2 * FreeRTOS Kernel <DEVELOPMENT BRANCH>
3 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
5 * SPDX-License-Identifier: MIT
7 * Permission is hereby granted, free of charge, to any person obtaining a copy of
8 * this software and associated documentation files (the "Software"), to deal in
9 * the Software without restriction, including without limitation the rights to
10 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
11 * the Software, and to permit persons to whom the Software is furnished to do so,
12 * subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included in all
15 * copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
19 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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21 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
24 * https://www.FreeRTOS.org
25 * https://github.com/FreeRTOS
29 /* Standard includes. */
32 /* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
33 * all the API functions to use the MPU wrappers. That should only be done when
34 * task.h is included from an application file. */
35 #define MPU_WRAPPERS_INCLUDED_FROM_API_FILE
42 #if ( INCLUDE_xTimerPendFunctionCall == 1 ) && ( configUSE_TIMERS == 0 )
43 #error configUSE_TIMERS must be set to 1 to make the xTimerPendFunctionCall() function available.
46 /* Lint e9021, e961 and e750 are suppressed as a MISRA exception justified
47 * because the MPU ports require MPU_WRAPPERS_INCLUDED_FROM_API_FILE to be defined
48 * for the header files above, but not in this file, in order to generate the
49 * correct privileged Vs unprivileged linkage and placement. */
50 #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE /*lint !e9021 !e961 !e750. */
53 /* This entire source file will be skipped if the application is not configured
54 * to include software timer functionality. This #if is closed at the very bottom
55 * of this file. If you want to include software timer functionality then ensure
56 * configUSE_TIMERS is set to 1 in FreeRTOSConfig.h. */
57 #if ( configUSE_TIMERS == 1 )
59 /* Misc definitions. */
60 #define tmrNO_DELAY ( ( TickType_t ) 0U )
61 #define tmrMAX_TIME_BEFORE_OVERFLOW ( ( TickType_t ) -1 )
63 /* The name assigned to the timer service task. This can be overridden by
64 * defining trmTIMER_SERVICE_TASK_NAME in FreeRTOSConfig.h. */
65 #ifndef configTIMER_SERVICE_TASK_NAME
66 #define configTIMER_SERVICE_TASK_NAME "Tmr Svc"
69 /* Bit definitions used in the ucStatus member of a timer structure. */
70 #define tmrSTATUS_IS_ACTIVE ( ( uint8_t ) 0x01 )
71 #define tmrSTATUS_IS_STATICALLY_ALLOCATED ( ( uint8_t ) 0x02 )
72 #define tmrSTATUS_IS_AUTORELOAD ( ( uint8_t ) 0x04 )
74 /* The definition of the timers themselves. */
75 typedef struct tmrTimerControl /* The old naming convention is used to prevent breaking kernel aware debuggers. */
77 const char * pcTimerName; /**< Text name. This is not used by the kernel, it is included simply to make debugging easier. */ /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
78 ListItem_t xTimerListItem; /**< Standard linked list item as used by all kernel features for event management. */
79 TickType_t xTimerPeriodInTicks; /**< How quickly and often the timer expires. */
80 void * pvTimerID; /**< An ID to identify the timer. This allows the timer to be identified when the same callback is used for multiple timers. */
81 portTIMER_CALLBACK_ATTRIBUTE TimerCallbackFunction_t pxCallbackFunction; /**< The function that will be called when the timer expires. */
82 #if ( configUSE_TRACE_FACILITY == 1 )
83 UBaseType_t uxTimerNumber; /**< An ID assigned by trace tools such as FreeRTOS+Trace */
85 uint8_t ucStatus; /**< Holds bits to say if the timer was statically allocated or not, and if it is active or not. */
88 /* The old xTIMER name is maintained above then typedefed to the new Timer_t
89 * name below to enable the use of older kernel aware debuggers. */
90 typedef xTIMER Timer_t;
92 /* The definition of messages that can be sent and received on the timer queue.
93 * Two types of message can be queued - messages that manipulate a software timer,
94 * and messages that request the execution of a non-timer related callback. The
95 * two message types are defined in two separate structures, xTimerParametersType
96 * and xCallbackParametersType respectively. */
97 typedef struct tmrTimerParameters
99 TickType_t xMessageValue; /**< An optional value used by a subset of commands, for example, when changing the period of a timer. */
100 Timer_t * pxTimer; /**< The timer to which the command will be applied. */
104 typedef struct tmrCallbackParameters
106 portTIMER_CALLBACK_ATTRIBUTE
107 PendedFunction_t pxCallbackFunction; /* << The callback function to execute. */
108 void * pvParameter1; /* << The value that will be used as the callback functions first parameter. */
109 uint32_t ulParameter2; /* << The value that will be used as the callback functions second parameter. */
110 } CallbackParameters_t;
112 /* The structure that contains the two message types, along with an identifier
113 * that is used to determine which message type is valid. */
114 typedef struct tmrTimerQueueMessage
116 BaseType_t xMessageID; /**< The command being sent to the timer service task. */
119 TimerParameter_t xTimerParameters;
121 /* Don't include xCallbackParameters if it is not going to be used as
122 * it makes the structure (and therefore the timer queue) larger. */
123 #if ( INCLUDE_xTimerPendFunctionCall == 1 )
124 CallbackParameters_t xCallbackParameters;
125 #endif /* INCLUDE_xTimerPendFunctionCall */
127 } DaemonTaskMessage_t;
129 /*lint -save -e956 A manual analysis and inspection has been used to determine
130 * which static variables must be declared volatile. */
132 /* The list in which active timers are stored. Timers are referenced in expire
133 * time order, with the nearest expiry time at the front of the list. Only the
134 * timer service task is allowed to access these lists.
