tasks.c

freescale k40/k60 freertos-uip 例程

		{
			/* Add ourselves to the suspended task list instead of a delayed task
			list to ensure we are not woken by a timing event.  We will block
			indefinitely. */
			vListInsertEnd( ( xList * ) &xSuspendedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
		}
		else
		{
			/* Calculate the time at which the task should be woken if the event does
			not occur.  This may overflow but this doesn't matter. */
			xTimeToWake = xTickCount + xTicksToWait;

			listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );

			if( xTimeToWake < xTickCount )
			{
				/* Wake time has overflowed.  Place this item in the overflow list. */
				vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
			}
			else
			{
				/* The wake time has not overflowed, so we can use the current block list. */
				vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
			}
		}
	}
	#else
	{
			/* Calculate the time at which the task should be woken if the event does
			not occur.  This may overflow but this doesn't matter. */
			xTimeToWake = xTickCount + xTicksToWait;

			listSET_LIST_ITEM_VALUE( &( pxCurrentTCB->xGenericListItem ), xTimeToWake );

			if( xTimeToWake < xTickCount )
			{
				/* Wake time has overflowed.  Place this item in the overflow list. */
				vListInsert( ( xList * ) pxOverflowDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
			}
			else
			{
				/* The wake time has not overflowed, so we can use the current block list. */
				vListInsert( ( xList * ) pxDelayedTaskList, ( xListItem * ) &( pxCurrentTCB->xGenericListItem ) );
			}
	}
	#endif
}
/*-----------------------------------------------------------*/

signed portBASE_TYPE xTaskRemoveFromEventList( const xList * const pxEventList )
{
tskTCB *pxUnblockedTCB;
portBASE_TYPE xReturn;

	/* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED OR THE
	SCHEDULER SUSPENDED.  It can also be called from within an ISR. */

	/* The event list is sorted in priority order, so we can remove the
	first in the list, remove the TCB from the delayed list, and add
	it to the ready list.

	If an event is for a queue that is locked then this function will never
	get called - the lock count on the queue will get modified instead.  This
	means we can always expect exclusive access to the event list here. */
	pxUnblockedTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( pxEventList );
	vListRemove( &( pxUnblockedTCB->xEventListItem ) );

	if( uxSchedulerSuspended == ( unsigned portBASE_TYPE ) pdFALSE )
	{
		vListRemove( &( pxUnblockedTCB->xGenericListItem ) );
		prvAddTaskToReadyQueue( pxUnblockedTCB );
	}
	else
	{
		/* We cannot access the delayed or ready lists, so will hold this
		task pending until the scheduler is resumed. */
		vListInsertEnd( ( xList * ) &( xPendingReadyList ), &( pxUnblockedTCB->xEventListItem ) );
	}

	if( pxUnblockedTCB->uxPriority >= pxCurrentTCB->uxPriority )
	{
		/* Return true if the task removed from the event list has
		a higher priority than the calling task.  This allows
		the calling task to know if it should force a context
		switch now. */
		xReturn = pdTRUE;
	}
	else
	{
		xReturn = pdFALSE;
	}

	return xReturn;
}
/*-----------------------------------------------------------*/

void vTaskSetTimeOutState( xTimeOutType * const pxTimeOut )
{
	pxTimeOut->xOverflowCount = xNumOfOverflows;
	pxTimeOut->xTimeOnEntering = xTickCount;
}
/*-----------------------------------------------------------*/

portBASE_TYPE xTaskCheckForTimeOut( xTimeOutType * const pxTimeOut, portTickType * const pxTicksToWait )
{
portBASE_TYPE xReturn;

	portENTER_CRITICAL();
	{
		#if ( INCLUDE_vTaskSuspend == 1 )
			/* If INCLUDE_vTaskSuspend is set to 1 and the block time specified is
			the maximum block time then the task should block indefinitely, and
			therefore never time out. */
			if( *pxTicksToWait == portMAX_DELAY )
			{
				xReturn = pdFALSE;
			}
			else /* We are not blocking indefinitely, perform the checks below. */
		#endif

