incubator-nuttx/sched/clock/clock_abstime2ticks.c

142 lines
4.2 KiB
C

/****************************************************************************
* sched/clock/clock_abstime2ticks.c
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <time.h>
#include <errno.h>
#include <debug.h>
#include "clock/clock.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: clock_abstime2ticks
*
* Description:
* Convert an absolute timespec delay to system timer ticks.
*
* Input Parameters:
* clockid - The timing source to use in the conversion
* reltime - Convert this absolute time to system clock ticks.
* ticks - Return the converted number of ticks here.
*
* Returned Value:
* OK on success; A non-zero error number on failure
*
* Assumptions:
* Interrupts should be disabled so that the time is not changing during
* the calculation
*
****************************************************************************/
int clock_abstime2ticks(clockid_t clockid,
FAR const struct timespec *abstime,
FAR sclock_t *ticks)
{
struct timespec currtime;
struct timespec reltime;
int ret;
/* Convert the timespec to clock ticks.
* NOTE: Here we use internal knowledge
* that CLOCK_REALTIME is defined to be zero!
*/
ret = clock_gettime(clockid, &currtime);
if (ret != OK)
{
return ret;
}
if (clock_timespec_compare(abstime, &currtime) < 0)
{
/* Every caller of clock_abstime2ticks check 'ticks < 0' to see if
* absolute time is in the past. So lets just return negative tick
* here.
*/
*ticks = -1;
return OK;
}
/* The relative time to wait is the absolute time minus the current time. */
reltime.tv_nsec = (abstime->tv_nsec - currtime.tv_nsec);
reltime.tv_sec = (abstime->tv_sec - currtime.tv_sec);
/* Check if we were supposed to borrow from the seconds. */
if (reltime.tv_nsec < 0)
{
reltime.tv_nsec += NSEC_PER_SEC;
reltime.tv_sec -= 1;
}
/* Convert this relative time into clock ticks. */
*ticks = clock_time2ticks(&reltime);
return OK;
}
/****************************************************************************
* Name: clock_realtime2absticks
*
* Description:
* Convert real time to monotonic ticks.
*
* Input Parameters:
* mono - Return the converted time here.
* abstime - Convert this absolute time to ticks
*
* Returned Value:
* OK (0) on success; a negated errno value on failure.
*
* Assumptions:
* Interrupts should be disabled so that the time is not changing during
* the calculation
*
****************************************************************************/
int clock_realtime2absticks(FAR const struct timespec *reltime,
FAR clock_t *absticks)
{
#ifndef CONFIG_CLOCK_TIMEKEEPING
struct timespec mono;
clock_timespec_subtract(reltime, &g_basetime, &mono);
*absticks = clock_time2ticks(&mono);
return OK;
#else
return -ENOSYS;
#endif
}