/*
 * 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.
 */

#include "qemu-timer.h"
#include "console.h"
#include "android/utils/system.h"

extern QEMUClock*  rtc_clock;

#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <errno.h>
#include <sys/time.h>
#include <signal.h>
#ifdef __FreeBSD__
#include <sys/param.h>
#endif

#ifdef __linux__
#include <sys/ioctl.h>
#endif

#ifdef _WIN32
#include <windows.h>
#include <mmsystem.h>
#endif

#include "qemu-timer.h"

/***********************************************************/
/* real time host monotonic timer */


static int64_t get_clock_realtime(void)
{
    struct timeval tv;

    gettimeofday(&tv, NULL);
    return tv.tv_sec * 1000000000LL + (tv.tv_usec * 1000);
}

#ifdef WIN32

static int64_t clock_freq;

static void init_get_clock(void)
{
    LARGE_INTEGER freq;
    int ret;
    ret = QueryPerformanceFrequency(&freq);
    if (ret == 0) {
        fprintf(stderr, "Could not calibrate ticks\n");
        exit(1);
    }
    clock_freq = freq.QuadPart;
}

static int64_t get_clock(void)
{
    LARGE_INTEGER ti;
    QueryPerformanceCounter(&ti);
    return muldiv64(ti.QuadPart, get_ticks_per_sec(), clock_freq);
}

#else

static int use_rt_clock;

static void init_get_clock(void)
{
    use_rt_clock = 0;
#if defined(__linux__) || (defined(__FreeBSD__) && __FreeBSD_version >= 500000) \
    || defined(__DragonFly__) || defined(__FreeBSD_kernel__)
    {
        struct timespec ts;
        if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
            use_rt_clock = 1;
        }
    }
#endif
}

static int64_t get_clock(void)
{
#if defined(__linux__) || (defined(__FreeBSD__) && __FreeBSD_version >= 500000) \
	|| defined(__DragonFly__) || defined(__FreeBSD_kernel__)
    if (use_rt_clock) {
        struct timespec ts;
        clock_gettime(CLOCK_MONOTONIC, &ts);
        return ts.tv_sec * 1000000000LL + ts.tv_nsec;
    } else
#endif
    {
        /* XXX: using gettimeofday leads to problems if the date
           changes, so it should be avoided. */
        return get_clock_realtime();
    }
}
#endif

/***********************************************************/
/* guest cycle counter */

typedef struct TimersState {
    int64_t cpu_ticks_prev;
    int64_t cpu_ticks_offset;
    int64_t cpu_clock_offset;
    int32_t cpu_ticks_enabled;
    int64_t dummy;
} TimersState;

TimersState timers_state;

/* return the host CPU cycle counter and handle stop/restart */
int64_t cpu_get_ticks(void)
{
    if (!timers_state.cpu_ticks_enabled) {
        return timers_state.cpu_ticks_offset;
    } else {
        int64_t ticks;
        ticks = cpu_get_real_ticks();
        if (timers_state.cpu_ticks_prev > ticks) {
            /* Note: non increasing ticks may happen if the host uses
               software suspend */
            timers_state.cpu_ticks_offset += timers_state.cpu_ticks_prev - ticks;
        }
        timers_state.cpu_ticks_prev = ticks;
        return ticks + timers_state.cpu_ticks_offset;
    }
}

/* return the host CPU monotonic timer and handle stop/restart */
static int64_t cpu_get_clock(void)
{
    int64_t ti;
    if (!timers_state.cpu_ticks_enabled) {
        return timers_state.cpu_clock_offset;
    } else {
        ti = get_clock();
        return ti + timers_state.cpu_clock_offset;
    }
}

/* enable cpu_get_ticks() */
void cpu_enable_ticks(void)
{
    if (!timers_state.cpu_ticks_enabled) {
        timers_state.cpu_ticks_offset -= cpu_get_real_ticks();
        timers_state.cpu_clock_offset -= get_clock();
        timers_state.cpu_ticks_enabled = 1;
    }
}

/* disable cpu_get_ticks() : the clock is stopped. You must not call
   cpu_get_ticks() after that.  */
void cpu_disable_ticks(void)
{
    if (timers_state.cpu_ticks_enabled) {
        timers_state.cpu_ticks_offset = cpu_get_ticks();
        timers_state.cpu_clock_offset = cpu_get_clock();
        timers_state.cpu_ticks_enabled = 0;
    }
}

