clock_time.c

/*
 * File      : clock_time.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2012, RT-Thread Development Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Change Logs:
 * Date           Author       Notes
 * 2012-12-08     Bernard      fix the issue of _timevalue.tv_usec initialization, 
 *                             which found by Rob <rdent@iinet.net.au>
 */

#include <rtthread.h>
#include <pthread.h>

struct timeval _timevalue;
void clock_time_system_init()
{
    time_t time;
    rt_tick_t tick;
    rt_device_t device;

    time = 0;
    device = rt_device_find("rtc");
    if (device != RT_NULL)
    {
        /* get realtime seconds */
        rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time);
    }

    /* get tick */
    tick = rt_tick_get();

    _timevalue.tv_usec = (tick%RT_TICK_PER_SECOND) * MICROSECOND_PER_TICK;
    _timevalue.tv_sec = time - tick/RT_TICK_PER_SECOND - 1;
}

int clock_time_to_tick(const struct timespec *time)
{
    int tick;
    int nsecond, second;
    struct timespec tp;

    RT_ASSERT(time != RT_NULL);

    tick = RT_WAITING_FOREVER;
    if (time != NULL)
    {
        /* get current tp */
        clock_gettime(CLOCK_REALTIME, &tp);

        if ((time->tv_nsec - tp.tv_nsec) < 0)
        {
            nsecond = NANOSECOND_PER_SECOND - (tp.tv_nsec - time->tv_nsec);
            second  = time->tv_sec - tp.tv_sec - 1;
        }
        else
        {
            nsecond = time->tv_nsec - tp.tv_nsec;
            second  = time->tv_sec - tp.tv_sec;
        }

        tick = second * RT_TICK_PER_SECOND + nsecond * RT_TICK_PER_SECOND / NANOSECOND_PER_SECOND;
        if (tick < 0) tick = 0;
    }

    return tick;
}
RTM_EXPORT(clock_time_to_tick);

int clock_getres(clockid_t clockid, struct timespec *res)
{
    if ((clockid != CLOCK_REALTIME) || (res == RT_NULL))
    {
        rt_set_errno(EINVAL);

        return -1;
    }

    res->tv_sec = 0;
    res->tv_nsec = NANOSECOND_PER_SECOND/RT_TICK_PER_SECOND;

    return 0;
}
RTM_EXPORT(clock_getres);

int clock_gettime(clockid_t clockid, struct timespec *tp)
{
    rt_tick_t tick;

    if ((clockid != CLOCK_REALTIME) || (tp == RT_NULL))
    {
        rt_set_errno(EINVAL);

        return -1;
    }

    /* get tick */
    tick = rt_tick_get();

    tp->tv_sec = _timevalue.tv_sec + tick / RT_TICK_PER_SECOND;
    tp->tv_nsec = (_timevalue.tv_usec + (tick % RT_TICK_PER_SECOND) * NANOSECOND_PER_TICK) * 1000;
    
    return 0;
}
RTM_EXPORT(clock_gettime);

int clock_settime(clockid_t clockid, const struct timespec *tp)
{
    int second;
    rt_tick_t tick;
    rt_device_t device;

    if ((clockid != CLOCK_REALTIME) || (tp == RT_NULL))
    {
        rt_set_errno(EINVAL);

        return -1;
    }

    /* get second */
    second = tp->tv_sec;
    /* get tick */
    tick = rt_tick_get();

    /* update timevalue */
    _timevalue.tv_usec = MICROSECOND_PER_SECOND - (tick % RT_TICK_PER_SECOND) * MICROSECOND_PER_TICK;
    _timevalue.tv_sec = second - tick/RT_TICK_PER_SECOND - 1;

    /* update for RTC device */
    device = rt_device_find("rtc");
    if (device != RT_NULL)
    {
        /* set realtime seconds */
        rt_device_control(device, RT_DEVICE_CTRL_RTC_SET_TIME, &second);
    }
    else
        return -1;

    return 0;
}
RTM_EXPORT(clock_settime);