135 * xActiveTimerList1 and xActiveTimerList2 could be at function scope but that
136 * breaks some kernel aware debuggers, and debuggers that reply on removing the
137 * static qualifier. */
138 PRIVILEGED_DATA static List_t xActiveTimerList1;
139 PRIVILEGED_DATA static List_t xActiveTimerList2;
140 PRIVILEGED_DATA static List_t * pxCurrentTimerList;
141 PRIVILEGED_DATA static List_t * pxOverflowTimerList;
143 /* A queue that is used to send commands to the timer service task. */
144 PRIVILEGED_DATA static QueueHandle_t xTimerQueue = NULL;
145 PRIVILEGED_DATA static TaskHandle_t xTimerTaskHandle = NULL;
149 /*-----------------------------------------------------------*/
152 * Initialise the infrastructure used by the timer service task if it has not
153 * been initialised already.
155 static void prvCheckForValidListAndQueue( void ) PRIVILEGED_FUNCTION;
158 * The timer service task (daemon). Timer functionality is controlled by this
159 * task. Other tasks communicate with the timer service task using the
162 static portTASK_FUNCTION_PROTO( prvTimerTask, pvParameters ) PRIVILEGED_FUNCTION;
165 * Called by the timer service task to interpret and process a command it
166 * received on the timer queue.
168 static void prvProcessReceivedCommands( void ) PRIVILEGED_FUNCTION;
171 * Insert the timer into either xActiveTimerList1, or xActiveTimerList2,
172 * depending on if the expire time causes a timer counter overflow.
174 static BaseType_t prvInsertTimerInActiveList( Timer_t * const pxTimer,
175 const TickType_t xNextExpiryTime,
176 const TickType_t xTimeNow,
177 const TickType_t xCommandTime ) PRIVILEGED_FUNCTION;
180 * Reload the specified auto-reload timer. If the reloading is backlogged,
181 * clear the backlog, calling the callback for each additional reload. When
182 * this function returns, the next expiry time is after xTimeNow.
184 static void prvReloadTimer( Timer_t * const pxTimer,
185 TickType_t xExpiredTime,
186 const TickType_t xTimeNow ) PRIVILEGED_FUNCTION;
189 * An active timer has reached its expire time. Reload the timer if it is an
190 * auto-reload timer, then call its callback.
192 static void prvProcessExpiredTimer( const TickType_t xNextExpireTime,
193 const TickType_t xTimeNow ) PRIVILEGED_FUNCTION;
196 * The tick count has overflowed. Switch the timer lists after ensuring the
197 * current timer list does not still reference some timers.
199 static void prvSwitchTimerLists( void ) PRIVILEGED_FUNCTION;
202 * Obtain the current tick count, setting *pxTimerListsWereSwitched to pdTRUE
203 * if a tick count overflow occurred since prvSampleTimeNow() was last called.
205 static TickType_t prvSampleTimeNow( BaseType_t * const pxTimerListsWereSwitched ) PRIVILEGED_FUNCTION;
208 * If the timer list contains any active timers then return the expire time of
209 * the timer that will expire first and set *pxListWasEmpty to false. If the
210 * timer list does not contain any timers then return 0 and set *pxListWasEmpty
213 static TickType_t prvGetNextExpireTime( BaseType_t * const pxListWasEmpty ) PRIVILEGED_FUNCTION;
216 * If a timer has expired, process it. Otherwise, block the timer service task
217 * until either a timer does expire or a command is received.
219 static void prvProcessTimerOrBlockTask( const TickType_t xNextExpireTime,
220 BaseType_t xListWasEmpty ) PRIVILEGED_FUNCTION;
223 * Called after a Timer_t structure has been allocated either statically or
224 * dynamically to fill in the structure's members.
226 static void prvInitialiseNewTimer( const char * const pcTimerName, /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
227 const TickType_t xTimerPeriodInTicks,
228 const BaseType_t xAutoReload,
229 void * const pvTimerID,
230 TimerCallbackFunction_t pxCallbackFunction,
231 Timer_t * pxNewTimer ) PRIVILEGED_FUNCTION;
232 /*-----------------------------------------------------------*/
234 BaseType_t xTimerCreateTimerTask( void )
236 BaseType_t xReturn = pdFAIL;
238 /* This function is called when the scheduler is started if
239 * configUSE_TIMERS is set to 1. Check that the infrastructure used by the
240 * timer service task has been created/initialised. If timers have already
241 * been created then the initialisation will already have been performed. */
242 prvCheckForValidListAndQueue();
244 if( xTimerQueue != NULL )
246 #if ( configSUPPORT_STATIC_ALLOCATION == 1 )
248 StaticTask_t * pxTimerTaskTCBBuffer = NULL;
249 StackType_t * pxTimerTaskStackBuffer = NULL;
250 uint32_t ulTimerTaskStackSize;
252 vApplicationGetTimerTaskMemory( &pxTimerTaskTCBBuffer, &pxTimerTaskStackBuffer, &ulTimerTaskStackSize );
253 xTimerTaskHandle = xTaskCreateStatic( prvTimerTask,