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

#define QEMU_CLOCK_REALTIME 0
#define QEMU_CLOCK_VIRTUAL  1
#define QEMU_CLOCK_HOST     2

struct QEMUClock {
    int type;
    int enabled;
    /* XXX: add frequency */
};

struct QEMUTimer {
    QEMUClock *clock;
    int64_t expire_time;
    QEMUTimerCB *cb;
    void *opaque;
    struct QEMUTimer *next;
};

struct qemu_alarm_timer {
    char const *name;
    int (*start)(struct qemu_alarm_timer *t);
    void (*stop)(struct qemu_alarm_timer *t);
    void (*rearm)(struct qemu_alarm_timer *t);
    void *priv;

    char expired;
    char pending;
};

static struct qemu_alarm_timer *alarm_timer;

int qemu_alarm_pending(void)
{
    return alarm_timer->pending;
}

static inline int alarm_has_dynticks(struct qemu_alarm_timer *t)
{
    return !!t->rearm;
}

static void qemu_rearm_alarm_timer(struct qemu_alarm_timer *t)
{
    if (!alarm_has_dynticks(t))
        return;

    t->rearm(t);
}

/* TODO: MIN_TIMER_REARM_US should be optimized */
#define MIN_TIMER_REARM_US 250

#ifdef _WIN32

struct qemu_alarm_win32 {
    MMRESULT timerId;
    unsigned int period;
} alarm_win32_data = {0, 0};

static int win32_start_timer(struct qemu_alarm_timer *t);
static void win32_stop_timer(struct qemu_alarm_timer *t);
static void win32_rearm_timer(struct qemu_alarm_timer *t);

#else

static int unix_start_timer(struct qemu_alarm_timer *t);
static void unix_stop_timer(struct qemu_alarm_timer *t);

#ifdef __linux__

static int dynticks_start_timer(struct qemu_alarm_timer *t);
static void dynticks_stop_timer(struct qemu_alarm_timer *t);
static void dynticks_rearm_timer(struct qemu_alarm_timer *t);

#endif /* __linux__ */

#endif /* _WIN32 */

static struct qemu_alarm_timer alarm_timers[] = {
#ifndef _WIN32
#ifdef __linux__
    {"dynticks", dynticks_start_timer,
     dynticks_stop_timer, dynticks_rearm_timer, NULL},
#endif
    {"unix", unix_start_timer, unix_stop_timer, NULL, NULL},
#else
    {"dynticks", win32_start_timer,
     win32_stop_timer, win32_rearm_timer, &alarm_win32_data},
    {"win32", win32_start_timer,
     win32_stop_timer, NULL, &alarm_win32_data},
#endif
    {NULL, }
};

#define QEMU_NUM_CLOCKS 3

QEMUClock *rt_clock;
QEMUClock *vm_clock;
QEMUClock *host_clock;

static QEMUTimer *active_timers[QEMU_NUM_CLOCKS];

static QEMUClock *qemu_new_clock(int type)
{
    QEMUClock *clock;
    ANEW0(clock);
    clock->type = type;
    clock->enabled = 1;
    return clock;
}

QEMUTimer *qemu_new_timer(QEMUClock *clock, QEMUTimerCB *cb, void *opaque)
{
    QEMUTimer *ts;

    ANEW0(ts);
    ts->clock = clock;
    ts->cb = cb;
    ts->opaque = opaque;
    return ts;
}

void qemu_free_timer(QEMUTimer *ts)
{
    AFREE(ts);
}

/* stop a timer, but do not dealloc it */
void qemu_del_timer(QEMUTimer *ts)
{
    QEMUTimer **pt, *t;

    /* NOTE: this code must be signal safe because
       qemu_timer_expired() can be called from a signal. */
    pt = &active_timers[ts->clock->type];
    for(;;) {
        t = *pt;
        if (!t)
            break;
        if (t == ts) {
            *pt = t->next;
            break;
        }
        pt = &t->next;
    }
}

/* modify the current timer so that it will be fired when current_time
   >= expire_time. The corresponding callback will be called. */
void qemu_mod_timer(QEMUTimer *ts, int64_t expire_time)
{
    QEMUTimer **pt, *t;

    qemu_del_timer(ts);

