172 lines
5.4 KiB
C
172 lines
5.4 KiB
C
/*
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* This file is subject to the terms of the GFX License. If a copy of
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* the license was not distributed with this file, you can obtain one at:
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*
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* http://chibios-gfx.com/license.html
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*/
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/**
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* @file include/gtimer/gtimer.h
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*
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* @addtogroup GTIMER
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*
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* @brief Module which provides software based timers for user-space applications
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*
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* @details The reason why ChibiOS/GFX has it's own timer abstraction is because
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* virtual timers provided by ChibiOS/RT are interrupt context only.
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* While great for what they are designed for, they make coding of the input
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* drivers much more complex.
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* For non-performance critical drivers like these input drivers, it would also
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* hog an in-ordinate amount of critical (interrupt locked) system time.
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* This contrary to the goals of a real-time operating system. So a user-land
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* (thread based) timer mechanism is also required.
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*
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* @pre GFX_USE_GTIMER must be set to TRUE in your gfxconf.h
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*
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* @{
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*/
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#ifndef _GTIMER_H
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#define _GTIMER_H
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#include "gfx.h"
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#if GFX_USE_GTIMER || defined(__DOXYGEN__)
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/*===========================================================================*/
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/* Type definitions */
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/*===========================================================================*/
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/* Data part of a static GTimer initialiser */
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#define _GTIMER_DATA() {0,0,0,0,0,0,0}
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/* Static GTimer initialiser */
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#define GTIMER_DECL(name) GTimer name = _GTIMER_DATA()
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/* A callback function (executed in a thread context) */
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typedef void (*GTimerFunction)(void *param);
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/**
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* @brief A GTimer structure
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*/
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typedef struct GTimer_t {
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GTimerFunction fn;
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void *param;
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systemticks_t when;
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systemticks_t period;
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uint16_t flags;
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struct GTimer_t *next;
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struct GTimer_t *prev;
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} GTimer;
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/*===========================================================================*/
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/* External declarations. */
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/*===========================================================================*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief Initialise a timer.
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*
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* @param[in] pt pointer to a GTimer structure
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*
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* @api
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*/
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void gtimerInit(GTimer *pt);
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/**
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* @brief Set a timer going or alter its properties if it is already going.
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*
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* @param[in] pt Pointer to a GTimer structure
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* @param[in] fn The callback function
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* @param[in] param The parameter to pass to the callback function
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* @param[in] periodic Is the timer a periodic timer? FALSE is a once-only timer.
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* @param[in] millisec The timer period. The following special values are allowed:
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* TIME_IMMEDIATE causes the callback function to be called asap.
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* A periodic timer with this value will fire once only.
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* TIME_INFINITE never timeout (unless triggered by gtimerJab or gtimerJabI)
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*
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* @note If the timer is already active its properties are updated with the new parameters.
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* The current period will be immediately canceled (without the callback function being
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* called) and the timer will be restart with the new timer properties.
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* @note The callback function should be careful not to over-run the thread stack.
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* Define a new value for the macro GTIME_THREAD_STACK_SIZE if you want to
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* change the default size.
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* @note The callback function should return as quickly as possible as all
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* timer callbacks are performed by a single thread. If a callback function
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* takes too long it could affect the timer response for other timers.
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* @note A timer callback function is not a replacement for a dedicated thread if the
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* function wants to perform computationally expensive stuff.
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* @note As the callback function is called on GTIMER's thread, the function must make sure it uses
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* appropriate synchronisation controls such as semaphores or mutexes around any data
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* structures it shares with other threads such as the main application thread.
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*
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* @api
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*/
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void gtimerStart(GTimer *pt, GTimerFunction fn, void *param, bool_t periodic, delaytime_t millisec);
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/**
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* @brief Stop a timer (periodic or otherwise)
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*
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* @param[in] pt Pointer to a GTimer structure
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*
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* @note If the timer is not active this does nothing.
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*
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* @api
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*/
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void gtimerStop(GTimer *pt);
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/**
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* @brief Test if a timer is currently active
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*
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* @param[in] pt Pointer to a GTimer structure
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*
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* @return TRUE if active, FALSE otherwise
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*
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* @api
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*/
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bool_t gtimerIsActive(GTimer *pt);
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/**
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* @brief Jab a timer causing the current period to immediate expire
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* @details The callback function will be called as soon as possible.
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*
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* @pre Use from a normal thread context.
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*
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* @param[in] pt Pointer to a GTimer structure
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*
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* @note If the timer is not active this does nothing.
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* @note Repeated Jabs before the callback function actually happens are ignored.
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*
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* @api
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*/
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void gtimerJab(GTimer *pt);
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/**
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* @brief Jab a timer causing the current period to immediate expire
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* @details The callback function will be called as soon as possible.
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*
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* @pre Use from an interrupt routine context.
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*
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* @param[in] pt Pointer to a GTimer structure
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*
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* @note If the timer is not active this does nothing.
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* @note Repeated Jabs before the callback function actually happens are ignored.
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*
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* @iclass
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* @api
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*/
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void gtimerJabI(GTimer *pt);
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#ifdef __cplusplus
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}
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#endif
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#endif /* GFX_USE_GTIMER */
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#endif /* _GTIMER_H */
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/** @} */
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