1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief Inlined Routines Associated with the SuperCore Semaphore |
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5 | * |
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6 | * This include file contains all of the inlined routines associated |
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7 | * with the SuperCore semaphore. |
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8 | */ |
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9 | |
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10 | /* |
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11 | * COPYRIGHT (c) 1989-2006. |
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12 | * On-Line Applications Research Corporation (OAR). |
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13 | * |
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14 | * The license and distribution terms for this file may be |
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15 | * found in the file LICENSE in this distribution or at |
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16 | * http://www.rtems.org/license/LICENSE. |
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17 | */ |
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18 | |
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19 | #ifndef _RTEMS_SCORE_CORESEMIMPL_H |
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20 | #define _RTEMS_SCORE_CORESEMIMPL_H |
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21 | |
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22 | #include <rtems/score/coresem.h> |
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23 | #include <rtems/score/objectimpl.h> |
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24 | #include <rtems/score/threaddispatch.h> |
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25 | #include <rtems/score/threadqimpl.h> |
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26 | #include <rtems/score/statesimpl.h> |
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27 | |
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28 | #ifdef __cplusplus |
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29 | extern "C" { |
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30 | #endif |
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31 | |
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32 | /** |
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33 | * @addtogroup ScoreSemaphore |
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34 | */ |
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35 | /**@{**/ |
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36 | |
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37 | /** |
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38 | * Core Semaphore handler return statuses. |
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39 | */ |
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40 | typedef enum { |
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41 | /** This status indicates that the operation completed successfully. */ |
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42 | CORE_SEMAPHORE_STATUS_SUCCESSFUL, |
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43 | /** This status indicates that the calling task did not want to block |
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44 | * and the operation was unable to complete immediately because the |
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45 | * resource was unavailable. |
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46 | */ |
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47 | CORE_SEMAPHORE_STATUS_UNSATISFIED_NOWAIT, |
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48 | /** This status indicates that the thread was blocked waiting for an |
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49 | * operation to complete and the semaphore was deleted. |
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50 | */ |
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51 | CORE_SEMAPHORE_WAS_DELETED, |
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52 | /** This status indicates that the calling task was willing to block |
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53 | * but the operation was unable to complete within the time allotted |
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54 | * because the resource never became available. |
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55 | */ |
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56 | CORE_SEMAPHORE_TIMEOUT, |
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57 | /** This status indicates that an attempt was made to unlock the semaphore |
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58 | * and this would have made its count greater than that allowed. |
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59 | */ |
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60 | CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED |
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61 | } CORE_semaphore_Status; |
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62 | |
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63 | /** |
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64 | * @brief Core semaphore last status value. |
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65 | * |
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66 | * This is the last status value. |
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67 | */ |
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68 | #define CORE_SEMAPHORE_STATUS_LAST CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED |
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69 | |
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70 | /** |
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71 | * @brief Initialize the semaphore based on the parameters passed. |
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72 | * |
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73 | * This package is the implementation of the CORE Semaphore Handler. |
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74 | * This core object utilizes standard Dijkstra counting semaphores to provide |
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75 | * synchronization and mutual exclusion capabilities. |
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76 | * |
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77 | * This routine initializes the semaphore based on the parameters passed. |
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78 | * |
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79 | * @param[in] the_semaphore is the semaphore to initialize |
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80 | * @param[in] discipline the blocking discipline |
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81 | * @param[in] initial_value is the initial count of the semaphore |
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82 | */ |
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83 | void _CORE_semaphore_Initialize( |
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84 | CORE_semaphore_Control *the_semaphore, |
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85 | CORE_semaphore_Disciplines discipline, |
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86 | uint32_t initial_value |
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87 | ); |
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88 | |
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89 | RTEMS_INLINE_ROUTINE void _CORE_semaphore_Acquire_critical( |
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90 | CORE_semaphore_Control *the_semaphore, |
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91 | Thread_queue_Context *queue_context |
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92 | ) |
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93 | { |
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94 | _Thread_queue_Acquire_critical( |
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95 | &the_semaphore->Wait_queue, |
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96 | &queue_context->Lock_context |
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97 | ); |
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98 | } |
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99 | |
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100 | RTEMS_INLINE_ROUTINE void _CORE_semaphore_Release( |
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101 | CORE_semaphore_Control *the_semaphore, |
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102 | Thread_queue_Context *queue_context |
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103 | ) |
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104 | { |
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105 | _Thread_queue_Release( |
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106 | &the_semaphore->Wait_queue, |
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107 | &queue_context->Lock_context |
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108 | ); |
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109 | } |
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110 | |
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111 | Thread_Control *_CORE_semaphore_Was_deleted( |
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112 | Thread_Control *the_thread, |
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113 | Thread_queue_Queue *queue, |
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114 | Thread_queue_Context *queue_context |
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115 | ); |
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116 | |
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117 | Thread_Control *_CORE_semaphore_Unsatisfied_nowait( |
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118 | Thread_Control *the_thread, |
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119 | Thread_queue_Queue *queue, |
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120 | Thread_queue_Context *queue_context |
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121 | ); |
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122 | |
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123 | RTEMS_INLINE_ROUTINE void _CORE_semaphore_Destroy( |
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124 | CORE_semaphore_Control *the_semaphore, |
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125 | Thread_queue_Context *queue_context |
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126 | ) |
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127 | { |
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128 | _Thread_queue_Flush_critical( |
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129 | &the_semaphore->Wait_queue.Queue, |
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130 | the_semaphore->operations, |
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131 | _CORE_semaphore_Was_deleted, |
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132 | queue_context |
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133 | ); |
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134 | _Thread_queue_Destroy( &the_semaphore->Wait_queue ); |
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135 | } |
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136 | |
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137 | /** |