254 configTIMER_SERVICE_TASK_NAME,
255 ulTimerTaskStackSize,
257 ( ( UBaseType_t ) configTIMER_TASK_PRIORITY ) | portPRIVILEGE_BIT,
258 pxTimerTaskStackBuffer,
259 pxTimerTaskTCBBuffer );
261 if( xTimerTaskHandle != NULL )
266 #else /* if ( configSUPPORT_STATIC_ALLOCATION == 1 ) */
268 xReturn = xTaskCreate( prvTimerTask,
269 configTIMER_SERVICE_TASK_NAME,
270 configTIMER_TASK_STACK_DEPTH,
272 ( ( UBaseType_t ) configTIMER_TASK_PRIORITY ) | portPRIVILEGE_BIT,
275 #endif /* configSUPPORT_STATIC_ALLOCATION */
279 mtCOVERAGE_TEST_MARKER();
282 configASSERT( xReturn );
285 /*-----------------------------------------------------------*/
287 #if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
289 TimerHandle_t xTimerCreate( const char * const pcTimerName, /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
290 const TickType_t xTimerPeriodInTicks,
291 const BaseType_t xAutoReload,
292 void * const pvTimerID,
293 TimerCallbackFunction_t pxCallbackFunction )
295 Timer_t * pxNewTimer;
297 pxNewTimer = ( Timer_t * ) pvPortMalloc( sizeof( Timer_t ) ); /*lint !e9087 !e9079 All values returned by pvPortMalloc() have at least the alignment required by the MCU's stack, and the first member of Timer_t is always a pointer to the timer's mame. */
299 if( pxNewTimer != NULL )
301 /* Status is thus far zero as the timer is not created statically
302 * and has not been started. The auto-reload bit may get set in
303 * prvInitialiseNewTimer. */
304 pxNewTimer->ucStatus = 0x00;
305 prvInitialiseNewTimer( pcTimerName, xTimerPeriodInTicks, xAutoReload, pvTimerID, pxCallbackFunction, pxNewTimer );
311 #endif /* configSUPPORT_DYNAMIC_ALLOCATION */
312 /*-----------------------------------------------------------*/
314 #if ( configSUPPORT_STATIC_ALLOCATION == 1 )
316 TimerHandle_t xTimerCreateStatic( const char * const pcTimerName, /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
317 const TickType_t xTimerPeriodInTicks,
318 const BaseType_t xAutoReload,
319 void * const pvTimerID,
320 TimerCallbackFunction_t pxCallbackFunction,
321 StaticTimer_t * pxTimerBuffer )
323 Timer_t * pxNewTimer;
325 #if ( configASSERT_DEFINED == 1 )
327 /* Sanity check that the size of the structure used to declare a
328 * variable of type StaticTimer_t equals the size of the real timer
330 volatile size_t xSize = sizeof( StaticTimer_t );
331 configASSERT( xSize == sizeof( Timer_t ) );
332 ( void ) xSize; /* Keeps lint quiet when configASSERT() is not defined. */
334 #endif /* configASSERT_DEFINED */
336 /* A pointer to a StaticTimer_t structure MUST be provided, use it. */
337 configASSERT( pxTimerBuffer );
338 pxNewTimer = ( Timer_t * ) pxTimerBuffer; /*lint !e740 !e9087 StaticTimer_t is a pointer to a Timer_t, so guaranteed to be aligned and sized correctly (checked by an assert()), so this is safe. */
340 if( pxNewTimer != NULL )
342 /* Timers can be created statically or dynamically so note this
343 * timer was created statically in case it is later deleted. The
344 * auto-reload bit may get set in prvInitialiseNewTimer(). */
345 pxNewTimer->ucStatus = tmrSTATUS_IS_STATICALLY_ALLOCATED;
347 prvInitialiseNewTimer( pcTimerName, xTimerPeriodInTicks, xAutoReload, pvTimerID, pxCallbackFunction, pxNewTimer );
353 #endif /* configSUPPORT_STATIC_ALLOCATION */
354 /*-----------------------------------------------------------*/
356 static void prvInitialiseNewTimer( const char * const pcTimerName, /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
357 const TickType_t xTimerPeriodInTicks,
358 const BaseType_t xAutoReload,
359 void * const pvTimerID,
360 TimerCallbackFunction_t pxCallbackFunction,
361 Timer_t * pxNewTimer )
363 /* 0 is not a valid value for xTimerPeriodInTicks. */
364 configASSERT( ( xTimerPeriodInTicks > 0 ) );
366 /* Ensure the infrastructure used by the timer service task has been
367 * created/initialised. */
368 prvCheckForValidListAndQueue();
370 /* Initialise the timer structure members using the function
372 pxNewTimer->pcTimerName = pcTimerName;
373 pxNewTimer->xTimerPeriodInTicks = xTimerPeriodInTicks;
374 pxNewTimer->pvTimerID = pvTimerID;
375 pxNewTimer->pxCallbackFunction = pxCallbackFunction;
376 vListInitialiseItem( &( pxNewTimer->xTimerListItem ) );
378 if( xAutoReload != pdFALSE )
380 pxNewTimer->ucStatus |= tmrSTATUS_IS_AUTORELOAD;
383 traceTIMER_CREATE( pxNewTimer );
385 /*-----------------------------------------------------------*/
387 BaseType_t xTimerGenericCommandFromTask( TimerHandle_t xTimer,
388 const BaseType_t xCommandID,
389 const TickType_t xOptionalValue,
390 BaseType_t * const pxHigherPriorityTaskWoken,
391 const TickType_t xTicksToWait )
393 BaseType_t xReturn = pdFAIL;
