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712 lines
36 KiB
Plaintext
712 lines
36 KiB
Plaintext
/*
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*********************************************************************************************************
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* uC/OS-II
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* The Real-Time Kernel
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* MUTUAL EXCLUSION SEMAPHORE MANAGEMENT
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*
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* (c) Copyright 1992-2007, Jean J. Labrosse, Weston, FL
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* All Rights Reserved
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*
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* File : OS_MUTEX.C
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* By : Jean J. Labrosse
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* Version : V2.85
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*
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* LICENSING TERMS:
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* ---------------
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* uC/OS-II is provided in source form for FREE evaluation, for educational use or for peaceful research.
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* If you plan on using uC/OS-II in a commercial product you need to contact Micriµm to properly license
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* its use in your product. We provide ALL the source code for your convenience and to help you experience
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* uC/OS-II. The fact that the source is provided does NOT mean that you can use it without paying a
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* licensing fee.
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*********************************************************************************************************
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*/
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#ifndef OS_MASTER_FILE
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#include <ucos_ii.h>
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#endif
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#if OS_MUTEX_EN > 0
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/*
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*********************************************************************************************************
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* LOCAL CONSTANTS
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*********************************************************************************************************
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*/
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#define OS_MUTEX_KEEP_LOWER_8 (INT16U)0x00FFu
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#define OS_MUTEX_KEEP_UPPER_8 (INT16U)0xFF00u
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#define OS_MUTEX_AVAILABLE (INT16U)0x00FFu
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/*
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*********************************************************************************************************
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* LOCAL CONSTANTS
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*********************************************************************************************************
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*/
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static void OSMutex_RdyAtPrio(OS_TCB *ptcb, INT8U prio);
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/*$PAGE*/
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/*
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*********************************************************************************************************
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* ACCEPT MUTUAL EXCLUSION SEMAPHORE
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*
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* Description: This function checks the mutual exclusion semaphore to see if a resource is available.
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* Unlike OSMutexPend(), OSMutexAccept() does not suspend the calling task if the resource is
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* not available or the event did not occur.
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*
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* Arguments : pevent is a pointer to the event control block
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*
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* perr is a pointer to an error code which will be returned to your application:
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* OS_ERR_NONE if the call was successful.
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* OS_ERR_EVENT_TYPE if 'pevent' is not a pointer to a mutex
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* OS_ERR_PEVENT_NULL 'pevent' is a NULL pointer
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* OS_ERR_PEND_ISR if you called this function from an ISR
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* OS_ERR_PIP_LOWER If the priority of the task that owns the Mutex is
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* HIGHER (i.e. a lower number) than the PIP. This error
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* indicates that you did not set the PIP higher (lower
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* number) than ALL the tasks that compete for the Mutex.
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* Unfortunately, this is something that could not be
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* detected when the Mutex is created because we don't know
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* what tasks will be using the Mutex.
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*
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* Returns : == OS_TRUE if the resource is available, the mutual exclusion semaphore is acquired
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* == OS_FALSE a) if the resource is not available
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* b) you didn't pass a pointer to a mutual exclusion semaphore
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* c) you called this function from an ISR
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*
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* Warning(s) : This function CANNOT be called from an ISR because mutual exclusion semaphores are
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* intended to be used by tasks only.
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*********************************************************************************************************
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*/
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#if OS_MUTEX_ACCEPT_EN > 0
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BOOLEAN OSMutexAccept (OS_EVENT *pevent, INT8U *perr)
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{
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INT8U pip; /* Priority Inheritance Priority (PIP) */
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#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
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OS_CPU_SR cpu_sr = 0;
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#endif
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#if OS_ARG_CHK_EN > 0
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if (perr == (INT8U *)0) { /* Validate 'perr' */
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return (OS_FALSE);
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}
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if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
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*perr = OS_ERR_PEVENT_NULL;
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return (OS_FALSE);
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}
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#endif
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if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) { /* Validate event block type */
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*perr = OS_ERR_EVENT_TYPE;
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return (OS_FALSE);
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}
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if (OSIntNesting > 0) { /* Make sure it's not called from an ISR */
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*perr = OS_ERR_PEND_ISR;
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return (OS_FALSE);
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}
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OS_ENTER_CRITICAL(); /* Get value (0 or 1) of Mutex */
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pip = (INT8U)(pevent->OSEventCnt >> 8); /* Get PIP from mutex */
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if ((pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8) == OS_MUTEX_AVAILABLE) {
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pevent->OSEventCnt &= OS_MUTEX_KEEP_UPPER_8; /* Mask off LSByte (Acquire Mutex) */
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pevent->OSEventCnt |= OSTCBCur->OSTCBPrio; /* Save current task priority in LSByte */
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pevent->OSEventPtr = (void *)OSTCBCur; /* Link TCB of task owning Mutex */
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if (OSTCBCur->OSTCBPrio <= pip) { /* PIP 'must' have a SMALLER prio ... */
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OS_EXIT_CRITICAL(); /* ... than current task! */
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*perr = OS_ERR_PIP_LOWER;
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} else {
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OS_EXIT_CRITICAL();
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*perr = OS_ERR_NONE;
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}
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return (OS_TRUE);
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}
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OS_EXIT_CRITICAL();
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*perr = OS_ERR_NONE;
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return (OS_FALSE);
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}
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#endif
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/*$PAGE*/
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/*
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*********************************************************************************************************
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* CREATE A MUTUAL EXCLUSION SEMAPHORE
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*
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* Description: This function creates a mutual exclusion semaphore.
