/************************************************************************
* sched/clock_gettime.c
*
* Copyright (C) 2007, 2009 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 <debug.h>
#include "clock_internal.h"
/************************************************************************
* Definitions
************************************************************************/
/************************************************************************
* Private Type Declarations
************************************************************************/
/************************************************************************
* Private Function Prototypes
************************************************************************/
/**********************************************************************
* Public Constant Data
**********************************************************************/
/************************************************************************
* Public Variables
************************************************************************/
/**********************************************************************
* Private Variables
**********************************************************************/
/************************************************************************
* Private Functions
************************************************************************/
/************************************************************************
* Public Functions
************************************************************************/
/************************************************************************
* Function: clock_gettime
*
* Description:
* Clock Functions based on POSIX APIs
*
************************************************************************/
int clock_gettime(clockid_t clock_id, struct timespec *tp)
{
uint32_t msecs;
uint32_t secs;
uint32_t nsecs;
int ret = OK;
sdbg("clock_id=%d\n", clock_id);
/* Only CLOCK_REALTIME is supported */
if (clock_id != CLOCK_REALTIME)
{
sdbg("Returning ERROR\n");
*get_errno_ptr() = EINVAL;
ret = ERROR;
}
else
{
/* Get the elapsed time since power up (in milliseconds) biased
* as appropriate.
*/
msecs = MSEC_PER_TICK * (g_system_timer - g_tickbias);
sdbg("msecs = %d g_tickbias=%d\n",
(int)msecs, (int)g_tickbias);
/* Get the elapsed time in seconds and nanoseconds. */
secs = msecs / MSEC_PER_SEC;
nsecs = (msecs - (secs * MSEC_PER_SEC)) * NSEC_PER_MSEC;
sdbg("secs = %d + %d nsecs = %d + %d\n",
(int)msecs, (int)g_basetime.tv_sec,
(int)nsecs, (int)g_basetime.tv_nsec);
/* Add the base time to this. */
secs += (uint32_t)g_basetime.tv_sec;
nsecs += (uint32_t)g_basetime.tv_nsec;
/* Handle carry to seconds. */
if (nsecs > NSEC_PER_SEC)
{
uint32_t dwCarrySecs = nsecs / NSEC_PER_SEC;
secs += dwCarrySecs;
nsecs -= (dwCarrySecs * NSEC_PER_SEC);
}
/* And return the result to the caller. */
tp->tv_sec = (time_t)secs;
tp->tv_nsec = (long)nsecs;
sdbg("Returning tp=(%d,%d)\n",
(int)tp->tv_sec, (int)tp->tv_nsec);
}
return ret;
}
