OS_RESULT os_mut_release (OS_ID mutex) {
/* Release a mutex object */
P_MUCB p_MCB = mutex;
P_TCB p_TCB;
tsk_lock();
if (p_MCB->level == 0 || p_MCB->owner != os_runtask) {
/* Unbalanced mutex release or task is not the owner */
tsk_unlock ();
return (OS_R_NOK);
}
if (--p_MCB->level != 0) {
goto ok;
}
/* Restore owner task's priority. */
os_runtask->prio = p_MCB->prio;
if (p_MCB->p_lnk != NULL) {
/* A task is waiting for this mutex. */
p_TCB = os_get_first ((P_XCB)p_MCB);
p_TCB->ret_val = OS_R_MUT;
os_rmv_dly (p_TCB);
/* A waiting task becomes the owner of this mutex. */
p_MCB->level = 1;
p_MCB->owner = p_TCB;
p_MCB->prio = p_TCB->prio;
/* Priority inversion, check which task continues. */
if (os_runtask->prio >= os_rdy_prio()) {
os_dispatch (p_TCB);
}
else {
/* Ready task has higher priority than running task. */
os_put_prio (&os_rdy, os_runtask);
os_put_prio (&os_rdy, p_TCB);
os_runtask->state = READY;
p_TCB->state = READY;
os_dispatch (NULL);
}
}
else {
/* Check if own priority raised by priority inversion. */
if (os_rdy_prio() > os_runtask->prio) {
os_put_prio (&os_rdy, os_runtask);
os_runtask->state = READY;
os_dispatch (NULL);
}
}
ok:tsk_unlock();
return (OS_R_OK);
}
void os_mbx_psh (P_MCB p_CB, void *p_msg) {
/* Store the message to the mailbox queue or pass it to task directly. */
P_TCB p_TCB;
/* Check if this was an 'isr_mbx_receive ()' post service request. */
if (p_CB->p_lnk != NULL && p_CB->isr_st == 2) {
/* A task is waiting to send message, remove it from the waiting list. */
p_CB->isr_st = 0;
p_TCB = os_get_first ((P_XCB)p_CB);
p_TCB->ret_val = OS_R_OK;
goto rdy;
}
/* A task is waiting for message, pass the message to task directly. */
if (p_CB->p_lnk != NULL && p_CB->count == 0) {
p_TCB = os_get_first ((P_XCB)p_CB);
p_TCB->p_msg = p_msg;
p_TCB->ret_val = OS_R_MBX;
rdy:p_TCB->state = READY;
os_rmv_dly (p_TCB);
os_put_prio (&os_rdy, p_TCB);
}
else {
/* No task is waiting for message, store it to the mailbox queue. */
if (p_CB->count < p_CB->size) {
p_CB->msg[p_CB->first] = p_msg;
_incw (&p_CB->count);
if (++p_CB->first == p_CB->size) {
p_CB->first = 0;
}
}
else {
os_error (OS_ERR_MBX_OVF);
}
}
}
void os_tsk_pass (void) {
/* Allow tasks of same priority level to run cooperatively.*/
P_TCB p_new;
tsk_lock();
p_new = os_get_same_rdy_prio();
if (p_new != NULL) {
os_put_prio ((P_XCB)&os_rdy, os_runtask);
os_runtask->state = READY;
os_switch_tasks (p_new);
}
tsk_unlock();
}
OS_RESULT os_mbx_send (OS_ID mailbox, void *p_msg, U16 timeout) {
/* Send message to a mailbox */
P_MCB p_MCB = mailbox;
P_TCB p_TCB;
tsk_lock();
m:if (p_MCB->p_lnk != NULL && p_MCB->count == 0) {
/* A task is waiting for message */
p_TCB = os_get_first ((P_XCB)p_MCB);
p_TCB->p_msg = p_msg;
p_TCB->ret_val = OS_R_MBX;
os_rmv_dly (p_TCB);
os_dispatch (p_TCB);
}
else {
/* Store message in mailbox queue */
if (p_MCB->count == p_MCB->size) {
/* No free message entry, wait for one. If message queue is full, */
/* then no task is waiting for message. The 'p_MCB->p_lnk' list */
/* pointer can now be reused for send message waits task list. */
if (timeout == 0) {
goto wto;
}
if (p_MCB->p_lnk != NULL) {
os_put_prio ((P_XCB)p_MCB, os_runtask);
}
else {
p_MCB->p_lnk = os_runtask;
os_runtask->p_lnk = NULL;
os_runtask->p_rlnk = (P_TCB)p_MCB;
/* Signal the 'isr_mbx_receive ()' that the task is waiting */
