os_mutex.c

MCB2300_ucgui_LCD320240.rar LPC2368的uc/gui的移植

/*
*********************************************************************************************************
*   											 uC/OS-II
*   									   The Real-Time Kernel
*   							   MUTUAL EXCLUSION SEMAPHORE MANAGEMENT
*
*   					   (c) Copyright 1992-2007, Jean J. Labrosse, Weston, FL
*   										All Rights Reserved
*
* File    : OS_MUTEX.C
* By	  : Jean J. Labrosse
* Version : V2.85
*
* LICENSING TERMS:
* ---------------
*   uC/OS-II is provided in source form for FREE evaluation, for educational use or for peaceful research.  
* If you plan on using  uC/OS-II  in a commercial product you need to contact Micri祄 to properly license 
* its use in your product. We provide ALL the source code for your convenience and to help you experience 
* uC/OS-II.   The fact that the  source is provided does  NOT  mean that you can use it without  paying a 
* licensing fee.
*********************************************************************************************************
*/

#ifndef  OS_MASTER_FILE
#include <ucos_ii.h>
#endif


#if OS_MUTEX_EN > 0
/*
*********************************************************************************************************
*   										 LOCAL CONSTANTS
*********************************************************************************************************
*/

#define  OS_MUTEX_KEEP_LOWER_8   (INT16U)0x00FFu
#define  OS_MUTEX_KEEP_UPPER_8   (INT16U)0xFF00u

#define  OS_MUTEX_AVAILABLE 	 (INT16U)0x00FFu

/*
*********************************************************************************************************
*   										 LOCAL CONSTANTS
*********************************************************************************************************
*/

static  void OSMutex_RdyAtPrio(OS_TCB *ptcb, INT8U prio);

/*$PAGE*/
/*
*********************************************************************************************************
*   								ACCEPT MUTUAL EXCLUSION SEMAPHORE
*
* Description: This  function checks the mutual exclusion semaphore to see if a resource is available.
*   		   Unlike OSMutexPend(), OSMutexAccept() does not suspend the calling task if the resource is
*   		   not available or the event did not occur.
*
* Arguments  : pevent     is a pointer to the event control block
*
*   		   perr 	  is a pointer to an error code which will be returned to your application:
*   						 OS_ERR_NONE		 if the call was successful.
*   						 OS_ERR_EVENT_TYPE   if 'pevent' is not 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
*   						 OS_ERR_PIP_LOWER    If the priority of the task that owns the Mutex is
*   											 HIGHER (i.e. a lower number) than the PIP.  This error
*   											 indicates that you did not set the PIP higher (lower
*   											 number) than ALL the tasks that compete for the Mutex.
*   											 Unfortunately, this is something that could not be
*   											 detected when the Mutex is created because we don't know
*   											 what tasks will be using the Mutex.
*
* Returns    : == OS_TRUE    if the resource is available, the mutual exclusion semaphore is acquired
*   		   == OS_FALSE   a) if the resource is not available
*   						 b) you didn't pass a pointer to a mutual exclusion semaphore
*   						 c) you called this function from an ISR
*
* Warning(s) : This function CANNOT be called from an ISR because mutual exclusion semaphores are
*   		   intended to be used by tasks only.
*********************************************************************************************************
*/

#if OS_MUTEX_ACCEPT_EN > 0
BOOLEAN OSMutexAccept(OS_EVENT *pevent, INT8U *perr)
{
	INT8U      pip; 								   /* Priority Inheritance Priority (PIP)   	   */
#if OS_CRITICAL_METHOD == 3 						   /* Allocate storage for CPU status register     */
	OS_CPU_SR  cpu_sr = 0;
#endif



