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/************************************************************************
* sched/clock_gettime.c
*
* Copyright (C) 2007, 2009, 2011, 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 <nuttx/rtc.h>
#include <stdint.h>
#include <time.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <arch/irq.h>
#include "clock_internal.h"
/************************************************************************
* Pre-processor Definitions
************************************************************************/
/************************************************************************
* Private Type Declarations
************************************************************************/
/************************************************************************
* Private Function Prototypes
************************************************************************/
/**********************************************************************
* Public Constant Data
**********************************************************************/
/************************************************************************
* Public Variables
************************************************************************/
/**********************************************************************
* Private Variables
**********************************************************************/
/************************************************************************
* Private Functions
************************************************************************/
/************************************************************************
* Public Functions
************************************************************************/
/************************************************************************
* Name: clock_gettime
*
* Description:
* Clock Functions based on POSIX APIs
*
************************************************************************/
int clock_gettime(clockid_t clock_id, struct timespec *tp)
{
#ifdef CONFIG_SYSTEM_TIME64
uint64_t msecs;
uint64_t secs;
uint64_t nsecs;
#else
uint32_t msecs;
uint32_t secs;
uint32_t nsecs;
#endif
uint32_t carry;
int ret = OK;
sdbg("clock_id=%d\n", clock_id);
DEBUGASSERT(tp != NULL);
#ifdef CLOCK_MONOTONIC
/* CLOCK_MONOTONIC is an optional under POSIX: "If the Monotonic Clock
* option is supported, all implementations shall support a clock_id
* of CLOCK_MONOTONIC defined in <time.h>. This clock represents the
* monotonic clock for the system. For this clock, the value returned
* by clock_gettime() represents the amount of time (in seconds and
* nanoseconds) since an unspecified point in the past (for example,
* system start-up time, or the Epoch). This point does not change
* after system start-up time. The value of the CLOCK_MONOTONIC clock
* cannot be set via clock_settime(). This function shall fail if it
* is invoked with a clock_id argument of CLOCK_MONOTONIC."
*/
if (clock_id == CLOCK_MONOTONIC)
{
/* Get the time since power-on in seconds and milliseconds */
msecs = MSEC_PER_TICK * g_system_timer;
secs = msecs / MSEC_PER_SEC;
/* Return the elapsed time in seconds and nanoseconds */
nsecs = (msecs - (secs * MSEC_PER_SEC)) * NSEC_PER_MSEC;
tp->tv_sec = (time_t)secs;
tp->tv_nsec = (long)nsecs;
}
else
#endif
/* CLOCK_REALTIME - POSIX demands this to be present. CLOCK_REALTIME
* represents the machine's best-guess as to the current wall-clock,
* time-of-day time. This means that CLOCK_REALTIME can jump forward and
* backward as the system time-of-day clock is changed.
*
* If an RTC is supported, then the non-standard CLOCK_ACTIVETIME is also
* supported to manage time based on the system timer interrupt separately
* from the RTC. This may be necessary, for example, in certain cases where
* the system timer interrupt has been stopped in low power modes.
*/
#ifdef CONFIG_RTC
if (clock_id == CLOCK_REALTIME || clock_id == CLOCK_ACTIVETIME)
#else
if (clock_id == CLOCK_REALTIME)
#endif
{
/* Do we have a high-resolution RTC that can provide us with the time? */
#ifdef CONFIG_RTC_HIRES
if (g_rtc_enabled && clock_id != CLOCK_ACTIVETIME)
{
/* Yes.. Get the hi-resolution time from the RTC unless the caller
* has specifically asked for the system timer (CLOCK_ACTIVETIME)
*/
ret = up_rtc_gettime(tp);
}
else
#endif
{
/* Get the elapsed time since the time-of-day was last set.
* g_system_timer provides the number of clock times since
* power was applied; the bias value corresponds to the time
* when the time-of-day was last set.
*/
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. The base time is the time-of-day
* setting. When added to the elapsed time since the time-of-day
* was last set, this gives us the current time.
*/
secs += (uint32_t)g_basetime.tv_sec;
nsecs += (uint32_t)g_basetime.tv_nsec;
/* Handle carry to seconds. */
if (nsecs > NSEC_PER_SEC)
{
carry = nsecs / NSEC_PER_SEC;
secs += carry;
nsecs -= (carry * 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);
}
else
{
sdbg("Returning ERROR\n");
set_errno(EINVAL);
ret = ERROR;
}
return ret;
}
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