394 DaemonTaskMessage_t xMessage;
396 ( void ) pxHigherPriorityTaskWoken;
398 configASSERT( xTimer );
400 /* Send a message to the timer service task to perform a particular action
401 * on a particular timer definition. */
402 if( xTimerQueue != NULL )
404 /* Send a command to the timer service task to start the xTimer timer. */
405 xMessage.xMessageID = xCommandID;
406 xMessage.u.xTimerParameters.xMessageValue = xOptionalValue;
407 xMessage.u.xTimerParameters.pxTimer = xTimer;
409 configASSERT( xCommandID < tmrFIRST_FROM_ISR_COMMAND );
411 if( xCommandID < tmrFIRST_FROM_ISR_COMMAND )
413 if( xTaskGetSchedulerState() == taskSCHEDULER_RUNNING )
415 xReturn = xQueueSendToBack( xTimerQueue, &xMessage, xTicksToWait );
419 xReturn = xQueueSendToBack( xTimerQueue, &xMessage, tmrNO_DELAY );
423 traceTIMER_COMMAND_SEND( xTimer, xCommandID, xOptionalValue, xReturn );
427 mtCOVERAGE_TEST_MARKER();
432 /*-----------------------------------------------------------*/
434 BaseType_t xTimerGenericCommandFromISR( TimerHandle_t xTimer,
435 const BaseType_t xCommandID,
436 const TickType_t xOptionalValue,
437 BaseType_t * const pxHigherPriorityTaskWoken,
438 const TickType_t xTicksToWait )
440 BaseType_t xReturn = pdFAIL;
441 DaemonTaskMessage_t xMessage;
443 ( void ) xTicksToWait;
445 configASSERT( xTimer );
447 /* Send a message to the timer service task to perform a particular action
448 * on a particular timer definition. */
449 if( xTimerQueue != NULL )
451 /* Send a command to the timer service task to start the xTimer timer. */
452 xMessage.xMessageID = xCommandID;
453 xMessage.u.xTimerParameters.xMessageValue = xOptionalValue;
454 xMessage.u.xTimerParameters.pxTimer = xTimer;
456 configASSERT( xCommandID >= tmrFIRST_FROM_ISR_COMMAND );
458 if( xCommandID >= tmrFIRST_FROM_ISR_COMMAND )
460 xReturn = xQueueSendToBackFromISR( xTimerQueue, &xMessage, pxHigherPriorityTaskWoken );
463 traceTIMER_COMMAND_SEND( xTimer, xCommandID, xOptionalValue, xReturn );
467 mtCOVERAGE_TEST_MARKER();
472 /*-----------------------------------------------------------*/
474 TaskHandle_t xTimerGetTimerDaemonTaskHandle( void )
476 /* If xTimerGetTimerDaemonTaskHandle() is called before the scheduler has been
477 * started, then xTimerTaskHandle will be NULL. */
478 configASSERT( ( xTimerTaskHandle != NULL ) );
479 return xTimerTaskHandle;
481 /*-----------------------------------------------------------*/
483 TickType_t xTimerGetPeriod( TimerHandle_t xTimer )
485 Timer_t * pxTimer = xTimer;
487 configASSERT( xTimer );
488 return pxTimer->xTimerPeriodInTicks;
490 /*-----------------------------------------------------------*/
492 void vTimerSetReloadMode( TimerHandle_t xTimer,
493 const BaseType_t xAutoReload )
495 Timer_t * pxTimer = xTimer;
497 configASSERT( xTimer );
498 taskENTER_CRITICAL();
500 if( xAutoReload != pdFALSE )
502 pxTimer->ucStatus |= tmrSTATUS_IS_AUTORELOAD;
506 pxTimer->ucStatus &= ( ( uint8_t ) ~tmrSTATUS_IS_AUTORELOAD );
511 /*-----------------------------------------------------------*/
513 BaseType_t xTimerGetReloadMode( TimerHandle_t xTimer )
515 Timer_t * pxTimer = xTimer;
518 configASSERT( xTimer );
519 taskENTER_CRITICAL();
521 if( ( pxTimer->ucStatus & tmrSTATUS_IS_AUTORELOAD ) == 0 )
523 /* Not an auto-reload timer. */
528 /* Is an auto-reload timer. */
537 UBaseType_t uxTimerGetReloadMode( TimerHandle_t xTimer )
539 return ( UBaseType_t ) xTimerGetReloadMode( xTimer );
541 /*-----------------------------------------------------------*/
543 TickType_t xTimerGetExpiryTime( TimerHandle_t xTimer )
545 Timer_t * pxTimer = xTimer;
548 configASSERT( xTimer );
549 xReturn = listGET_LIST_ITEM_VALUE( &( pxTimer->xTimerListItem ) );
552 /*-----------------------------------------------------------*/
554 #if ( configSUPPORT_STATIC_ALLOCATION == 1 )
555 BaseType_t xTimerGetStaticBuffer( TimerHandle_t xTimer,
556 StaticTimer_t ** ppxTimerBuffer )
559 Timer_t * pxTimer = xTimer;
561 configASSERT( ppxTimerBuffer != NULL );
563 if( ( pxTimer->ucStatus & tmrSTATUS_IS_STATICALLY_ALLOCATED ) != 0 )
565 *ppxTimerBuffer = ( StaticTimer_t * ) pxTimer;
575 #endif /* configSUPPORT_STATIC_ALLOCATION */
576 /*-----------------------------------------------------------*/
578 const char * pcTimerGetName( TimerHandle_t xTimer ) /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
580 Timer_t * pxTimer = xTimer;
582 configASSERT( xTimer );
583 return pxTimer->pcTimerName;
585 /*-----------------------------------------------------------*/
587 static void prvReloadTimer( Timer_t * const pxTimer,
588 TickType_t xExpiredTime,
589 const TickType_t xTimeNow )
591 /* Insert the timer into the appropriate list for the next expiry time.