#if OS_ARG_CHK_EN > 0
	if (perr == (INT8U *) 0)
	{
		/* Validate 'perr'  							*/
		return (OS_FALSE);
	}
	if (pevent == (OS_EVENT *) 0)
	{
		/* Validate 'pevent'							*/
		*perr = OS_ERR_PEVENT_NULL;
		return (OS_FALSE);
	}
#endif
	if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX)
	{
		/* Validate event block type					*/
		*perr = OS_ERR_EVENT_TYPE;
		return (OS_FALSE);
	}
	if (OSIntNesting > 0)
	{
		/* Make sure it's not called from an ISR        */
		*perr = OS_ERR_PEND_ISR;
		return (OS_FALSE);
	}
	OS_ENTER_CRITICAL();							   /* Get value (0 or 1) of Mutex   			   */
	pip = (INT8U) (pevent->OSEventCnt >> 8);			/* Get PIP from mutex   						*/
	if ((pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8) == OS_MUTEX_AVAILABLE)
	{
		pevent->OSEventCnt &= OS_MUTEX_KEEP_UPPER_8;   /*      Mask off LSByte (Acquire Mutex)  	   */
		pevent->OSEventCnt |= OSTCBCur->OSTCBPrio;     /*      Save current task priority in LSByte    */
		pevent->OSEventPtr = (void *) OSTCBCur; 	   /*      Link TCB of task owning Mutex		   */
		if (OSTCBCur->OSTCBPrio <= pip)
		{
			/*  	PIP 'must' have a SMALLER prio ...  	*/
			OS_EXIT_CRITICAL(); 					   /*      ... than current task!   			   */
			*perr = OS_ERR_PIP_LOWER;
		}
		else
		{
			OS_EXIT_CRITICAL();
			*perr = OS_ERR_NONE;
		}
		return (OS_TRUE);
	}
	OS_EXIT_CRITICAL();
	*perr = OS_ERR_NONE;
	return (OS_FALSE);
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*   							   CREATE A MUTUAL EXCLUSION SEMAPHORE
*
* Description: This function creates a mutual exclusion semaphore.
*
* Arguments  : prio 		 is the priority to use when accessing the mutual exclusion semaphore.  In
*   						 other words, when the semaphore is acquired and a higher priority task
*   						 attempts to obtain the semaphore then the priority of the task owning the
*   						 semaphore is raised to this priority.  It is assumed that you will specify
*   						 a priority that is LOWER in value than ANY of the tasks competing for the
*   						 mutex.
*
*   		   perr 		 is a pointer to an error code which will be returned to your application:
*   							OS_ERR_NONE 		if the call was successful.
*   							OS_ERR_CREATE_ISR   if you attempted to create a MUTEX from an ISR
*   							OS_ERR_PRIO_EXIST   if a task at the priority inheritance priority
*   												already exist.
*   							OS_ERR_PEVENT_NULL  No more event control blocks available.
*   							OS_ERR_PRIO_INVALID if the priority you specify is higher that the
*   												maximum allowed (i.e. > OS_LOWEST_PRIO)
*
* Returns    : != (void *)0  is a pointer to the event control clock (OS_EVENT) associated with the
*   						 created mutex.
*   		   == (void *)0  if an error is detected.
*
* Note(s)    : 1) The LEAST significant 8 bits of '.OSEventCnt' are used to hold the priority number
*   			  of the task owning the mutex or 0xFF if no task owns the mutex.
*
*   		   2) The MOST  significant 8 bits of '.OSEventCnt' are used to hold the priority number
*   			  to use to reduce priority inversion.
*********************************************************************************************************
*/

OS_EVENT * OSMutexCreate(INT8U prio, INT8U *perr)
{
	OS_EVENT  *pevent;
#if OS_CRITICAL_METHOD == 3 							   /* Allocate storage for CPU status register */
	OS_CPU_SR  cpu_sr = 0;
#endif



