nuttx/sched/clock/clock_systimespec.c

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/****************************************************************************
* sched/clock/clock_systimespec.c
*
* Copyright (C) 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <time.h>
#include <errno.h>
#include <nuttx/arch.h>
#include <nuttx/clock.h>
2015-02-03 13:44:59 +01:00
#include "clock/clock.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: clock_systimespec
*
* Description:
* Return the current value of the system timer counter as a struct
* timespec. The returned time is the elapsed time since power up.
*
* Parameters:
* ts - Location to return the time
*
* Return Value:
* Current version always returns OK
*
* Assumptions:
*
****************************************************************************/
int clock_systimespec(FAR struct timespec *ts)
{
#ifdef CONFIG_RTC_HIRES
/* Do we have a high-resolution RTC that can provide us with the time? */
if (g_rtc_enabled)
{
int ret;
/* Get the hi-resolution time from the RTC. This will return the
* current time, not the time since power up.
*/
ret = up_rtc_gettime(ts);
if (ret < 0)
{
return ret;
}
/* Subtract the base time to this in order to convert this to the
* time since power up.
*/
DEBUGASSERT(ts->tv_sec >= g_basetime.tv_sec);
if (ts->tv_sec < g_basetime.tv_sec)
{
/* Negative times are not supported */
return -ENOSYS;
}
ts->tv_sec -= g_basetime.tv_sec;
if (ts->tv_nsec < g_basetime.tv_nsec)
{
/* Borrow */
if (ts->tv_sec < 1)
{
/* Negative times are not supported */
return -ENOSYS;
}
ts->tv_sec--;
ts->tv_nsec += NSEC_PER_SEC;
}
ts->tv_nsec -= g_basetime.tv_nsec;
return OK;
}
else
#endif
{
#if defined(CONFIG_SCHED_TICKLESS)
/* In tickless mode, all timing is controlled by platform-specific
* code. Let the platform timer do the work.
*/
return up_timer_gettime(ts);
#elif defined(CONFIG_HAVE_LONG_LONG) && (CONFIG_USEC_PER_TICK % 1000) != 0
/* 64-bit microsecond calculations should improve our accuracy. */
uint64_t usecs;
uint64_t secs;
uint64_t nsecs;
/* Get the time since power-on in seconds and milliseconds */
usecs = TICK2MSEC(clock_systimer());
secs = usecs / USEC_PER_SEC;
/* Return the elapsed time in seconds and nanoseconds */
nsecs = (usecs - (secs * USEC_PER_SEC)) * NSEC_PER_USEC;
ts->tv_sec = (time_t)secs;
ts->tv_nsec = (long)nsecs;
return OK;
#else
/* 32-bit millisecond calculations should be just fine. */
uint32_t msecs;
uint32_t secs;
uint32_t nsecs;
/* Get the time since power-on in seconds and milliseconds */
msecs = TICK2MSEC(clock_systimer());
secs = msecs / MSEC_PER_SEC;
/* Return the elapsed time in seconds and nanoseconds */
nsecs = (msecs - (secs * MSEC_PER_SEC)) * NSEC_PER_MSEC;
ts->tv_sec = (time_t)secs;
ts->tv_nsec = (long)nsecs;
return OK;
#endif
}
}