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138 | * @brief Surrender a unit to a semaphore. |
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139 | * |
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140 | * This routine frees a unit to the semaphore. If a task was blocked waiting |
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141 | * for a unit from this semaphore, then that task will be readied and the unit |
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142 | * given to that task. Otherwise, the unit will be returned to the semaphore. |
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143 | * |
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144 | * @param[in] the_semaphore is the semaphore to surrender |
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145 | * @param[in] queue_context is a temporary variable used to contain the ISR |
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146 | * disable level cookie |
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147 | * |
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148 | * @retval an indication of whether the routine succeeded or failed |
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149 | */ |
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150 | RTEMS_INLINE_ROUTINE CORE_semaphore_Status _CORE_semaphore_Surrender( |
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151 | CORE_semaphore_Control *the_semaphore, |
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152 | uint32_t maximum_count, |
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153 | Thread_queue_Context *queue_context |
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154 | ) |
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155 | { |
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156 | Thread_Control *the_thread; |
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157 | CORE_semaphore_Status status; |
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158 | |
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159 | status = CORE_SEMAPHORE_STATUS_SUCCESSFUL; |
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160 | |
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161 | _CORE_semaphore_Acquire_critical( the_semaphore, queue_context ); |
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162 | |
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163 | the_thread = _Thread_queue_First_locked( |
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164 | &the_semaphore->Wait_queue, |
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165 | the_semaphore->operations |
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166 | ); |
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167 | if ( the_thread != NULL ) { |
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168 | _Thread_queue_Extract_critical( |
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169 | &the_semaphore->Wait_queue.Queue, |
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170 | the_semaphore->operations, |
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171 | the_thread, |
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172 | queue_context |
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173 | ); |
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174 | } else { |
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175 | if ( the_semaphore->count < maximum_count ) |
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176 | the_semaphore->count += 1; |
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177 | else |
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178 | status = CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED; |
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179 | |
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180 | _CORE_semaphore_Release( the_semaphore, queue_context ); |
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181 | } |
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182 | |
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183 | return status; |
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184 | } |
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185 | |
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186 | RTEMS_INLINE_ROUTINE void _CORE_semaphore_Flush( |
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187 | CORE_semaphore_Control *the_semaphore, |
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188 | Thread_queue_Context *queue_context |
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189 | ) |
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190 | { |
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191 | _Thread_queue_Flush_critical( |
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192 | &the_semaphore->Wait_queue.Queue, |
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193 | the_semaphore->operations, |
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194 | _CORE_semaphore_Unsatisfied_nowait, |
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195 | queue_context |
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196 | ); |
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197 | } |
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198 | |
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199 | /** |
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200 | * This routine returns the current count associated with the semaphore. |
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201 | * |
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202 | * @param[in] the_semaphore is the semaphore to obtain the count of |
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203 | * |
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204 | * @return the current count of this semaphore |
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205 | */ |
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206 | RTEMS_INLINE_ROUTINE uint32_t _CORE_semaphore_Get_count( |
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207 | CORE_semaphore_Control *the_semaphore |
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208 | ) |
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209 | { |
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210 | return the_semaphore->count; |
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211 | } |
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212 | |
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213 | /** |
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214 | * This routine attempts to receive a unit from the_semaphore. |
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215 | * If a unit is available or if the wait flag is false, then the routine |
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216 | * returns. Otherwise, the calling task is blocked until a unit becomes |
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217 | * available. |
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218 | * |
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219 | * @param[in] the_semaphore is the semaphore to obtain |
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220 | * @param[in,out] executing The currently executing thread. |
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221 | * @param[in] wait is true if the thread is willing to wait |
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222 | * @param[in] timeout is the maximum number of ticks to block |
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223 | * @param[in] queue_context is a temporary variable used to contain the ISR |
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224 | * disable level cookie |
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225 | * |
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226 | * @note There is currently no MACRO version of this routine. |
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227 | */ |
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228 | RTEMS_INLINE_ROUTINE void _CORE_semaphore_Seize( |
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229 | CORE_semaphore_Control *the_semaphore, |
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230 | Thread_Control *executing, |
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231 | bool wait, |
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232 | Watchdog_Interval timeout, |
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233 | Thread_queue_Context *queue_context |
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234 | ) |
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235 | { |
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236 | /* disabled when you get here */ |
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237 | |
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238 | executing->Wait.return_code = CORE_SEMAPHORE_STATUS_SUCCESSFUL; |
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239 | _CORE_semaphore_Acquire_critical( the_semaphore, queue_context ); |
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240 | if ( the_semaphore->count != 0 ) { |
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241 | the_semaphore->count -= 1; |
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242 | _CORE_semaphore_Release( the_semaphore, queue_context ); |
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243 | return; |
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244 | } |
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245 | |
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246 | if ( !wait ) { |
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247 | _CORE_semaphore_Release( the_semaphore, queue_context ); |
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248 | executing->Wait.return_code = CORE_SEMAPHORE_STATUS_UNSATISFIED_NOWAIT; |
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249 | return; |
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250 | } |
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251 | |
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252 | _Thread_queue_Enqueue_critical( |
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253 | &the_semaphore->Wait_queue.Queue, |
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254 | the_semaphore->operations, |
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255 | executing, |
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256 | STATES_WAITING_FOR_SEMAPHORE, |
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257 | timeout, |
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258 | CORE_SEMAPHORE_TIMEOUT, |
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259 | &queue_context->Lock_context |
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260 | ); |
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261 | } |
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262 | |
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263 | /** @} */ |
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264 | |
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265 | #ifdef __cplusplus |
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266 | } |
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267 | #endif |
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268 | |
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269 | #endif |
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270 | /* end of include file */ |
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