#if OS_ARG_CHK_EN > 0
	if (perr == (INT8U *) 0)
	{
		/* Validate 'perr'  						*/
		return ((OS_EVENT *) 0);
	}
	if (prio >= OS_LOWEST_PRIO)
	{
		/* Validate PIP 							*/
		*perr = OS_ERR_PRIO_INVALID;
		return ((OS_EVENT *) 0);
	}
#endif
	if (OSIntNesting > 0)
	{
		/* See if called from ISR ...   			*/
		*perr = OS_ERR_CREATE_ISR;  					   /* ... can't CREATE mutex from an ISR       */
		return ((OS_EVENT *) 0);
	}
	OS_ENTER_CRITICAL();
	if (OSTCBPrioTbl[prio] != (OS_TCB *) 0)
	{
		/* Mutex priority must not already exist	*/
		OS_EXIT_CRITICAL(); 							   /* Task already exist at priority ...	   */
		*perr = OS_ERR_PRIO_EXIST;  					   /* ... inheritance priority  			   */
		return ((OS_EVENT *) 0);
	}
	OSTCBPrioTbl[prio] = OS_TCB_RESERVED;   			   /* Reserve the table entry   			   */
	pevent = OSEventFreeList;   			   /* Get next free event control block 	   */
	if (pevent == (OS_EVENT *) 0)
	{
		/* See if an ECB was available  			*/
		OSTCBPrioTbl[prio] = (OS_TCB *) 0;  				/* No, Release the table entry  			*/
		OS_EXIT_CRITICAL();
		*perr = OS_ERR_PEVENT_NULL; 		  /* No more event control blocks   		  */
		return (pevent);
	}
	OSEventFreeList = (OS_EVENT *) OSEventFreeList->OSEventPtr;   /* Adjust the free list   	 */
	OS_EXIT_CRITICAL();
	pevent->OSEventType = OS_EVENT_TYPE_MUTEX;
	pevent->OSEventCnt = (INT16U) ((INT16U) prio << 8) | OS_MUTEX_AVAILABLE; /* Resource is avail.   */
	pevent->OSEventPtr = (void *) 0;								 /* No task owning the mutex	*/
#if OS_EVENT_NAME_SIZE > 1
	pevent->OSEventName[0] = '?';
	pevent->OSEventName[1] = OS_ASCII_NUL;
#endif
	OS_EventWaitListInit(pevent);
	*perr = OS_ERR_NONE;
	return (pevent);
}

/*$PAGE*/
/*
*********************************************************************************************************
*   									   DELETE A MUTEX
*
* Description: This function deletes a mutual exclusion semaphore and readies all tasks pending on the it.
*
* Arguments  : pevent   	 is a pointer to the event control block associated with the desired mutex.
*
*   		   opt  		 determines delete options as follows:
*   						 opt == OS_DEL_NO_PEND   Delete mutex ONLY if no task pending
*   						 opt == OS_DEL_ALWAYS    Deletes the mutex even if tasks are waiting.
*   												 In this case, all the tasks pending will be readied.
*
*   		   perr 		 is a pointer to an error code that can contain one of the following values:
*   						 OS_ERR_NONE			 The call was successful and the mutex was deleted
*   						 OS_ERR_DEL_ISR 		 If you attempted to delete the MUTEX from an ISR
*   						 OS_ERR_INVALID_OPT 	 An invalid option was specified
*   						 OS_ERR_TASK_WAITING	 One or more tasks were waiting on the mutex
*   						 OS_ERR_EVENT_TYPE  	 If you didn't pass a pointer to a mutex
*   						 OS_ERR_PEVENT_NULL 	 If 'pevent' is a NULL pointer.
*
* Returns    : pevent   	 upon error
*   		   (OS_EVENT *)0 if the mutex was successfully deleted.
*
* Note(s)    : 1) This function must be used with care.  Tasks that would normally expect the presence of
*   			  the mutex MUST check the return code of OSMutexPend().
*
*   		   2) 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 mutex.
*
*   		   3) Because ALL tasks pending on the mutex will be readied, you MUST be careful because the
*   			  resource(s) will no longer be guarded by the mutex.
*
*   		   4) IMPORTANT: In the 'OS_DEL_ALWAYS' case, we assume that the owner of the Mutex (if there
*   						 is one) is ready-to-run and is thus NOT pending on another kernel object or
*   						 has delayed itself.  In other words, if a task owns the mutex being deleted,
*   						 that task will be made ready-to-run at its original priority.
*********************************************************************************************************
*/

#if OS_MUTEX_DEL_EN
OS_EVENT * OSMutexDel(OS_EVENT *pevent, INT8U opt, INT8U *perr)
{
	BOOLEAN    tasks_waiting;
	OS_EVENT  *pevent_return;
	INT8U      pip; 									   /* Priority inheritance priority 		   */
	INT8U      prio;
	OS_TCB    *ptcb;
#if OS_CRITICAL_METHOD == 3 							   /* Allocate storage for CPU status register */
	OS_CPU_SR  cpu_sr = 0;
#endif



