/*
* Copyright (C) 2001-2004 Jakub Jermar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @file condvar.c
* @brief Condition variables.
*/
#include <synch/condvar.h>
#include <synch/mutex.h>
#include <synch/waitq.h>
#include <synch/synch.h>
#include <arch.h>
#include <typedefs.h>
/** Initialize condition variable.
*
* @param cv Condition variable.
*/
void condvar_initialize(condvar_t *cv)
{
waitq_initialize(&cv->wq);
}
/**
* Signal the condition has become true
* to the first waiting thread by waking it up.
*
* @param cv Condition variable.
*/
void condvar_signal(condvar_t *cv)
{
waitq_wakeup(&cv->wq, WAKEUP_FIRST);
}
/**
* Signal the condition has become true
* to all waiting threads by waking them up.
*
* @param cv Condition variable.
*/
void condvar_broadcast(condvar_t *cv)
{
waitq_wakeup(&cv->wq, WAKEUP_ALL);
}
/** Wait for the condition becoming true.
*
* @param cv Condition variable.
* @param mtx Mutex.
* @param usec Timeout value in microseconds.
* @param flags Select mode of operation.
*
* For exact description of meaning of possible combinations
* of usec and flags, see comment for waitq_sleep_timeout().
* Note that when SYNCH_FLAGS_NON_BLOCKING is specified here,
* ESYNCH_WOULD_BLOCK is always returned.
*
* @return See comment for waitq_sleep_timeout().
*/
int _condvar_wait_timeout(condvar_t *cv, mutex_t *mtx, __u32 usec, int flags)
{
int rc;
ipl_t ipl;
ipl = waitq_sleep_prepare(&cv->wq);
mutex_unlock(mtx);
cv->wq.missed_wakeups = 0; /* Enforce blocking. */
rc = waitq_sleep_timeout_unsafe(&cv->wq, usec, flags);
mutex_lock(mtx);
waitq_sleep_finish(&cv->wq, rc, ipl);
return rc;
}