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*
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* Arguments : prio is the priority to use when accessing the mutual exclusion semaphore. In
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* other words, when the semaphore is acquired and a higher priority task
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* attempts to obtain the semaphore then the priority of the task owning the
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* semaphore is raised to this priority. It is assumed that you will specify
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* a priority that is LOWER in value than ANY of the tasks competing for the
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* mutex.
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*
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* perr is a pointer to an error code which will be returned to your application:
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* OS_ERR_NONE if the call was successful.
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* OS_ERR_CREATE_ISR if you attempted to create a MUTEX from an ISR
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* OS_ERR_PRIO_EXIST if a task at the priority inheritance priority
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* already exist.
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* OS_ERR_PEVENT_NULL No more event control blocks available.
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* OS_ERR_PRIO_INVALID if the priority you specify is higher that the
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* maximum allowed (i.e. > OS_LOWEST_PRIO)
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*
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* Returns : != (void *)0 is a pointer to the event control clock (OS_EVENT) associated with the
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* created mutex.
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* == (void *)0 if an error is detected.
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*
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* Note(s) : 1) The LEAST significant 8 bits of '.OSEventCnt' are used to hold the priority number
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* of the task owning the mutex or 0xFF if no task owns the mutex.
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*
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* 2) The MOST significant 8 bits of '.OSEventCnt' are used to hold the priority number
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* to use to reduce priority inversion.
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*********************************************************************************************************
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*/
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OS_EVENT *OSMutexCreate (INT8U prio, INT8U *perr)
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{
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OS_EVENT *pevent;
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#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
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OS_CPU_SR cpu_sr = 0;
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#endif
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#if OS_ARG_CHK_EN > 0
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if (perr == (INT8U *)0) { /* Validate 'perr' */
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return ((OS_EVENT *)0);
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}
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if (prio >= OS_LOWEST_PRIO) { /* Validate PIP */
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*perr = OS_ERR_PRIO_INVALID;
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return ((OS_EVENT *)0);
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}
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#endif
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if (OSIntNesting > 0) { /* See if called from ISR ... */
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*perr = OS_ERR_CREATE_ISR; /* ... can't CREATE mutex from an ISR */
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return ((OS_EVENT *)0);
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}
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OS_ENTER_CRITICAL();
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if (OSTCBPrioTbl[prio] != (OS_TCB *)0) { /* Mutex priority must not already exist */
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OS_EXIT_CRITICAL(); /* Task already exist at priority ... */
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*perr = OS_ERR_PRIO_EXIST; /* ... inheritance priority */
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return ((OS_EVENT *)0);
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}
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OSTCBPrioTbl[prio] = OS_TCB_RESERVED; /* Reserve the table entry */
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pevent = OSEventFreeList; /* Get next free event control block */
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if (pevent == (OS_EVENT *)0) { /* See if an ECB was available */
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OSTCBPrioTbl[prio] = (OS_TCB *)0; /* No, Release the table entry */
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OS_EXIT_CRITICAL();
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*perr = OS_ERR_PEVENT_NULL; /* No more event control blocks */
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return (pevent);
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}
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OSEventFreeList = (OS_EVENT *)OSEventFreeList->OSEventPtr; /* Adjust the free list */
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OS_EXIT_CRITICAL();
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pevent->OSEventType = OS_EVENT_TYPE_MUTEX;
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pevent->OSEventCnt = (INT16U)((INT16U)prio << 8) | OS_MUTEX_AVAILABLE; /* Resource is avail. */
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pevent->OSEventPtr = (void *)0; /* No task owning the mutex */
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#if OS_EVENT_NAME_SIZE > 1
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pevent->OSEventName[0] = '?';
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pevent->OSEventName[1] = OS_ASCII_NUL;
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#endif
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OS_EventWaitListInit(pevent);
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*perr = OS_ERR_NONE;
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return (pevent);
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}
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/*$PAGE*/
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/*
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*********************************************************************************************************
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* DELETE A MUTEX
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*
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* Description: This function deletes a mutual exclusion semaphore and readies all tasks pending on the it.