    /* add the timer in the sorted list */
    /* NOTE: this code must be signal safe because
       qemu_timer_expired() can be called from a signal. */
    pt = &active_timers[ts->clock->type];
    for(;;) {
        t = *pt;
        if (!t)
            break;
        if (t->expire_time > expire_time)
            break;
        pt = &t->next;
    }
    ts->expire_time = expire_time;
    ts->next = *pt;
    *pt = ts;

    /* Rearm if necessary  */
    if (pt == &active_timers[ts->clock->type]) {
        if (!alarm_timer->pending) {
            qemu_rearm_alarm_timer(alarm_timer);
        }
    }
}

int qemu_timer_expired(QEMUTimer *timer_head, int64_t current_time)
{
    if (!timer_head)
        return 0;
    return (timer_head->expire_time <= current_time);
}

static void qemu_run_timers(QEMUClock *clock)
{
    QEMUTimer **ptimer_head, *ts;
    int64_t current_time;

    if (!clock->enabled)
        return;

    current_time = qemu_get_clock (clock);
    ptimer_head = &active_timers[clock->type];
    for(;;) {
        ts = *ptimer_head;
        if (!ts || ts->expire_time > current_time)
            break;
        /* remove timer from the list before calling the callback */
        *ptimer_head = ts->next;
        ts->next = NULL;

        /* run the callback (the timer list can be modified) */
        ts->cb(ts->opaque);
    }
}

int64_t qemu_get_clock(QEMUClock *clock)
{
    switch(clock->type) {
    case QEMU_CLOCK_REALTIME:
        return get_clock() / 1000000;
    default:
    case QEMU_CLOCK_VIRTUAL:
        return cpu_get_clock();
    case QEMU_CLOCK_HOST:
        return get_clock_realtime();
    }
}

int64_t qemu_get_clock_ns(QEMUClock *clock)
{
    switch(clock->type) {
    case QEMU_CLOCK_REALTIME:
        return get_clock();
    default:
    case QEMU_CLOCK_VIRTUAL:
        return cpu_get_clock();
    case QEMU_CLOCK_HOST:
        return get_clock_realtime();
    }
}

void init_clocks(void)
{
    init_get_clock();
    rt_clock = qemu_new_clock(QEMU_CLOCK_REALTIME);
    vm_clock = qemu_new_clock(QEMU_CLOCK_VIRTUAL);
    host_clock = qemu_new_clock(QEMU_CLOCK_HOST);

    rtc_clock = host_clock;
}

void qemu_run_all_timers(void)
{
    alarm_timer->pending = 0;

    /* rearm timer, if not periodic */
    if (alarm_timer->expired) {
        alarm_timer->expired = 0;
        qemu_rearm_alarm_timer(alarm_timer);
    }

    /* vm time timers */
    qemu_run_timers(vm_clock);

    qemu_run_timers(rt_clock);
    qemu_run_timers(host_clock);
}

#ifdef _WIN32
static void CALLBACK host_alarm_handler(UINT uTimerID, UINT uMsg,
                                        DWORD_PTR dwUser, DWORD_PTR dw1,
                                        DWORD_PTR dw2)
#else
static void host_alarm_handler(int host_signum)
#endif
{
    struct qemu_alarm_timer *t = alarm_timer;
    if (!t)
	return;

#if 0
#define DISP_FREQ 1000
    {
        static int64_t delta_min = INT64_MAX;
        static int64_t delta_max, delta_cum, last_clock, delta, ti;
        static int count;
        ti = qemu_get_clock(vm_clock);
        if (last_clock != 0) {
            delta = ti - last_clock;
            if (delta < delta_min)
                delta_min = delta;
            if (delta > delta_max)
                delta_max = delta;
            delta_cum += delta;
            if (++count == DISP_FREQ) {
                printf("timer: min=%" PRId64 " us max=%" PRId64 " us avg=%" PRId64 " us avg_freq=%0.3f Hz\n",
                       muldiv64(delta_min, 1000000, get_ticks_per_sec()),
                       muldiv64(delta_max, 1000000, get_ticks_per_sec()),
                       muldiv64(delta_cum, 1000000 / DISP_FREQ, get_ticks_per_sec()),
                       (double)get_ticks_per_sec() / ((double)delta_cum / DISP_FREQ));
                count = 0;
                delta_min = INT64_MAX;
                delta_max = 0;
                delta_cum = 0;
            }
        }
        last_clock = ti;
    }
#endif
    if (alarm_has_dynticks(t) ||
        (qemu_timer_expired(active_timers[QEMU_CLOCK_VIRTUAL],
                               qemu_get_clock(vm_clock))) ||
        qemu_timer_expired(active_timers[QEMU_CLOCK_REALTIME],
                           qemu_get_clock(rt_clock)) ||
        qemu_timer_expired(active_timers[QEMU_CLOCK_HOST],
                           qemu_get_clock(host_clock))) {

