os_mutex.c

lpc2368-keil环境下的ucos的移植例程

/*$PAGE*/
/*
*********************************************************************************************************
*   							   PEND ON MUTUAL EXCLUSION SEMAPHORE
*
* Description: This function waits for a mutual exclusion semaphore.
*
* Arguments  : pevent   	 is a pointer to the event control block associated with the desired
*   						 mutex.
*
*   		   timeout  	 is an optional timeout period (in clock ticks).  If non-zero, your task will
*   						 wait for the resource up to the amount of time specified by this argument.
*   						 If you specify 0, however, your task will wait forever at the specified
*   						 mutex or, until the resource becomes available.
*
*   		   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 owns the mutex
*   							OS_TIMEOUT  	   The mutex was not available within the specified time.
*   							OS_ERR_EVENT_TYPE  If you didn't pass a pointer to a mutex
*   							OS_ERR_PEVENT_NULL '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    : none
*
* Note(s)    : 1) The task that owns the Mutex MUST NOT pend on any other event while it owns the mutex.
*   		   2) You MUST NOT change the priority of the task that owns the mutex
*********************************************************************************************************
*/
void OSMutexPend(OS_EVENT *pevent, INT16U timeout, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 							   /* Allocate storage for CPU status register */
	OS_CPU_SR  cpu_sr;
#endif    
	INT8U      pip; 									   /* Priority Inheritance Priority (PIP)      */
	INT8U      mprio;   								   /* Mutex owner priority  				   */
	BOOLEAN    rdy; 									   /* Flag indicating task was ready		   */
	OS_TCB    *ptcb;


	if (OSIntNesting > 0)
	{
		/* See if called from ISR ...   			*/
		*err = OS_ERR_PEND_ISR; 						   /* ... can't PEND from an ISR               */
		return;
	}
#if OS_ARG_CHK_EN > 0
	if (pevent == (OS_EVENT *) 0)
	{
		/* Validate 'pevent'						*/
		*err = OS_ERR_PEVENT_NULL;
		return;
	}
	if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX)
	{
		/* Validate event block type				*/
		*err = OS_ERR_EVENT_TYPE;
		return;
	}
#endif
	OS_ENTER_CRITICAL();								   /* Is Mutex available?   				   */
	if ((INT8U) (pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8) == OS_MUTEX_AVAILABLE)
	{
		pevent->OSEventCnt &= OS_MUTEX_KEEP_UPPER_8;	   /* Yes, Acquire the resource 			   */
		pevent->OSEventCnt |= OSTCBCur->OSTCBPrio;  	   /*      Save priority of owning task 	   */
		pevent->OSEventPtr = (void *) OSTCBCur; 		   /*      Point to owning task's OS_TCB       */
		OS_EXIT_CRITICAL();
		*err = OS_NO_ERR;
		return;
	}
	pip = (INT8U) (pevent->OSEventCnt >> 8);					 /* No, Get PIP from mutex  		  */
	mprio = (INT8U) (pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8);  /*     Get priority of mutex owner   */
	ptcb = (OS_TCB *) (pevent->OSEventPtr); 					  /*	 Point to TCB of mutex owner   */
	if (ptcb->OSTCBPrio != pip && mprio > OSTCBCur->OSTCBPrio)
	{
		/*     Need to promote prio of owner?*/
		if ((OSRdyTbl[ptcb->OSTCBY] & ptcb->OSTCBBitX) != 0x00)
		{
			/*     See if mutex owner is ready   */
			/*     Yes, Remove owner from Rdy ...*/
			/*  		... list at current prio */
			if ((OSRdyTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0x00)
			{
				OSRdyGrp &= ~ptcb->OSTCBBitY;
			}
			rdy = TRUE;
		}
		else
		{
			rdy = FALSE;										  /* No 							   */
		}
		ptcb->OSTCBPrio = pip;  				   /* Change owner task prio to PIP 		   */
		ptcb->OSTCBY = ptcb->OSTCBPrio >> 3;
		ptcb->OSTCBBitY = OSMapTbl[ptcb->OSTCBY];
		ptcb->OSTCBX = ptcb->OSTCBPrio & 0x07;
		ptcb->OSTCBBitX = OSMapTbl[ptcb->OSTCBX];
		if (rdy == TRUE)
		{
			/* If task was ready at owner's priority ...*/
			OSRdyGrp |= ptcb->OSTCBBitY;	 /* ... make it ready at new priority.  	 */
			OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
		}
		OSTCBPrioTbl[pip] = (OS_TCB *) ptcb;
	}
	OSTCBCur->OSTCBStat |= OS_STAT_MUTEX;   		  /* Mutex not available, pend current task 	   */
	OSTCBCur->OSTCBDly = timeout;   				/* Store timeout in current task's TCB           */
	OS_EventTaskWait(pevent);   					  /* Suspend task until event or timeout occurs    */
	OS_EXIT_CRITICAL();
	OS_Sched(); 									   /* Find next highest priority task ready 		*/
	OS_ENTER_CRITICAL();
	if (OSTCBCur->OSTCBStat & OS_STAT_MUTEX)
	{
		/* Must have timed out if still waiting for event*/
		OS_EventTO(pevent);
		OS_EXIT_CRITICAL();
		*err = OS_TIMEOUT;  						  /* Indicate that we didn't get mutex within TO   */
		return;
	}
	OSTCBCur->OSTCBEventPtr = (OS_EVENT *) 0;
	OS_EXIT_CRITICAL();
	*err = OS_NO_ERR;
}
/*$PAGE*/
/*
*********************************************************************************************************
*   							   POST TO A MUTUAL EXCLUSION SEMAPHORE
*
* Description: This function signals a mutual exclusion semaphore
*
* Arguments  : pevent   		   is a pointer to the event control block associated with the desired
*   							   mutex.
*
* Returns    : OS_NO_ERR			   The call was successful and the mutex was signaled.
*   		   OS_ERR_EVENT_TYPE	   If you didn't pass a pointer to a mutex
*   		   OS_ERR_PEVENT_NULL      'pevent' is a NULL pointer
*   		   OS_ERR_POST_ISR  	   Attempted to post from an ISR (not valid for MUTEXes)
*   		   OS_ERR_NOT_MUTEX_OWNER  The task that did the post is NOT the owner of the MUTEX.
*********************************************************************************************************
*/

