Mutex.cpp

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2012 ARM Limited
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
00020  * SOFTWARE.
00021  */
00022 #include "rtos/Mutex.h"
00023 #include "rtos/Kernel.h"
00024 
00025 #include <string.h>
00026 #include "mbed_error.h"
00027 #include "mbed_assert.h"
00028 
00029 namespace rtos {
00030 
00031 Mutex::Mutex(): _count(0)
00032 {
00033     constructor();
00034 }
00035 
00036 Mutex::Mutex(const char *name)
00037 {
00038     constructor(name);
00039 }
00040 
00041 void Mutex::constructor(const char *name)
00042 {
00043     memset(&_obj_mem, 0, sizeof(_obj_mem));
00044     osMutexAttr_t attr =
00045     { 0 };
00046     attr.name = name ? name : "aplication_unnamed_mutex";
00047     attr.cb_mem = &_obj_mem;
00048     attr.cb_size = sizeof(_obj_mem);
00049     attr.attr_bits = osMutexRecursive | osMutexPrioInherit | osMutexRobust;
00050     _id = osMutexNew(&attr);
00051     MBED_ASSERT(_id);
00052 }
00053 
00054 osStatus Mutex::lock(void)
00055 {
00056     osStatus status = osMutexAcquire(_id, osWaitForever);
00057     if (osOK == status) {
00058         _count++;
00059     }
00060 
00061     if (status != osOK) {
00062         MBED_ERROR1(MBED_MAKE_ERROR(MBED_MODULE_KERNEL, MBED_ERROR_CODE_MUTEX_LOCK_FAILED), "Mutex lock failed", status);
00063     }
00064 
00065     return osOK;
00066 }
00067 
00068 osStatus Mutex::lock(uint32_t millisec)
00069 {
00070     osStatus status = osMutexAcquire(_id, millisec);
00071     if (osOK == status) {
00072         _count++;
00073     }
00074 
00075     bool success = (status == osOK ||
00076                     (status == osErrorResource && millisec == 0) ||
00077                     (status == osErrorTimeout && millisec != osWaitForever));
00078 
00079     if (!success) {
00080         MBED_ERROR1(MBED_MAKE_ERROR(MBED_MODULE_KERNEL, MBED_ERROR_CODE_MUTEX_LOCK_FAILED), "Mutex lock failed", status);
00081     }
00082 
00083     return status;
00084 }
00085 
00086 bool Mutex::trylock()
00087 {
00088     return trylock_for(0);
00089 }
00090 
00091 bool Mutex::trylock_for(uint32_t millisec)
00092 {
00093     osStatus status = osMutexAcquire(_id, millisec);
00094     if (status == osOK) {
00095         return true;
00096     }
00097 
00098     bool success = (status == osOK ||
00099                     (status == osErrorResource && millisec == 0) ||
00100                     (status == osErrorTimeout && millisec != osWaitForever));
00101 
00102     if (!success) {
00103         MBED_ERROR1(MBED_MAKE_ERROR(MBED_MODULE_KERNEL, MBED_ERROR_CODE_MUTEX_LOCK_FAILED), "Mutex lock failed", status);
00104     }
00105 
00106     return false;
00107 }
00108 
00109 bool Mutex::trylock_until(uint64_t millisec)
00110 {
00111     uint64_t now = Kernel::get_ms_count();
00112 
00113     if (now >= millisec) {
00114         return trylock();
00115     } else if (millisec - now >= osWaitForever) {
00116         // API permits early return
00117         return trylock_for(osWaitForever - 1);
00118     } else {
00119         return trylock_for(millisec - now);
00120     }
00121 }
00122 
00123 osStatus Mutex::unlock()
00124 {
00125     _count--;
00126 
00127     osStatus status = osMutexRelease(_id);
00128 
00129     if (status != osOK) {
00130         MBED_ERROR1(MBED_MAKE_ERROR(MBED_MODULE_KERNEL, MBED_ERROR_CODE_MUTEX_UNLOCK_FAILED), "Mutex unlock failed", status);
00131     }
00132 
00133     return osOK;
00134 }
00135 
00136 osThreadId Mutex::get_owner()
00137 {
00138     return osMutexGetOwner(_id);
00139 }
00140 
00141 Mutex::~Mutex()
00142 {
00143     osMutexDelete(_id);
00144 }
00145 
00146 }