os_q.c

lpc2368-keil环境下的ucos的移植例程

/*
*********************************************************************************************************
*   											 uC/OS-II
*   									   The Real-Time Kernel
*   									 MESSAGE QUEUE MANAGEMENT
*
*   					   (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL
*   										All Rights Reserved
*
* File : OS_Q.C
* By   : Jean J. Labrosse
*********************************************************************************************************
*/

#ifndef  OS_MASTER_FILE
#include "..\APP\includes.h"
#endif

#if (OS_Q_EN > 0) && (OS_MAX_QS > 0)
/*
*********************************************************************************************************
*   								   ACCEPT MESSAGE FROM QUEUE
*
* Description: This function checks the queue to see if a message is available.  Unlike OSQPend(),
*   		   OSQAccept() does not suspend the calling task if a message is not available.
*
* Arguments  : pevent   	 is a pointer to the event control block
*
* Returns    : != (void *)0  is the message in the queue if one is available.  The message is removed
*   						 from the so the next time OSQAccept() is called, the queue will contain
*   						 one less entry.
*   		   == (void *)0  if the queue is empty or,
*   						 if 'pevent' is a NULL pointer or,
*   						 if you passed an invalid event type
*********************************************************************************************************
*/

#if OS_Q_ACCEPT_EN > 0
void * OSQAccept(OS_EVENT *pevent)
{
#if OS_CRITICAL_METHOD == 3 					 /* Allocate storage for CPU status register		   */
	OS_CPU_SR  cpu_sr;
#endif
	void	  *msg;
	OS_Q	  *pq;


#if OS_ARG_CHK_EN > 0
	if (pevent == (OS_EVENT *) 0)
	{
		/* Validate 'pevent'								  */
		return ((void *) 0);
	}
	if (pevent->OSEventType != OS_EVENT_TYPE_Q)
	{
		/* Validate event block type						  */
		return ((void *) 0);
	}
#endif
	OS_ENTER_CRITICAL();
	pq = (OS_Q *) pevent->OSEventPtr;   		  /* Point at queue control block   					*/
	if (pq->OSQEntries > 0)
	{
		/* See if any messages in the queue 				  */
		msg = *pq->OSQOut++;					 /* Yes, extract oldest message from the queue  	   */
		pq->OSQEntries--;   					 /* Update the number of entries in the queue   	   */
		if (pq->OSQOut == pq->OSQEnd)
		{
			/* Wrap OUT pointer if we are at the end of the queue */
			pq->OSQOut = pq->OSQStart;
		}
	}
	else
	{
		msg = (void *) 0;   					  /* Queue is empty 									*/
	}
	OS_EXIT_CRITICAL();
	return (msg);   							 /* Return message received (or NULL)   			   */
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*   									 CREATE A MESSAGE QUEUE
*
* Description: This function creates a message queue if free event control blocks are available.
*
* Arguments  : start		 is a pointer to the base address of the message queue storage area.  The
*   						 storage area MUST be declared as an array of pointers to 'void' as follows
*
*   						 void *MessageStorage[size]
*
*   		   size 		 is the number of elements in the storage area
*
* Returns    : != (OS_EVENT *)0  is a pointer to the event control clock (OS_EVENT) associated with the
*   							 created queue
*   		   == (OS_EVENT *)0  if no event control blocks were available or an error was detected
*********************************************************************************************************
*/

OS_EVENT * OSQCreate(void **start, INT16U size)
{
#if OS_CRITICAL_METHOD == 3 					 /* Allocate storage for CPU status register		   */
	OS_CPU_SR  cpu_sr;
#endif
	OS_EVENT  *pevent;
	OS_Q	  *pq;


