/* $NetBSD: sunxi_wdt.c,v 1.7 2026/03/18 06:37:09 skrll Exp $ */

/*-
 * Copyright (c) 2017 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: sunxi_wdt.c,v 1.7 2026/03/18 06:37:09 skrll Exp $");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/device.h>
#include <sys/intr.h>
#include <sys/systm.h>
#include <sys/mutex.h>
#include <sys/wdog.h>

#include <dev/sysmon/sysmonvar.h>

#include <dev/fdt/fdtvar.h>

#define SUNXI_WDT_PERIOD_DEFAULT        16

#define SUN4I_WDT_CTRL_REG              0x00
#define  SUN4I_WDT_CTRL_KEY_FIELD       __BITS(12,1)
#define   SUN4I_WDT_CTRL_KEY_FIELD_V    0xa57
#define  SUN4I_WDT_CTRL_RSTART          __BIT(0)
#define SUN4I_WDT_MODE_REG              0x04
#define  SUN4I_WDT_MODE_INTV            __BITS(6,3)
#define  SUN4I_WDT_MODE_RST_EN          __BIT(1)
#define  SUN4I_WDT_MODE_EN              __BIT(0)

#define SUN6I_WDT_IRQ_EN_REG            0x00
#define  SUN6I_WDT_IRQ_EN_EN            __BIT(0)
#define SUN6I_WDT_IRQ_STA_REG           0x04
#define  SUN6I_WDT_IRQ_STA_PEND         __BIT(0)
#define SUN6I_WDT_CTRL_REG              0x10
#define  SUN6I_WDT_CTRL_KEY_FIELD       __BITS(12,1)
#define   SUN6I_WDT_CTRL_KEY_FIELD_V    0xa57
#define  SUN6I_WDT_CTRL_RSTART          __BIT(0)
#define SUN6I_WDT_CFG_REG               0x14
#define  SUN6I_WDT_CFG_CONFIG           __BITS(1,0)
#define   SUN6I_WDT_CFG_CONFIG_SYS      1
#define   SUN6I_WDT_CFG_CONFIG_IRQ      2
#define SUN6I_WDT_MODE_REG              0x18
#define  SUN6I_WDT_MODE_INTV            __BITS(7,4)
#define  SUN6I_WDT_MODE_EN              __BIT(0)

#define  SUNXI_WDT_KEY_FIELD            __BITS(31,16)
#define   SUNXI_WDT_KEY_FIELD_V         0x16aa

static const int sunxi_periods[] = {
        500, 1000, 2000, 3000,
        4000, 5000, 6000, 8000,
        10000, 12000, 14000, 16000,
        -1
};

enum sunxi_wdt_type {
        WDT_SUN4I = 1,
        WDT_SUN6I,
        WDT_SUN20I,
};

static const struct device_compatible_entry compat_data[] = {
        { .compat = "allwinner,sun4i-a10-wdt",  .value = WDT_SUN4I },
        { .compat = "allwinner,sun6i-a31-wdt",  .value = WDT_SUN6I },
        { .compat = "allwinner,sun20i-d1-wdt",  .value = WDT_SUN20I },
        DEVICE_COMPAT_EOL
};

struct sunxi_wdt_softc {
        device_t sc_dev;
        bus_space_tag_t sc_bst;
        bus_space_handle_t sc_bsh;

        const int *sc_periods;

        struct sysmon_wdog sc_smw;
};

#define WDT_READ(sc, reg) \
    bus_space_read_4((sc)->sc_bst, (sc)->sc_bsh, (reg))
#define WDT_WRITE(sc, reg, val) \
    bus_space_write_4((sc)->sc_bst, (sc)->sc_bsh, (reg), (val))

static int
sunxi_wdt_map_period(struct sunxi_wdt_softc *sc, u_int period,
    u_int *aperiod)
{
        const int *p = sc->sc_periods;
        int i;

        if (period == 0)
                return -1;

        for (i = 0; *p != -1; i++, p++)
                if (*p >= period * 1000) {
                        *aperiod = *p / 1000;
                        return i;
                }

        return -1;
}

static int
sun4i_wdt_setmode(struct sysmon_wdog *smw)
{
        struct sunxi_wdt_softc * const sc = smw->smw_cookie;
        uint32_t mode;
        int intv;

        if ((smw->smw_mode & WDOG_MODE_MASK) == WDOG_MODE_DISARMED) {
                WDT_WRITE(sc, SUN4I_WDT_MODE_REG, 0);
        } else {
                if (smw->smw_period == WDOG_PERIOD_DEFAULT)
                        smw->smw_period = SUNXI_WDT_PERIOD_DEFAULT;
                intv = sunxi_wdt_map_period(sc, smw->smw_period,
                    &sc->sc_smw.smw_period);
                if (intv == -1)
                        return EINVAL;

                mode = SUN4I_WDT_MODE_EN | SUN4I_WDT_MODE_RST_EN |
                    __SHIFTIN(intv, SUN4I_WDT_MODE_INTV);

                WDT_WRITE(sc, SUN4I_WDT_MODE_REG, mode);
        }

        return 0;
}

static int
sun4i_wdt_tickle(struct sysmon_wdog *smw)
{
        struct sunxi_wdt_softc * const sc = smw->smw_cookie;
        const uint32_t ctrl = SUN4I_WDT_CTRL_RSTART |
            __SHIFTIN(SUN4I_WDT_CTRL_KEY_FIELD_V, SUN4I_WDT_CTRL_KEY_FIELD);

