os_mutex.c

操作系统ucosii的源码

            ptcb->OSTCBBitX = (INT8U)(1 << ptcb->OSTCBX);
#else
            ptcb->OSTCBY    = (INT8U)((ptcb->OSTCBPrio >> 4) & 0xFF);
            ptcb->OSTCBX    = (INT8U)( ptcb->OSTCBPrio & 0x0F);
            ptcb->OSTCBBitY = (INT16U)(1 << ptcb->OSTCBY);
            ptcb->OSTCBBitX = (INT16U)(1 << ptcb->OSTCBX);
#endif
            if (rdy == OS_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] = ptcb;
        }
    }
    OSTCBCur->OSTCBStat   |= OS_STAT_MUTEX;           /* Mutex not available, pend current task        */
    OSTCBCur->OSTCBPendTO  = OS_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 == OS_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.
*              OS_ERR_PIP_LOWER        If the priority of the new 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.
*********************************************************************************************************
*/

INT8U  OSMutexPost (OS_EVENT *pevent)
{
    INT8U      pip;                                   /* Priority inheritance priority                 */
    INT8U      prio;
#if OS_CRITICAL_METHOD == 3                           /* Allocate storage for CPU status register      */
    OS_CPU_SR  cpu_sr = 0;
#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? */
        OSMutex_RdyAtPrio(OSTCBCur, prio);            /* Restore the task's original priority          */
    }
    OSTCBPrioTbl[pip] = (OS_TCB *)1;                  /* Reserve table entry                           */
    if (pevent->OSEventGrp != 0) {                    /* 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 new mutex owner's OS_TCB         */
        if (prio <= pip) {                            /*      PIP 'must' have a SMALLER prio ...       */
            OS_EXIT_CRITICAL();                       /*      ... than current task!                   */
            OS_Sched();                               /*      Find highest priority task ready to run  */
            return (OS_ERR_PIP_LOWER);
        } else {
            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   If 'pevent'       is a NULL pointer
*              OS_ERR_PDATA_NULL    If 'p_mutex_data' 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      i;
#if OS_LOWEST_PRIO <= 63
    INT8U     *psrc;
    INT8U     *pdest;
#else
    INT16U    *psrc;
    INT16U    *pdest;
#endif
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr = 0;
#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);
    }
    if (p_mutex_data == (OS_MUTEX_DATA *)0) {              /* Validate 'p_mutex_data'                  */
        return (OS_ERR_PDATA_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];
    for (i = 0; i < OS_EVENT_TBL_SIZE; i++) {
        *pdest++ = *psrc++;
    }
    OS_EXIT_CRITICAL();
    return (OS_NO_ERR);
}
#endif                                                     /* OS_MUTEX_QUERY_EN                        */

/*$PAGE*/
/*
*********************************************************************************************************
*                                RESTORE A TASK BACK TO ITS ORIGINAL PRIORITY
*
* Description: This function makes a task ready at the specified priority
*
* Arguments  : ptcb            is a pointer to OS_TCB of the task to make ready
*
*              prio            is the desired priority
*
* Returns    : none
*********************************************************************************************************
*/

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


    y            =  ptcb->OSTCBY;                          /* Remove owner from ready list at 'pip'    */
    OSRdyTbl[y] &= ~ptcb->OSTCBBitX;
    if (OSRdyTbl[y] == 0) {
        OSRdyGrp &= ~ptcb->OSTCBBitY;
    }
    ptcb->OSTCBPrio         = prio;
#if OS_LOWEST_PRIO <= 63
    ptcb->OSTCBY            = (INT8U)((prio >> 3) & 0x07);
    ptcb->OSTCBX            = (INT8U) (prio & 0x07);
    ptcb->OSTCBBitY         = (INT8U)(1 << ptcb->OSTCBY);
    ptcb->OSTCBBitX         = (INT8U)(1 << ptcb->OSTCBX);
#else
    ptcb->OSTCBY            = (INT8U)((prio >> 4) & 0x0F);
    ptcb->OSTCBX            = (INT8U) (prio & 0x0F);
    ptcb->OSTCBBitY         = (INT16U)(1 << ptcb->OSTCBY);
    ptcb->OSTCBBitX         = (INT16U)(1 << ptcb->OSTCBX);
#endif
    OSRdyGrp               |= ptcb->OSTCBBitY;             /* Make task ready at original priority     */
    OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
    OSTCBPrioTbl[prio]      = ptcb;
}


#endif                                                     /* OS_MUTEX_EN                              */