Contiki 2.6
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00001 /* 00002 * Copyright (c) 2004, Swedish Institute of Computer Science. 00003 * All rights reserved. 00004 * 00005 * Redistribution and use in source and binary forms, with or without 00006 * modification, are permitted provided that the following conditions 00007 * are met: 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 Institute nor the names of its contributors 00014 * may be used to endorse or promote products derived from this software 00015 * without specific prior written permission. 00016 * 00017 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 00018 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 00019 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 00020 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 00021 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 00022 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 00023 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 00024 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 00025 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 00026 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 00027 * SUCH DAMAGE. 00028 * 00029 * This file is part of the Contiki operating system. 00030 * 00031 * Author: Adam Dunkels <adam@sics.se> 00032 * 00033 * $Id: mt.h,v 1.6 2008/10/14 12:46:39 nvt-se Exp $ 00034 */ 00035 00036 /** \addtogroup sys 00037 * @{ 00038 */ 00039 00040 /** 00041 * \defgroup mt Multi-threading library 00042 * 00043 * The event driven Contiki kernel does not provide multi-threading 00044 * by itself - instead, preemptive multi-threading is implemented 00045 * as a library that optionally can be linked with applications. This 00046 * library consists of two parts: a platform independent part, which is 00047 * the same for all platforms on which Contiki runs, and a platform 00048 * specific part, which must be implemented specifically for the 00049 * platform that the multi-threading library should run. 00050 * 00051 * @{ 00052 */ 00053 00054 /** 00055 * \defgroup mtarch Architecture support for multi-threading 00056 * @{ 00057 * 00058 * The Contiki multi-threading library requires some architecture 00059 * specific support for setting up and switching stacks. This support 00060 * requires four stack manipulation functions to be implemented: 00061 * mtarch_start(), which sets up the stack frame for a new thread, 00062 * mtarch_exec(), which switches in the stack of a thread, 00063 * mtarch_yield(), which restores the kernel stack from a thread's 00064 * stack and mtarch_stop(), which cleans up the stack of a thread. 00065 * Additionally, two functions for controlling the preemption 00066 * (if any) must be implemented: mtarch_pstart() and mtarch_pstop(). 00067 * If no preemption is used, these functions can be implemented as 00068 * empty functions. Finally, the function mtarch_init() is called by 00069 * mt_init(), and can be used for initialization of timer interrupts, 00070 * or any other mechanisms required for correct operation of the 00071 * architecture specific support functions while mtarch_remove() is 00072 * called by mt_remove() to clean up those resources. 00073 * 00074 */ 00075 00076 /** 00077 * \file 00078 * Header file for the preemptive multitasking library for Contiki. 00079 * \author 00080 * Adam Dunkels <adam@sics.se> 00081 * 00082 */ 00083 #ifndef __MT_H__ 00084 #define __MT_H__ 00085 00086 #include "contiki.h" 00087 00088 00089 /** 00090 * An opaque structure that is used for holding the state of a thread. 00091 * 00092 * The structure should be defined in the "mtarch.h" file. This 00093 * structure typically holds the entire stack for the thread. 00094 */ 00095 struct mtarch_thread; 00096 00097 /** 00098 * Initialize the architecture specific support functions for the 00099 * multi-thread library. 00100 * 00101 * This function is implemented by the architecture specific functions 00102 * for the multi-thread library and is called by the mt_init() 00103 * function as part of the initialization of the library. The 00104 * mtarch_init() function can be used for, e.g., starting preemption 00105 * timers or other architecture specific mechanisms required for the 00106 * operation of the library. 00107 */ 00108 void mtarch_init(void); 00109 00110 /** 00111 * Uninstall library and clean up. 00112 * 00113 */ 00114 void mtarch_remove(void); 00115 00116 /** 00117 * Setup the stack frame for a thread that is being started. 