i++;
                if (wd_intervals[i].milliseconds) {
                        WRITE(sc, sc->wdog_mode, sc->wdog_mode_key |
                          (wd_intervals[i].value << sc->wdog_mode_intvl_shift) |
                            sc->wdog_mode_en);
                        WRITE(sc, sc->wdog_ctrl,
                            WDOG_CTRL_RESTART | sc->wdog_ctrl_key);
                        if (sc->wdog_config)
                                WRITE(sc, sc->wdog_config,
                                    sc->wdog_config_value);
                        *error = 0;
                }
                else {
                        /*
                         * Can't arm
                         * disable watchdog as watchdog(9) requires
                         */
                        device_printf(sc->dev,
                            "Can't arm, timeout is more than 16 sec\n");
                        mtx_unlock(&sc->mtx);
                        WRITE(sc, sc->wdog_mode, sc->wdog_mode_key);
                        return;
                }
        }
        else
                WRITE(sc, sc->wdog_mode, sc->wdog_mode_key);

        mtx_unlock(&sc->mtx);
}

static void
aw_wdog_shutdown_fn(void *private, int howto)
{
        if ((howto & (RB_POWEROFF|RB_HALT)) == 0)
                aw_wdog_watchdog_reset();
}

void
aw_wdog_watchdog_reset(void)
{

        if (aw_wdog_sc == NULL) {
                printf("Reset: watchdog device has not been initialized\n");
                return;
        }

        WRITE(aw_wdog_sc, aw_wdog_sc->wdog_mode, aw_wdog_sc->wdog_mode_key |
            (wd_intervals[0].value << aw_wdog_sc->wdog_mode_intvl_shift) |
            aw_wdog_sc->wdog_mode_en);
        if (aw_wdog_sc->wdog_config)
                WRITE(aw_wdog_sc, aw_wdog_sc->wdog_config,
                      aw_wdog_sc->wdog_config_value);
        WRITE(aw_wdog_sc, aw_wdog_sc->wdog_ctrl,
            WDOG_CTRL_RESTART | aw_wdog_sc->wdog_ctrl_key);
        while(1)
                ;

}

static device_method_t aw_wdog_methods[] = {
        DEVMETHOD(device_probe, aw_wdog_probe),
        DEVMETHOD(device_attach, aw_wdog_attach),

        DEVMETHOD_END
};

static driver_t aw_wdog_driver = {
        "aw_wdog",
        aw_wdog_methods,
        sizeof(struct aw_wdog_softc),
};

DRIVER_MODULE(aw_wdog, simplebus, aw_wdog_driver, 0, 0);