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incubator-nuttx/sched/clock/clock_initialize.c

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/****************************************************************************
* sched/clock/clock_initialize.c
*
* 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 <nuttx/compiler.h>
#include <stdint.h>
#include <time.h>
#include <errno.h>
#include <debug.h>
#ifdef CONFIG_RTC
# include <nuttx/irq.h>
#endif
#include <nuttx/arch.h>
#include <nuttx/clock.h>
#include <nuttx/trace.h>
#include "clock/clock.h"
#ifdef CONFIG_CLOCK_TIMEKEEPING
# include "clock/clock_timekeeping.h"
#endif
/****************************************************************************
* Public Data
****************************************************************************/
#ifndef CONFIG_SCHED_TICKLESS
#ifdef CONFIG_SYSTEM_TIME64
volatile uint64_t g_system_ticks = INITIAL_SYSTEM_TIMER_TICKS;
#else
volatile uint32_t g_system_ticks = INITIAL_SYSTEM_TIMER_TICKS;
#endif
#endif
#ifndef CONFIG_CLOCK_TIMEKEEPING
struct timespec g_basetime;
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: clock_basetime
*
* Description:
* Get the initial time value from the best source available.
*
****************************************************************************/
#ifdef CONFIG_RTC
#if defined(CONFIG_RTC_DATETIME)
/* Initialize the system time using a broken out date/time structure */
int clock_basetime(FAR struct timespec *tp)
{
struct tm rtctime;
long nsecs = 0;
int ret;
/* Get the broken-out time from the date/time RTC. */
#ifdef CONFIG_ARCH_HAVE_RTC_SUBSECONDS
ret = up_rtc_getdatetime_with_subseconds(&rtctime, &nsecs);
#else
ret = up_rtc_getdatetime(&rtctime);
#endif
if (ret >= 0)
{
/* And use the broken-out time to initialize the system time */
tp->tv_sec = timegm(&rtctime);
tp->tv_nsec = nsecs;
}
return ret;
}
#elif defined(CONFIG_RTC_HIRES)
/* Initialize the system time using a high-resolution structure */
int clock_basetime(FAR struct timespec *tp)
{
/* Get the complete time from the hi-res RTC. */
return up_rtc_gettime(tp);
}
#else
/* Initialize the system time using seconds only */
int clock_basetime(FAR struct timespec *tp)
{
/* Get the seconds (only) from the lo-resolution RTC */
tp->tv_sec = up_rtc_time();
tp->tv_nsec = 0;
return OK;
}
#endif /* CONFIG_RTC_HIRES */
#else /* CONFIG_RTC */
int clock_basetime(FAR struct timespec *tp)
{
time_t jdn = 0;
/* Get the EPOCH-relative julian date from the calendar year,
* month, and date
*/
jdn = clock_calendar2utc(CONFIG_START_YEAR, CONFIG_START_MONTH - 1,
CONFIG_START_DAY);
/* Set the base time as seconds into this julian day. */
tp->tv_sec = jdn * SEC_PER_DAY;
tp->tv_nsec = 0;
return OK;
}
#endif /* CONFIG_RTC */
/****************************************************************************
* Name: clock_inittime
*
* Description:
* Get the initial time value from the best source available.
*
****************************************************************************/
#ifdef CONFIG_RTC
static void clock_inittime(FAR const struct timespec *tp)
{
/* (Re-)initialize the time value to match the RTC */
#ifndef CONFIG_CLOCK_TIMEKEEPING
struct timespec ts;
if (tp)
{
memcpy(&g_basetime, tp, sizeof(struct timespec));
}
else
{
clock_basetime(&g_basetime);
}
clock_systime_timespec(&ts);
/* Adjust base time to hide initial timer ticks. */
g_basetime.tv_sec -= ts.tv_sec;
g_basetime.tv_nsec -= ts.tv_nsec;
while (g_basetime.tv_nsec < 0)
{
g_basetime.tv_nsec += NSEC_PER_SEC;
g_basetime.tv_sec--;
}
#else
clock_inittimekeeping(tp);
#endif
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: clock_initialize
*
* Description:
* Perform one-time initialization of the timing facilities.
*
****************************************************************************/
void clock_initialize(void)
{
sched_trace_begin();
#if !defined(CONFIG_SUPPRESS_INTERRUPTS) && \
!defined(CONFIG_SUPPRESS_TIMER_INTS) && \
!defined(CONFIG_SYSTEMTICK_EXTCLK)
/* Initialize the system timer interrupt */
up_timer_initialize();
#endif
#if defined(CONFIG_RTC)
/* Initialize the internal RTC hardware. Initialization of external RTC
* must be deferred until the system has booted.
*/
up_rtc_initialize();
#if !defined(CONFIG_RTC_EXTERNAL)
/* Initialize the time value to match the RTC */
clock_inittime(NULL);
#endif
#endif
perf_init();
sched_trace_end();
}
/****************************************************************************
* Name: clock_synchronize
*
* Description:
* Synchronize the system timer to a hardware RTC. This operation is
* normally performed automatically by the system during clock
* initialization. However, the user may also need to explicitly re-
* synchronize the system timer to the RTC under certain conditions where
* the system timer is known to be in error. For example, in certain low-
* power states, the system timer may be stopped but the RTC will continue
* keep correct time. After recovering from such low-power state, this
* function should be called to restore the correct system time.
