OS_RESULT rt_tsk_prio (OS_TID task_id, U8 new_prio) {
/* Change execution priority of a task to "new_prio". */
P_TCB p_task;
if (task_id == 0) {
/* Change execution priority of calling task. */
os_tsk.run->prio = new_prio;
run:if (rt_rdy_prio() > new_prio) {
rt_put_prio (&os_rdy, os_tsk.run);
os_tsk.run->state = READY;
rt_dispatch (NULL);
}
return (OS_R_OK);
}
/* Find the task in the "os_active_TCB" array. */
if (task_id > os_maxtaskrun || os_active_TCB[task_id-1] == NULL) {
/* Task with "task_id" not found or not started. */
return (OS_R_NOK);
}
p_task = os_active_TCB[task_id-1];
p_task->prio = new_prio;
if (p_task == os_tsk.run) {
goto run;
}
rt_resort_prio (p_task);
if (p_task->state == READY) {
/* Task enqueued in a ready list. */
p_task = rt_get_first (&os_rdy);
rt_dispatch (p_task);
}
return (OS_R_OK);
}
OS_RESULT rt_mut_delete (OS_ID mutex) {
/* Delete a mutex object */
P_MUCB p_MCB = mutex;
P_TCB p_TCB;
__DMB();
/* Restore owner task's priority. */
if (p_MCB->level != 0) {
p_MCB->owner->prio = p_MCB->prio;
if (p_MCB->owner != os_tsk.run) {
rt_resort_prio (p_MCB->owner);
}
}
while (p_MCB->p_lnk != NULL) {
/* A task is waiting for mutex. */
p_TCB = rt_get_first ((P_XCB)p_MCB);
rt_ret_val(p_TCB, 0/*osOK*/);
rt_rmv_dly(p_TCB);
p_TCB->state = READY;
rt_put_prio (&os_rdy, p_TCB);
}
if (os_rdy.p_lnk && (os_rdy.p_lnk->prio > os_tsk.run->prio)) {
/* preempt running task */
rt_put_prio (&os_rdy, os_tsk.run);
os_tsk.run->state = READY;
rt_dispatch (NULL);
}
p_MCB->cb_type = 0;
return (OS_R_OK);
}
OS_RESULT rt_mut_wait (OS_ID mutex, U16 timeout) {
/* Wait for a mutex, continue when mutex is free. */
P_MUCB p_MCB = mutex;
if (p_MCB->level == 0) {
p_MCB->owner = os_tsk.run;
p_MCB->prio = os_tsk.run->prio;
goto inc;
}
if (p_MCB->owner == os_tsk.run) {
/* OK, running task is the owner of this mutex. */
inc:p_MCB->level++;
return (OS_R_OK);
}
/* Mutex owned by another task, wait until released. */
if (timeout == 0) {
return (OS_R_TMO);
}
/* Raise the owner task priority if lower than current priority. */
/* This priority inversion is called priority inheritance. */
if (p_MCB->prio < os_tsk.run->prio) {
p_MCB->owner->prio = os_tsk.run->prio;
rt_resort_prio (p_MCB->owner);
}
if (p_MCB->p_lnk != NULL) {
rt_put_prio ((P_XCB)p_MCB, os_tsk.run);
}
else {
p_MCB->p_lnk = os_tsk.run;
os_tsk.run->p_lnk = NULL;
os_tsk.run->p_rlnk = (P_TCB)p_MCB;
}
rt_block(timeout, WAIT_MUT);
return (OS_R_TMO);
}
OS_RESULT rt_mut_delete (OS_ID mutex) {
/* Delete a mutex object */
P_MUCB p_MCB = mutex;
P_TCB p_TCB;
P_MUCB p_mlnk;
U8 prio;
if (p_MCB->level != 0U) {
p_TCB = p_MCB->owner;
/* Remove mutex from task mutex owner list. */
p_mlnk = p_TCB->p_mlnk;
if (p_mlnk == p_MCB) {
p_TCB->p_mlnk = p_MCB->p_mlnk;
}
else {
while (p_mlnk) {
if (p_mlnk->p_mlnk == p_MCB) {
p_mlnk->p_mlnk = p_MCB->p_mlnk;
break;
}
p_mlnk = p_mlnk->p_mlnk;
}
}
/* Restore owner task's priority. */
prio = p_TCB->prio_base;
p_mlnk = p_TCB->p_mlnk;
while (p_mlnk) {
if ((p_mlnk->p_lnk != NULL) && (p_mlnk->p_lnk->prio > prio)) {
/* A task with higher priority is waiting for mutex. */
prio = p_mlnk->p_lnk->prio;
}
p_mlnk = p_mlnk->p_mlnk;
}
if (p_TCB->prio != prio) {
p_TCB->prio = prio;
if (p_TCB != os_tsk.run) {
rt_resort_prio (p_TCB);
}
}
}
while (p_MCB->p_lnk != NULL) {
/* A task is waiting for mutex. */
p_TCB = rt_get_first ((P_XCB)p_MCB);
rt_ret_val(p_TCB, 0U/*osOK*/);
rt_rmv_dly(p_TCB);
p_TCB->state = READY;
rt_put_prio (&os_rdy, p_TCB);
}
if ((os_rdy.p_lnk != NULL) && (os_rdy.p_lnk->prio > os_tsk.run->prio)) {
/* preempt running task */
rt_put_prio (&os_rdy, os_tsk.run);
os_tsk.run->state = READY;
rt_dispatch (NULL);
}
p_MCB->cb_type = 0U;
return (OS_R_OK);
}