/* to send a message */
p_MCB->isr_st = 1;
}
if (os_block(timeout, WAIT_MBX) == OS_R_TMO) {
wto: tsk_unlock();
return (OS_R_TMO);
}
/* A message has been fetched, check the mailbox again. */
goto m;
}
/* Yes, there is a free entry in a mailbox. */
p_MCB->msg[p_MCB->first] = p_msg;
_incw (&p_MCB->count);
if (++p_MCB->first == p_MCB->size) {
p_MCB->first = 0;
}
}
tsk_unlock();
return (OS_R_OK);
}
OS_RESULT os_mbx_wait (OS_ID mailbox, void **message, U16 timeout) {
/* Receive a message; possibly wait for it */
P_MCB p_MCB = mailbox;
P_TCB p_TCB;
tsk_lock();
/* If a message is available in the fifo buffer */
/* remove it from the fifo buffer and return. */
if (p_MCB->count) {
*message = p_MCB->msg[p_MCB->last];
_decw (&p_MCB->count);
if (++p_MCB->last == p_MCB->size) {
p_MCB->last = 0;
}
if (p_MCB->p_lnk != NULL) {
/* A task is waiting to send message */
p_TCB = os_get_first ((P_XCB)p_MCB);
os_rmv_dly (p_TCB);
os_dispatch (p_TCB);
}
tsk_unlock();
return (OS_R_OK);
}
/* No message available: wait for one */
if (timeout == 0) {
goto rto;
}
if (p_MCB->p_lnk != NULL) {
os_put_prio ((P_XCB)p_MCB, os_runtask);
}
else {
p_MCB->p_lnk = os_runtask;
os_runtask->p_lnk = NULL;
os_runtask->p_rlnk = (P_TCB)p_MCB;
}
if (os_block(timeout, WAIT_MBX) == OS_R_TMO) {
rto:tsk_unlock();
*message = NULL;
return (OS_R_TMO);
}
tsk_unlock();
*message = os_runtask->p_msg;
return (OS_R_MBX);
}
OS_RESULT os_mut_wait (OS_ID mutex, U16 timeout) {
/* Wait for a mutex, continue when mutex is free. */
P_MUCB p_MCB = mutex;
tsk_lock();
if (p_MCB->level == 0) {
p_MCB->owner = os_runtask;
p_MCB->prio = os_runtask->prio;
goto inc;
}
if (p_MCB->owner == os_runtask) {
/* OK, running task is the owner of this mutex. */
inc:p_MCB->level++;
tsk_unlock();
return (OS_R_OK);
}
/* Mutex owned by another task, wait until released. */
if (timeout == 0) {
goto rto;
}
/* Raise the owner task priority if lower than current priority. */
/* This priority inversion is called priority inheritance. */
if (p_MCB->prio < os_runtask->prio) {
p_MCB->owner->prio = os_runtask->prio;
os_resort_prio (p_MCB->owner);
}
if (p_MCB->p_lnk != NULL) {
os_put_prio ((P_XCB)p_MCB, os_runtask);
}
else {
p_MCB->p_lnk = os_runtask;
os_runtask->p_lnk = NULL;
os_runtask->p_rlnk = (P_TCB)p_MCB;
}
if (os_block(timeout, WAIT_MUT) == OS_R_TMO) {
rto:tsk_unlock();
return (OS_R_TMO);
}
/* A mutex has been released. */
tsk_unlock();
return (OS_R_MUT);
}
OS_RESULT os_tsk_prio (OS_TID task_id, U8 new_prio) {
/* Change execution priority of a task to "new_prio". */
P_TCB p_task;
tsk_lock();
if (task_id == 0) {
/* Change execution priority of calling task. */
os_runtask->prio = new_prio;
os_runtask->prio_base = new_prio;
run:if (os_rdy_prio() > new_prio) {
os_put_prio (&os_rdy, os_runtask);
os_runtask->state = READY;
os_dispatch (NULL);
}
tsk_unlock();
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. */
tsk_unlock ();
return (OS_R_NOK);
}
p_task = os_active_TCB[task_id-1];
p_task->prio = new_prio;
p_task->prio_base = new_prio;
if (p_task == os_runtask) {
goto run;
}
os_resort_prio (p_task);
if (p_task->state == READY) {
/* Task enqueued in a ready list. */
p_task = os_get_first (&os_rdy);
os_dispatch (p_task);
}
tsk_unlock ();
return (OS_R_OK);
}
void os_dispatch (P_TCB next_TCB) {
/* Dispatch next task if any identified or dispatch highest ready task */