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*
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* Arguments : pevent is a pointer to the event control block associated with the desired mutex.
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*
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* opt determines delete options as follows:
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* opt == OS_DEL_NO_PEND Delete mutex ONLY if no task pending
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* opt == OS_DEL_ALWAYS Deletes the mutex even if tasks are waiting.
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* In this case, all the tasks pending will be readied.
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*
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* perr is a pointer to an error code that can contain one of the following values:
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* OS_ERR_NONE The call was successful and the mutex was deleted
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* OS_ERR_DEL_ISR If you attempted to delete the MUTEX from an ISR
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* OS_ERR_INVALID_OPT An invalid option was specified
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* OS_ERR_TASK_WAITING One or more tasks were waiting on the mutex
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* OS_ERR_EVENT_TYPE If you didn't pass a pointer to a mutex
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* OS_ERR_PEVENT_NULL If 'pevent' is a NULL pointer.
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*
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* Returns : pevent upon error
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* (OS_EVENT *)0 if the mutex was successfully deleted.
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*
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* Note(s) : 1) This function must be used with care. Tasks that would normally expect the presence of
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* the mutex MUST check the return code of OSMutexPend().
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*
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* 2) This call can potentially disable interrupts for a long time. The interrupt disable
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* time is directly proportional to the number of tasks waiting on the mutex.
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*
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* 3) Because ALL tasks pending on the mutex will be readied, you MUST be careful because the
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* resource(s) will no longer be guarded by the mutex.
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*
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* 4) IMPORTANT: In the 'OS_DEL_ALWAYS' case, we assume that the owner of the Mutex (if there
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* is one) is ready-to-run and is thus NOT pending on another kernel object or
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* has delayed itself. In other words, if a task owns the mutex being deleted,
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* that task will be made ready-to-run at its original priority.
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*********************************************************************************************************
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*/
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#if OS_MUTEX_DEL_EN
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OS_EVENT *OSMutexDel (OS_EVENT *pevent, INT8U opt, INT8U *perr)
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{
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BOOLEAN tasks_waiting;
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OS_EVENT *pevent_return;
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INT8U pip; /* Priority inheritance priority */
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INT8U prio;
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OS_TCB *ptcb;
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#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
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OS_CPU_SR cpu_sr = 0;
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#endif
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#if OS_ARG_CHK_EN > 0
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if (perr == (INT8U *)0) { /* Validate 'perr' */
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return (pevent);
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}
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if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
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*perr = OS_ERR_PEVENT_NULL;
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return (pevent);
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}
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#endif
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if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) { /* Validate event block type */
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*perr = OS_ERR_EVENT_TYPE;
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return (pevent);
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}
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if (OSIntNesting > 0) { /* See if called from ISR ... */
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*perr = OS_ERR_DEL_ISR; /* ... can't DELETE from an ISR */
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return (pevent);
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}
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OS_ENTER_CRITICAL();
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if (pevent->OSEventGrp != 0) { /* See if any tasks waiting on mutex */
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tasks_waiting = OS_TRUE; /* Yes */
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} else {
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tasks_waiting = OS_FALSE; /* No */
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}
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switch (opt) {
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case OS_DEL_NO_PEND: /* DELETE MUTEX ONLY IF NO TASK WAITING --- */
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if (tasks_waiting == OS_FALSE) {
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#if OS_EVENT_NAME_SIZE > 1
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pevent->OSEventName[0] = '?'; /* Unknown name */
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pevent->OSEventName[1] = OS_ASCII_NUL;
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#endif
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pip = (INT8U)(pevent->OSEventCnt >> 8);
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OSTCBPrioTbl[pip] = (OS_TCB *)0; /* Free up the PIP */
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pevent->OSEventType = OS_EVENT_TYPE_UNUSED;
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pevent->OSEventPtr = OSEventFreeList; /* Return Event Control Block to free list */
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pevent->OSEventCnt = 0;
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OSEventFreeList = pevent;
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OS_EXIT_CRITICAL();
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*perr = OS_ERR_NONE;
