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 * $Log$ 00041 * Revision 1.6 2009/01/17 15:37:52 haraldkipp 00042 * Added some NUTASSERT macros to check function parameters. 00043 * 00044 * Revision 1.5 2006/10/08 16:48:22 haraldkipp 00045 * Documentation fixed 00046 * 00047 * Revision 1.4 2005/08/02 17:47:04 haraldkipp 00048 * Major API documentation update. 00049 * 00050 * Revision 1.3 2004/07/19 16:24:23 freckle 00051 * Code contained same bug as os/semaphore.c. 00052 * Unfortunately I didn't understand the other fix, but anyway made 00053 * NutMutexLock more robust. 00054 * Fixed wrong indention of all functions 00055 * 00056 * Revision 1.2 2004/05/18 18:38:42 drsung 00057 * Added $Log keyword for CVS. 00058 * 00059 */ 00060 00065 00066 #ifdef __cplusplus 00067 extern "C" { 00068 #endif 00069 00070 #include <sys/nutdebug.h> 00071 #include <sys/mutex.h> 00072 #include <sys/event.h> 00073 00080 void NutMutexInit(MUTEX * mutex) { 00081 NUTASSERT(mutex != NULL); 00082 mutex->thread = 0; 00083 mutex->count = 0; 00084 mutex->qhp = 0; 00085 } 00086 00096 void NutMutexLock(MUTEX * mutex) { 00097 NUTASSERT(mutex != NULL); 00098 if (mutex->thread != runningThread) { 00099 while( mutex->count != 0) 00100 NutEventWaitNext(&mutex->qhp, NUT_WAIT_INFINITE); 00101 } 00102 mutex->thread = runningThread; 00103 mutex->count++; 00104 } 00105 00114 int NutMutexTrylock(MUTEX * mutex) { 00115 NUTASSERT(mutex != NULL); 00116 if ((mutex->count != 0) && (mutex->thread != runningThread)) 00117 return -1; 00118 NutMutexLock(mutex); 00119 return 0; 00120 } 00121 00130 int NutMutexUnlock(MUTEX * mutex) { 00131 NUTASSERT(mutex != NULL); 00132 if (mutex->thread != runningThread) 00133 return -1; 00134 if (--mutex->count == 0) { 00135 NutEventPost(&mutex->qhp); 00136 } 00137 return 0; 00138 } 00139 00147 int NutMutexDestroy(MUTEX * mutex) { 00148 NUTASSERT(mutex != NULL); 00149 if (mutex->count == 0) 00150 return 0; 00151 if (mutex->thread == runningThread) 00152 return 0; 00153 return -1; 00154 } 00155 00156 #ifdef __cplusplus 00157 } 00158 #endif 00159