/*
 * QEMU System Emulator
 *
 * Copyright (c) 2003-2008 Fabrice Bellard
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

/* Modified for Unicorn Engine by Nguyen Anh Quynh, 2015 */

#include "sysemu/sysemu.h"

#include "hw/hw.h"

#include "qemu/timer.h"
#ifdef CONFIG_POSIX
#include <pthread.h>
#endif

#ifdef CONFIG_PPOLL
#include <poll.h>
#endif

#ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK
#include <sys/prctl.h>
#endif

#include "uc_priv.h"

/***********************************************************/
/* timers */

typedef struct QEMUClock {
    /* We rely on BQL to protect the timerlists */
    QLIST_HEAD(, QEMUTimerList) timerlists;

    NotifierList reset_notifiers;
    int64_t last;

    QEMUClockType type;
    bool enabled;
} QEMUClock;

static QEMUClock qemu_clocks[QEMU_CLOCK_MAX];

/* A QEMUTimerList is a list of timers attached to a clock. More
 * than one QEMUTimerList can be attached to each clock, for instance
 * used by different AioContexts / threads. Each clock also has
 * a list of the QEMUTimerLists associated with it, in order that
 * reenabling the clock can call all the notifiers.
 */

struct QEMUTimerList {
    QEMUClock *clock;
    QemuMutex active_timers_lock;
    QEMUTimer *active_timers;
    QLIST_ENTRY(QEMUTimerList) list;
    QEMUTimerListNotifyCB *notify_cb;
    void *notify_opaque;

    /* lightweight method to mark the end of timerlist's running */
    QemuEvent timers_done_ev;
};

/**
 * qemu_clock_ptr:
 * @type: type of clock
 *
 * Translate a clock type into a pointer to QEMUClock object.
 *
 * Returns: a pointer to the QEMUClock object
 */
static inline QEMUClock *qemu_clock_ptr(QEMUClockType type)
{
    return &qemu_clocks[type];
}

static bool timer_expired_ns(QEMUTimer *timer_head, int64_t current_time)
{
    return timer_head && (timer_head->expire_time <= current_time);
}

void timerlist_free(QEMUTimerList *timer_list)
{
    assert(!timerlist_has_timers(timer_list));
    if (timer_list->clock) {
        QLIST_REMOVE(timer_list, list);
    }
    qemu_mutex_destroy(&timer_list->active_timers_lock);
    free(timer_list);
}

bool timerlist_has_timers(QEMUTimerList *timer_list)
{
    return !!timer_list->active_timers;
}

void timerlist_notify(QEMUTimerList *timer_list)
{
    if (timer_list->notify_cb) {
        timer_list->notify_cb(timer_list->notify_opaque);
    }
}

void timer_init(QEMUTimer *ts,
                QEMUTimerList *timer_list, int scale,
                QEMUTimerCB *cb, void *opaque)
{
    ts->timer_list = timer_list;
    ts->cb = cb;
    ts->opaque = opaque;
    ts->scale = scale;
    ts->expire_time = -1;
}

static void timer_del_locked(QEMUTimerList *timer_list, QEMUTimer *ts)
{
    QEMUTimer **pt, *t;

    ts->expire_time = -1;
    pt = &timer_list->active_timers;
    for(;;) {
        t = *pt;
        if (!t)
            break;
        if (t == ts) {
            *pt = t->next;
            break;
        }
        pt = &t->next;
    }
}

static bool timer_mod_ns_locked(QEMUTimerList *timer_list,
                                QEMUTimer *ts, int64_t expire_time)
{
    QEMUTimer **pt, *t;

    /* add the timer in the sorted list */
    pt = &timer_list->active_timers;
    for (;;) {
        t = *pt;
        if (!timer_expired_ns(t, expire_time)) {
            break;
        }
        pt = &t->next;
    }
    ts->expire_time = MAX(expire_time, 0);
    ts->next = *pt;
    *pt = ts;

    return pt == &timer_list->active_timers;
}

static void timerlist_rearm(QEMUTimerList *timer_list)
{
    /* Interrupt execution to force deadline recalculation.  */
    timerlist_notify(timer_list);
}

/* stop a timer, but do not dealloc it */
void timer_del(QEMUTimer *ts)
{
    QEMUTimerList *timer_list = ts->timer_list;

    qemu_mutex_lock(&timer_list->active_timers_lock);
    timer_del_locked(timer_list, ts);
    qemu_mutex_unlock(&timer_list->active_timers_lock);
}

/* modify the current timer so that it will be fired when current_time
   >= expire_time. The corresponding callback will be called. */
void timer_mod_ns(QEMUTimer *ts, int64_t expire_time)
{
    QEMUTimerList *timer_list = ts->timer_list;
    bool rearm;

    qemu_mutex_lock(&timer_list->active_timers_lock);
    timer_del_locked(timer_list, ts);
    rearm = timer_mod_ns_locked(timer_list, ts, expire_time);
    qemu_mutex_unlock(&timer_list->active_timers_lock);

    if (rearm) {
        timerlist_rearm(timer_list);
    }
}

void timer_mod(QEMUTimer *ts, int64_t expire_time)
{
    timer_mod_ns(ts, expire_time * ts->scale);
}

bool timer_pending(QEMUTimer *ts)
{
    return ts->expire_time >= 0;
}

uint64_t timer_expire_time_ns(QEMUTimer *ts)
{
    return timer_pending(ts) ? ts->expire_time : -1;
}

/* return the host CPU cycle counter and handle stop/restart */
int64_t cpu_get_ticks(void)
{
    return cpu_get_real_ticks();
}

/* return the host CPU monotonic timer and handle stop/restart */
int64_t cpu_get_clock(void)
{
    return get_clock();
}

int64_t qemu_clock_get_ns(QEMUClockType type)
{
    int64_t now, last;
    QEMUClock *clock = qemu_clock_ptr(type);

    switch (type) {
        case QEMU_CLOCK_REALTIME:
            return get_clock();
        default:
        case QEMU_CLOCK_VIRTUAL:
            return cpu_get_clock();
        case QEMU_CLOCK_HOST:
            now = get_clock_realtime();
            last = clock->last;
            clock->last = now;
            if (now < last) {
                // notifier_list_notify(&clock->reset_notifiers, &now); // FIXME
            }
            return now;
    }
}