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pevent_return = (OS_EVENT *)0; /* Mutex has been deleted */
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} else {
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OS_EXIT_CRITICAL();
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*perr = OS_ERR_TASK_WAITING;
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pevent_return = pevent;
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}
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break;
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case OS_DEL_ALWAYS: /* ALWAYS DELETE THE MUTEX ---------------- */
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pip = (INT8U)(pevent->OSEventCnt >> 8); /* Get PIP of mutex */
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prio = (INT8U)(pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8); /* Get owner's original prio */
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ptcb = (OS_TCB *)pevent->OSEventPtr;
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if (ptcb != (OS_TCB *)0) { /* See if any task owns the mutex */
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if (ptcb->OSTCBPrio == pip) { /* See if original prio was changed */
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OSMutex_RdyAtPrio(ptcb, prio); /* Yes, Restore the task's original prio */
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}
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}
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while (pevent->OSEventGrp != 0) { /* Ready ALL tasks waiting for mutex */
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(void)OS_EventTaskRdy(pevent, (void *)0, OS_STAT_MUTEX, OS_STAT_PEND_OK);
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}
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#if OS_EVENT_NAME_SIZE > 1
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pevent->OSEventName[0] = '?'; /* Unknown name */
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pevent->OSEventName[1] = OS_ASCII_NUL;
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#endif
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pip = (INT8U)(pevent->OSEventCnt >> 8);
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OSTCBPrioTbl[pip] = (OS_TCB *)0; /* Free up the PIP */
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pevent->OSEventType = OS_EVENT_TYPE_UNUSED;
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pevent->OSEventPtr = OSEventFreeList; /* Return Event Control Block to free list */
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pevent->OSEventCnt = 0;
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OSEventFreeList = pevent; /* Get next free event control block */
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OS_EXIT_CRITICAL();
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if (tasks_waiting == OS_TRUE) { /* Reschedule only if task(s) were waiting */
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OS_Sched(); /* Find highest priority task ready to run */
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}
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*perr = OS_ERR_NONE;
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pevent_return = (OS_EVENT *)0; /* Mutex has been deleted */
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break;
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default:
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OS_EXIT_CRITICAL();
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*perr = OS_ERR_INVALID_OPT;
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pevent_return = pevent;
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break;
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}
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return (pevent_return);
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}
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#endif
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/*$PAGE*/
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/*
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*********************************************************************************************************
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* PEND ON MUTUAL EXCLUSION SEMAPHORE
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*
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* Description: This function waits for a mutual exclusion semaphore.
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*
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* Arguments : pevent is a pointer to the event control block associated with the desired
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* mutex.
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*
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* timeout is an optional timeout period (in clock ticks). If non-zero, your task will
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* wait for the resource up to the amount of time specified by this argument.
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* If you specify 0, however, your task will wait forever at the specified
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* mutex or, until the resource becomes available.
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*
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* perr is a pointer to where an error message will be deposited. Possible error
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* messages are:
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* OS_ERR_NONE The call was successful and your task owns the mutex
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* OS_ERR_TIMEOUT The mutex was not available within the specified 'timeout'.
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* OS_ERR_PEND_ABORT The wait on the mutex was aborted.
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* OS_ERR_EVENT_TYPE If you didn't pass a pointer to a mutex
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* OS_ERR_PEVENT_NULL 'pevent' is a NULL pointer
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* OS_ERR_PEND_ISR If you called this function from an ISR and the result
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* would lead to a suspension.
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* OS_ERR_PIP_LOWER If the priority of the task that owns the Mutex is
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* HIGHER (i.e. a lower number) than the PIP. This error
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* indicates that you did not set the PIP higher (lower
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* number) than ALL the tasks that compete for the Mutex.
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* Unfortunately, this is something that could not be
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* detected when the Mutex is created because we don't know
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* what tasks will be using the Mutex.
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* OS_ERR_PEND_LOCKED If you called this function when the scheduler is locked
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*
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* Returns : none
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*
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* Note(s) : 1) The task that owns the Mutex MUST NOT pend on any other event while it owns the mutex.