INT8U OSMutexPost(OS_EVENT *pevent)
{
#if OS_CRITICAL_METHOD == 3 						  /* Allocate storage for CPU status register      */
	OS_CPU_SR  cpu_sr;
#endif    
	INT8U      pip; 								  /* Priority inheritance priority  			   */
	INT8U      prio;


	if (OSIntNesting > 0)
	{
		/* See if called from ISR ...   				 */
		return (OS_ERR_POST_ISR);   				  /* ... can't POST mutex from an ISR              */
	}
#if OS_ARG_CHK_EN > 0
	if (pevent == (OS_EVENT *) 0)
	{
		/* Validate 'pevent'							 */
		return (OS_ERR_PEVENT_NULL);
	}
	if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX)
	{
		/* Validate event block type					 */
		return (OS_ERR_EVENT_TYPE);
	}   											  
#endif
	OS_ENTER_CRITICAL();
	pip = (INT8U) (pevent->OSEventCnt >> 8);		  /* Get priority inheritance priority of mutex    */
	prio = (INT8U) (pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8);  /* Get owner's original priority      */
	if (OSTCBCur->OSTCBPrio != pip && OSTCBCur->OSTCBPrio != prio)
	{
		/* See if posting task owns the MUTEX   		 */
		OS_EXIT_CRITICAL();
		return (OS_ERR_NOT_MUTEX_OWNER);
	}
	if (OSTCBCur->OSTCBPrio == pip)
	{
		/* Did we have to raise current task's priority? */
		/* Yes, Return to original priority 			 */
		/*  	Remove owner from ready list at 'pip'    */
		if ((OSRdyTbl[OSTCBCur->OSTCBY] &= ~OSTCBCur->OSTCBBitX) == 0)
		{
			OSRdyGrp &= ~OSTCBCur->OSTCBBitY;
		}
		OSTCBCur->OSTCBPrio = prio;
		OSTCBCur->OSTCBY = prio >> 3;
		OSTCBCur->OSTCBBitY = OSMapTbl[OSTCBCur->OSTCBY];
		OSTCBCur->OSTCBX = prio & 0x07;
		OSTCBCur->OSTCBBitX = OSMapTbl[OSTCBCur->OSTCBX];
		OSRdyGrp |= OSTCBCur->OSTCBBitY;
		OSRdyTbl[OSTCBCur->OSTCBY] |= OSTCBCur->OSTCBBitX;
		OSTCBPrioTbl[prio] = (OS_TCB *) OSTCBCur;
	}
	OSTCBPrioTbl[pip] = (OS_TCB *) 1;   			   /* Reserve table entry   						*/
	if (pevent->OSEventGrp != 0x00)
	{
		/* Any task waiting for the mutex?  			 */
		/* Yes, Make HPT waiting for mutex ready		 */
		prio = OS_EventTaskRdy(pevent, (void *) 0, OS_STAT_MUTEX);
		pevent->OSEventCnt &= OS_MUTEX_KEEP_UPPER_8;  /*	  Save priority of mutex's new owner       */
		pevent->OSEventCnt |= prio;
		pevent->OSEventPtr = OSTCBPrioTbl[prio];	 /* 	 Link to mutex owner's OS_TCB             */
		OS_EXIT_CRITICAL();
		OS_Sched(); 								  /*	  Find highest priority task ready to run  */
		return (OS_NO_ERR);
	}
	pevent->OSEventCnt |= OS_MUTEX_AVAILABLE;   	  /* No,  Mutex is now available				   */
	pevent->OSEventPtr = (void *) 0;
	OS_EXIT_CRITICAL();
	return (OS_NO_ERR);
}
/*$PAGE*/
/*
*********************************************************************************************************
*   								  QUERY A MUTUAL EXCLUSION SEMAPHORE
*
* Description: This function obtains information about a mutex
*
* Arguments  : pevent   	 is a pointer to the event control block associated with the desired mutex
*
*   		   pdata		 is a pointer to a structure that will contain information about the mutex
*
* Returns    : OS_NO_ERR			The call was successful and the message was sent
*   		   OS_ERR_QUERY_ISR 	If you called this function from an ISR
*   		   OS_ERR_PEVENT_NULL   'pevent' is a NULL pointer
*   		   OS_ERR_EVENT_TYPE	If you are attempting to obtain data from a non mutex.
*********************************************************************************************************
*/

