queue.c

freescale k40/k60 freertos-uip 例程

{
	/* THIS FUNCTION MUST BE CALLED WITH THE SCHEDULER SUSPENDED. */

	/* The lock counts contains the number of extra data items placed or
	removed from the queue while the queue was locked.  When a queue is
	locked items can be added or removed, but the event lists cannot be
	updated. */
	taskENTER_CRITICAL();
	{
		/* See if data was added to the queue while it was locked. */
		while( pxQueue->xTxLock > queueLOCKED_UNMODIFIED )
		{
			/* Data was posted while the queue was locked.  Are any tasks
			blocked waiting for data to become available? */
			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 so record that a
					context	switch is required. */
					vTaskMissedYield();
				}

				--( pxQueue->xTxLock );
			}
			else
			{
				break;
			}
		}

		pxQueue->xTxLock = queueUNLOCKED;
	}
	taskEXIT_CRITICAL();

	/* Do the same for the Rx lock. */
	taskENTER_CRITICAL();
	{
		while( pxQueue->xRxLock > queueLOCKED_UNMODIFIED )
		{
			if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )
			{
				if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )
				{
					vTaskMissedYield();
				}

				--( pxQueue->xRxLock );
			}
			else
			{
				break;
			}
		}

		pxQueue->xRxLock = queueUNLOCKED;
	}
	taskEXIT_CRITICAL();
}
/*-----------------------------------------------------------*/

static signed portBASE_TYPE prvIsQueueEmpty( const xQueueHandle pxQueue )
{
signed portBASE_TYPE xReturn;

	taskENTER_CRITICAL();
		xReturn = ( pxQueue->uxMessagesWaiting == ( unsigned portBASE_TYPE ) 0 );
	taskEXIT_CRITICAL();

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

signed portBASE_TYPE xQueueIsQueueEmptyFromISR( const xQueueHandle pxQueue )
{
signed portBASE_TYPE xReturn;

	xReturn = ( pxQueue->uxMessagesWaiting == ( unsigned portBASE_TYPE ) 0 );

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

static signed portBASE_TYPE prvIsQueueFull( const xQueueHandle pxQueue )
{
signed portBASE_TYPE xReturn;

	taskENTER_CRITICAL();
		xReturn = ( pxQueue->uxMessagesWaiting == pxQueue->uxLength );
	taskEXIT_CRITICAL();

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

signed portBASE_TYPE xQueueIsQueueFullFromISR( const xQueueHandle pxQueue )
{
signed portBASE_TYPE xReturn;

	xReturn = ( pxQueue->uxMessagesWaiting == pxQueue->uxLength );

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

#if configUSE_CO_ROUTINES == 1
signed portBASE_TYPE xQueueCRSend( xQueueHandle pxQueue, const void *pvItemToQueue, portTickType xTicksToWait )
{
signed portBASE_TYPE xReturn;

	/* If the queue is already full we may have to block.  A critical section
	is required to prevent an interrupt removing something from the queue
	between the check to see if the queue is full and blocking on the queue. */
	portDISABLE_INTERRUPTS();
	{
		if( prvIsQueueFull( pxQueue ) )
		{
			/* The queue is full - do we want to block or just leave without
			posting? */
			if( xTicksToWait > ( portTickType ) 0 )
			{
				/* As this is called from a coroutine we cannot block directly, but
				return indicating that we need to block. */
				vCoRoutineAddToDelayedList( xTicksToWait, &( pxQueue->xTasksWaitingToSend ) );
				portENABLE_INTERRUPTS();
				return errQUEUE_BLOCKED;
			}
			else
			{
				portENABLE_INTERRUPTS();
				return errQUEUE_FULL;
			}
		}
	}
	portENABLE_INTERRUPTS();

	portNOP();

	portDISABLE_INTERRUPTS();
	{
		if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )
		{
			/* There is room in the queue, copy the data into the queue. */
			prvCopyDataToQueue( pxQueue, pvItemToQueue, queueSEND_TO_BACK );
			xReturn = pdPASS;

			/* Were any co-routines waiting for data to become available? */
			if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )
			{
				/* In this instance the co-routine could be placed directly
				into the ready list as we are within a critical section.
				Instead the same pending ready list mechanism is used as if
				the event were caused from within an interrupt. */
				if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )
				{
					/* The co-routine waiting has a higher priority so record
					that a yield might be appropriate. */
					xReturn = errQUEUE_YIELD;
				}
			}
		}
		else
		{
			xReturn = errQUEUE_FULL;
		}
	}
	portENABLE_INTERRUPTS();

	return xReturn;
}
#endif
/*-----------------------------------------------------------*/

#if configUSE_CO_ROUTINES == 1
signed portBASE_TYPE xQueueCRReceive( xQueueHandle pxQueue, void *pvBuffer, portTickType xTicksToWait )
{
signed portBASE_TYPE xReturn;

