queue.c

freescale k40/k60 freertos-uip 例程

						traceBLOCKING_ON_QUEUE_RECEIVE( pxQueue );

						#if ( configUSE_MUTEXES == 1 )
						{
							if( pxQueue->uxQueueType == queueQUEUE_IS_MUTEX )
							{
								portENTER_CRITICAL();
									vTaskPriorityInherit( ( void * ) pxQueue->pxMutexHolder );
								portEXIT_CRITICAL();
							}
						}
						#endif

						vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToReceive ), xTicksToWait );
						portYIELD_WITHIN_API();
					}
				}
				else
				{
					taskEXIT_CRITICAL();
					traceQUEUE_RECEIVE_FAILED( pxQueue );
					return errQUEUE_EMPTY;
				}
			}
			taskEXIT_CRITICAL();
		}
	}


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

signed portBASE_TYPE xQueueGenericSendFromISR( xQueueHandle pxQueue, const void * const pvItemToQueue, signed portBASE_TYPE *pxHigherPriorityTaskWoken, portBASE_TYPE xCopyPosition )
{
signed portBASE_TYPE xReturn;
unsigned portBASE_TYPE uxSavedInterruptStatus;

	/* Similar to xQueueGenericSend, except we don't block if there is no room
	in the queue.  Also we don't directly wake a task that was blocked on a
	queue read, instead we return a flag to say whether a context switch is
	required or not (i.e. has a task with a higher priority than us been woken
	by this	post). */
	uxSavedInterruptStatus = portSET_INTERRUPT_MASK_FROM_ISR();
	{
		if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )
		{
			traceQUEUE_SEND_FROM_ISR( pxQueue );

			prvCopyDataToQueue( pxQueue, pvItemToQueue, xCopyPosition );

			/* If the queue is locked we do not alter the event list.  This will
			be done when the queue is unlocked later. */
			if( pxQueue->xTxLock == queueUNLOCKED )
			{
				if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )
				{
					if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )
					{
						/* The task waiting has a higher priority so record that a
						context	switch is required. */
						*pxHigherPriorityTaskWoken = pdTRUE;
					}
				}
			}
			else
			{
				/* Increment the lock count so the task that unlocks the queue
				knows that data was posted while it was locked. */
				++( pxQueue->xTxLock );
			}

			xReturn = pdPASS;
		}
		else
		{
			traceQUEUE_SEND_FROM_ISR_FAILED( pxQueue );
			xReturn = errQUEUE_FULL;
		}
	}
	portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus );

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

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

	/* 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 data in the queue now?  To be running we must be
			the highest priority task wanting to access the queue. */
			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 )
				{
					/* The queue was empty and no block time is specified (or
					the block time has expired) so leave now. */
					taskEXIT_CRITICAL();
					traceQUEUE_RECEIVE_FAILED( pxQueue );
					return errQUEUE_EMPTY;
				}
				else if( xEntryTimeSet == pdFALSE )
				{
					/* The queue was empty 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( prvIsQueueEmpty( pxQueue ) )
			{
				traceBLOCKING_ON_QUEUE_RECEIVE( pxQueue );

				#if ( configUSE_MUTEXES == 1 )
				{
					if( pxQueue->uxQueueType == queueQUEUE_IS_MUTEX )
					{
						portENTER_CRITICAL();
						{
							vTaskPriorityInherit( ( void * ) pxQueue->pxMutexHolder );
						}
						portEXIT_CRITICAL();
					}
				}
				#endif

				vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToReceive ), xTicksToWait );
				prvUnlockQueue( pxQueue );
				if( !xTaskResumeAll() )
				{
					portYIELD_WITHIN_API();
				}
			}
			else
			{
				/* Try again. */
				prvUnlockQueue( pxQueue );
				( void ) xTaskResumeAll();
			}
		}
		else
		{
			prvUnlockQueue( pxQueue );
			( void ) xTaskResumeAll();
			traceQUEUE_RECEIVE_FAILED( pxQueue );
			return errQUEUE_EMPTY;
		}
	}
}
/*-----------------------------------------------------------*/

signed portBASE_TYPE xQueueReceiveFromISR( xQueueHandle pxQueue, void * const pvBuffer, signed portBASE_TYPE *pxTaskWoken )
{
signed portBASE_TYPE xReturn;
unsigned portBASE_TYPE uxSavedInterruptStatus;

	uxSavedInterruptStatus = portSET_INTERRUPT_MASK_FROM_ISR();
	{
		/* We cannot block from an ISR, so check there is data available. */
		if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )
		{
			traceQUEUE_RECEIVE_FROM_ISR( pxQueue );

			prvCopyDataFromQueue( pxQueue, pvBuffer );
			--( pxQueue->uxMessagesWaiting );