        t->expired = alarm_has_dynticks(t);
        t->pending = 1;
    }
}

int64_t qemu_next_deadline(void)
{
    /* To avoid problems with overflow limit this to 2^32.  */
    int64_t delta = INT32_MAX;

    if (active_timers[QEMU_CLOCK_VIRTUAL]) {
        delta = active_timers[QEMU_CLOCK_VIRTUAL]->expire_time -
                     qemu_get_clock(vm_clock);
    }
    if (active_timers[QEMU_CLOCK_HOST]) {
        int64_t hdelta = active_timers[QEMU_CLOCK_HOST]->expire_time -
                 qemu_get_clock(host_clock);
        if (hdelta < delta)
            delta = hdelta;
    }

    if (delta < 0)
        delta = 0;

    return delta;
}

#ifndef _WIN32

#if defined(__linux__)

static uint64_t qemu_next_deadline_dyntick(void)
{
    int64_t delta;
    int64_t rtdelta;

    delta = (qemu_next_deadline() + 999) / 1000;

    if (active_timers[QEMU_CLOCK_REALTIME]) {
        rtdelta = (active_timers[QEMU_CLOCK_REALTIME]->expire_time -
                 qemu_get_clock(rt_clock))*1000;
        if (rtdelta < delta)
            delta = rtdelta;
    }

    if (delta < MIN_TIMER_REARM_US)
        delta = MIN_TIMER_REARM_US;

    return delta;
}

static int dynticks_start_timer(struct qemu_alarm_timer *t)
{
    struct sigevent ev;
    timer_t host_timer;
    struct sigaction act;

    sigfillset(&act.sa_mask);
    act.sa_flags = 0;
    act.sa_handler = host_alarm_handler;

    sigaction(SIGALRM, &act, NULL);

    /*
     * Initialize ev struct to 0 to avoid valgrind complaining
     * about uninitialized data in timer_create call
     */
    memset(&ev, 0, sizeof(ev));
    ev.sigev_value.sival_int = 0;
    ev.sigev_notify = SIGEV_SIGNAL;
    ev.sigev_signo = SIGALRM;

    if (timer_create(CLOCK_REALTIME, &ev, &host_timer)) {
        perror("timer_create");

        /* disable dynticks */
        fprintf(stderr, "Dynamic Ticks disabled\n");

        return -1;
    }

    t->priv = (void *)(long)host_timer;

    return 0;
}

static void dynticks_stop_timer(struct qemu_alarm_timer *t)
{
    timer_t host_timer = (timer_t)(long)t->priv;

    timer_delete(host_timer);
}

static void dynticks_rearm_timer(struct qemu_alarm_timer *t)
{
    timer_t host_timer = (timer_t)(long)t->priv;
    struct itimerspec timeout;
    int64_t nearest_delta_us = INT64_MAX;
    int64_t current_us;

    assert(alarm_has_dynticks(t));
    if (!active_timers[QEMU_CLOCK_REALTIME] &&
        !active_timers[QEMU_CLOCK_VIRTUAL] &&
        !active_timers[QEMU_CLOCK_HOST])
        return;

    nearest_delta_us = qemu_next_deadline_dyntick();

