1 | /* |
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2 | * Copyright (c) 2015 embedded brains GmbH. All rights reserved. |
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3 | * |
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4 | * embedded brains GmbH |
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5 | * Dornierstr. 4 |
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6 | * 82178 Puchheim |
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7 | * Germany |
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8 | * <rtems@embedded-brains.de> |
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9 | * |
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10 | * The license and distribution terms for this file may be |
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11 | * found in the file LICENSE in this distribution or at |
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12 | * http://www.rtems.org/license/LICENSE. |
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13 | */ |
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14 | |
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15 | #if HAVE_CONFIG_H |
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16 | #include "config.h" |
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17 | #endif |
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18 | |
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19 | #if HAVE_STRUCT__THREAD_QUEUE_QUEUE |
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20 | |
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21 | #include <sys/lock.h> |
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22 | |
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23 | #include <rtems/score/assert.h> |
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24 | #include <rtems/score/threadimpl.h> |
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25 | #include <rtems/score/threadqimpl.h> |
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26 | |
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27 | #define SEMAPHORE_TQ_OPERATIONS &_Thread_queue_Operations_priority |
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28 | |
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29 | typedef struct { |
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30 | Thread_queue_Syslock_queue Queue; |
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31 | unsigned int count; |
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32 | } Semaphore_Control; |
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33 | |
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34 | RTEMS_STATIC_ASSERT( |
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35 | offsetof( Semaphore_Control, Queue ) |
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36 | == offsetof( struct _Semaphore_Control, _Queue ), |
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37 | SEMAPHORE_CONTROL_QUEUE |
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38 | ); |
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39 | |
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40 | RTEMS_STATIC_ASSERT( |
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41 | offsetof( Semaphore_Control, count ) |
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42 | <= offsetof( struct _Semaphore_Control, _count ), |
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43 | SEMAPHORE_CONTROL_COUNT |
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44 | ); |
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45 | |
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46 | RTEMS_STATIC_ASSERT( |
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47 | sizeof( Semaphore_Control ) <= sizeof( struct _Semaphore_Control ), |
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48 | SEMAPHORE_CONTROL_SIZE |
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49 | ); |
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50 | |
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51 | static Semaphore_Control *_Semaphore_Get( |
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52 | struct _Semaphore_Control *_sem |
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53 | ) |
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54 | { |
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55 | return (Semaphore_Control *) _sem; |
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56 | } |
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57 | |
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58 | static Thread_Control *_Semaphore_Queue_acquire_critical( |
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59 | Semaphore_Control *sem, |
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60 | Thread_queue_Context *queue_context |
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61 | ) |
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62 | { |
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63 | Thread_Control *executing; |
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64 | |
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65 | executing = _Thread_Executing; |
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66 | _Thread_queue_Queue_acquire_critical( |
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67 | &sem->Queue.Queue, |
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68 | &executing->Potpourri_stats, |
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69 | &queue_context->Lock_context.Lock_context |
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70 | ); |
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71 | |
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72 | return executing; |
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73 | } |
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74 | |
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75 | static void _Semaphore_Queue_release( |
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76 | Semaphore_Control *sem, |
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77 | ISR_Level level, |
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78 | Thread_queue_Context *queue_context |
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79 | ) |
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80 | { |
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81 | _Thread_queue_Queue_release_critical( |
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82 | &sem->Queue.Queue, |
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83 | &queue_context->Lock_context.Lock_context |
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84 | ); |
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85 | _ISR_Local_enable( level ); |
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86 | } |
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87 | |
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88 | void _Semaphore_Wait( struct _Semaphore_Control *_sem ) |
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89 | { |
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90 | Semaphore_Control *sem ; |
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91 | ISR_Level level; |
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92 | Thread_queue_Context queue_context; |
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93 | Thread_Control *executing; |
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94 | unsigned int count; |
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95 | |
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96 | sem = _Semaphore_Get( _sem ); |
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97 | _Thread_queue_Context_initialize( &queue_context ); |
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98 | _Thread_queue_Context_ISR_disable( &queue_context, level ); |
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99 | executing = _Semaphore_Queue_acquire_critical( sem, &queue_context ); |
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100 | |
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101 | count = sem->count; |
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102 | if ( __predict_true( count > 0 ) ) { |
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103 | sem->count = count - 1; |
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104 | _Semaphore_Queue_release( sem, level, &queue_context ); |
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105 | } else { |
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106 | _Thread_queue_Context_set_thread_state( |
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107 | &queue_context, |
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108 | STATES_WAITING_FOR_SYS_LOCK_SEMAPHORE |
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109 | ); |
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110 | _Thread_queue_Context_set_do_nothing_enqueue_callout( &queue_context ); |
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111 | _Thread_queue_Context_set_no_timeout( &queue_context ); |
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112 | _Thread_queue_Context_set_ISR_level( &queue_context, level ); |
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113 | _Thread_queue_Enqueue( |
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114 | &sem->Queue.Queue, |
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115 | SEMAPHORE_TQ_OPERATIONS, |
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116 | executing, |
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117 | &queue_context |
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118 | ); |
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119 | } |
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120 | } |
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121 | |
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122 | void _Semaphore_Post( struct _Semaphore_Control *_sem ) |
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123 | { |
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124 | Semaphore_Control *sem; |
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125 | ISR_Level level; |
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126 | Thread_queue_Context queue_context; |
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127 | Thread_queue_Heads *heads; |
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128 | |
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129 | sem = _Semaphore_Get( _sem ); |
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130 | _Thread_queue_Context_initialize( &queue_context ); |
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131 | _Thread_queue_Context_ISR_disable( &queue_context, level ); |
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132 | _Semaphore_Queue_acquire_critical( sem, &queue_context ); |
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133 | |
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134 | heads = sem->Queue.Queue.heads; |
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135 | if ( __predict_true( heads == NULL ) ) { |
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136 | _Assert( sem->count < UINT_MAX ); |
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137 | ++sem->count; |
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138 | _Semaphore_Queue_release( sem, level, &queue_context ); |
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139 | } else { |
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140 | const Thread_queue_Operations *operations; |
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141 | Thread_Control *first; |
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142 | |
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143 | _Thread_queue_Context_set_ISR_level( &queue_context, level ); |
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144 | operations = SEMAPHORE_TQ_OPERATIONS; |
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145 | first = ( *operations->first )( heads ); |
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146 | |
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147 | _Thread_queue_Extract_critical( |
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148 | &sem->Queue.Queue, |
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149 | operations, |
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150 | first, |
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151 | &queue_context |
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152 | ); |
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153 | } |
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154 | } |
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155 | |
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156 | #endif /* HAVE_STRUCT__THREAD_QUEUE_QUEUE */ |
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