// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright 2017 Google, Inc
 */

#define LOG_CATEGORY UCLASS_WDT

#include <common.h>
#include <dm.h>
#include <errno.h>
#include <hang.h>
#include <log.h>
#include <sysreset.h>
#include <time.h>
#include <wdt.h>
#include <asm/global_data.h>
#include <dm/device-internal.h>
#include <dm/lists.h>

DECLARE_GLOBAL_DATA_PTR;

#define WATCHDOG_TIMEOUT_SECS   (CONFIG_WATCHDOG_TIMEOUT_MSECS / 1000)

struct wdt_priv {
        /* Timeout, in seconds, to configure this device to. */
        u32 timeout;
        /*
         * Time, in milliseconds, between calling the device's ->reset()
         * method from watchdog_reset().
         */
        ulong reset_period;
        /*
         * Next time (as returned by get_timer(0)) to call
         * ->reset().
         */
        ulong next_reset;
        /* Whether watchdog_start() has been called on the device. */
        bool running;
};

static void init_watchdog_dev(struct udevice *dev)
{
        struct wdt_priv *priv;
        int ret;

        priv = dev_get_uclass_priv(dev);

        if (IS_ENABLED(CONFIG_SYSRESET_WATCHDOG_AUTO)) {
                ret = sysreset_register_wdt(dev);
                if (ret)
                        printf("WDT:   Failed to register %s for sysreset\n",
                               dev->name);
        }

        if (!IS_ENABLED(CONFIG_WATCHDOG_AUTOSTART)) {
                printf("WDT:   Not starting %s\n", dev->name);
                return;
        }

        ret = wdt_start(dev, priv->timeout * 1000, 0);
        if (ret != 0) {
                printf("WDT:   Failed to start %s\n", dev->name);
                return;
        }

        printf("WDT:   Started %s with%s servicing (%ds timeout)\n", dev->name,
               IS_ENABLED(CONFIG_WATCHDOG) ? "" : "out", priv->timeout);
}

int initr_watchdog(void)
{
        struct udevice *dev;
        struct uclass *uc;
        int ret;

        ret = uclass_get(UCLASS_WDT, &uc);
        if (ret) {
                log_debug("Error getting UCLASS_WDT: %d\n", ret);
                return 0;
        }

        uclass_foreach_dev(dev, uc) {
                ret = device_probe(dev);
                if (ret) {
                        log_debug("Error probing %s: %d\n", dev->name, ret);
                        continue;
                }
                init_watchdog_dev(dev);
        }

        gd->flags |= GD_FLG_WDT_READY;
        return 0;
}

int wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
{
        const struct wdt_ops *ops = device_get_ops(dev);
        int ret;

        if (!ops->start)
                return -ENOSYS;

        ret = ops->start(dev, timeout_ms, flags);
        if (ret == 0) {
                struct wdt_priv *priv = dev_get_uclass_priv(dev);

                priv->running = true;
        }

        return ret;
}

int wdt_stop(struct udevice *dev)
{
        const struct wdt_ops *ops = device_get_ops(dev);
        int ret;

        if (!ops->stop)
                return -ENOSYS;

        ret = ops->stop(dev);
        if (ret == 0) {
                struct wdt_priv *priv = dev_get_uclass_priv(dev);

                priv->running = false;
        }

        return ret;
}

int wdt_stop_all(void)
{
        struct wdt_priv *priv;
        struct udevice *dev;
        struct uclass *uc;
        int ret, err;

        ret = uclass_get(UCLASS_WDT, &uc);
        if (ret)
                return ret;

        uclass_foreach_dev(dev, uc) {
                if (!device_active(dev))
                        continue;
                priv = dev_get_uclass_priv(dev);
                if (!priv->running)
                        continue;
                err = wdt_stop(dev);
                if (!ret)
                        ret = err;
        }

        return ret;
}

int wdt_reset(struct udevice *dev)
{
        const struct wdt_ops *ops = device_get_ops(dev);

        if (!ops->reset)
                return -ENOSYS;

        return ops->reset(dev);
}

int wdt_expire_now(struct udevice *dev, ulong flags)
{
        int ret = 0;
        const struct wdt_ops *ops;

        debug("WDT Resetting: %lu\n", flags);
        ops = device_get_ops(dev);
        if (ops->expire_now) {
                return ops->expire_now(dev, flags);
        } else {
                ret = wdt_start(dev, 1, flags);

                if (ret < 0)
                        return ret;

                hang();
        }

        return ret;
}

#if defined(CONFIG_WATCHDOG)
/*
 * Called by macro WATCHDOG_RESET. This function be called *very* early,
 * so we need to make sure, that the watchdog driver is ready before using
 * it in this function.
 */
void watchdog_reset(void)
{
        struct wdt_priv *priv;
        struct udevice *dev;
        struct uclass *uc;
        ulong now;

        /* Exit if GD is not ready or watchdog is not initialized yet */
        if (!gd || !(gd->flags & GD_FLG_WDT_READY))
                return;

        if (uclass_get(UCLASS_WDT, &uc))
                return;

        /*
         * All devices bound to the wdt uclass should have been probed
         * in initr_watchdog(). But just in case something went wrong,
         * check device_active() before accessing the uclass private
         * data.
         */
        uclass_foreach_dev(dev, uc) {
                if (!device_active(dev))
                        continue;
                priv = dev_get_uclass_priv(dev);
                if (!priv->running)
                        continue;
                /* Do not reset the watchdog too often */
                now = get_timer(0);
                if (time_after_eq(now, priv->next_reset)) {
                        priv->next_reset = now + priv->reset_period;
                        wdt_reset(dev);
                }
        }
}
#endif

static int wdt_post_bind(struct udevice *dev)
{
#if defined(CONFIG_NEEDS_MANUAL_RELOC)
        struct wdt_ops *ops = (struct wdt_ops *)device_get_ops(dev);
        static int reloc_done;

        if (!reloc_done) {
                if (ops->start)
                        ops->start += gd->reloc_off;
                if (ops->stop)
                        ops->stop += gd->reloc_off;
                if (ops->reset)
                        ops->reset += gd->reloc_off;
                if (ops->expire_now)
                        ops->expire_now += gd->reloc_off;

                reloc_done++;
        }
#endif
        return 0;
}

static int wdt_pre_probe(struct udevice *dev)
{
        u32 timeout = WATCHDOG_TIMEOUT_SECS;
        /*
         * Reset every 1000ms, or however often is required as
         * indicated by a hw_margin_ms property.
         */
        ulong reset_period = 1000;
        struct wdt_priv *priv;

        if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) {
                timeout = dev_read_u32_default(dev, "timeout-sec", timeout);
                reset_period = dev_read_u32_default(dev, "hw_margin_ms",
                                                    4 * reset_period) / 4;
        }
        priv = dev_get_uclass_priv(dev);
        priv->timeout = timeout;
        priv->reset_period = reset_period;
        /*
         * Pretend this device was last reset "long" ago so the first
         * watchdog_reset will actually call its ->reset method.
         */
        priv->next_reset = get_timer(0);

        return 0;
}

UCLASS_DRIVER(wdt) = {
        .id                     = UCLASS_WDT,
        .name                   = "watchdog",
        .flags                  = DM_UC_FLAG_SEQ_ALIAS,
        .post_bind              = wdt_post_bind,
        .pre_probe              = wdt_pre_probe,
        .per_device_auto        = sizeof(struct wdt_priv),
};