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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011,2012,2013 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT 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/RT 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 macros and structures.
*
* @addtogroup time
* @{
*/
#ifndef _CHVT_H_
#define _CHVT_H_
/**
* @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)((sec) * CH_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)(((((msec) - 1L) * CH_FREQUENCY) / \
1000L) + 1L))
/**
* @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)(((((usec) - 1L) * CH_FREQUENCY) / \
1000000L) + 1L))
/** @} */
/**
* @brief Virtual Timer callback function.
*/
typedef void (*vtfunc_t)(void *);
/**
* @brief Virtual Timer structure type.
*/
typedef struct VirtualTimer VirtualTimer;
/**
* @extends DeltaList
*
* @brief Virtual Timer descriptor structure.
*/
struct VirtualTimer {
VirtualTimer *vt_next; /**< @brief Next timer in the delta
list. */
VirtualTimer *vt_prev; /**< @brief Previous timer in the delta
list. */
systime_t vt_time; /**< @brief Time delta before timeout. */
vtfunc_t vt_func; /**< @brief Timer callback function
pointer. */
void *vt_par; /**< @brief Timer callback function
parameter. */
};
/**
* @brief Virtual timers list header.
* @note The delta list is implemented as a double link bidirectional list
* in order to make the unlink time constant, the reset of a virtual
* timer is often used in the code.
*/
typedef struct {
VirtualTimer *vt_next; /**< @brief Next timer in the delta
list. */
VirtualTimer *vt_prev; /**< @brief Last timer in the delta
list. */
systime_t vt_time; /**< @brief Must be initialized to -1. */
volatile systime_t vt_systime; /**< @brief System Time counter. */
} VTList;
/**
* @name Macro Functions
* @{
*/
/**
* @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
*/
#define chVTDoTickI() { \
vtlist.vt_systime++; \
if (&vtlist != (VTList *)vtlist.vt_next) { \
VirtualTimer *vtp; \
\
--vtlist.vt_next->vt_time; \
while (!(vtp = vtlist.vt_next)->vt_time) { \
vtfunc_t fn = vtp->vt_func; \
vtp->vt_func = (vtfunc_t)NULL; \
vtp->vt_next->vt_prev = (void *)&vtlist; \
(&vtlist)->vt_next = vtp->vt_next; \
chSysUnlockFromIsr(); \
fn(vtp->vt_par); \
chSysLockFromIsr(); \
} \
} \
}
/**
* @brief Returns @p TRUE if the specified timer is armed.
*
* @iclass
*/
#define chVTIsArmedI(vtp) ((vtp)->vt_func != NULL)
/**
* @brief Enables a virtual timer.
* @note The associated function is invoked from interrupt context.
*
* @param[out] vtp the @p VirtualTimer structure pointer
* @param[in] time 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
*/
#define chVTSet(vtp, time, vtfunc, par) { \
chSysLock(); \
chVTSetI(vtp, time, vtfunc, par); \
chSysUnlock(); \
}
/**
* @brief Disables a Virtual Timer.
* @note The timer is first checked and disabled only if armed.
*
* @param[in] vtp the @p VirtualTimer structure pointer
*
* @api
*/
#define chVTReset(vtp) { \
chSysLock(); \
if (chVTIsArmedI(vtp)) \
chVTResetI(vtp); \
chSysUnlock(); \
}
/**
* @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 is designed to work with the @p chThdSleepUntil().
*
* @return The system time in ticks.
*
* @api
*/
#define chTimeNow() (vtlist.vt_systime)
/** @} */
extern VTList vtlist;
/*
* Virtual Timers APIs.
*/
#ifdef __cplusplus
extern "C" {
#endif
void _vt_init(void);
void chVTSetI(VirtualTimer *vtp, systime_t time, vtfunc_t vtfunc, void *par);
void chVTResetI(VirtualTimer *vtp);
bool_t chTimeIsWithin(systime_t start, systime_t end);
#ifdef __cplusplus
}
#endif
#endif /* _CHVT_H_ */
/** @} */
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