		if( ( xNumOfOverflows != pxTimeOut->xOverflowCount ) && ( ( portTickType ) xTickCount >= ( portTickType ) pxTimeOut->xTimeOnEntering ) )
		{
			/* The tick count is greater than the time at which vTaskSetTimeout()
			was called, but has also overflowed since vTaskSetTimeOut() was called.
			It must have wrapped all the way around and gone past us again. This
			passed since vTaskSetTimeout() was called. */
			xReturn = pdTRUE;
		}
		else if( ( ( portTickType ) ( ( portTickType ) xTickCount - ( portTickType ) pxTimeOut->xTimeOnEntering ) ) < ( portTickType ) *pxTicksToWait )
		{
			/* Not a genuine timeout. Adjust parameters for time remaining. */
			*pxTicksToWait -= ( ( portTickType ) xTickCount - ( portTickType ) pxTimeOut->xTimeOnEntering );
			vTaskSetTimeOutState( pxTimeOut );
			xReturn = pdFALSE;
		}
		else
		{
			xReturn = pdTRUE;
		}
	}
	portEXIT_CRITICAL();

	return xReturn;
}
/*-----------------------------------------------------------*/

void vTaskMissedYield( void )
{
	xMissedYield = pdTRUE;
}

/*
 * -----------------------------------------------------------
 * The Idle task.
 * ----------------------------------------------------------
 *
 * The portTASK_FUNCTION() macro is used to allow port/compiler specific
 * language extensions.  The equivalent prototype for this function is:
 *
 * void prvIdleTask( void *pvParameters );
 *
 */
static portTASK_FUNCTION( prvIdleTask, pvParameters )
{
	/* Stop warnings. */
	( void ) pvParameters;

	for( ;; )
	{
		/* See if any tasks have been deleted. */
		prvCheckTasksWaitingTermination();

		#if ( configUSE_PREEMPTION == 0 )
		{
			/* If we are not using preemption we keep forcing a task switch to
			see if any other task has become available.  If we are using
			preemption we don't need to do this as any task becoming available
			will automatically get the processor anyway. */
			taskYIELD();
		}
		#endif

		#if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )
		{
			/* When using preemption tasks of equal priority will be
			timesliced.  If a task that is sharing the idle priority is ready
			to run then the idle task should yield before the end of the
			timeslice.

			A critical region is not required here as we are just reading from
			the list, and an occasional incorrect value will not matter.  If
			the ready list at the idle priority contains more than one task
			then a task other than the idle task is ready to execute. */
			if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )
			{
				taskYIELD();
			}
		}
		#endif

		#if ( configUSE_IDLE_HOOK == 1 )
		{
			extern void vApplicationIdleHook( void );

			/* Call the user defined function from within the idle task.  This
			allows the application designer to add background functionality
			without the overhead of a separate task.
			NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,
			CALL A FUNCTION THAT MIGHT BLOCK. */
			vApplicationIdleHook();
		}
		#endif
	}
} /*lint !e715 pvParameters is not accessed but all task functions require the same prototype. */







/*-----------------------------------------------------------
 * File private functions documented at the top of the file.
 *----------------------------------------------------------*/



static void prvInitialiseTCBVariables( tskTCB *pxTCB, const signed char * const pcName, unsigned portBASE_TYPE uxPriority, const xMemoryRegion * const xRegions, unsigned short usStackDepth )
{
	/* Store the function name in the TCB. */
	#if configMAX_TASK_NAME_LEN > 1
	{
		/* Don't bring strncpy into the build unnecessarily. */
		strncpy( ( char * ) pxTCB->pcTaskName, ( const char * ) pcName, ( unsigned short ) configMAX_TASK_NAME_LEN );
	}
	#endif
	pxTCB->pcTaskName[ ( unsigned short ) configMAX_TASK_NAME_LEN - ( unsigned short ) 1 ] = '\0';

	/* This is used as an array index so must ensure it's not too large.  First
	remove the privilege bit if one is present. */
	if( uxPriority >= configMAX_PRIORITIES )
	{
		uxPriority = configMAX_PRIORITIES - 1;
	}

	pxTCB->uxPriority = uxPriority;
	#if ( configUSE_MUTEXES == 1 )
	{
		pxTCB->uxBasePriority = uxPriority;
	}
	#endif

	vListInitialiseItem( &( pxTCB->xGenericListItem ) );
	vListInitialiseItem( &( pxTCB->xEventListItem ) );

	/* Set the pxTCB as a link back from the xListItem.  This is so we can get
	back to	the containing TCB from a generic item in a list. */
	listSET_LIST_ITEM_OWNER( &( pxTCB->xGenericListItem ), pxTCB );

	/* Event lists are always in priority order. */
	listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), configMAX_PRIORITIES - ( portTickType ) uxPriority );
	listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );

	#if ( portCRITICAL_NESTING_IN_TCB == 1 )
	{
		pxTCB->uxCriticalNesting = ( unsigned portBASE_TYPE ) 0;
	}
	#endif

	#if ( configUSE_APPLICATION_TASK_TAG == 1 )
	{
		pxTCB->pxTaskTag = NULL;
	}
	#endif

