/*
ChibiOS - Copyright (C) 2006..2015 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; either version 3 of the License, or
(at your option) any later version.
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 chvt.h
* @brief Time and Virtual Timers module macros and structures.
*
* @addtogroup time
* @{
*/
#ifndef _CHVT_H_
#define _CHVT_H_
/*===========================================================================*/
/* Module constants. */
/*===========================================================================*/
/**
* @name Special time constants
* @{
*/
/**
* @brief Zero time specification for some functions with a timeout
* specification.
* @note Not all functions accept @p TIME_IMMEDIATE as timeout parameter,
* see the specific function documentation.
*/
#define TIME_IMMEDIATE ((systime_t)0)
/**
* @brief Infinite time specification for all functions with a timeout
* specification.
* @note Not all functions accept @p TIME_INFINITE as timeout parameter,
* see the specific function documentation.
*/
#define TIME_INFINITE ((systime_t)-1)
/** @} */
/*===========================================================================*/
/* Module pre-compile time settings. */
/*===========================================================================*/
/*===========================================================================*/
/* Derived constants and error checks. */
/*===========================================================================*/
#if (CH_CFG_ST_RESOLUTION != 16) && (CH_CFG_ST_RESOLUTION != 32)
#error "invalid CH_CFG_ST_RESOLUTION specified, must be 16 or 32"
#endif
#if CH_CFG_ST_FREQUENCY <= 0
#error "invalid CH_CFG_ST_FREQUENCY specified, must be greater than zero"
#endif
#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. */
/*===========================================================================*/
/**
* @name Time conversion utilities
* @{
*/
/**
* @brief Seconds to system ticks.
* @details Converts from seconds to system ticks number.
* @note The result is rounded upward to the next tick boundary.
*
* @param[in] sec number of seconds
* @return The number of ticks.
*
* @api
*/
#define S2ST(sec) \
((systime_t)((uint32_t)(sec) * (uint32_t)CH_CFG_ST_FREQUENCY))
/**
* @brief Milliseconds to system ticks.
* @details Converts from milliseconds to system ticks number.
* @note The result is rounded upward to the next tick boundary.
*
* @param[in] msec number of milliseconds
* @return The number of ticks.
*
* @api
*/
#define MS2ST(msec) \
((systime_t)((((((uint32_t)(msec)) * \
((uint32_t)CH_CFG_ST_FREQUENCY)) - 1UL) / 1000UL) + 1UL))
/**
* @brief Microseconds to system ticks.
* @details Converts from microseconds to system ticks number.
* @note The result is rounded upward to the next tick boundary.
*
* @param[in] usec number of microseconds
* @return The number of ticks.
*
* @api
*/
#define US2ST(usec) \
((systime_t)((((((uint32_t)(usec)) * \
((uint32_t)CH_CFG_ST_FREQUENCY)) - 1UL) / 1000000UL) + 1UL))
/**
* @brief System ticks to seconds.
* @details Converts from system ticks number to seconds.
* @note The result is rounded up to the next second boundary.
*
* @param[in] n number of system ticks
* @return The number of seconds.
*
* @api
*/
#define ST2S(n) (((((n) - 1UL) * 1UL) / CH_CFG_ST_FREQUENCY) + 1UL)
/**
* @brief System ticks to milliseconds.
* @details Converts from system ticks number to milliseconds.
* @note The result is rounded up to the next millisecond boundary.
*
* @param[in] n number of system ticks
* @return The number of milliseconds.
*
* @api
*/
#define ST2MS(n) (((((n) - 1UL) * 1000UL) / CH_CFG_ST_FREQUENCY) + 1UL)
/**
* @brief System ticks to microseconds.
* @details Converts from system ticks number to microseconds.
* @note The result is rounded up to the next microsecond boundary.
*
* @param[in] n number of system ticks
* @return The number of microseconds.
*
* @api
*/
#define ST2US(n) (((((n) - 1UL) * 1000000UL) / CH_CFG_ST_FREQUENCY) + 1UL)
/** @} */
/*===========================================================================*/
/* External declarations. */
/*===========================================================================*/
/*
* Virtual Timers APIs.
*/
#ifdef __cplusplus
extern "C" {
#endif
void _vt_init(void);
void chVTDoSetI(virtual_timer_t *vtp, systime_t delay,
vtfunc_t vtfunc, void *par);
void chVTDoResetI(virtual_timer_t *vtp);
#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->vt_func = 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 ch.vtlist.vt_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 systime_t chVTTimeElapsedSinceX(systime_t start) {
return chVTGetSystemTimeX() - start;
}
/**
* @brief Checks if the specified time is within the specified time window.
* @note When start==end then the function returns always true because the
* whole time range is specified.
* @note This function can be called from any context.
*
* @param[in] time the time to be verified
* @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 chVTIsTimeWithinX(systime_t time,
systime_t start,
systime_t end) {
return (bool)((time - start) < (end - start));
}
/**
* @brief Checks if the current system time is within the specified time
* window.