	if (OSIntNesting > 0)
	{
		/* See if called from ISR ...   					  */
		return ((OS_EVENT *) 0);				  /* ... can't CREATE from an ISR                       */
	}
	OS_ENTER_CRITICAL();
	pevent = OSEventFreeList;   				 /* Get next free event control block   			   */
	if (OSEventFreeList != (OS_EVENT *) 0)
	{
		/* See if pool of free ECB pool was empty   		  */
		OSEventFreeList = (OS_EVENT *) OSEventFreeList->OSEventPtr;
	}
	OS_EXIT_CRITICAL();
	if (pevent != (OS_EVENT *) 0)
	{
		/* See if we have an event control block			  */
		OS_ENTER_CRITICAL();
		pq = OSQFreeList;   					 /* Get a free queue control block  				   */
		if (pq != (OS_Q *) 0)
		{
			/* Were we able to get a queue control block ?  	  */
			OSQFreeList = OSQFreeList->OSQPtr;    /* Yes, Adjust free list pointer to next free*/
			OS_EXIT_CRITICAL();
			pq->OSQStart = start;   			   /*      Initialize the queue 				*/
			pq->OSQEnd = &start[size];
			pq->OSQIn = start;
			pq->OSQOut = start;
			pq->OSQSize = size;
			pq->OSQEntries = 0;
			pevent->OSEventType = OS_EVENT_TYPE_Q;
			pevent->OSEventCnt = 0;
			pevent->OSEventPtr = pq;
			OS_EventWaitListInit(pevent);   			  /*	  Initalize the wait list   		   */
		}
		else
		{
			pevent->OSEventPtr = (void *) OSEventFreeList; /* No,  Return event control block on error  */
			OSEventFreeList = pevent;
			OS_EXIT_CRITICAL();
			pevent = (OS_EVENT *) 0;
		}
	}
	return (pevent);
}
/*$PAGE*/
/*
*********************************************************************************************************
*   									 DELETE A MESSAGE QUEUE
*
* Description: This function deletes a message queue and readies all tasks pending on the queue.
*
* Arguments  : pevent   	 is a pointer to the event control block associated with the desired
*   						 queue.
*
*   		   opt  		 determines delete options as follows:
*   						 opt == OS_DEL_NO_PEND   Delete the queue ONLY if no task pending
*   						 opt == OS_DEL_ALWAYS    Deletes the queue even if tasks are waiting.
*   												 In this case, all the tasks pending will be readied.
*
*   		   err  		 is a pointer to an error code that can contain one of the following values:
*   						 OS_NO_ERR  			 The call was successful and the queue was deleted
*   						 OS_ERR_DEL_ISR 		 If you tried to delete the queue from an ISR
*   						 OS_ERR_INVALID_OPT 	 An invalid option was specified
*   						 OS_ERR_TASK_WAITING	 One or more tasks were waiting on the queue
*   						 OS_ERR_EVENT_TYPE  	 If you didn't pass a pointer to a queue
*   						 OS_ERR_PEVENT_NULL 	 If 'pevent' is a NULL pointer.
*
* Returns    : pevent   	 upon error
*   		   (OS_EVENT *)0 if the queue was successfully deleted.
*
* Note(s)    : 1) This function must be used with care.  Tasks that would normally expect the presence of
*   			  the queue MUST check the return code of OSQPend().
*   		   2) OSQAccept() callers will not know that the intended queue has been deleted unless
*   			  they check 'pevent' to see that it's a NULL pointer.
*   		   3) This call can potentially disable interrupts for a long time.  The interrupt disable
*   			  time is directly proportional to the number of tasks waiting on the queue.
*   		   4) Because ALL tasks pending on the queue will be readied, you MUST be careful in
*   			  applications where the queue is used for mutual exclusion because the resource(s)
*   			  will no longer be guarded by the queue.
*   		   5) If the storage for the message queue was allocated dynamically (i.e. using a malloc()
*   			  type call) then your application MUST release the memory storage by call the counterpart
*   			  call of the dynamic allocation scheme used.  If the queue storage was created statically
*   			  then, the storage can be reused.
*********************************************************************************************************
*/

