chvt.h

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/*
    ChibiOS - Copyright (C) 2006-2026 Giovanni Di Sirio.
 
    This file is part of ChibiOS.
 
    ChibiOS is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation version 3 of the License.
 
    ChibiOS is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
 
/**
 * @file    rt/include/chvt.h
 * @brief   Time and Virtual Timers module macros and structures.
 *
 * @addtogroup time
 * @{
 */
 
#ifndef CHVT_H
#define CHVT_H
 
/*===========================================================================*/
/* Module constants.                                                         */
/*===========================================================================*/
 
/*===========================================================================*/
/* Module pre-compile time settings.                                         */
/*===========================================================================*/
 
/*===========================================================================*/
/* Derived constants and error checks.                                       */
/*===========================================================================*/
 
#if (CH_CFG_ST_TIMEDELTA < 0) || (CH_CFG_ST_TIMEDELTA == 1)
#error "invalid CH_CFG_ST_TIMEDELTA specified, must "                       \
       "be zero or greater than one"
#endif
 
#if (CH_CFG_ST_TIMEDELTA > 0) && (CH_CFG_TIME_QUANTUM > 0)
#error "CH_CFG_TIME_QUANTUM not supported in tickless mode"
#endif
 
#if (CH_CFG_ST_TIMEDELTA > 0) && (CH_DBG_THREADS_PROFILING == TRUE)
#error "CH_DBG_THREADS_PROFILING not supported in tickless mode"
#endif
 
/*===========================================================================*/
/* Module data structures and types.                                         */
/*===========================================================================*/
 
/*===========================================================================*/
/* Module macros.                                                            */
/*===========================================================================*/
 
/*===========================================================================*/
/* External declarations.                                                    */
/*===========================================================================*/
 
/*
 * Virtual Timers APIs.
 */
#ifdef __cplusplus
extern "C" {
#endif
  void chVTDoSetI(virtual_timer_t *vtp, sysinterval_t delay,
                  vtfunc_t vtfunc, void *par);
  void chVTDoSetContinuousI(virtual_timer_t *vtp, sysinterval_t delay,
                            vtfunc_t vtfunc, void *par);
  void chVTDoResetI(virtual_timer_t *vtp);
  sysinterval_t chVTGetRemainingIntervalI(virtual_timer_t *vtp);
  void chVTDoTickI(void);
#if CH_CFG_USE_TIMESTAMP == TRUE
  systimestamp_t chVTGetTimeStampI(void);
  void chVTResetTimeStampI(void);
#endif
#ifdef __cplusplus
}
#endif
 
/*===========================================================================*/
/* Module inline functions.                                                  */
/*===========================================================================*/
 
/**
 * @brief   Initializes a @p virtual_timer_t object.
 * @note    Initializing a timer object is not strictly required because
 *          the function @p chVTSetI() initializes the object too. This
 *          function is only useful if you need to perform a @p chVTIsArmed()
 *          check before calling @p chVTSetI().
 *
 * @param[out] vtp      the @p virtual_timer_t structure pointer
 *
 * @init
 */
static inline void chVTObjectInit(virtual_timer_t *vtp) {
 
  vtp->dlist.next = NULL;
}
 
/**
 * @brief   Current system time.
 * @details Returns the number of system ticks since the @p chSysInit()
 *          invocation.
 * @note    The counter can reach its maximum and then restart from zero.
 * @note    This function can be called from any context but its atomicity
 *          is not guaranteed on architectures whose word size is less than
 *          @p systime_t size.
 *
 * @return              The system time in ticks.
 *
 * @xclass
 */
static inline systime_t chVTGetSystemTimeX(void) {
 
#if CH_CFG_ST_TIMEDELTA == 0
  return currcore->vtlist.systime;
#else /* CH_CFG_ST_TIMEDELTA > 0 */
  return port_timer_get_time();
#endif /* CH_CFG_ST_TIMEDELTA > 0 */
}
 