* @note When start==end then the function returns always true because the
* whole time range is specified.
*
* @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 chVTIsTimeWithinX(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 true because the
* whole time range is specified.
*
* @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 chVTIsTimeWithinX(chVTGetSystemTime(), start, end);
}
/**
* @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(virtual_timer_t *vtp) {
chDbgCheckClassI();
return (bool)(vtp->vt_func != NULL);
}
/**
* @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 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, systime_t delay,
vtfunc_t vtfunc, void *par) {
chVTResetI(vtp);
chVTDoSetI(vtp, delay, vtfunc, par);
}
/**
* @brief Enables a 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, systime_t delay,
vtfunc_t vtfunc, void *par) {
chSysLock();
chVTSetI(vtp, delay, vtfunc, par);
chSysUnlock();
}
/**
* @brief Virtual timers ticker.
* @note The system lock is released before entering the callback and
* re-acquired immediately after. It is callback's responsibility
* to acquire the lock if needed. This is done in order to reduce
* interrupts jitter when many timers are in use.
*
* @iclass
*/
static inline void chVTDoTickI(void) {
chDbgCheckClassI();
#if CH_CFG_ST_TIMEDELTA == 0
ch.vtlist.vt_systime++;
if (&ch.vtlist != (virtual_timers_list_t *)ch.vtlist.vt_next) {
/* The list is not empty, processing elements on top.*/
--ch.vtlist.vt_next->vt_delta;
while (ch.vtlist.vt_next->vt_delta == (systime_t)0) {
virtual_timer_t *vtp;
vtfunc_t fn;
vtp = ch.vtlist.vt_next;
fn = vtp->vt_func;
vtp->vt_func = NULL;
vtp->vt_next->vt_prev = (virtual_timer_t *)&ch.vtlist;
ch.vtlist.vt_next = vtp->vt_next;
chSysUnlockFromISR();
fn(vtp->vt_par);
chSysLockFromISR();
}
}
#else /* CH_CFG_ST_TIMEDELTA > 0 */
virtual_timer_t *vtp;
systime_t now, delta;
/* The list is assumed to be non-empty because an tick interrupt just
occurred.*/
chDbgAssert(&ch.vtlist != (virtual_timers_list_t *)ch.vtlist.vt_next,
"timers list empty");
/* First timer to be processed, its time is assumed to be between
"vt_lasttime" and "now".*/
vtp = ch.vtlist.vt_next;
chDbgAssert(chVTIsTimeWithinX(ch.vtlist.vt_lasttime + vtp->vt_delta,
ch.vtlist.vt_lasttime,
chVTGetSystemTimeX() + 1),
"out of time window");
/* Timers processing loop.*/
while (true) {
vtfunc_t fn;
/* The "last time" becomes this timer's expiration time.*/
ch.vtlist.vt_lasttime += vtp->vt_delta;
/* The timer is removed from the list and marked as non-armed.*/
vtp->vt_next->vt_prev = (virtual_timer_t *)&ch.vtlist;
ch.vtlist.vt_next = vtp->vt_next;
fn = vtp->vt_func;
vtp->vt_func = NULL;
/* If the list is empty then the timer is stopped.*/
if (&ch.vtlist == (virtual_timers_list_t *)ch.vtlist.vt_next) {
port_timer_stop_alarm();
}
/* Leaving the system critical zone in order to execute the callback
and in order to give a preemption chance to higher priority
interrupts.*/
chSysUnlockFromISR();
/* The callback is invoked outside the kernel critical zone.*/
fn(vtp->vt_par);
/* Re-entering the critical zone in order to continue the exploration
of the list.*/
chSysLockFromISR();
/* If the list is empty then ending the loop, the list has to be
re-checked because new timers could have been added from within
the callback.*/
vtp = ch.vtlist.vt_next;
if (&ch.vtlist == (virtual_timers_list_t *)vtp) {
return;
}
/* Getting the current system time and calculating the time window since
the last time has expired.*/
now = chVTGetSystemTimeX();
delta = now - ch.vtlist.vt_lasttime;
/* The next element is outside the current time window, the loop
is stopped here.*/
if (vtp->vt_delta > delta) {
/* Updating the alarm to the next deadline, deadline that must not be
closer in time than the minimum time delta.*/
delta = (vtp->vt_delta >= (systime_t)CH_CFG_ST_TIMEDELTA) ?
vtp->vt_delta : (systime_t)CH_CFG_ST_TIMEDELTA;
port_timer_set_alarm(now + delta);
chDbgAssert((chVTGetSystemTimeX() - ch.vtlist.vt_lasttime) < delta,
"exceeding delta");
return;
}
}
#endif /* CH_CFG_ST_TIMEDELTA > 0 */
}
#endif /* _CHVT_H_ */
/** @} */