592 * If the next expiry time has already passed, advance the expiry time,
593 * call the callback function, and try again. */
594 while( prvInsertTimerInActiveList( pxTimer, ( xExpiredTime + pxTimer->xTimerPeriodInTicks ), xTimeNow, xExpiredTime ) != pdFALSE )
596 /* Advance the expiry time. */
597 xExpiredTime += pxTimer->xTimerPeriodInTicks;
599 /* Call the timer callback. */
600 traceTIMER_EXPIRED( pxTimer );
601 pxTimer->pxCallbackFunction( ( TimerHandle_t ) pxTimer );
604 /*-----------------------------------------------------------*/
606 static void prvProcessExpiredTimer( const TickType_t xNextExpireTime,
607 const TickType_t xTimeNow )
609 Timer_t * const pxTimer = ( Timer_t * ) listGET_OWNER_OF_HEAD_ENTRY( pxCurrentTimerList ); /*lint !e9087 !e9079 void * is used as this macro is used with tasks and co-routines too. Alignment is known to be fine as the type of the pointer stored and retrieved is the same. */
611 /* Remove the timer from the list of active timers. A check has already
612 * been performed to ensure the list is not empty. */
614 ( void ) uxListRemove( &( pxTimer->xTimerListItem ) );
616 /* If the timer is an auto-reload timer then calculate the next
617 * expiry time and re-insert the timer in the list of active timers. */
618 if( ( pxTimer->ucStatus & tmrSTATUS_IS_AUTORELOAD ) != 0 )
620 prvReloadTimer( pxTimer, xNextExpireTime, xTimeNow );
624 pxTimer->ucStatus &= ( ( uint8_t ) ~tmrSTATUS_IS_ACTIVE );
627 /* Call the timer callback. */
628 traceTIMER_EXPIRED( pxTimer );
629 pxTimer->pxCallbackFunction( ( TimerHandle_t ) pxTimer );
631 /*-----------------------------------------------------------*/
633 static portTASK_FUNCTION( prvTimerTask, pvParameters )
635 TickType_t xNextExpireTime;
636 BaseType_t xListWasEmpty;
638 /* Just to avoid compiler warnings. */
639 ( void ) pvParameters;
641 #if ( configUSE_DAEMON_TASK_STARTUP_HOOK == 1 )
643 /* Allow the application writer to execute some code in the context of
644 * this task at the point the task starts executing. This is useful if the
645 * application includes initialisation code that would benefit from
646 * executing after the scheduler has been started. */
647 vApplicationDaemonTaskStartupHook();
649 #endif /* configUSE_DAEMON_TASK_STARTUP_HOOK */
653 /* Query the timers list to see if it contains any timers, and if so,
654 * obtain the time at which the next timer will expire. */
655 xNextExpireTime = prvGetNextExpireTime( &xListWasEmpty );
657 /* If a timer has expired, process it. Otherwise, block this task
658 * until either a timer does expire, or a command is received. */
659 prvProcessTimerOrBlockTask( xNextExpireTime, xListWasEmpty );
661 /* Empty the command queue. */
662 prvProcessReceivedCommands();
665 /*-----------------------------------------------------------*/
667 static void prvProcessTimerOrBlockTask( const TickType_t xNextExpireTime,
668 BaseType_t xListWasEmpty )
671 BaseType_t xTimerListsWereSwitched;
675 /* Obtain the time now to make an assessment as to whether the timer
676 * has expired or not. If obtaining the time causes the lists to switch
677 * then don't process this timer as any timers that remained in the list
678 * when the lists were switched will have been processed within the
679 * prvSampleTimeNow() function. */
680 xTimeNow = prvSampleTimeNow( &xTimerListsWereSwitched );
682 if( xTimerListsWereSwitched == pdFALSE )
684 /* The tick count has not overflowed, has the timer expired? */
685 if( ( xListWasEmpty == pdFALSE ) && ( xNextExpireTime <= xTimeNow ) )
687 ( void ) xTaskResumeAll();
688 prvProcessExpiredTimer( xNextExpireTime, xTimeNow );
692 /* The tick count has not overflowed, and the next expire
693 * time has not been reached yet. This task should therefore
694 * block to wait for the next expire time or a command to be
695 * received - whichever comes first. The following line cannot
696 * be reached unless xNextExpireTime > xTimeNow, except in the
697 * case when the current timer list is empty. */
698 if( xListWasEmpty != pdFALSE )
700 /* The current timer list is empty - is the overflow list
702 xListWasEmpty = listLIST_IS_EMPTY( pxOverflowTimerList );
705 vQueueWaitForMessageRestricted( xTimerQueue, ( xNextExpireTime - xTimeNow ), xListWasEmpty );
707 if( xTaskResumeAll() == pdFALSE )
709 /* Yield to wait for either a command to arrive, or the
710 * block time to expire. If a command arrived between the
711 * critical section being exited and this yield then the yield
712 * will not cause the task to block. */
713 #if ( configNUMBER_OF_CORES == 1 )
715 portYIELD_WITHIN_API();
717 #else /* #if ( configNUMBER_OF_CORES == 1 ) */
719 vTaskYieldWithinAPI();
721 #endif /* #if ( configNUMBER_OF_CORES == 1 ) */
725 mtCOVERAGE_TEST_MARKER();
