incubator-nuttx/sched/clock/clock_systime_ticks.c

129 lines
3.8 KiB
C

/****************************************************************************
* sched/clock/clock_systime_ticks.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 <stdint.h>
#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <nuttx/clock.h>
#include "clock/clock.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* See nuttx/clock.h */
#undef clock_systime_ticks
/* 32-bit mask for 64-bit timer values */
#define TIMER_MASK32 0x00000000ffffffff
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: clock_systime_ticks
*
* Description:
* Return the current value of the 32/64-bit system timer counter.
*
* Indirect access to the system timer counter is required through this
* function if the execution environment does not have direct access to
* kernel global data.
*
* Use of this function is also required to assure atomic access to the
* 64-bit system timer.
*
* NOTE: This is an internal OS interface and should not be called from
* application code. Rather, the functionally equivalent, standard
* interface clock() should be used.
*
* Input Parameters:
* None
*
* Returned Value:
* The current value of the system timer counter
*
****************************************************************************/
clock_t clock_systime_ticks(void)
{
#ifdef CONFIG_RTC_HIRES
struct timespec ts =
{
0
};
clock_systime_timespec(&ts);
return clock_time2ticks(&ts);
#elif defined(CONFIG_SCHED_TICKLESS_TICK_ARGUMENT)
clock_t ticks = 0;
up_timer_gettick(&ticks);
return ticks;
#elif defined(CONFIG_SCHED_TICKLESS)
struct timespec ts =
{
0
};
up_timer_gettime(&ts);
return clock_time2ticks(&ts);
#elif defined(CONFIG_SYSTEM_TIME64)
clock_t sample;
clock_t verify;
/* 64-bit accesses are not atomic on most architectures. The following
* loop samples the 64-bit timer twice and loops in the rare event that
* there was 32-bit rollover between samples.
*
* If there is no 32-bit rollover, then:
*
* - The MS 32-bits of each sample will be the same, and
* - The LS 32-bits of the second sample will be greater than or equal
* to the LS 32-bits for the first sample.
*/
do
{
verify = g_system_ticks;
sample = g_system_ticks;
}
while ((sample & TIMER_MASK32) < (verify & TIMER_MASK32) ||
(sample & ~TIMER_MASK32) != (verify & ~TIMER_MASK32));
return sample;
#else
return g_system_ticks;
#endif
}