#if OS_ARG_CHK_EN > 0
	if (perr == (INT8U *) 0)
	{
		/* Validate 'perr'  						*/
		return (pevent);
	}
	if (pevent == (OS_EVENT *) 0)
	{
		/* Validate 'pevent'						*/
		*perr = OS_ERR_PEVENT_NULL;
		return (pevent);
	}
#endif
	if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX)
	{
		/* Validate event block type				*/
		*perr = OS_ERR_EVENT_TYPE;
		return (pevent);
	}
	if (OSIntNesting > 0)
	{
		/* See if called from ISR ...   			*/
		*perr = OS_ERR_DEL_ISR; 							/* ... can't DELETE from an ISR             */
		return (pevent);
	}
	OS_ENTER_CRITICAL();
	if (pevent->OSEventGrp != 0)
	{
		/* See if any tasks waiting on mutex		*/
		tasks_waiting = OS_TRUE;						   /* Yes   								   */
	}
	else
	{
		tasks_waiting = OS_FALSE;   					   /* No									   */
	}
	switch (opt)
	{
		case OS_DEL_NO_PEND:
			/* DELETE MUTEX ONLY IF NO TASK WAITING --- */
			if (tasks_waiting == OS_FALSE)
			{
#if OS_EVENT_NAME_SIZE > 1
				pevent->OSEventName[0] = '?';   		  /* Unknown name   						  */
				pevent->OSEventName[1] = OS_ASCII_NUL;
#endif
				pip = (INT8U) (pevent->OSEventCnt >> 8);
				OSTCBPrioTbl[pip] = (OS_TCB *) 0;   	 /* Free up the PIP 						 */
				pevent->OSEventType = OS_EVENT_TYPE_UNUSED;
				pevent->OSEventPtr = OSEventFreeList;    /* Return Event Control Block to free list  */
				pevent->OSEventCnt = 0;
				OSEventFreeList = pevent;
				OS_EXIT_CRITICAL();
				*perr = OS_ERR_NONE;
				pevent_return = (OS_EVENT *) 0; 	 /* Mutex has been deleted  				 */
			}
			else
			{
				OS_EXIT_CRITICAL();
				*perr = OS_ERR_TASK_WAITING;
				pevent_return = pevent;
			}
			break;

		case OS_DEL_ALWAYS:
			/* ALWAYS DELETE THE MUTEX ---------------- */
			pip = (INT8U) (pevent->OSEventCnt >> 8);					 /* Get PIP of mutex		  */
			prio = (INT8U) (pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8);  /* Get owner's original prio */
			ptcb = (OS_TCB *) pevent->OSEventPtr;
			if (ptcb != (OS_TCB *) 0)
			{
				/* See if any task owns the mutex   		*/
				if (ptcb->OSTCBPrio == pip)
				{
					/* See if original prio was changed 		*/
					OSMutex_RdyAtPrio(ptcb, prio);  	  /* Yes, Restore the task's original prio    */
				}
			}
			while (pevent->OSEventGrp != 0)
			{
				/* Ready ALL tasks waiting for mutex		*/
				(void) OS_EventTaskRdy(pevent, (void *) 0, OS_STAT_MUTEX, OS_STAT_PEND_OK);
			}
#if OS_EVENT_NAME_SIZE > 1
			pevent->OSEventName[0] = '?';   			  /* Unknown name   						  */
			pevent->OSEventName[1] = OS_ASCII_NUL;
#endif
			pip = (INT8U) (pevent->OSEventCnt >> 8);
			OSTCBPrioTbl[pip] = (OS_TCB *) 0;   		 /* Free up the PIP 						 */
			pevent->OSEventType = OS_EVENT_TYPE_UNUSED;
			pevent->OSEventPtr = OSEventFreeList;   	 /* Return Event Control Block to free list  */
			pevent->OSEventCnt = 0;
			OSEventFreeList = pevent;   			  /* Get next free event control block  	  */
			OS_EXIT_CRITICAL();
			if (tasks_waiting == OS_TRUE)
			{
				/* Reschedule only if task(s) were waiting  */
				OS_Sched(); 							  /* Find highest priority task ready to run  */
			}
			*perr = OS_ERR_NONE;
			pevent_return = (OS_EVENT *) 0; 			   /* Mutex has been deleted				   */
			break;

		default:
			OS_EXIT_CRITICAL();
			*perr = OS_ERR_INVALID_OPT;
			pevent_return = pevent;
			break;
	}
	return (pevent_return);
}
#endif

/*$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