731 ( void ) xTaskResumeAll();
735 /*-----------------------------------------------------------*/
737 static TickType_t prvGetNextExpireTime( BaseType_t * const pxListWasEmpty )
739 TickType_t xNextExpireTime;
741 /* Timers are listed in expiry time order, with the head of the list
742 * referencing the task that will expire first. Obtain the time at which
743 * the timer with the nearest expiry time will expire. If there are no
744 * active timers then just set the next expire time to 0. That will cause
745 * this task to unblock when the tick count overflows, at which point the
746 * timer lists will be switched and the next expiry time can be
748 *pxListWasEmpty = listLIST_IS_EMPTY( pxCurrentTimerList );
750 if( *pxListWasEmpty == pdFALSE )
752 xNextExpireTime = listGET_ITEM_VALUE_OF_HEAD_ENTRY( pxCurrentTimerList );
756 /* Ensure the task unblocks when the tick count rolls over. */
757 xNextExpireTime = ( TickType_t ) 0U;
760 return xNextExpireTime;
762 /*-----------------------------------------------------------*/
764 static TickType_t prvSampleTimeNow( BaseType_t * const pxTimerListsWereSwitched )
767 PRIVILEGED_DATA static TickType_t xLastTime = ( TickType_t ) 0U; /*lint !e956 Variable is only accessible to one task. */
769 xTimeNow = xTaskGetTickCount();
771 if( xTimeNow < xLastTime )
773 prvSwitchTimerLists();
774 *pxTimerListsWereSwitched = pdTRUE;
778 *pxTimerListsWereSwitched = pdFALSE;
781 xLastTime = xTimeNow;
785 /*-----------------------------------------------------------*/
787 static BaseType_t prvInsertTimerInActiveList( Timer_t * const pxTimer,
788 const TickType_t xNextExpiryTime,
789 const TickType_t xTimeNow,
790 const TickType_t xCommandTime )
792 BaseType_t xProcessTimerNow = pdFALSE;
794 listSET_LIST_ITEM_VALUE( &( pxTimer->xTimerListItem ), xNextExpiryTime );
795 listSET_LIST_ITEM_OWNER( &( pxTimer->xTimerListItem ), pxTimer );
797 if( xNextExpiryTime <= xTimeNow )
799 /* Has the expiry time elapsed between the command to start/reset a
800 * timer was issued, and the time the command was processed? */
801 if( ( ( TickType_t ) ( xTimeNow - xCommandTime ) ) >= pxTimer->xTimerPeriodInTicks ) /*lint !e961 MISRA exception as the casts are only redundant for some ports. */
803 /* The time between a command being issued and the command being
804 * processed actually exceeds the timers period. */
805 xProcessTimerNow = pdTRUE;
809 vListInsert( pxOverflowTimerList, &( pxTimer->xTimerListItem ) );
814 if( ( xTimeNow < xCommandTime ) && ( xNextExpiryTime >= xCommandTime ) )
816 /* If, since the command was issued, the tick count has overflowed
817 * but the expiry time has not, then the timer must have already passed
818 * its expiry time and should be processed immediately. */
819 xProcessTimerNow = pdTRUE;
823 vListInsert( pxCurrentTimerList, &( pxTimer->xTimerListItem ) );
827 return xProcessTimerNow;
829 /*-----------------------------------------------------------*/
831 static void prvProcessReceivedCommands( void )
833 DaemonTaskMessage_t xMessage;
835 BaseType_t xTimerListsWereSwitched;
838 while( xQueueReceive( xTimerQueue, &xMessage, tmrNO_DELAY ) != pdFAIL ) /*lint !e603 xMessage does not have to be initialised as it is passed out, not in, and it is not used unless xQueueReceive() returns pdTRUE. */
840 #if ( INCLUDE_xTimerPendFunctionCall == 1 )
842 /* Negative commands are pended function calls rather than timer
844 if( xMessage.xMessageID < ( BaseType_t ) 0 )
846 const CallbackParameters_t * const pxCallback = &( xMessage.u.xCallbackParameters );
848 /* The timer uses the xCallbackParameters member to request a
849 * callback be executed. Check the callback is not NULL. */
850 configASSERT( pxCallback );
852 /* Call the function. */
853 pxCallback->pxCallbackFunction( pxCallback->pvParameter1, pxCallback->ulParameter2 );
857 mtCOVERAGE_TEST_MARKER();
860 #endif /* INCLUDE_xTimerPendFunctionCall */
862 /* Commands that are positive are timer commands rather than pended
864 if( xMessage.xMessageID >= ( BaseType_t ) 0 )
866 /* The messages uses the xTimerParameters member to work on a
868 pxTimer = xMessage.u.xTimerParameters.pxTimer;
870 if( listIS_CONTAINED_WITHIN( NULL, &( pxTimer->xTimerListItem ) ) == pdFALSE ) /*lint !e961. The cast is only redundant when NULL is passed into the macro. */
872 /* The timer is in a list, remove it. */
873 ( void ) uxListRemove( &( pxTimer->xTimerListItem ) );
877 mtCOVERAGE_TEST_MARKER();
880 traceTIMER_COMMAND_RECEIVED( pxTimer, xMessage.xMessageID, xMessage.u.xTimerParameters.xMessageValue );
882 /* In this case the xTimerListsWereSwitched parameter is not used, but
883 * it must be present in the function call. prvSampleTimeNow() must be
884 * called after the message is received from xTimerQueue so there is no