/**
 * @brief   Current system time.
 * @details Returns the number of system ticks since the @p chSysInit()
 *          invocation.
 * @note    The counter can reach its maximum and then restart from zero.
 *
 * @return              The system time in ticks.
 *
 * @api
 */
static inline systime_t chVTGetSystemTime(void) {
  systime_t systime;
 
  chSysLock();
  systime = chVTGetSystemTimeX();
  chSysUnlock();
 
  return systime;
}
 
/**
 * @brief   Returns the elapsed time since the specified start time.
 *
 * @param[in] start     start time
 * @return              The elapsed time.
 *
 * @xclass
 */
static inline sysinterval_t chVTTimeElapsedSinceX(systime_t start) {
 
  return chTimeDiffX(start, chVTGetSystemTimeX());
}
 
/**
 * @brief   Checks if the current system time is within the specified time
 *          window.
 * @note    When start==end then the function returns always false because the
 *          time window has zero size.
 *
 * @param[in] start     the start of the time window (inclusive)
 * @param[in] end       the end of the time window (non inclusive)
 * @retval true         current time within the specified time window.
 * @retval false        current time not within the specified time window.
 *
 * @xclass
 */
static inline bool chVTIsSystemTimeWithinX(systime_t start, systime_t end) {
 
  return chTimeIsInRangeX(chVTGetSystemTimeX(), start, end);
}
 
/**
 * @brief   Checks if the current system time is within the specified time
 *          window.
 * @note    When start==end then the function returns always false because the
 *          time window has zero size.
 *
 * @param[in] start     the start of the time window (inclusive)
 * @param[in] end       the end of the time window (non inclusive)
 * @retval true         current time within the specified time window.
 * @retval false        current time not within the specified time window.
 *
 * @api
 */
static inline bool chVTIsSystemTimeWithin(systime_t start, systime_t end) {
 
  return chTimeIsInRangeX(chVTGetSystemTime(), start, end);
}
 
/**
 * @brief   Returns the time interval until the next timer event.
 * @note    The return value is not perfectly accurate and can report values
 *          in excess of @p CH_CFG_ST_TIMEDELTA ticks.
 * @note    The interval returned by this function is only meaningful if
 *          more timers are not added to the list until the returned time.
 *
 * @param[out] timep    pointer to a variable that will contain the time
 *                      interval until the next timer elapses. This pointer
 *                      can be @p NULL if the information is not required.
 * @return              The time, in ticks, until next time event.
 * @retval false        if the timers list is empty.
 * @retval true         if the timers list contains at least one timer.
 *
 * @iclass
 */
static inline bool chVTGetTimersStateI(sysinterval_t *timep) {
  virtual_timers_list_t *vtlp = &currcore->vtlist;
  ch_delta_list_t *dlp = &vtlp->dlist;
 
  chDbgCheckClassI();
 
  if (dlp == dlp->next) {
    return false;
  }
 
  if (timep != NULL) {
#if CH_CFG_ST_TIMEDELTA == 0
    *timep = dlp->next->delta;
#else
    *timep = (dlp->next->delta + (sysinterval_t)CH_CFG_ST_TIMEDELTA) -
             chTimeDiffX(vtlp->lasttime, chVTGetSystemTimeX());
#endif
  }
 
  return true;
}
 
/**
 * @brief   Returns @p true if the specified timer is armed.
 * @pre     The timer must have been initialized using @p chVTObjectInit()
 *          or @p chVTDoSetI().
 *
 * @param[in] vtp       the @p virtual_timer_t structure pointer
 * @return              true if the timer is armed.
 *
 * @iclass
 */
static inline bool chVTIsArmedI(const virtual_timer_t *vtp) {
 
  chDbgCheckClassI();
 
  return (bool)(vtp->dlist.next != NULL);
}
 
/**
 * @brief   Returns @p true if the specified timer is armed.
 * @pre     The timer must have been initialized using @p chVTObjectInit()
 *          or @p chVTDoSetI().
 *
 * @param[in] vtp       the @p virtual_timer_t structure pointer
 * @return              true if the timer is armed.
 *
 * @api
 */
static inline bool chVTIsArmed(const virtual_timer_t *vtp) {
  bool b;
 
  chSysLock();
  b = chVTIsArmedI(vtp);
  chSysUnlock();
 
