os_mutex.c

完整的ucos实例

} 
#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) 
{ 
#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                              */