1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief Inlined Routines Associated with the SuperCore RWLock |
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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 RWLock. |
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8 | */ |
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9 | |
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10 | /* |
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11 | * COPYRIGHT (c) 1989-2008. |
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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_CORERWLOCKIMPL_H |
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20 | #define _RTEMS_SCORE_CORERWLOCKIMPL_H |
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21 | |
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22 | #include <rtems/score/percpu.h> |
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23 | #include <rtems/score/status.h> |
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24 | #include <rtems/score/thread.h> |
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25 | #include <rtems/score/threadqimpl.h> |
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26 | #include <rtems/score/watchdog.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 ScoreRWLock |
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34 | */ |
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35 | /**@{**/ |
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36 | |
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37 | #define CORE_RWLOCK_TQ_OPERATIONS &_Thread_queue_Operations_FIFO |
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38 | |
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39 | /** |
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40 | * This is used to denote that a thread is blocking waiting for |
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41 | * read-only access to the RWLock. |
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42 | */ |
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43 | #define CORE_RWLOCK_THREAD_WAITING_FOR_READ 0 |
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44 | |
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45 | /** |
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46 | * This is used to denote that a thread is blocking waiting for |
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47 | * write-exclusive access to the RWLock. |
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48 | */ |
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49 | #define CORE_RWLOCK_THREAD_WAITING_FOR_WRITE 1 |
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50 | |
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51 | /** |
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52 | * RWLock State. |
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53 | */ |
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54 | typedef enum { |
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55 | /** This indicates the the RWLock is not currently locked. |
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56 | */ |
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57 | CORE_RWLOCK_UNLOCKED, |
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58 | /** This indicates the the RWLock is currently locked for reading. |
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59 | */ |
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60 | CORE_RWLOCK_LOCKED_FOR_READING, |
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61 | /** This indicates the the RWLock is currently locked for reading. |
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62 | */ |
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63 | CORE_RWLOCK_LOCKED_FOR_WRITING |
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64 | } CORE_RWLock_States; |
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65 | |
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66 | /** |
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67 | * The following defines the control block used to manage each |
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68 | * RWLock. |
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69 | */ |
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70 | typedef struct { |
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71 | /** This field is the Waiting Queue used to manage the set of tasks |
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72 | * which are blocked waiting for the RWLock to be released. |
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73 | */ |
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74 | Thread_queue_Syslock_queue Queue; |
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75 | |
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76 | /** This element is the current state of the RWLock. |
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77 | */ |
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78 | CORE_RWLock_States current_state; |
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79 | |
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80 | /** This element contains the current number of thread waiting for this |
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81 | * RWLock to be released. */ |
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82 | unsigned int number_of_readers; |
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83 | } CORE_RWLock_Control; |
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84 | |
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85 | /** |
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86 | * @brief Initialize a RWlock. |
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87 | * |
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88 | * This routine initializes the RWLock based on the parameters passed. |
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89 | * |
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90 | * @param[in] the_rwlock is the RWLock to initialize |
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91 | */ |
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92 | void _CORE_RWLock_Initialize( |
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93 | CORE_RWLock_Control *the_rwlock |
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94 | ); |
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95 | |
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96 | RTEMS_INLINE_ROUTINE void _CORE_RWLock_Destroy( |
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97 | CORE_RWLock_Control *the_rwlock |
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98 | ) |
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99 | { |
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100 | (void) the_rwlock; |
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101 | } |
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102 | |
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103 | RTEMS_INLINE_ROUTINE Thread_Control *_CORE_RWLock_Acquire( |
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104 | CORE_RWLock_Control *the_rwlock, |
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105 | Thread_queue_Context *queue_context |
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106 | ) |
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107 | { |
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108 | ISR_Level level; |
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109 | Thread_Control *executing; |
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110 | |
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111 | _Thread_queue_Context_ISR_disable( queue_context, level ); |
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112 | _Thread_queue_Context_set_ISR_level( queue_context, level ); |
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113 | executing = _Thread_Executing; |
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114 | _Thread_queue_Queue_acquire_critical( |
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115 | &the_rwlock->Queue.Queue, |
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116 | &executing->Potpourri_stats, |
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117 | &queue_context->Lock_context.Lock_context |
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118 | ); |
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119 | |
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120 | return executing; |
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121 | } |
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122 | |
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123 | RTEMS_INLINE_ROUTINE void _CORE_RWLock_Release( |
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124 | CORE_RWLock_Control *the_rwlock, |
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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_Queue_release( |
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129 | &the_rwlock->Queue.Queue, |
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130 | &queue_context->Lock_context.Lock_context |
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131 | ); |
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132 | } |
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133 | |
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134 | /** |
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135 | * @brief Obtain RWLock for reading. |
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136 | * |
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137 | * This routine attempts to obtain the RWLock for read access. |
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138 | * |
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139 | * @param[in] the_rwlock is the RWLock to wait for |
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140 | * @param[in] wait is true if the calling thread is willing to wait |
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141 | */ |
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142 | |
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143 | Status_Control _CORE_RWLock_Seize_for_reading( |
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144 | CORE_RWLock_Control *the_rwlock, |
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145 | bool wait, |
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146 | Thread_queue_Context *queue_context |
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147 | ); |
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148 | |
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149 | /** |
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150 | * @brief Obtain RWLock for writing. |
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151 | * |
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152 | * This routine attempts to obtain the RWLock for write exclusive access. |
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153 | * |
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154 | * @param[in] the_rwlock is the RWLock to wait for |
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155 | * @param[in] wait is true if the calling thread is willing to wait |
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156 | */ |
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157 | Status_Control _CORE_RWLock_Seize_for_writing( |
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158 | CORE_RWLock_Control *the_rwlock, |
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159 | bool wait, |
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160 | Thread_queue_Context *queue_context |
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161 | ); |
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162 | |
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163 | /** |
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164 | * @brief Release the RWLock. |
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165 | * |
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166 | * This routine manually releases @a the_rwlock. All of the threads waiting |
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167 | * for the RWLock will be readied. |
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168 | * |
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169 | * @param[in] the_rwlock is the RWLock to surrender |
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170 | * |
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171 | * @retval Status is returned to indicate successful or failure. |
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172 | */ |
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173 | Status_Control _CORE_RWLock_Surrender( CORE_RWLock_Control *the_rwlock ); |
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174 | |
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175 | /** @} */ |
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176 | |
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177 | #ifdef __cplusplus |
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178 | } |
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179 | #endif |
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180 | |
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181 | #endif |
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182 | /* end of include file */ |
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