  return b;
}
 
/**
 * @brief   Disables a Virtual Timer.
 * @note    The timer is first checked and disabled only if armed.
 * @pre     The timer must have been initialized using @p chVTObjectInit()
 *          or @p chVTDoSetI().
 *
 * @param[in] vtp       the @p virtual_timer_t structure pointer
 *
 * @iclass
 */
static inline void chVTResetI(virtual_timer_t *vtp) {
 
  if (chVTIsArmedI(vtp)) {
    chVTDoResetI(vtp);
  }
}
 
/**
 * @brief   Disables a Virtual Timer.
 * @note    The timer is first checked and disabled only if armed.
 * @pre     The timer must have been initialized using @p chVTObjectInit()
 *          or @p chVTDoSetI().
 *
 * @param[in] vtp       the @p virtual_timer_t structure pointer
 *
 * @api
 */
static inline void chVTReset(virtual_timer_t *vtp) {
 
  chSysLock();
  chVTResetI(vtp);
  chSysUnlock();
}
 
/**
 * @brief   Enables a one-shot virtual timer.
 * @details If the virtual timer was already enabled then it is re-enabled
 *          using the new parameters.
 * @pre     The timer must have been initialized using @p chVTObjectInit()
 *          or @p chVTDoSetI().
 *
 * @param[in] vtp       the @p virtual_timer_t structure pointer
 * @param[in] delay     the number of ticks before the operation timeouts, the
 *                      special values are handled as follow:
 *                      - @a TIME_INFINITE is allowed but interpreted as a
 *                        normal time specification.
 *                      - @a TIME_IMMEDIATE this value is not allowed.
 *                      .
 * @param[in] vtfunc    the timer callback function. After invoking the
 *                      callback the timer is disabled and the structure can
 *                      be disposed or reused.
 * @param[in] par       a parameter that will be passed to the callback
 *                      function
 *
 * @iclass
 */
static inline void chVTSetI(virtual_timer_t *vtp, sysinterval_t delay,
                            vtfunc_t vtfunc, void *par) {
 
  chVTResetI(vtp);
  chVTDoSetI(vtp, delay, vtfunc, par);
}
 
/**
 * @brief   Enables a one-shot virtual timer.
 * @details If the virtual timer was already enabled then it is re-enabled
 *          using the new parameters.
 * @pre     The timer must have been initialized using @p chVTObjectInit()
 *          or @p chVTDoSetI().
 *
 * @param[in] vtp       the @p virtual_timer_t structure pointer
 * @param[in] delay     the number of ticks before the operation timeouts, the
 *                      special values are handled as follow:
 *                      - @a TIME_INFINITE is allowed but interpreted as a
 *                        normal time specification.
 *                      - @a TIME_IMMEDIATE this value is not allowed.
 *                      .
 * @param[in] vtfunc    the timer callback function. After invoking the
 *                      callback the timer is disabled and the structure can
 *                      be disposed or reused.
 * @param[in] par       a parameter that will be passed to the callback
 *                      function
 *
 * @api
 */
static inline void chVTSet(virtual_timer_t *vtp, sysinterval_t delay,
                           vtfunc_t vtfunc, void *par) {
 
  chSysLock();
  chVTSetI(vtp, delay, vtfunc, par);
  chSysUnlock();
}
 
/**
 * @brief   Enables a continuous virtual timer.
 * @details If the virtual timer was already enabled then it is re-enabled
 *          using the new parameters.
 * @pre     The timer must have been initialized using @p chVTObjectInit()
 *          or @p chVTDoSetI().
 *
 * @param[in] vtp       the @p virtual_timer_t structure pointer
 * @param[in] delay     the number of ticks before the operation timeouts, the
 *                      special values are handled as follow:
 *                      - @a TIME_INFINITE is allowed but interpreted as a
 *                        normal time specification.
 *                      - @a TIME_IMMEDIATE this value is not allowed.
 *                      .
 * @param[in] vtfunc    the timer callback function. After invoking the
 *                      callback the timer is disabled and the structure can
 *                      be disposed or reused.
 * @param[in] par       a parameter that will be passed to the callback
 *                      function
 *
 * @iclass
 */
static inline void chVTSetContinuousI(virtual_timer_t *vtp, sysinterval_t delay,
                                      vtfunc_t vtfunc, void *par) {
 