885 * possibility of a higher priority task adding a message to the message
886 * queue with a time that is ahead of the timer daemon task (because it
887 * pre-empted the timer daemon task after the xTimeNow value was set). */
888 xTimeNow = prvSampleTimeNow( &xTimerListsWereSwitched );
890 switch( xMessage.xMessageID )
892 case tmrCOMMAND_START:
893 case tmrCOMMAND_START_FROM_ISR:
894 case tmrCOMMAND_RESET:
895 case tmrCOMMAND_RESET_FROM_ISR:
896 /* Start or restart a timer. */
897 pxTimer->ucStatus |= tmrSTATUS_IS_ACTIVE;
899 if( prvInsertTimerInActiveList( pxTimer, xMessage.u.xTimerParameters.xMessageValue + pxTimer->xTimerPeriodInTicks, xTimeNow, xMessage.u.xTimerParameters.xMessageValue ) != pdFALSE )
901 /* The timer expired before it was added to the active
902 * timer list. Process it now. */
903 if( ( pxTimer->ucStatus & tmrSTATUS_IS_AUTORELOAD ) != 0 )
905 prvReloadTimer( pxTimer, xMessage.u.xTimerParameters.xMessageValue + pxTimer->xTimerPeriodInTicks, xTimeNow );
909 pxTimer->ucStatus &= ( ( uint8_t ) ~tmrSTATUS_IS_ACTIVE );
912 /* Call the timer callback. */
913 traceTIMER_EXPIRED( pxTimer );
914 pxTimer->pxCallbackFunction( ( TimerHandle_t ) pxTimer );
918 mtCOVERAGE_TEST_MARKER();
923 case tmrCOMMAND_STOP:
924 case tmrCOMMAND_STOP_FROM_ISR:
925 /* The timer has already been removed from the active list. */
926 pxTimer->ucStatus &= ( ( uint8_t ) ~tmrSTATUS_IS_ACTIVE );
929 case tmrCOMMAND_CHANGE_PERIOD:
930 case tmrCOMMAND_CHANGE_PERIOD_FROM_ISR:
931 pxTimer->ucStatus |= tmrSTATUS_IS_ACTIVE;
932 pxTimer->xTimerPeriodInTicks = xMessage.u.xTimerParameters.xMessageValue;
933 configASSERT( ( pxTimer->xTimerPeriodInTicks > 0 ) );
935 /* The new period does not really have a reference, and can
936 * be longer or shorter than the old one. The command time is
937 * therefore set to the current time, and as the period cannot
938 * be zero the next expiry time can only be in the future,
939 * meaning (unlike for the xTimerStart() case above) there is
940 * no fail case that needs to be handled here. */
941 ( void ) prvInsertTimerInActiveList( pxTimer, ( xTimeNow + pxTimer->xTimerPeriodInTicks ), xTimeNow, xTimeNow );
944 case tmrCOMMAND_DELETE:
945 #if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
947 /* The timer has already been removed from the active list,
948 * just free up the memory if the memory was dynamically
950 if( ( pxTimer->ucStatus & tmrSTATUS_IS_STATICALLY_ALLOCATED ) == ( uint8_t ) 0 )
952 vPortFree( pxTimer );
956 pxTimer->ucStatus &= ( ( uint8_t ) ~tmrSTATUS_IS_ACTIVE );
959 #else /* if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 ) */
961 /* If dynamic allocation is not enabled, the memory
962 * could not have been dynamically allocated. So there is
963 * no need to free the memory - just mark the timer as
965 pxTimer->ucStatus &= ( ( uint8_t ) ~tmrSTATUS_IS_ACTIVE );
967 #endif /* configSUPPORT_DYNAMIC_ALLOCATION */
971 /* Don't expect to get here. */
977 /*-----------------------------------------------------------*/
979 static void prvSwitchTimerLists( void )
981 TickType_t xNextExpireTime;
984 /* The tick count has overflowed. The timer lists must be switched.
985 * If there are any timers still referenced from the current timer list
986 * then they must have expired and should be processed before the lists
988 while( listLIST_IS_EMPTY( pxCurrentTimerList ) == pdFALSE )
990 xNextExpireTime = listGET_ITEM_VALUE_OF_HEAD_ENTRY( pxCurrentTimerList );
992 /* Process the expired timer. For auto-reload timers, be careful to
993 * process only expirations that occur on the current list. Further
994 * expirations must wait until after the lists are switched. */
995 prvProcessExpiredTimer( xNextExpireTime, tmrMAX_TIME_BEFORE_OVERFLOW );
998 pxTemp = pxCurrentTimerList;
999 pxCurrentTimerList = pxOverflowTimerList;
1000 pxOverflowTimerList = pxTemp;
1002 /*-----------------------------------------------------------*/
1004 static void prvCheckForValidListAndQueue( void )
1006 /* Check that the list from which active timers are referenced, and the
1007 * queue used to communicate with the timer service, have been
1009 taskENTER_CRITICAL();
1011 if( xTimerQueue == NULL )
1013 vListInitialise( &xActiveTimerList1 );
1014 vListInitialise( &xActiveTimerList2 );
1015 pxCurrentTimerList = &xActiveTimerList1;
1016 pxOverflowTimerList = &xActiveTimerList2;
1018 #if ( configSUPPORT_STATIC_ALLOCATION == 1 )
1020 /* The timer queue is allocated statically in case
1021 * configSUPPORT_DYNAMIC_ALLOCATION is 0. */
1022 PRIVILEGED_DATA static StaticQueue_t xStaticTimerQueue; /*lint !e956 Ok to declare in this manner to prevent additional conditional compilation guards in other locations. */
