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/*
* Copyright (C) 2014 Hamburg University of Applied Sciences (HAW)
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup sys
* @{
*
* @file
* @brief Condition variable implementation
*
* @author Martin Landsmann <martin.landsmann@haw-hamburg.de>
* @author René Kijewski <rene.kijewski@fu-berlin.de>
*
* @}
*/
#include "pthread_cond.h"
#include "thread.h"
#include "xtimer.h"
#include "sched.h"
#include "irq.h"
#include "debug.h"
int pthread_cond_condattr_destroy(pthread_condattr_t *attr)
{
if (attr != NULL) {
DEBUG("pthread_cond_condattr_destroy: currently attributes are not supported.\n");
}
return 0;
}
int pthread_cond_condattr_init(pthread_condattr_t *attr)
{
if (attr != NULL) {
DEBUG("pthread_cond_condattr_init: currently attributes are not supported.\n");
}
return 0;
}
int pthread_condattr_getpshared(const pthread_condattr_t *attr, int *pshared)
{
(void)attr;
(void)pshared;
return 0;
}
int pthread_condattr_setpshared(pthread_condattr_t *attr, int pshared)
{
(void)attr;
(void)pshared;
return 0;
}
int pthread_condattr_getclock(const pthread_condattr_t *attr, clockid_t *clock_id)
{
(void)attr;
(void)clock_id;
return 0;
}
int pthread_condattr_setclock(pthread_condattr_t *attr, clockid_t clock_id)
{
(void)attr;
(void)clock_id;
return 0;
}
int pthread_cond_init(pthread_cond_t *cond, pthread_condattr_t *attr)
{
if (attr != NULL) {
DEBUG("pthread_cond_init: currently attributes are not supported.\n");
}
cond->queue.first = NULL;
return 0;
}
int pthread_cond_destroy(pthread_cond_t *cond)
{
pthread_cond_init(cond, NULL);
return 0;
}
int pthread_cond_wait(pthread_cond_t *cond, mutex_t *mutex)
{
priority_queue_node_t n;
n.priority = sched_active_thread->priority;
n.data = sched_active_pid;
n.next = NULL;
/* the signaling thread may not hold the mutex, the queue is not thread safe */
unsigned old_state = irq_disable();
priority_queue_add(&(cond->queue), &n);
irq_restore(old_state);
mutex_unlock_and_sleep(mutex);
if (n.data != -1u) {
/* on signaling n.data is set to -1u */
/* if it isn't set, then the wakeup is either spurious or a timer wakeup */
old_state = irq_disable();
priority_queue_remove(&(cond->queue), &n);
irq_restore(old_state);
}
mutex_lock(mutex);
return 0;
}
int pthread_cond_timedwait(pthread_cond_t *cond, mutex_t *mutex, const struct timespec *abstime)
{
timex_t now, then, reltime;
xtimer_now_timex(&now);
then.seconds = abstime->tv_sec;
then.microseconds = abstime->tv_nsec / 1000u;
reltime = timex_sub(then, now);
xtimer_t timer;
xtimer_set_wakeup64(&timer, timex_uint64(reltime) , sched_active_pid);
int result = pthread_cond_wait(cond, mutex);
xtimer_remove(&timer);
return result;
}
int pthread_cond_signal(pthread_cond_t *cond)
{
unsigned old_state = irq_disable();
priority_queue_node_t *head = priority_queue_remove_head(&(cond->queue));
int other_prio = -1;
if (head != NULL) {
thread_t *other_thread = (thread_t *) sched_threads[head->data];
if (other_thread) {
other_prio = other_thread->priority;
sched_set_status(other_thread, STATUS_PENDING);
}
head->data = -1u;
}
irq_restore(old_state);
if (other_prio >= 0) {
sched_switch(other_prio);
}
return 0;
}
static int max_prio(int a, int b)
{
return (a < 0) ? b : ((a < b) ? a : b);
}
int pthread_cond_broadcast(pthread_cond_t *cond)
{
unsigned old_state = irq_disable();
int other_prio = -1;
while (1) {
priority_queue_node_t *head = priority_queue_remove_head(&(cond->queue));
if (head == NULL) {
break;
}
thread_t *other_thread = (thread_t *) sched_threads[head->data];
if (other_thread) {
other_prio = max_prio(other_prio, other_thread->priority);
sched_set_status(other_thread, STATUS_PENDING);
}
head->data = -1u;
}
irq_restore(old_state);
if (other_prio >= 0) {
sched_switch(other_prio);
}
return 0;
}
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