#if OS_Q_DEL_EN > 0
OS_EVENT * OSQDel(OS_EVENT *pevent, INT8U opt, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 							   /* Allocate storage for CPU status register */
	OS_CPU_SR  cpu_sr;
#endif
	BOOLEAN    tasks_waiting;
	OS_Q	  *pq;


	if (OSIntNesting > 0)
	{
		/* See if called from ISR ...   			*/
		*err = OS_ERR_DEL_ISR;  						   /* ... can't DELETE from an ISR             */
		return ((OS_EVENT *) 0);
	}
#if OS_ARG_CHK_EN > 0
	if (pevent == (OS_EVENT *) 0)
	{
		/* Validate 'pevent'						*/
		*err = OS_ERR_PEVENT_NULL;
		return (pevent);
	}
	if (pevent->OSEventType != OS_EVENT_TYPE_Q)
	{
		/* Validate event block type				*/
		*err = OS_ERR_EVENT_TYPE;
		return (pevent);
	}
#endif
	OS_ENTER_CRITICAL();
	if (pevent->OSEventGrp != 0x00)
	{
		/* See if any tasks waiting on queue		*/
		tasks_waiting = TRUE;   						   /* Yes   								   */
	}
	else
	{
		tasks_waiting = FALSE;  						   /* No									   */
	}
	switch (opt)
	{
		case OS_DEL_NO_PEND:
			/* Delete queue only if no task waiting 	*/
			if (tasks_waiting == FALSE)
			{
				pq = (OS_Q *) pevent->OSEventPtr;  /* Return OS_Q to free list  	  */
				pq->OSQPtr = OSQFreeList;
				OSQFreeList = pq;
				pevent->OSEventType = OS_EVENT_TYPE_UNUSED;
				pevent->OSEventPtr = OSEventFreeList;    /* Return Event Control Block to free list  */
				OSEventFreeList = pevent;   		  /* Get next free event control block  	  */
				OS_EXIT_CRITICAL();
				*err = OS_NO_ERR;
				return ((OS_EVENT *) 0);				   /* Queue has been deleted				   */
			}
			else
			{
				OS_EXIT_CRITICAL();
				*err = OS_ERR_TASK_WAITING;
				return (pevent);
			}

		case OS_DEL_ALWAYS:
			/* Always delete the queue  				*/
			while (pevent->OSEventGrp != 0x00)
			{
				/* Ready ALL tasks waiting for queue		*/
				OS_EventTaskRdy(pevent, (void *) 0, OS_STAT_Q);
			}
			pq = (OS_Q *) pevent->OSEventPtr;      /* Return OS_Q to free list  	  */
			pq->OSQPtr = OSQFreeList;
			OSQFreeList = pq;
			pevent->OSEventType = OS_EVENT_TYPE_UNUSED;
			pevent->OSEventPtr = OSEventFreeList;   	 /* Return Event Control Block to free list  */
			OSEventFreeList = pevent;   			  /* Get next free event control block  	  */
			OS_EXIT_CRITICAL();
			if (tasks_waiting == TRUE)
			{
				/* Reschedule only if task(s) were waiting  */
				OS_Sched(); 							  /* Find highest priority task ready to run  */
			}
			*err = OS_NO_ERR;
			return ((OS_EVENT *) 0);					   /* Queue has been deleted				   */

		default:
			OS_EXIT_CRITICAL();
			*err = OS_ERR_INVALID_OPT;
			return (pevent);
	}
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*   										FLUSH QUEUE
*
* Description : This function is used to flush the contents of the message queue.
*
* Arguments   : none
*
* Returns     : OS_NO_ERR   		upon success
*   			OS_ERR_EVENT_TYPE   If you didn't pass a pointer to a queue
*   			OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer
*********************************************************************************************************
*/

#if OS_Q_FLUSH_EN > 0
INT8U OSQFlush(OS_EVENT *pevent)
{
#if OS_CRITICAL_METHOD == 3 						  /* Allocate storage for CPU status register      */
	OS_CPU_SR  cpu_sr;
#endif
	OS_Q	  *pq;