*
* Calling this function could result in system time going "backward" in
* time, especially with certain lower resolution RTC implementations.
* Time going backward could have bad consequences if there are ongoing
* timers and delays. So use this interface with care.
*
* Input Parameters:
* tp: rtc time should be synced, set NULL to re-get time
*
* Returned Value:
* None
*
* Assumptions:
*
****************************************************************************/
#ifdef CONFIG_RTC
void clock_synchronize(FAR const struct timespec *tp)
{
irqstate_t flags;
/* Re-initialize the time value to match the RTC */
flags = enter_critical_section();
clock_inittime(tp);
leave_critical_section(flags);
}
#endif
/****************************************************************************
* Name: clock_resynchronize
*
* Description:
* Resynchronize the system timer to a hardware RTC. The user can
* explicitly re-synchronize the system timer to the RTC under certain
* conditions where the system timer is known to be in error. For example,
* in certain low-power states, the system timer may be stopped but the
* RTC will continue keep correct time. After recovering from such
* low-power state, this function should be called to restore the correct
* system time. Function also keeps monotonic clock at rate of RTC.
*
* Calling this function will not result in system time going "backward" in
* time. If setting system time with RTC would result time going "backward"
* then resynchronization is not performed.
*
* Input Parameters:
* rtc_diff: amount of time system-time is adjusted forward with RTC
*
* Returned Value:
* None
*
* Assumptions:
*
****************************************************************************/
#if defined(CONFIG_RTC) && !defined(CONFIG_SCHED_TICKLESS) && !defined(CONFIG_CLOCK_TIMEKEEPING)
void clock_resynchronize(FAR struct timespec *rtc_diff)
{
struct timespec rtc_time;
struct timespec bias;
struct timespec curr_ts;
struct timespec rtc_diff_tmp;
irqstate_t flags;
int32_t carry;
int ret;
if (rtc_diff == NULL)
{
rtc_diff = &rtc_diff_tmp;
}
/* Set the time value to match the RTC */
flags = enter_critical_section();
/* Get RTC time */
ret = clock_basetime(&rtc_time);
if (ret < 0)
{
/* Error reading RTC, skip resynchronization. */
sinfo("rtc error %d, skip resync\n", ret);
rtc_diff->tv_sec = 0;
rtc_diff->tv_nsec = 0;
goto skip;
}
/* Get the elapsed time since power up (in milliseconds). This is a
* bias value that we need to use to correct the base time.
*/
clock_systime_timespec(&bias);
/* 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.
*/
curr_ts.tv_sec = bias.tv_sec + g_basetime.tv_sec;
curr_ts.tv_nsec = bias.tv_nsec + g_basetime.tv_nsec;
/* Handle carry to seconds. */
if (curr_ts.tv_nsec >= NSEC_PER_SEC)
{
carry = curr_ts.tv_nsec / NSEC_PER_SEC;
curr_ts.tv_sec += carry;
curr_ts.tv_nsec -= (carry * NSEC_PER_SEC);
}
/* Check if RTC has advanced past system time. */
if (curr_ts.tv_sec > rtc_time.tv_sec ||
(curr_ts.tv_sec == rtc_time.tv_sec &&
curr_ts.tv_nsec >= rtc_time.tv_nsec))
{
/* Setting system time with RTC now would result time going
* backwards. Skip resynchronization.
*/
sinfo("skip resync\n");
rtc_diff->tv_sec = 0;
rtc_diff->tv_nsec = 0;
}
else
{
/* Output difference between time at entry and new current time. */
rtc_diff->tv_sec = rtc_time.tv_sec - curr_ts.tv_sec;
rtc_diff->tv_nsec = rtc_time.tv_nsec - curr_ts.tv_nsec;
/* Handle carry to seconds. */
if (rtc_diff->tv_nsec < 0)
{
carry = -((-(rtc_diff->tv_nsec + 1)) / NSEC_PER_SEC + 1);
}
else if (rtc_diff->tv_nsec >= NSEC_PER_SEC)
{
carry = rtc_diff->tv_nsec / NSEC_PER_SEC;
}
else
{
carry = 0;
}
if (carry != 0)
{
rtc_diff->tv_sec += carry;
rtc_diff->tv_nsec -= (carry * NSEC_PER_SEC);
}
/* Add the sleep time to correct system timer */
g_system_ticks += SEC2TICK(rtc_diff->tv_sec);
g_system_ticks += NSEC2TICK(rtc_diff->tv_nsec);
}
skip:
leave_critical_section(flags);
}
#endif
/****************************************************************************
* Name: clock_timer
*
* Description:
* This function must be called once every time the real time clock
* interrupt occurs. The interval of this clock interrupt must be
* USEC_PER_TICK
*
****************************************************************************/
#ifndef CONFIG_SCHED_TICKLESS
void clock_timer(void)
{
/* Increment the per-tick system counter */
g_system_ticks++;
}
#endif
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