queue.c

freescale k40/k60 freertos-lwip例程

			/* Have we unwound the call count? */
			if( pxMutex->uxRecursiveCallCount == 0 )
			{
				/* Return the mutex.  This will automatically unblock any other
				task that might be waiting to access the mutex. */
				xQueueGenericSend( pxMutex, NULL, queueMUTEX_GIVE_BLOCK_TIME, queueSEND_TO_BACK );
			}

			xReturn = pdPASS;
		}
		else
		{
			/* We cannot give the mutex because we are not the holder. */
			xReturn = pdFAIL;

			traceGIVE_MUTEX_RECURSIVE_FAILED( pxMutex );
		}

		return xReturn;
	}

#endif /* configUSE_RECURSIVE_MUTEXES */
/*-----------------------------------------------------------*/

#if configUSE_RECURSIVE_MUTEXES == 1

	portBASE_TYPE xQueueTakeMutexRecursive( xQueueHandle pxMutex, portTickType xBlockTime )
	{
	portBASE_TYPE xReturn;

		/* Comments regarding mutual exclusion as per those within
		xQueueGiveMutexRecursive(). */

		traceTAKE_MUTEX_RECURSIVE( pxMutex );

		if( pxMutex->pxMutexHolder == xTaskGetCurrentTaskHandle() )
		{
			( pxMutex->uxRecursiveCallCount )++;
			xReturn = pdPASS;
		}
		else
		{
			xReturn = xQueueGenericReceive( pxMutex, NULL, xBlockTime, pdFALSE );

			/* pdPASS will only be returned if we successfully obtained the mutex,
			we may have blocked to reach here. */
			if( xReturn == pdPASS )
			{
				( pxMutex->uxRecursiveCallCount )++;
			}
		}

		return xReturn;
	}

#endif /* configUSE_RECURSIVE_MUTEXES */
/*-----------------------------------------------------------*/

#if configUSE_COUNTING_SEMAPHORES == 1

	xQueueHandle xQueueCreateCountingSemaphore( unsigned portBASE_TYPE uxCountValue, unsigned portBASE_TYPE uxInitialCount )
	{
	xQueueHandle pxHandle;

		pxHandle = xQueueCreate( ( unsigned portBASE_TYPE ) uxCountValue, queueSEMAPHORE_QUEUE_ITEM_LENGTH );

		if( pxHandle != NULL )
		{
			pxHandle->uxMessagesWaiting = uxInitialCount;

			traceCREATE_COUNTING_SEMAPHORE();
		}
		else
		{
			traceCREATE_COUNTING_SEMAPHORE_FAILED();
		}

		return pxHandle;
	}

#endif /* configUSE_COUNTING_SEMAPHORES */
/*-----------------------------------------------------------*/

signed portBASE_TYPE xQueueGenericSend( xQueueHandle pxQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition )
{
signed portBASE_TYPE xEntryTimeSet = pdFALSE;
xTimeOutType xTimeOut;

	/* This function relaxes the coding standard somewhat to allow return
	statements within the function itself.  This is done in the interest
	of execution time efficiency. */
	for( ;; )
	{
		taskENTER_CRITICAL();
		{
			/* Is there room on the queue now?  To be running we must be
			the highest priority task wanting to access the queue. */
			if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )
			{
				traceQUEUE_SEND( pxQueue );
				prvCopyDataToQueue( pxQueue, pvItemToQueue, xCopyPosition );

				/* If there was a task waiting for data to arrive on the
				queue then unblock it now. */
				if( listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) == pdFALSE )
				{
					if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) == pdTRUE )
					{
						/* The unblocked task has a priority higher than
						our own so yield immediately.  Yes it is ok to do
						this from within the critical section - the kernel
						takes care of that. */
						portYIELD_WITHIN_API();
					}
				}

				taskEXIT_CRITICAL();

				/* Return to the original privilege level before exiting the
				function. */
				return pdPASS;
			}
			else
			{
				if( xTicksToWait == ( portTickType ) 0 )
				{
					/* The queue was full and no block time is specified (or
					the block time has expired) so leave now. */
					taskEXIT_CRITICAL();

					/* Return to the original privilege level before exiting
					the function. */
					traceQUEUE_SEND_FAILED( pxQueue );
					return errQUEUE_FULL;
				}
				else if( xEntryTimeSet == pdFALSE )
				{
					/* The queue was full and a block time was specified so
					configure the timeout structure. */
					vTaskSetTimeOutState( &xTimeOut );
					xEntryTimeSet = pdTRUE;
				}
			}
		}
		taskEXIT_CRITICAL();

		/* Interrupts and other tasks can send to and receive from the queue
		now the critical section has been exited. */

		vTaskSuspendAll();
		prvLockQueue( pxQueue );

		/* Update the timeout state to see if it has expired yet. */
		if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )
		{
			if( prvIsQueueFull( pxQueue ) )
			{
				traceBLOCKING_ON_QUEUE_SEND( pxQueue );
				vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToSend ), xTicksToWait );

				/* Unlocking the queue means queue events can effect the
				event list.  It is possible	that interrupts occurring now
				remove this task from the event	list again - but as the
				scheduler is suspended the task will go onto the pending
				ready last instead of the actual ready list. */
				prvUnlockQueue( pxQueue );