    /* check whether a timer is already running */
    if (timer_gettime(host_timer, &timeout)) {
        perror("gettime");
        fprintf(stderr, "Internal timer error: aborting\n");
        exit(1);
    }
    current_us = timeout.it_value.tv_sec * 1000000 + timeout.it_value.tv_nsec/1000;
    if (current_us && current_us <= nearest_delta_us)
        return;

    timeout.it_interval.tv_sec = 0;
    timeout.it_interval.tv_nsec = 0; /* 0 for one-shot timer */
    timeout.it_value.tv_sec =  nearest_delta_us / 1000000;
    timeout.it_value.tv_nsec = (nearest_delta_us % 1000000) * 1000;
    if (timer_settime(host_timer, 0 /* RELATIVE */, &timeout, NULL)) {
        perror("settime");
        fprintf(stderr, "Internal timer error: aborting\n");
        exit(1);
    }
}

#endif /* defined(__linux__) */

static int unix_start_timer(struct qemu_alarm_timer *t)
{
    struct sigaction act;
    struct itimerval itv;
    int err;

    /* timer signal */
    sigfillset(&act.sa_mask);
    act.sa_flags = 0;
    act.sa_handler = host_alarm_handler;

    sigaction(SIGALRM, &act, NULL);

    itv.it_interval.tv_sec = 0;
    /* for i386 kernel 2.6 to get 1 ms */
    itv.it_interval.tv_usec = 999;
    itv.it_value.tv_sec = 0;
    itv.it_value.tv_usec = 10 * 1000;

    err = setitimer(ITIMER_REAL, &itv, NULL);
    if (err)
        return -1;

    return 0;
}

static void unix_stop_timer(struct qemu_alarm_timer *t)
{
    struct itimerval itv;

    memset(&itv, 0, sizeof(itv));
    setitimer(ITIMER_REAL, &itv, NULL);
}

#endif /* !defined(_WIN32) */


#ifdef _WIN32

static int win32_start_timer(struct qemu_alarm_timer *t)
{
    TIMECAPS tc;
    struct qemu_alarm_win32 *data = t->priv;
    UINT flags;

    memset(&tc, 0, sizeof(tc));
    timeGetDevCaps(&tc, sizeof(tc));

    data->period = tc.wPeriodMin;
    timeBeginPeriod(data->period);

    flags = TIME_CALLBACK_FUNCTION;
    if (alarm_has_dynticks(t))
        flags |= TIME_ONESHOT;
    else
        flags |= TIME_PERIODIC;

    data->timerId = timeSetEvent(1,         // interval (ms)
                        data->period,       // resolution
                        host_alarm_handler, // function
                        (DWORD)t,           // parameter
                        flags);

    if (!data->timerId) {
        fprintf(stderr, "Failed to initialize win32 alarm timer: %ld\n",
                GetLastError());
        timeEndPeriod(data->period);
        return -1;
    }

    return 0;
}

static void win32_stop_timer(struct qemu_alarm_timer *t)
{
    struct qemu_alarm_win32 *data = t->priv;

    timeKillEvent(data->timerId);
    timeEndPeriod(data->period);
}

static void win32_rearm_timer(struct qemu_alarm_timer *t)
{
    struct qemu_alarm_win32 *data = t->priv;

    assert(alarm_has_dynticks(t));
    if (!active_timers[QEMU_CLOCK_REALTIME] &&
        !active_timers[QEMU_CLOCK_VIRTUAL] &&
        !active_timers[QEMU_CLOCK_HOST])
        return;

    timeKillEvent(data->timerId);

    data->timerId = timeSetEvent(1,
                        data->period,
                        host_alarm_handler,
                        (DWORD)t,
                        TIME_ONESHOT | TIME_CALLBACK_FUNCTION);

    if (!data->timerId) {
        fprintf(stderr, "Failed to re-arm win32 alarm timer %ld\n",
                GetLastError());

        timeEndPeriod(data->period);
        exit(1);
    }
}

#endif /* _WIN32 */

int init_timer_alarm(void)
{
    struct qemu_alarm_timer *t = NULL;
    int i, err = -1;

    for (i = 0; alarm_timers[i].name; i++) {
        t = &alarm_timers[i];

        err = t->start(t);
        if (!err)
            break;
    }

    if (err) {
        err = -ENOENT;
        goto fail;
    }

    /* first event is at time 0 */
    t->pending = 1;
    alarm_timer = t;

    return 0;

fail:
    return err;
}

void quit_timers(void)
{
    struct qemu_alarm_timer *t = alarm_timer;
    alarm_timer = NULL;
    t->stop(t);
}

int qemu_calculate_timeout(void)
{
	/* Deliver user events at 30 Hz */
	return 1000/30;
}