kernel/generic/src/synch/mutex.c

   1 /*
   2  * Copyright (c) 2001-2004 Jakub Jermar
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @addtogroup sync
  30  * @{
  31  */
  32
  33 /**
  34  * @file
  35  * @brief       Mutexes.
  36  */
  37
  38 #include <synch/mutex.h>
  39 #include <synch/semaphore.h>
  40 #include <synch/synch.h>
  41
  42 /** Initialize mutex
  43  *
  44  * Initialize mutex.
  45  *
  46  * @param mtx Mutex.
  47  */
  48 void mutex_initialize(mutex_t *mtx)
  49 {
  50         semaphore_initialize(&mtx->sem, 1);
  51 }
  52
  53 /** Acquire mutex
  54  *
  55  * Acquire mutex.
  56  * Timeout mode and non-blocking mode can be requested.
  57  *
  58  * @param mtx Mutex.
  59  * @param usec Timeout in microseconds.
  60  * @param flags Specify mode of operation.
  61  *
  62  * For exact description of possible combinations of
  63  * usec and flags, see comment for waitq_sleep_timeout().
  64  *
  65  * @return See comment for waitq_sleep_timeout().
  66  */
  67 int _mutex_lock_timeout(mutex_t *mtx, uint32_t usec, int flags)
  68 {
  69         return _semaphore_down_timeout(&mtx->sem, usec, flags);
  70 }
  71
  72 /** Release mutex
  73  *
  74  * Release mutex.
  75  *
  76  * @param mtx Mutex.
  77  */
  78 void mutex_unlock(mutex_t *mtx)
  79 {
  80         semaphore_up(&mtx->sem);
  81 }
  82
  83 /** @}
  84  */