?? os_mutex.c
字號:
}
#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 */
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