        WDT_WRITE(sc, SUN4I_WDT_CTRL_REG, ctrl);

        return 0;
}

static int
sun6i_wdt_setmode(struct sysmon_wdog *smw)
{
        struct sunxi_wdt_softc * const sc = smw->smw_cookie;
        uint32_t cfg, mode;
        int intv;

        if ((smw->smw_mode & WDOG_MODE_MASK) == WDOG_MODE_DISARMED) {
                WDT_WRITE(sc, SUN6I_WDT_MODE_REG, 0);
        } else {
                if (smw->smw_period == WDOG_PERIOD_DEFAULT)
                        smw->smw_period = SUNXI_WDT_PERIOD_DEFAULT;
                intv = sunxi_wdt_map_period(sc, smw->smw_period,
                    &sc->sc_smw.smw_period);
                if (intv == -1)
                        return EINVAL;

                cfg = __SHIFTIN(SUN6I_WDT_CFG_CONFIG_SYS, SUN6I_WDT_CFG_CONFIG);
                mode = SUN6I_WDT_MODE_EN | __SHIFTIN(intv, SUN6I_WDT_MODE_INTV);

                WDT_WRITE(sc, SUN6I_WDT_CFG_REG, cfg);
                WDT_WRITE(sc, SUN6I_WDT_MODE_REG, mode);
        }

        return 0;
}

static int
sun6i_wdt_tickle(struct sysmon_wdog *smw)
{
        struct sunxi_wdt_softc * const sc = smw->smw_cookie;
        const uint32_t ctrl = SUN6I_WDT_CTRL_RSTART |
            __SHIFTIN(SUN6I_WDT_CTRL_KEY_FIELD_V, SUN6I_WDT_CTRL_KEY_FIELD);

        WDT_WRITE(sc, SUN6I_WDT_CTRL_REG, ctrl);

        return 0;
}

static int
sun20i_wdt_setmode(struct sysmon_wdog *smw)
{
        struct sunxi_wdt_softc * const sc = smw->smw_cookie;
        uint32_t cfg, mode;
        int intv;

        if ((smw->smw_mode & WDOG_MODE_MASK) == WDOG_MODE_DISARMED) {
                mode = __SHIFTIN(SUNXI_WDT_KEY_FIELD_V, SUNXI_WDT_KEY_FIELD);
                WDT_WRITE(sc, SUN6I_WDT_MODE_REG, mode);
        } else {
                if (smw->smw_period == WDOG_PERIOD_DEFAULT)
                        smw->smw_period = SUNXI_WDT_PERIOD_DEFAULT;
                intv = sunxi_wdt_map_period(sc, smw->smw_period,
                    &sc->sc_smw.smw_period);
                if (intv == -1)
                        return EINVAL;

                cfg = __SHIFTIN(SUN6I_WDT_CFG_CONFIG_SYS, SUN6I_WDT_CFG_CONFIG);
                cfg |= __SHIFTIN(SUNXI_WDT_KEY_FIELD_V, SUNXI_WDT_KEY_FIELD);
                mode = SUN6I_WDT_MODE_EN | __SHIFTIN(intv, SUN6I_WDT_MODE_INTV);
                mode |= __SHIFTIN(SUNXI_WDT_KEY_FIELD_V, SUNXI_WDT_KEY_FIELD);

                WDT_WRITE(sc, SUN6I_WDT_CFG_REG, cfg);
                WDT_WRITE(sc, SUN6I_WDT_MODE_REG, mode);
        }

        return 0;
}

static int
sunxi_wdt_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
sunxi_wdt_attach(device_t parent, device_t self, void *aux)
{
        struct sunxi_wdt_softc * const sc = device_private(self);
        struct fdt_attach_args * const faa = aux;
        const int phandle = faa->faa_phandle;
        enum sunxi_wdt_type type;
        bus_addr_t addr;
        bus_size_t size;
        uint32_t mode;

        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;
        }
        sc->sc_periods = sunxi_periods;

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

        sc->sc_smw.smw_name = device_xname(self);
        sc->sc_smw.smw_cookie = sc;
        sc->sc_smw.smw_period = SUNXI_WDT_PERIOD_DEFAULT;

        type = of_compatible_lookup(phandle, compat_data)->value;
        switch (type) {
        case WDT_SUN4I:
                sc->sc_smw.smw_setmode = sun4i_wdt_setmode;
                sc->sc_smw.smw_tickle = sun4i_wdt_tickle;
                break;
        case WDT_SUN6I:
                sc->sc_smw.smw_setmode = sun6i_wdt_setmode;
                sc->sc_smw.smw_tickle = sun6i_wdt_tickle;

                /* Disable watchdog IRQs */
                WDT_WRITE(sc, SUN6I_WDT_IRQ_EN_REG, 0);
                break;
        case WDT_SUN20I:
                sc->sc_smw.smw_setmode = sun20i_wdt_setmode;
                sc->sc_smw.smw_tickle = sun6i_wdt_tickle;

                /* Disable watchdog */
                mode = __SHIFTIN(SUNXI_WDT_KEY_FIELD_V, SUNXI_WDT_KEY_FIELD);
                WDT_WRITE(sc, SUN6I_WDT_MODE_REG, mode);

                /* Disable watchdog IRQs */
                WDT_WRITE(sc, SUN6I_WDT_IRQ_EN_REG, 0);
                break;
        }

        aprint_normal_dev(self,
            "default watchdog period is %u seconds\n",
            sc->sc_smw.smw_period);

        if (sysmon_wdog_register(&sc->sc_smw) != 0) {
                aprint_error_dev(self,
                    "couldn't register with sysmon\n");
        }
}

CFATTACH_DECL_NEW(sunxi_wdt, sizeof(struct sunxi_wdt_softc),
        sunxi_wdt_match, sunxi_wdt_attach, NULL, NULL);