0,0 → 1,98 |
/* |
* 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. |
*/ |
|
/** @addtogroup sync |
* @{ |
*/ |
|
/** |
* @file |
* @brief Semaphores. |
*/ |
|
#include <synch/semaphore.h> |
#include <synch/waitq.h> |
#include <synch/spinlock.h> |
#include <synch/synch.h> |
#include <arch/asm.h> |
#include <arch.h> |
|
/** Initialize semaphore |
* |
* Initialize semaphore. |
* |
* @param s Semaphore. |
* @param val Maximal number of threads allowed to enter critical section. |
*/ |
void semaphore_initialize(semaphore_t *s, int val) |
{ |
ipl_t ipl; |
|
waitq_initialize(&s->wq); |
|
ipl = interrupts_disable(); |
|
spinlock_lock(&s->wq.lock); |
s->wq.missed_wakeups = val; |
spinlock_unlock(&s->wq.lock); |
|
interrupts_restore(ipl); |
} |
|
/** Semaphore down |
* |
* Semaphore down. |
* Conditional mode and mode with timeout can be requested. |
* |
* @param s Semaphore. |
* @param usec Timeout in microseconds. |
* @param flags Select mode of operation. |
* |
* For exact description of possible combinations of |
* usec and flags, see comment for waitq_sleep_timeout(). |
* |
* @return See comment for waitq_sleep_timeout(). |
*/ |
int _semaphore_down_timeout(semaphore_t *s, uint32_t usec, int flags) |
{ |
return waitq_sleep_timeout(&s->wq, usec, flags); |
} |
|
/** Semaphore up |
* |
* Semaphore up. |
* |
* @param s Semaphore. |
*/ |
void semaphore_up(semaphore_t *s) |
{ |
waitq_wakeup(&s->wq, WAKEUP_FIRST); |
} |
|
/** @} |
*/ |