	/* If the queue is already empty we may have to block.  A critical section
	is required to prevent an interrupt adding something to the queue
	between the check to see if the queue is empty and blocking on the queue. */
	portDISABLE_INTERRUPTS();
	{
		if( pxQueue->uxMessagesWaiting == ( unsigned portBASE_TYPE ) 0 )
		{
			/* There are no messages in the queue, do we want to block or just
			leave with nothing? */
			if( xTicksToWait > ( portTickType ) 0 )
			{
				/* As this is a co-routine we cannot block directly, but return
				indicating that we need to block. */
				vCoRoutineAddToDelayedList( xTicksToWait, &( pxQueue->xTasksWaitingToReceive ) );
				portENABLE_INTERRUPTS();
				return errQUEUE_BLOCKED;
			}
			else
			{
				portENABLE_INTERRUPTS();
				return errQUEUE_FULL;
			}
		}
	}
	portENABLE_INTERRUPTS();

	portNOP();

	portDISABLE_INTERRUPTS();
	{
		if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )
		{
			/* Data is available from the queue. */
			pxQueue->pcReadFrom += pxQueue->uxItemSize;
			if( pxQueue->pcReadFrom >= pxQueue->pcTail )
			{
				pxQueue->pcReadFrom = pxQueue->pcHead;
			}
			--( pxQueue->uxMessagesWaiting );
			memcpy( ( void * ) pvBuffer, ( void * ) pxQueue->pcReadFrom, ( unsigned ) pxQueue->uxItemSize );

			xReturn = pdPASS;

			/* Were any co-routines waiting for space to become available? */
			if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )
			{
				/* In this instance the co-routine could be placed directly
				into the ready list as we are within a critical section.
				Instead the same pending ready list mechanism is used as if
				the event were caused from within an interrupt. */
				if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )
				{
					xReturn = errQUEUE_YIELD;
				}
			}
		}
		else
		{
			xReturn = pdFAIL;
		}
	}
	portENABLE_INTERRUPTS();

	return xReturn;
}
#endif
/*-----------------------------------------------------------*/



#if configUSE_CO_ROUTINES == 1
signed portBASE_TYPE xQueueCRSendFromISR( xQueueHandle pxQueue, const void *pvItemToQueue, signed portBASE_TYPE xCoRoutinePreviouslyWoken )
{
	/* Cannot block within an ISR so if there is no space on the queue then
	exit without doing anything. */
	if( pxQueue->uxMessagesWaiting < pxQueue->uxLength )
	{
		prvCopyDataToQueue( pxQueue, pvItemToQueue, queueSEND_TO_BACK );

		/* We only want to wake one co-routine per ISR, so check that a
		co-routine has not already been woken. */
		if( !xCoRoutinePreviouslyWoken )
		{
			if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToReceive ) ) )
			{
				if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) != pdFALSE )
				{
					return pdTRUE;
				}
			}
		}
	}

	return xCoRoutinePreviouslyWoken;
}
#endif
/*-----------------------------------------------------------*/

#if configUSE_CO_ROUTINES == 1
signed portBASE_TYPE xQueueCRReceiveFromISR( xQueueHandle pxQueue, void *pvBuffer, signed portBASE_TYPE *pxCoRoutineWoken )
{
signed portBASE_TYPE xReturn;

	/* We cannot block from an ISR, so check there is data available. If
	not then just leave without doing anything. */
	if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )
	{
		/* Copy the data from the queue. */
		pxQueue->pcReadFrom += pxQueue->uxItemSize;
		if( pxQueue->pcReadFrom >= pxQueue->pcTail )
		{
			pxQueue->pcReadFrom = pxQueue->pcHead;
		}
		--( pxQueue->uxMessagesWaiting );
		memcpy( ( void * ) pvBuffer, ( void * ) pxQueue->pcReadFrom, ( unsigned ) pxQueue->uxItemSize );

		if( !( *pxCoRoutineWoken ) )
		{
			if( !listLIST_IS_EMPTY( &( pxQueue->xTasksWaitingToSend ) ) )
			{
				if( xCoRoutineRemoveFromEventList( &( pxQueue->xTasksWaitingToSend ) ) != pdFALSE )
				{
					*pxCoRoutineWoken = pdTRUE;
				}
			}
		}

		xReturn = pdPASS;
	}
	else
	{
		xReturn = pdFAIL;
	}

	return xReturn;
}
#endif
/*-----------------------------------------------------------*/

#if configQUEUE_REGISTRY_SIZE > 0

	void vQueueAddToRegistry( xQueueHandle xQueue, signed char *pcQueueName )
	{
	unsigned portBASE_TYPE ux;

		/* See if there is an empty space in the registry.  A NULL name denotes
		a free slot. */
		for( ux = 0; ux < configQUEUE_REGISTRY_SIZE; ux++ )
		{
			if( xQueueRegistry[ ux ].pcQueueName == NULL )
			{
				/* Store the information on this queue. */
				xQueueRegistry[ ux ].pcQueueName = pcQueueName;
				xQueueRegistry[ ux ].xHandle = xQueue;
				break;
			}
		}
	}

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

#if configQUEUE_REGISTRY_SIZE > 0

	static void vQueueUnregisterQueue( xQueueHandle xQueue )
	{
	unsigned portBASE_TYPE ux;

		/* See if the handle of the queue being unregistered in actually in the
		registry. */
		for( ux = 0; ux < configQUEUE_REGISTRY_SIZE; ux++ )
		{
			if( xQueueRegistry[ ux ].xHandle == xQueue )
			{
				/* Set the name to NULL to show that this slot if free again. */
				xQueueRegistry[ ux ].pcQueueName = NULL;
				break;
			}
		}

	}

#endif