os_mutex.c

嵌入式实时操作系统uCOS-II源码

#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
*                            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)
{
    INT8U      pip;                                        /* Priority Inheritance Priority (PIP)      */
    INT8U      mprio;                                      /* Mutex owner priority                     */
    BOOLEAN    rdy;                                        /* Flag indicating task was ready           */
    OS_TCB    *ptcb;
    OS_EVENT  *pevent2;
    INT8U      y;
#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */
    OS_CPU_SR  cpu_sr;



    cpu_sr = 0;                                            /* Prevent compiler warning                 */
#endif    
    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;
    }
#endif
    if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) {      /* Validate event block type                */
        *err = OS_ERR_EVENT_TYPE;
        return;
    }
    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) {                                 /*     Need to promote prio of owner?*/
        if (mprio > OSTCBCur->OSTCBPrio) {  
            y = ptcb->OSTCBY;                          
            if ((OSRdyTbl[y] & ptcb->OSTCBBitX) != 0x00) {        /*     See if mutex owner is ready   */
                OSRdyTbl[y] &= ~ptcb->OSTCBBitX;                  /*     Yes, Remove owner from Rdy ...*/
                if (OSRdyTbl[y] == 0x00) {                        /*          ... list at current prio */
                    OSRdyGrp &= ~ptcb->OSTCBBitY;
                }
                rdy = TRUE;
            } else {
                pevent2 = ptcb->OSTCBEventPtr;
                if (pevent2 != (OS_EVENT *)0) {                   /* Remove from event wait list       */
                    if ((pevent2->OSEventTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0) {
                        pevent2->OSEventGrp &= ~ptcb->OSTCBBitY;
                    }
                }
                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;
            } else {
                pevent2 = ptcb->OSTCBEventPtr;
                if (pevent2 != (OS_EVENT *)0) {            /* Remove from event wait list              */
                    pevent2->OSEventGrp               |= ptcb->OSTCBBitY;
                    pevent2->OSEventTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
                }
            }
            OSTCBPrioTbl[pip] = (OS_TCB *)ptcb;
        }
    }
    OSTCBCur->OSTCBStat   |= OS_STAT_MUTEX;           /* Mutex not available, pend current task        */
    OSTCBCur->OSTCBPendTO  = FALSE;
    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->OSTCBPendTO == TRUE) {              /* See if we timed out during the pend           */
        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)
{
    INT8U      pip;                                   /* Priority inheritance priority                 */
    INT8U      prio;
    INT8U      y;
#if OS_CRITICAL_METHOD == 3                           /* Allocate storage for CPU status register      */
    OS_CPU_SR  cpu_sr;



    cpu_sr = 0;                                       /* Prevent compiler warning                      */
#endif    
    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);
    }
#endif
    if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) { /* Validate event block type                     */
        return (OS_ERR_EVENT_TYPE);
    }                                                 
    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 != (OS_TCB *)pevent->OSEventPtr) {   /* 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? */
        y            = OSTCBCur->OSTCBY;              /* Yes, Return to original priority              */
        OSRdyTbl[y] &= ~OSTCBCur->OSTCBBitX;          /*      Remove owner from ready list at 'pip'    */
        if (OSRdyTbl[y] == 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
*
*              p_mutex_data    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 *p_mutex_data)
{
    INT8U     *psrc;
    INT8U     *pdest;
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr;



    cpu_sr = 0;                                            /* Prevent compiler warning                 */
#endif    
    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);
    }
#endif
    if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) {      /* Validate event block type                */
        return (OS_ERR_EVENT_TYPE);
    }
    OS_ENTER_CRITICAL();
    p_mutex_data->OSMutexPIP  = (INT8U)(pevent->OSEventCnt >> 8);
    p_mutex_data->OSOwnerPrio = (INT8U)(pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8);
    if (p_mutex_data->OSOwnerPrio == 0xFF) {
        p_mutex_data->OSValue = 1;
    } else {
        p_mutex_data->OSValue = 0;
    }
    p_mutex_data->OSEventGrp  = pevent->OSEventGrp;        /* Copy wait list                           */
    psrc                      = &pevent->OSEventTbl[0];
    pdest                     = &p_mutex_data->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                              */