	#if ( configGENERATE_RUN_TIME_STATS == 1 )
	{
		pxTCB->ulRunTimeCounter = 0UL;
	}
	#endif

	#if ( portUSING_MPU_WRAPPERS == 1 )
	{
		vPortStoreTaskMPUSettings( &( pxTCB->xMPUSettings ), xRegions, pxTCB->pxStack, usStackDepth );
	}
	#else
	{
		( void ) xRegions;
		( void ) usStackDepth;
	}
	#endif
}
/*-----------------------------------------------------------*/

#if ( portUSING_MPU_WRAPPERS == 1 )

	void vTaskAllocateMPURegions( xTaskHandle xTaskToModify, const xMemoryRegion * const xRegions )
	{
	tskTCB *pxTCB;
	
		if( xTaskToModify == pxCurrentTCB )
		{
			xTaskToModify = NULL;
		}

		/* If null is passed in here then we are deleting ourselves. */
		pxTCB = prvGetTCBFromHandle( xTaskToModify );

        vPortStoreTaskMPUSettings( &( pxTCB->xMPUSettings ), xRegions, NULL, 0 );
	}
	/*-----------------------------------------------------------*/
#endif

static void prvInitialiseTaskLists( void )
{
unsigned portBASE_TYPE uxPriority;

	for( uxPriority = 0; uxPriority < configMAX_PRIORITIES; uxPriority++ )
	{
		vListInitialise( ( xList * ) &( pxReadyTasksLists[ uxPriority ] ) );
	}

	vListInitialise( ( xList * ) &xDelayedTaskList1 );
	vListInitialise( ( xList * ) &xDelayedTaskList2 );
	vListInitialise( ( xList * ) &xPendingReadyList );

	#if ( INCLUDE_vTaskDelete == 1 )
	{
		vListInitialise( ( xList * ) &xTasksWaitingTermination );
	}
	#endif

	#if ( INCLUDE_vTaskSuspend == 1 )
	{
		vListInitialise( ( xList * ) &xSuspendedTaskList );
	}
	#endif

	/* Start with pxDelayedTaskList using list1 and the pxOverflowDelayedTaskList
	using list2. */
	pxDelayedTaskList = &xDelayedTaskList1;
	pxOverflowDelayedTaskList = &xDelayedTaskList2;
}
/*-----------------------------------------------------------*/

static void prvCheckTasksWaitingTermination( void )
{
	#if ( INCLUDE_vTaskDelete == 1 )
	{
		portBASE_TYPE xListIsEmpty;

		/* ucTasksDeleted is used to prevent vTaskSuspendAll() being called
		too often in the idle task. */
		if( uxTasksDeleted > ( unsigned portBASE_TYPE ) 0 )
		{
			vTaskSuspendAll();
				xListIsEmpty = listLIST_IS_EMPTY( &xTasksWaitingTermination );
			xTaskResumeAll();

			if( !xListIsEmpty )
			{
				tskTCB *pxTCB;

				portENTER_CRITICAL();
				{
					pxTCB = ( tskTCB * ) listGET_OWNER_OF_HEAD_ENTRY( ( ( xList * ) &xTasksWaitingTermination ) );
					vListRemove( &( pxTCB->xGenericListItem ) );
					--uxCurrentNumberOfTasks;
					--uxTasksDeleted;
				}
				portEXIT_CRITICAL();

				prvDeleteTCB( pxTCB );
			}
		}
	}
	#endif
}
/*-----------------------------------------------------------*/

static tskTCB *prvAllocateTCBAndStack( unsigned short usStackDepth, portSTACK_TYPE *puxStackBuffer )
{
tskTCB *pxNewTCB;

	/* Allocate space for the TCB.  Where the memory comes from depends on
	the implementation of the port malloc function. */
	pxNewTCB = ( tskTCB * ) pvPortMalloc( sizeof( tskTCB ) );

	if( pxNewTCB != NULL )
	{
		/* Allocate space for the stack used by the task being created.
		The base of the stack memory stored in the TCB so the task can
		be deleted later if required. */
		pxNewTCB->pxStack = ( portSTACK_TYPE * ) pvPortMallocAligned( ( ( ( size_t )usStackDepth ) * sizeof( portSTACK_TYPE ) ), puxStackBuffer );

		if( pxNewTCB->pxStack == NULL )
		{
			/* Could not allocate the stack.  Delete the allocated TCB. */
			vPortFree( pxNewTCB );
			pxNewTCB = NULL;
		}
		else
		{
			/* Just to