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  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. #include <debug.h>
  42.  
  43. /** Initialize mutex.
  44.  *
  45.  * @param mtx       Mutex.
  46.  * @param type      Type of the mutex.
  47.  */
  48. void mutex_initialize(mutex_t *mtx, mutex_type_t type)
  49. {
  50.     mtx->type = type;
  51.     semaphore_initialize(&mtx->sem, 1);
  52. }
  53.  
  54. /** Acquire mutex.
  55.  *
  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.     int rc;
  70.  
  71.     if (mtx->type == MUTEX_PASSIVE) {
  72.         rc = _semaphore_down_timeout(&mtx->sem, usec, flags);
  73.     } else {
  74.         ASSERT(mtx->type == MUTEX_ACTIVE);
  75.         ASSERT(usec == SYNCH_NO_TIMEOUT);
  76.         ASSERT(!(flags & SYNCH_FLAGS_INTERRUPTIBLE));
  77.         do {
  78.             rc = semaphore_trydown(&mtx->sem);
  79.         } while (SYNCH_FAILED(rc) &&
  80.             !(flags & SYNCH_FLAGS_NON_BLOCKING));
  81.     }
  82.  
  83.     return rc;
  84. }
  85.  
  86. /** Release mutex.
  87.  *
  88.  * @param mtx       Mutex.
  89.  */
  90. void mutex_unlock(mutex_t *mtx)
  91. {
  92.     semaphore_up(&mtx->sem);
  93. }
  94.  
  95. /** @}
  96.  */
  97.