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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. /**
  30.  * @file    condvar.c
  31.  * @brief   Condition variables.
  32.  */
  33.  
  34. #include <synch/condvar.h>
  35. #include <synch/mutex.h>
  36. #include <synch/waitq.h>
  37. #include <synch/synch.h>
  38.  
  39. /** Initialize condition variable
  40.  *
  41.  * Initialize condition variable.
  42.  *
  43.  * @param cv Condition variable.
  44.  */
  45. void condvar_initialize(condvar_t *cv)
  46. {
  47.     waitq_initialize(&cv->wq);
  48. }
  49.  
  50. /** Signal the condition has become true
  51.  *
  52.  * Signal the condition has become true
  53.  * to the first waiting thread by waking it up.
  54.  *
  55.  * @param cv Condition variable.
  56.  */
  57. void condvar_signal(condvar_t *cv)
  58. {
  59.     waitq_wakeup(&cv->wq, WAKEUP_FIRST);
  60. }
  61.  
  62. /** Signal the condition has become true
  63.  *
  64.  * Signal the condition has become true
  65.  * to all waiting threads by waking them up.
  66.  *
  67.  * @param cv Condition variable.
  68.  */
  69. void condvar_broadcast(condvar_t *cv)
  70. {
  71.     waitq_wakeup(&cv->wq, WAKEUP_ALL);
  72. }
  73.  
  74. /** Wait for the condition becoming true
  75.  *
  76.  * Wait for the condition becoming true.
  77.  *
  78.  * @param cv Condition variable.
  79.  * @param mtx Mutex.
  80.  * @param usec Timeout value in microseconds.
  81.  * @param trywait Blocking versus non-blocking operation mode switch.
  82.  *
  83.  * For exact description of possible combinations of
  84.  * usec and trywait, see comment for waitq_sleep_timeout().
  85.  *
  86.  * @return See comment for waitq_sleep_timeout().
  87.  */
  88. int _condvar_wait_timeout(condvar_t *cv, mutex_t *mtx, __u32 usec, int trywait)
  89. {
  90.     int rc;
  91.  
  92.     mutex_unlock(mtx);
  93.     rc = waitq_sleep_timeout(&cv->wq, usec, trywait);
  94.     mutex_lock(mtx);
  95.     return rc;
  96. }
  97.