| 1 | /*
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| 2 | * Copyright (c) 2001-2004 Jakub Jermar
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | *
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| 9 | * - Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * - Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * - The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 | /** @addtogroup sync
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| 30 | * @{
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| 31 | */
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| 32 |
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| 33 | /**
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| 34 | * @file
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| 35 | * @brief Mutexes.
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| 36 | */
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| 37 |
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| 38 | #include <synch/mutex.h>
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| 39 | #include <synch/semaphore.h>
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| 40 | #include <synch/synch.h>
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| 41 | #include <debug.h>
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| 42 |
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| 43 | /** Initialize mutex.
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| 44 | *
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| 45 | * @param mtx Mutex.
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| 46 | * @param type Type of the mutex.
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| 47 | */
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| 48 | void mutex_initialize(mutex_t *mtx, mutex_type_t type)
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| 49 | {
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| 50 | mtx->type = type;
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| 51 | semaphore_initialize(&mtx->sem, 1);
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| 52 | }
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| 53 |
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| 54 | /** Acquire mutex.
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| 55 | *
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| 56 | * Timeout mode and non-blocking mode can be requested.
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| 57 | *
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| 58 | * @param mtx Mutex.
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| 59 | * @param usec Timeout in microseconds.
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| 60 | * @param flags Specify mode of operation.
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| 61 | *
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| 62 | * For exact description of possible combinations of
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| 63 | * usec and flags, see comment for waitq_sleep_timeout().
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| 64 | *
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| 65 | * @return See comment for waitq_sleep_timeout().
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| 66 | */
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| 67 | int _mutex_lock_timeout(mutex_t *mtx, uint32_t usec, int flags)
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| 68 | {
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| 69 | int rc;
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| 70 |
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| 71 | if (mtx->type == MUTEX_PASSIVE) {
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| 72 | rc = _semaphore_down_timeout(&mtx->sem, usec, flags);
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| 73 | } else {
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| 74 | ASSERT(mtx->type == MUTEX_ACTIVE);
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| 75 | ASSERT(usec == SYNCH_NO_TIMEOUT);
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| 76 | ASSERT(!(flags & SYNCH_FLAGS_INTERRUPTIBLE));
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| 77 | do {
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| 78 | rc = semaphore_trydown(&mtx->sem);
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| 79 | } while (SYNCH_FAILED(rc) &&
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| 80 | !(flags & SYNCH_FLAGS_NON_BLOCKING));
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| 81 | }
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| 82 |
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| 83 | return rc;
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| 84 | }
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| 85 |
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| 86 | /** Release mutex.
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| 87 | *
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| 88 | * @param mtx Mutex.
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| 89 | */
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| 90 | void mutex_unlock(mutex_t *mtx)
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| 91 | {
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| 92 | semaphore_up(&mtx->sem);
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| 93 | }
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| 94 |
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| 95 | /** @}
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| 96 | */
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