00118 * 00119 * This function is called by the mt_start() function in order to set 00120 * up the architecture specific stack of the thread to be started. 00121 * 00122 * \param thread A pointer to a struct mtarch_thread for the thread to 00123 * be started. 00124 * 00125 * \param function A pointer to the function that the thread will 00126 * start executing the first time it is scheduled to run. 00127 * 00128 * \param data A pointer to the argument that the function should be 00129 * passed. 00130 */ 00131 void mtarch_start(struct mtarch_thread *thread, 00132 void (* function)(void *data), 00133 void *data); 00134 00135 /** 00136 * Start executing a thread. 00137 * 00138 * This function is called from mt_exec() and the purpose of the 00139 * function is to start execution of the thread. The function should 00140 * switch in the stack of the thread, and does not return until the 00141 * thread has explicitly yielded (using mt_yield()) or until it is 00142 * preempted. 00143 * 00144 * \param thread A pointer to a struct mtarch_thread for the thread to 00145 * be executed. 00146 * 00147 */ 00148 void mtarch_exec(struct mtarch_thread *thread); 00149 00150 /** 00151 * Yield the processor. 00152 * 00153 * This function is called by the mt_yield() function, which is called 00154 * from the running thread in order to give up the processor. 00155 * 00156 */ 00157 void mtarch_yield(void); 00158 00159 /** 00160 * Clean up the stack of a thread. 00161 * 00162 * This function is called by the mt_stop() function in order to clean 00163 * up the architecture specific stack of the thread to be stopped. 00164 * 00165 * \note If the stack is wholly contained in struct mtarch_thread this 00166 * function may very well be empty. 00167 * 00168 * \param thread A pointer to a struct mtarch_thread for the thread to 00169 * be stopped. 00170 * 00171 */ 00172 void mtarch_stop(struct mtarch_thread *thread); 00173 00174 void mtarch_pstart(void); 00175 void mtarch_pstop(void); 00176 00177 /** @} */ 00178 00179 00180 #include "mtarch.h" 00181 00182 struct mt_thread { 00183 int state; 00184 process_event_t *evptr; 00185 process_data_t *dataptr; 00186 struct mtarch_thread thread; 00187 }; 00188 00189 /** 00190 * No error. 00191 * 00192 * \hideinitializer 00193 */ 00194 #define MT_OK 1 00195 00196 /** 00197 * Initializes the multithreading library. 00198 * 00199 */ 00200 void mt_init(void); 00201 00202 /** 00203 * Uninstalls library and cleans up. 00204 * 00205 */ 00206 void mt_remove(void); 00207 00208 00209 /** 00210 * Starts a multithreading thread. 00211 * 00212 * \param thread Pointer to an mt_thread struct that must have been 00213 * previously allocated by the caller. 00214 * 00215 * \param function A pointer to the entry function of the thread that is 00216 * to be set up. 00217 * 00218 * \param data A pointer that will be passed to the entry function. 00219 * 00220 */ 00221 void mt_start(struct mt_thread *thread, void (* function)(void *), void *data); 00222 00223 /** 00224 * Execute parts of a thread. 00225 * 00226 * This function is called by a Contiki process and runs a 00227 * thread. The function does not return until the thread has yielded, 00228 * or is preempted. 00229 * 00230 * \note The thread library must first be initialized with the mt_init() 00231 * function. 00232 * 00233 * \param thread A pointer to a struct mt_thread block that must be 00234 * allocated by the caller. 00235 * 00236 */ 00237 void mt_exec(struct mt_thread *thread); 00238 00239 /** 00240 * Voluntarily give up the processor. 00241 * 00242 * This function is called by a running thread in order to give up 00243 * control of the CPU. 00244 * 00245 */ 00246 void mt_yield(void); 00247 00248 /** 00249 * Exit a thread. 00250 * 00251 * This function is called from within an executing thread in order to 00252 * exit the thread. The function never returns. 00253 * 00254 */ 00255 void mt_exit(void); 00256 00257 /** 00258 * Stop a thread. 00259 * 00260 * This function is called by a Contiki process in order to clean up a 00261 * thread. The struct mt_thread block may then be discarded by the caller. 00262 * 00263 * \param thread A pointer to a struct mt_thread block that must be 00264 * allocated by the caller. 00265 * 00266 */ 00267 void mt_stop(struct mt_thread *thread); 00268 00269 /** @} */ 00270 /** @} */ 00271 #endif /* __MT_H__ */