				/* Resuming the scheduler will move tasks from the pending
				ready list into the ready list - so it is feasible that this
				task is already in a ready list before it yields - in which
				case the yield will not cause a context switch unless there
				is also a higher priority task in the pending ready list. */
				if( !xTaskResumeAll() )
				{
					portYIELD_WITHIN_API();
				}
			}
			else
			{
				/* Try again. */
				prvUnlockQueue( pxQueue );
				( void ) xTaskResumeAll();
			}
		}
		else
		{
			/* The timeout has expired. */
			prvUnlockQueue( pxQueue );
			( void ) xTaskResumeAll();

			/* Return to the original privilege level before exiting the
			function. */
			traceQUEUE_SEND_FAILED( pxQueue );
			return errQUEUE_FULL;
		}
	}
}
/*-----------------------------------------------------------*/

#if configUSE_ALTERNATIVE_API == 1

	signed portBASE_TYPE xQueueAltGenericSend( xQueueHandle pxQueue, const void * const pvItemToQueue, portTickType xTicksToWait, portBASE_TYPE xCopyPosition )
	{
	signed portBASE_TYPE xEntryTimeSet = pdFALSE;
	xTimeOutType xTimeOut;

		for( ;; )
		{
			taskENTER_CRITICAL();
			{
				/* Is there room on the queue now?  To be running we must be
				the highest priority task wanting to access the queue. */
				if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )
				{
					traceQUEUE_SEND( pxQueue );
					prvCopyDataToQueue( pxQueue, pvItemToQueue, xCopyPosition );

					/* If there was a task waiting for data to arrive on the
					queue then unblock it now. */
					if( listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) == pdFALSE )
					{
						if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) == pdTRUE )
						{
							/* The unblocked task has a priority higher than
							our own so yield immediately. */
							portYIELD_WITHIN_API();
						}
					}

					taskEXIT_CRITICAL();
					return pdPASS;
				}
				else
				{
					if( xTicksToWait == ( portTickType ) 0 )
					{
						taskEXIT_CRITICAL();
						return errQUEUE_FULL;
					}
					else if( xEntryTimeSet == pdFALSE )
					{
						vTaskSetTimeOutState( &xTimeOut );
						xEntryTimeSet = pdTRUE;
					}
				}
			}
			taskEXIT_CRITICAL();

			taskENTER_CRITICAL();
			{
				if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )
				{
					if( prvIsQueueFull( pxQueue ) )
					{
						traceBLOCKING_ON_QUEUE_SEND( pxQueue );
						vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToSend ), xTicksToWait );
						portYIELD_WITHIN_API();
					}
				}
				else
				{
					taskEXIT_CRITICAL();
					traceQUEUE_SEND_FAILED( pxQueue );
					return errQUEUE_FULL;
				}
			}
			taskEXIT_CRITICAL();
		}
	}

#endif /* configUSE_ALTERNATIVE_API */
/*-----------------------------------------------------------*/

#if configUSE_ALTERNATIVE_API == 1

	signed portBASE_TYPE xQueueAltGenericReceive( xQueueHandle pxQueue, void * const pvBuffer, portTickType xTicksToWait, portBASE_TYPE xJustPeeking )
	{
	signed portBASE_TYPE xEntryTimeSet = pdFALSE;
	xTimeOutType xTimeOut;
	signed char *pcOriginalReadPosition;

		for( ;; )
		{
			taskENTER_CRITICAL();
			{
				if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )
				{
					/* Remember our read position in case we are just peeking. */
					pcOriginalReadPosition = pxQueue->pcReadFrom;

					prvCopyDataFromQueue( pxQueue, pvBuffer );

					if( xJustPeeking == pdFALSE )
					{
						traceQUEUE_RECEIVE( pxQueue );

						/* We are actually removing data. */
						--( pxQueue->uxMessagesWaiting );

						#if ( configUSE_MUTEXES == 1 )
						{
							if( pxQueue->uxQueueType == queueQUEUE_IS_MUTEX )
							{
								/* Record the information required to implement
								priority inheritance should it become necessary. */
								pxQueue->pxMutexHolder = xTaskGetCurrentTaskHandle();
							}
						}
						#endif

						if( listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) == pdFALSE )
						{
							if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) == pdTRUE )
							{
								portYIELD_WITHIN_API();
							}
						}
					}
					else
					{
						traceQUEUE_PEEK( pxQueue );

						/* We are not removing the data, so reset our read
						pointer. */
						pxQueue->pcReadFrom = pcOriginalReadPosition;

						/* The data is being left in the queue, so see if there are
						any other tasks waiting for the data. */
						if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )
						{
							/* Tasks that are removed from the event list will get added to
							the pending ready list as the scheduler is still suspended. */
							if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )
							{
								/* The task waiting has a higher priority than this task. */
								portYIELD_WITHIN_API();
							}
						}

					}

					taskEXIT_CRITICAL();
					return pdPASS;
				}
				else
				{
					if( xTicksToWait == ( portTickType ) 0 )
					{
						taskEXIT_CRITICAL();
						traceQUEUE_RECEIVE_FAILED( pxQueue );
						return errQUEUE_EMPTY;
					}
					else if( xEntryTimeSet == pdFALSE )
					{
						vTaskSetTimeOutState( &xTimeOut );
						xEntryTimeSet = pdTRUE;
					}
				}
			}
			taskEXIT_CRITICAL();

			taskENTER_CRITICAL();
			{
				if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )
				{
					if( prvIsQueueEmpty( pxQueue ) )
					{