/* "next_TCB" identifies a task to run or has value NULL (=no next task) */
if (next_TCB == NULL) {
/* Running task was blocked: continue with highest ready task */
next_TCB = os_get_first (&os_rdy);
os_switch_tasks (next_TCB);
}
else {
/* Check which task continues */
if (next_TCB->prio > os_runtask->prio) {
/* preempt running task */
os_put_rdy_first (os_runtask);
os_runtask->state = READY;
os_switch_tasks (next_TCB);
}
else {
/* put next task into ready list, no task switch takes place */
next_TCB->state = READY;
os_put_prio (&os_rdy, next_TCB);
}
}
}
void os_evt_psh (P_TCB p_CB, U16 set_flags) {
/* Check if task has to be waken up */
U16 event_flags;
p_CB->events |= set_flags;
event_flags = p_CB->waits;
if (p_CB->state == WAIT_AND) {
/* Check for AND-connected events */
if ((p_CB->events & event_flags) == event_flags) {
goto rdy;
}
}
if (p_CB->state == WAIT_OR) {
/* Check for OR-connected events */
if (p_CB->events & event_flags) {
p_CB->waits &= p_CB->events;
rdy: p_CB->events &= ~event_flags;
os_rmv_dly (p_CB);
p_CB->state = READY;
p_CB->ret_val = OS_R_EVT;
os_put_prio (&os_rdy, p_CB);
}
}
}
OS_RESULT os_tsk_delete (OS_TID task_id) {
/* Terminate the task identified with "task_id". */
P_TCB task_context;
P_TCB p_TCB;
P_MUCB p_MCB, p_MCB0;
tsk_lock();
if (task_id == 0 || task_id == os_runtask->task_id) {
/* Terminate itself. */
os_runtask->state = INACTIVE;
os_stk_check (0);
p_MCB = os_runtask->p_mlnk;
while (p_MCB) {
/* Release mutexes owned by this task */
if (p_MCB->p_lnk) {
/* A task is waiting for mutex. */
p_TCB = os_get_first ((P_XCB)p_MCB);
p_TCB->ret_val = OS_R_MUT;
os_rmv_dly (p_TCB);
p_TCB->state = READY;
os_put_prio (&os_rdy, p_TCB);
/* A waiting task becomes the owner of this mutex. */
p_MCB0 = p_MCB;
p_MCB->level = 1;
p_MCB->owner = p_TCB;
p_MCB->p_mlnk = p_TCB->p_mlnk;
p_TCB->p_mlnk = p_MCB;
p_MCB = p_MCB0->p_mlnk;
}
else {
p_MCB = p_MCB->p_mlnk;
}
}
os_active_TCB[os_runtask->task_id-1] = NULL;
_free_box (mp_stk, os_runtask->stack);
os_runtask->stack = NULL;
rt_notify (os_runtask->ptask, (__FALSE << 8) | os_runtask->task_id);
_free_box (mp_tcb, os_runtask);
os_runtask = NULL;
os_dispatch (NULL);
/* The program should never come to this point. */
}
else {
/* 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. */
tsk_unlock ();
return (OS_R_NOK);
}
task_context = os_active_TCB[task_id-1];
os_rmv_list (task_context);
os_rmv_dly (task_context);
p_MCB = task_context->p_mlnk;
while (p_MCB) {
/* Release mutexes owned by this task */
if (p_MCB->p_lnk) {
/* A task is waiting for mutex. */
p_TCB = os_get_first ((P_XCB)p_MCB);
p_TCB->ret_val = OS_R_MUT;
os_rmv_dly (p_TCB);
p_TCB->state = READY;
os_put_prio (&os_rdy, p_TCB);
/* A waiting task becomes the owner of this mutex. */
p_MCB0 = p_MCB;
p_MCB->level = 1;
p_MCB->owner = p_TCB;
p_MCB->p_mlnk = p_TCB->p_mlnk;
p_TCB->p_mlnk = p_MCB;
p_MCB = p_MCB0->p_mlnk;
}
else {
p_MCB = p_MCB->p_mlnk;
}
}
os_active_TCB[task_id-1] = NULL;
_free_box (mp_stk, task_context->stack);
task_context->stack = NULL;
rt_notify (task_context->ptask, (__FALSE << 8) | task_context->task_id);
_free_box (mp_tcb, task_context);
tsk_unlock ();
if (os_rdy_prio() > os_runtask->prio) {
/* Ready task has higher priority than running task. */
os_runtask->state = READY;
os_put_prio (&os_rdy, os_runtask);
os_dispatch (NULL);
}
}
return (OS_R_OK);
}