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*
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* 2) You MUST NOT change the priority of the task that owns the mutex
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*********************************************************************************************************
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*/
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void OSMutexPend (OS_EVENT *pevent, INT16U timeout, INT8U *perr)
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{
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INT8U pip; /* Priority Inheritance Priority (PIP) */
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INT8U mprio; /* Mutex owner priority */
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BOOLEAN rdy; /* Flag indicating task was ready */
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OS_TCB *ptcb;
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OS_EVENT *pevent2;
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INT8U y;
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INT8U pend_stat;
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#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
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OS_CPU_SR cpu_sr = 0;
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#endif
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#if OS_ARG_CHK_EN > 0
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if (perr == (INT8U *)0) { /* Validate 'perr' */
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return;
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}
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if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
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*perr = OS_ERR_PEVENT_NULL;
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return;
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}
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#endif
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if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) { /* Validate event block type */
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*perr = OS_ERR_EVENT_TYPE;
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return;
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}
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if (OSIntNesting > 0) { /* See if called from ISR ... */
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*perr = OS_ERR_PEND_ISR; /* ... can't PEND from an ISR */
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return;
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}
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if (OSLockNesting > 0) { /* See if called with scheduler locked ... */
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*perr = OS_ERR_PEND_LOCKED; /* ... can't PEND when locked */
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return;
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}
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OS_ENTER_CRITICAL();
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pip = (INT8U)(pevent->OSEventCnt >> 8); /* Get PIP from mutex */
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/* 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 */
|
||
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;
|
||
}
|
||
mprio = (INT8U)(pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8); /* No, 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) != 0) { /* See if mutex owner is ready */
|
||
OSRdyTbl[y] &= ~ptcb->OSTCBBitX; /* Yes, Remove owner from Rdy ...*/
|
||
if (OSRdyTbl[y] == 0) { /* ... list at current prio */
|
||
OSRdyGrp &= ~ptcb->OSTCBBitY;
|
||
}
|
||
rdy = OS_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 = OS_FALSE; /* No */
|
||
}
|
||
ptcb->OSTCBPrio = pip; /* Change owner task prio to PIP */
|
||
#if OS_LOWEST_PRIO <= 63
|
||
ptcb->OSTCBY = (INT8U)( ptcb->OSTCBPrio >> 3);
|
||
ptcb->OSTCBX = (INT8U)( ptcb->OSTCBPrio & 0x07);
|
||
ptcb->OSTCBBitY = (INT8U)(1 << ptcb->OSTCBY);
|
||
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) { /* Add to 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->OSTCBStatPend = OS_STAT_PEND_OK;
|
||
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->OSTCBStatPend != OS_STAT_PEND_OK) { /* See if we timed out during the pend */
|
||
pend_stat = OSTCBCur->OSTCBStatPend;
|
||
OS_EventTOAbort(pevent);
|
||
OS_EXIT_CRITICAL();
|
||
switch (pend_stat) {
|
||
case OS_STAT_PEND_TO:
|
||
default:
|
||
*perr = OS_ERR_TIMEOUT; /* Indicate that we didn't get mutex within TO */
|
||
break;
|
||
|
||
case OS_STAT_PEND_ABORT:
|
||
*perr = OS_ERR_PEND_ABORT; /* Indicate that we aborted getting mutex */
|
||
break;
|
||
}
|
||
return;
|
||
}
|
||
OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0;
|
||
OS_EXIT_CRITICAL();
|
||
*perr = OS_ERR_NONE;
|
||
}
|
||
/*$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_ERR_NONE 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_RESERVED; /* 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, OS_STAT_PEND_OK);
|
||
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_ERR_NONE);
|
||
}
|
||
}
|
||
pevent->OSEventCnt |= OS_MUTEX_AVAILABLE; /* No, Mutex is now available */
|
||
pevent->OSEventPtr = (void *)0;
|
||
OS_EXIT_CRITICAL();
|
||
return (OS_ERR_NONE);
|
||
}
|
||
/*$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_ERR_NONE 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 = OS_TRUE;
|
||
} else {
|
||
p_mutex_data->OSValue = OS_FALSE;
|
||
}
|
||
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_ERR_NONE);
|
||
}
|
||
#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 >> (INT8U)3) & (INT8U)0x07);
|
||
ptcb->OSTCBX = (INT8U) (prio & (INT8U)0x07);
|
||
ptcb->OSTCBBitY = (INT8U)(1 << ptcb->OSTCBY);
|
||
ptcb->OSTCBBitX = (INT8U)(1 << ptcb->OSTCBX);
|
||
#else
|
||
ptcb->OSTCBY = (INT8U)((prio >> (INT8U)4) & (INT8U)0x0F);
|
||
ptcb->OSTCBX = (INT8U) (prio & (INT8U)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 */
|