			/* If the queue is locked we will not modify the event list.  Instead
			we update the lock count so the task that unlocks the queue will know
			that an ISR has removed data while the queue was locked. */
			if( pxQueue->xRxLock == queueUNLOCKED )
			{
				if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )
				{
					if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )
					{
						/* The task waiting has a higher priority than us so
						force a context switch. */
						*pxTaskWoken = pdTRUE;
					}
				}
			}
			else
			{
				/* Increment the lock count so the task that unlocks the queue
				knows that data was removed while it was locked. */
				++( pxQueue->xRxLock );
			}

			xReturn = pdPASS;
		}
		else
		{
			xReturn = pdFAIL;
			traceQUEUE_RECEIVE_FROM_ISR_FAILED( pxQueue );
		}
	}
	portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus );

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

unsigned portBASE_TYPE uxQueueMessagesWaiting( const xQueueHandle pxQueue )
{
unsigned portBASE_TYPE uxReturn;

	taskENTER_CRITICAL();
		uxReturn = pxQueue->uxMessagesWaiting;
	taskEXIT_CRITICAL();

	return uxReturn;
}
/*-----------------------------------------------------------*/

unsigned portBASE_TYPE uxQueueMessagesWaitingFromISR( const xQueueHandle pxQueue )
{
unsigned portBASE_TYPE uxReturn;

	uxReturn = pxQueue->uxMessagesWaiting;

	return uxReturn;
}
/*-----------------------------------------------------------*/

void vQueueDelete( xQueueHandle pxQueue )
{
	traceQUEUE_DELETE( pxQueue );
	vQueueUnregisterQueue( pxQueue );
	vPortFree( pxQueue->pcHead );
	vPortFree( pxQueue );
}
/*-----------------------------------------------------------*/

static void prvCopyDataToQueue( xQUEUE *pxQueue, const void *pvItemToQueue, portBASE_TYPE xPosition )
{
	if( pxQueue->uxItemSize == ( unsigned portBASE_TYPE ) 0 )
	{
		#if ( configUSE_MUTEXES == 1 )
		{
			if( pxQueue->uxQueueType == queueQUEUE_IS_MUTEX )
			{
				/* The mutex is no longer being held. */
				vTaskPriorityDisinherit( ( void * ) pxQueue->pxMutexHolder );
				pxQueue->pxMutexHolder = NULL;
			}
		}
		#endif
	}
	else if( xPosition == queueSEND_TO_BACK )
	{
		memcpy( ( void * ) pxQueue->pcWriteTo, pvItemToQueue, ( unsigned ) pxQueue->uxItemSize );
		pxQueue->pcWriteTo += pxQueue->uxItemSize;
		if( pxQueue->pcWriteTo >= pxQueue->pcTail )
		{
			pxQueue->pcWriteTo = pxQueue->pcHead;
		}
	}
	else
	{
		memcpy( ( void * ) pxQueue->pcReadFrom, pvItemToQueue, ( unsigned ) pxQueue->uxItemSize );
		pxQueue->pcReadFrom -= pxQueue->uxItemSize;
		if( pxQueue->pcReadFrom < pxQueue->pcHead )
		{
			pxQueue->pcReadFrom = ( pxQueue->pcTail - pxQueue->uxItemSize );
		}
	}

	++( pxQueue->uxMessagesWaiting );
}
/*-----------------------------------------------------------*/

static void prvCopyDataFromQueue( xQUEUE * const pxQueue, const void *pvBuffer )
{
	if( pxQueue->uxQueueType != queueQUEUE_IS_MUTEX )
	{
		pxQueue->pcReadFrom += pxQueue->uxItemSize;
		if( pxQueue->pcReadFrom >= pxQueue->pcTail )
		{
			pxQueue->pcReadFrom = pxQueue->pcHead;
		}
		memcpy( ( void * ) pvBuffer, ( void * ) pxQueue->pcReadFrom, ( unsigned ) pxQueue->uxItemSize );
	}
}
/*-----------------------------------------------------------*/

static void prvUnlockQueue( xQueueHandle pxQueue )