1023 PRIVILEGED_DATA static uint8_t ucStaticTimerQueueStorage[ ( size_t ) configTIMER_QUEUE_LENGTH * sizeof( DaemonTaskMessage_t ) ]; /*lint !e956 Ok to declare in this manner to prevent additional conditional compilation guards in other locations. */
1025 xTimerQueue = xQueueCreateStatic( ( UBaseType_t ) configTIMER_QUEUE_LENGTH, ( UBaseType_t ) sizeof( DaemonTaskMessage_t ), &( ucStaticTimerQueueStorage[ 0 ] ), &xStaticTimerQueue );
1029 xTimerQueue = xQueueCreate( ( UBaseType_t ) configTIMER_QUEUE_LENGTH, sizeof( DaemonTaskMessage_t ) );
1031 #endif /* if ( configSUPPORT_STATIC_ALLOCATION == 1 ) */
1033 #if ( configQUEUE_REGISTRY_SIZE > 0 )
1035 if( xTimerQueue != NULL )
1037 vQueueAddToRegistry( xTimerQueue, "TmrQ" );
1041 mtCOVERAGE_TEST_MARKER();
1044 #endif /* configQUEUE_REGISTRY_SIZE */
1048 mtCOVERAGE_TEST_MARKER();
1051 taskEXIT_CRITICAL();
1053 /*-----------------------------------------------------------*/
1055 BaseType_t xTimerIsTimerActive( TimerHandle_t xTimer )
1058 Timer_t * pxTimer = xTimer;
1060 configASSERT( xTimer );
1062 /* Is the timer in the list of active timers? */
1063 taskENTER_CRITICAL();
1065 if( ( pxTimer->ucStatus & tmrSTATUS_IS_ACTIVE ) == 0 )
1074 taskEXIT_CRITICAL();
1077 } /*lint !e818 Can't be pointer to const due to the typedef. */
1078 /*-----------------------------------------------------------*/
1080 void * pvTimerGetTimerID( const TimerHandle_t xTimer )
1082 Timer_t * const pxTimer = xTimer;
1085 configASSERT( xTimer );
1087 taskENTER_CRITICAL();
1089 pvReturn = pxTimer->pvTimerID;
1091 taskEXIT_CRITICAL();
1095 /*-----------------------------------------------------------*/
1097 void vTimerSetTimerID( TimerHandle_t xTimer,
1100 Timer_t * const pxTimer = xTimer;
1102 configASSERT( xTimer );
1104 taskENTER_CRITICAL();
1106 pxTimer->pvTimerID = pvNewID;
1108 taskEXIT_CRITICAL();
1110 /*-----------------------------------------------------------*/
1112 #if ( INCLUDE_xTimerPendFunctionCall == 1 )
1114 BaseType_t xTimerPendFunctionCallFromISR( PendedFunction_t xFunctionToPend,
1115 void * pvParameter1,
1116 uint32_t ulParameter2,
1117 BaseType_t * pxHigherPriorityTaskWoken )
1119 DaemonTaskMessage_t xMessage;
1122 /* Complete the message with the function parameters and post it to the
1124 xMessage.xMessageID = tmrCOMMAND_EXECUTE_CALLBACK_FROM_ISR;
1125 xMessage.u.xCallbackParameters.pxCallbackFunction = xFunctionToPend;
1126 xMessage.u.xCallbackParameters.pvParameter1 = pvParameter1;
1127 xMessage.u.xCallbackParameters.ulParameter2 = ulParameter2;
1129 xReturn = xQueueSendFromISR( xTimerQueue, &xMessage, pxHigherPriorityTaskWoken );
1131 tracePEND_FUNC_CALL_FROM_ISR( xFunctionToPend, pvParameter1, ulParameter2, xReturn );
1136 #endif /* INCLUDE_xTimerPendFunctionCall */
1137 /*-----------------------------------------------------------*/
1139 #if ( INCLUDE_xTimerPendFunctionCall == 1 )
1141 BaseType_t xTimerPendFunctionCall( PendedFunction_t xFunctionToPend,
1142 void * pvParameter1,
1143 uint32_t ulParameter2,
1144 TickType_t xTicksToWait )
1146 DaemonTaskMessage_t xMessage;
1149 /* This function can only be called after a timer has been created or
1150 * after the scheduler has been started because, until then, the timer
1151 * queue does not exist. */
1152 configASSERT( xTimerQueue );
1154 /* Complete the message with the function parameters and post it to the
1156 xMessage.xMessageID = tmrCOMMAND_EXECUTE_CALLBACK;
1157 xMessage.u.xCallbackParameters.pxCallbackFunction = xFunctionToPend;
1158 xMessage.u.xCallbackParameters.pvParameter1 = pvParameter1;
1159 xMessage.u.xCallbackParameters.ulParameter2 = ulParameter2;
1161 xReturn = xQueueSendToBack( xTimerQueue, &xMessage, xTicksToWait );
1163 tracePEND_FUNC_CALL( xFunctionToPend, pvParameter1, ulParameter2, xReturn );
1168 #endif /* INCLUDE_xTimerPendFunctionCall */
1169 /*-----------------------------------------------------------*/
1171 #if ( configUSE_TRACE_FACILITY == 1 )
1173 UBaseType_t uxTimerGetTimerNumber( TimerHandle_t xTimer )
1175 return ( ( Timer_t * ) xTimer )->uxTimerNumber;
1178 #endif /* configUSE_TRACE_FACILITY */
1179 /*-----------------------------------------------------------*/
1181 #if ( configUSE_TRACE_FACILITY == 1 )
1183 void vTimerSetTimerNumber( TimerHandle_t xTimer,
1184 UBaseType_t uxTimerNumber )
1186 ( ( Timer_t * ) xTimer )->uxTimerNumber = uxTimerNumber;
1189 #endif /* configUSE_TRACE_FACILITY */
1190 /*-----------------------------------------------------------*/
1192 /* This entire source file will be skipped if the application is not configured
1193 * to include software timer functionality. If you want to include software timer
1194 * functionality then ensure configUSE_TIMERS is set to 1 in FreeRTOSConfig.h. */
1195 #endif /* configUSE_TIMERS == 1 */