/*
* === FUNCTION ======================================================================
* Name: OS_SemDestroy
* Description: Destroys a binary semaphore and resets the associated list.
* =====================================================================================
*/
int OS_SemDestroy(OS_SemID_t *_sem)
{
OS_SemID_t id_sem = *_sem;
_sem = NULL;
OS_ListReset(&(SEM(id_sem)->list));
return 0;
}
/*
* === FUNCTION ======================================================================
* Name: OS_SemPost
* Description: This functions release the semaphore and wakes up the task
* being blocked on it. A task can be also be waiting for a time event, so this
* function vefiries whether the relased task is also waiting for a time event
* or not. In case it is, the task is also removed from the time queue.
* =====================================================================================
*/
int OS_SemPost(OS_SemID_t _sem)
{
OS_task_t *task;
OS_Node_t *n;
OS_SemID_t id_sem = _sem;
KTRACE_EVENT_SEM(KEVENT_UNLOCK, SEM(id_sem)->sem_id);
if(OS_ListGetNum(&(SEM(id_sem)->list)) != 0)
{
/* Outs the task from the semaphore queue */
n = OS_ListGetNode(&(SEM(id_sem)->list));
task = GET_ELEMENT(OS_task_t, n, resource_node);
/* Store what is the blocked thread in the semaphore structure */
SEM(id_sem)->tid_in = task->tid;
KTRACE_EVENT_SEM_TID(KEVENT_LOCK_CATCHED, SEM(id_sem)->sem_id, task->tid);
/*
* Verifies if the thread is blocked in the time queue
* due to a TimedWait system call
*/
if(task->status | TS_TIME_BLOCKED) {
OS_TimeRemoveFromQueue(task);
}
/* Reset the wait_sem value */
task->wait_sem = 0;
/* Add the blocked task to the ready task queue */
OS_SchedTaskReady(task->tid);
}
else {
/* Increment the semaphore counter */
SEM(id_sem)->sem_value = 1;
OS_ListReset(&(SEM(id_sem)->list));
}
return 0;
}
/*
* === FUNCTION ======================================================================
* Name: OS_SemInit
* Description: This function initializes a binary semaphore. The parameters
* taken from the function is the pointer to the binary semaphore structure and
* the initial value. The value only can be 0 (catched) or 1 (free).
* =====================================================================================
*/
int OS_SemInit(OS_SemID_t *_sem, uint32 _value)
{
OS_SemID_t id_sem;
GET_NEXT_SEM_ID(id_sem);
SEM(id_sem)->sem_id = id_sem;
if(_value <= 0)
SEM(id_sem)->sem_value = 0; /* Binary semaphore */
else
SEM(id_sem)->sem_value = 1; /* Counter semaphore = 1 */
SEM(id_sem)->tid_in = 0;
OS_ListReset(&(SEM(id_sem)->list));
*_sem = id_sem;
return 0;
}
/*
* Function: void OS_TCBInit(void)
*
* This function initializes all the Thread Control Blocks to the init state
*/
void OS_TCBInit(void)
{
int i;
OS_ListReset(&tcb_list);
/* Assure that the priority of the task 0 is 0. This is important if ERCOS
* is linked to C++ stuff; constructors (called from OS_CPPInit) may do
* system calls and the task 0 will store the context of OS_Start function
* before the first official dispatch (at the end of the function). Until
* now, priority was 0 because task_table is allocated in the bss which is
* zeroed at startup time (!!) */
task_table[0].priority = 0;
for (i = MAIN_THREAD_TID; i < CONFIG_ERCOS_MAX_THREADS; ++i)
{
/* Init the thread status */
task_table[i].status = 0;
/* Traps off, set S, PS and FP unit */
//task_table[i].context.psr = 0x000010c0;
/* Init the thread identifier */
task_table[i].tid = i;
/* Reset all the nodes associated with each thread */
OS_ListNodeReset(&task_table[i].node);
OS_ListNodeReset(&task_table[i].time_node);
OS_ListNodeReset(&task_table[i].resource_node);
/* Add the TCB into the free TCBs queue */
OS_ListAppend(&tcb_list, &task_table[i].node);
}
/* create the idle task, with the minimum priority */
OS_TaskCreate (NULL, 0x600, OS_IdleTask, NULL, SCHED_MIN_PRIORITY);
/* create the main task, with the maximum priority */
OS_TaskCreate (NULL, CONFIG_ERCOS_MAIN_STACK_SIZE, (void *) main, NULL, SCHED_MAX_PRIORITY);
}