#if OS_MUTEX_QUERY_EN > 0
INT8U OSMutexQuery(OS_EVENT *pevent, OS_MUTEX_DATA *pdata)
{
#if OS_CRITICAL_METHOD == 3 					 /* Allocate storage for CPU status register		   */
	OS_CPU_SR  cpu_sr;
#endif    
	INT8U     *psrc;
	INT8U     *pdest;


	if (OSIntNesting > 0)
	{
		/* See if called from ISR ...   			*/
		return (OS_ERR_QUERY_ISR);  					   /* ... can't QUERY mutex from an ISR        */
	}
#if OS_ARG_CHK_EN > 0
	if (pevent == (OS_EVENT *) 0)
	{
		/* Validate 'pevent'						*/
		return (OS_ERR_PEVENT_NULL);
	}
	if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX)
	{
		/* Validate event block type				*/
		return (OS_ERR_EVENT_TYPE);
	}
#endif
	OS_ENTER_CRITICAL();
	pdata->OSMutexPIP = (INT8U) (pevent->OSEventCnt >> 8);
	pdata->OSOwnerPrio = (INT8U) (pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8);
	if (pdata->OSOwnerPrio == 0xFF)
	{
		pdata->OSValue = 1;
	}
	else
	{
		pdata->OSValue = 0;
	}
	pdata->OSEventGrp = pevent->OSEventGrp; 			  /* Copy wait list 						  */
	psrc = &pevent->OSEventTbl[0];
	pdest = &pdata->OSEventTbl[0];
#if OS_EVENT_TBL_SIZE > 0
	*pdest++ = *psrc++;
#endif

#if OS_EVENT_TBL_SIZE > 1
	*pdest++ = *psrc++;
#endif

#if OS_EVENT_TBL_SIZE > 2
	*pdest++ = *psrc++;
#endif

#if OS_EVENT_TBL_SIZE > 3
	*pdest++ = *psrc++;
#endif

#if OS_EVENT_TBL_SIZE > 4
	*pdest++ = *psrc++;
#endif

#if OS_EVENT_TBL_SIZE > 5
	*pdest++ = *psrc++;
#endif

#if OS_EVENT_TBL_SIZE > 6
	*pdest++ = *psrc++;
#endif

#if OS_EVENT_TBL_SIZE > 7
	*pdest = *psrc;
#endif
	OS_EXIT_CRITICAL();
	return (OS_NO_ERR);
}
#endif  												   /* OS_MUTEX_QUERY_EN 					   */
#endif  												   /* OS_MUTEX_EN   						   */