  chVTResetI(vtp);
  chVTDoSetContinuousI(vtp, delay, vtfunc, par);
}
 
/**
 * @brief   Enables a continuous virtual timer.
 * @details If the virtual timer was already enabled then it is re-enabled
 *          using the new parameters.
 * @pre     The timer must have been initialized using @p chVTObjectInit()
 *          or @p chVTDoSetI().
 *
 * @param[in] vtp       the @p virtual_timer_t structure pointer
 * @param[in] delay     the number of ticks before the operation timeouts, the
 *                      special values are handled as follow:
 *                      - @a TIME_INFINITE is allowed but interpreted as a
 *                        normal time specification.
 *                      - @a TIME_IMMEDIATE this value is not allowed.
 *                      .
 * @param[in] vtfunc    the timer callback function. After invoking the
 *                      callback the timer is disabled and the structure can
 *                      be disposed or reused.
 * @param[in] par       a parameter that will be passed to the callback
 *                      function
 *
 * @api
 */
static inline void chVTSetContinuous(virtual_timer_t *vtp, sysinterval_t delay,
                                     vtfunc_t vtfunc, void *par) {
 
  chSysLock();
  chVTSetContinuousI(vtp, delay, vtfunc, par);
  chSysUnlock();
}
 
/**
 * @brief   Returns the current reload value.
 *
 * @param[in] vtp       the @p virtual_timer_t structure pointer
 * @return              The reload value.
 *
 * @xclass
 */
static inline sysinterval_t chVTGetReloadIntervalX(virtual_timer_t *vtp) {
 
  return vtp->reload;
}
 
/**
 * @brief   Changes a timer reload time interval.
 * @note    This function is meant to be called from a timer callback, it
 *          does nothing in any other context.
 * @note    Calling this function from a one-shot timer callback turns it
 *          into a continuous timer.
 *
 * @param[in] vtp       the @p virtual_timer_t structure pointer
 * @param[in] reload    the new reload value, zero means no reload
 *
 * @xclass
 */
static inline void chVTSetReloadIntervalX(virtual_timer_t *vtp,
                                          sysinterval_t reload) {
 
  vtp->reload = reload;
}
 
#if (CH_CFG_USE_TIMESTAMP == TRUE) || defined(__DOXYGEN__)
/**
 * @brief   Generates a monotonic time stamp.
 * @details This function generates a monotonic time stamp synchronized with
 *          the system time. The time stamp has the same resolution of
 *          system time.
 * @note    There is an assumption, this function must be called at
 *          least once before the system time wraps back to zero or
 *          synchronization is lost. You may use a periodic virtual timer with
 *          a very large interval in order to keep time stamps synchronized
 *          by calling this function.
 *
 * @return              The time stamp.
 *
 * @api
 */
static inline systimestamp_t chVTGetTimeStamp(void) {
  systimestamp_t stamp;
 
  chSysLock();
 
  stamp = chVTGetTimeStampI();
 
  chSysUnlock();
 
  return stamp;
}
 
/**
 * @brief   Resets and re-synchronizes the time stamps monotonic counter.
 *
 * @api
 */
static inline void chVTResetTimeStamp(void) {
 
  chSysLock();
 
  chVTResetTimeStampI();
 
  chSysUnlock();
}
#endif /* CH_CFG_USE_TIMESTAMP == TRUE */
 
/**
 * @brief   Virtual Timers instance initialization.
 * @note    Internal use only.
 *
 * @param[out] vtlp     pointer to the @p virtual_timers_list_t structure
 *
 * @notapi
 */
static inline void __vt_object_init(virtual_timers_list_t *vtlp) {
 
  ch_dlist_init(&vtlp->dlist);
#if CH_CFG_ST_TIMEDELTA == 0
  vtlp->systime = (systime_t)0;
#else /* CH_CFG_ST_TIMEDELTA > 0 */
  vtlp->lasttime = (systime_t)0;
#endif /* CH_CFG_ST_TIMEDELTA > 0 */
#if CH_CFG_USE_TIMESTAMP == TRUE
  vtlp->laststamp = (systimestamp_t)chVTGetSystemTimeX();
#endif
}
 
#endif /* CHVT_H */
 
/** @} */