#if OS_ARG_CHK_EN > 0
	if (pevent == (OS_EVENT *) 0)
	{
		/* Validate 'pevent'							 */
		return (OS_ERR_PEVENT_NULL);
	}
	if (pevent->OSEventType != OS_EVENT_TYPE_Q)
	{
		/* Validate event block type					 */
		return (OS_ERR_EVENT_TYPE);
	}
#endif
	OS_ENTER_CRITICAL();
	pq = (OS_Q *) pevent->OSEventPtr;      /* Point to queue storage structure  			*/
	pq->OSQIn = pq->OSQStart;
	pq->OSQOut = pq->OSQStart;
	pq->OSQEntries = 0;
	OS_EXIT_CRITICAL();
	return (OS_NO_ERR);
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*   								  PEND ON A QUEUE FOR A MESSAGE
*
* Description: This function waits for a message to be sent to a queue
*
* Arguments  : pevent   	 is a pointer to the event control block associated with the desired queue
*
*   		   timeout  	 is an optional timeout period (in clock ticks).  If non-zero, your task will
*   						 wait for a message to arrive at the queue up to the amount of time
*   						 specified by this argument.  If you specify 0, however, your task will wait
*   						 forever at the specified queue or, until a message arrives.
*
*   		   err  		 is a pointer to where an error message will be deposited.  Possible error
*   						 messages are:
*
*   						 OS_NO_ERR  		 The call was successful and your task received a
*   											 message.
*   						 OS_TIMEOUT 		 A message was not received within the specified timeout
*   						 OS_ERR_EVENT_TYPE   You didn't pass a pointer to a queue
*   						 OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer
*   						 OS_ERR_PEND_ISR	 If you called this function from an ISR and the result
*   											 would lead to a suspension.
*
* Returns    : != (void *)0  is a pointer to the message received
*   		   == (void *)0  if no message was received or,
*   						 if 'pevent' is a NULL pointer or,
*   						 if you didn't pass a pointer to a queue.
*********************************************************************************************************
*/

void * OSQPend(OS_EVENT *pevent, INT16U timeout, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 					 /* Allocate storage for CPU status register		   */
	OS_CPU_SR  cpu_sr;
#endif
	void	  *msg;
	OS_Q	  *pq;


	if (OSIntNesting > 0)
	{
		/* See if called from ISR ...   					  */
		*err = OS_ERR_PEND_ISR; 				 /* ... can't PEND from an ISR                         */
		return ((void *) 0);
	}
#if OS_ARG_CHK_EN > 0
	if (pevent == (OS_EVENT *) 0)
	{
		/* Validate 'pevent'								  */
		*err = OS_ERR_PEVENT_NULL;
		return ((void *) 0);
	}
	if (pevent->OSEventType != OS_EVENT_TYPE_Q)
	{
		/* Validate event block type						  */
		*err = OS_ERR_EVENT_TYPE;
		return ((void *) 0);
	}
#endif
	OS_ENTER_CRITICAL();
	pq = (OS_Q *) pevent->OSEventPtr;   		  /* Point at queue control block   					*/
	if (pq->OSQEntries > 0)
	{
		/* See if any messages in the queue 				  */
		msg = *pq->OSQOut++;					 /* Yes, extract oldest message from the queue  	   */
		pq->OSQEntries--;   					 /* Update the number of entries in the queue   	   */
		if (pq->OSQOut == pq->OSQEnd)
		{
			/* Wrap OUT pointer if we are at the end of the queue */
			pq->OSQOut = pq->OSQStart;
		}
		OS_EXIT_CRITICAL();
		*err = OS_NO_ERR;
		return (msg);   						 /* Return message received 						   */
	}
	OSTCBCur->OSTCBStat |= OS_STAT_Q;   		 /* Task will have to pend for a message to be posted  */
	OSTCBCur->OSTCBDly = timeout;   		   /* Load timeout into TCB 							 */
	OS_EventTaskWait(pevent);   				 /* Suspend task until event or timeout occurs  	   */
	OS_EXIT_CRITICAL();
	OS_Sched(); 								 /* Find next highest priority task ready to run	   */
	OS_ENTER_CRITICAL();
	msg = OSTCBCur->OSTCBMsg;
	if (msg != (void *) 0)
	{