00001 /* 00002 * Copyright (C) 2000-2004 by ETH Zurich 00003 * 00004 * Redistribution and use in source and binary forms, with or without 00005 * modification, are permitted provided that the following conditions 00006 * are met: 00007 * 00008 * 1. Redistributions of source code must retain the above copyright 00009 * notice, this list of conditions and the following disclaimer. 00010 * 2. Redistributions in binary form must reproduce the above copyright 00011 * notice, this list of conditions and the following disclaimer in the 00012 * documentation and/or other materials provided with the distribution. 00013 * 3. Neither the name of the copyright holders nor the names of 00014 * contributors may be used to endorse or promote products derived 00015 * from this software without specific prior written permission. 00016 * 00017 * THIS SOFTWARE IS PROVIDED BY ETH ZURICH AND CONTRIBUTORS 00018 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 00019 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 00020 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ETH ZURICH 00021 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 00022 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 00023 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 00024 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 00025 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 00026 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 00027 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 00028 * SUCH DAMAGE. 00029 * 00030 * For additional information see http://www.ethernut.de/ 00031 * 00032 */ 00033 00034 /* mutex.c - a nut/os implementation of recursive mutex functions 00035 * 00036 * 2004.05.06 Matthias Ringwald <matthias.ringwald@inf.ethz.ch> 00037 * 00038 */ 00039 /* 00040 * $Log: mutex.c,v $ 00041 * Revision 1.5 2006/10/08 16:48:22 haraldkipp 00042 * Documentation fixed 00043 * 00044 * Revision 1.4 2005/08/02 17:47:04 haraldkipp 00045 * Major API documentation update. 00046 * 00047 * Revision 1.3 2004/07/19 16:24:23 freckle 00048 * Code contained same bug as os/semaphore.c. 00049 * Unfortunately I didn't understand the other fix, but anyway made 00050 * NutMutexLock more robust. 00051 * Fixed wrong indention of all functions 00052 * 00053 * Revision 1.2 2004/05/18 18:38:42 drsung 00054 * Added $Log keyword for CVS. 00055 * 00056 */ 00057 00062 00063 #ifdef __cplusplus 00064 extern "C" { 00065 #endif 00066 00067 #include <sys/mutex.h> 00068 #include <sys/event.h> 00069 00076 void NutMutexInit(MUTEX * mutex) { 00077 mutex->thread = 0; 00078 mutex->count = 0; 00079 mutex->qhp = 0; 00080 } 00081 00091 void NutMutexLock(MUTEX * mutex) { 00092 if (mutex->thread != runningThread) { 00093 while( mutex->count != 0) 00094 NutEventWaitNext(&mutex->qhp, NUT_WAIT_INFINITE); 00095 } 00096 mutex->thread = runningThread; 00097 mutex->count++; 00098 } 00099 00108 int NutMutexTrylock(MUTEX * mutex) { 00109 if ((mutex->count != 0) && (mutex->thread != runningThread)) 00110 return -1; 00111 NutMutexLock(mutex); 00112 return 0; 00113 } 00114 00123 int NutMutexUnlock(MUTEX * mutex) { 00124 if (mutex->thread != runningThread) 00125 return -1; 00126 if (--mutex->count == 0) { 00127 NutEventPost(&mutex->qhp); 00128 } 00129 return 0; 00130 } 00131 00139 int NutMutexDestroy(MUTEX * mutex) { 00140 if (mutex->count == 0) 00141 return 0; 00142 if (mutex->thread == runningThread) 00143 return 0; 00144 return -1; 00145 } 00146 00147 #ifdef __cplusplus 00148 } 00149 #endif 00150