1 | /** |
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2 | * @file rtems/score/smplock.h |
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3 | * |
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4 | * @brief Interface for Atomic Locks |
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5 | * |
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6 | * This include file defines the interface for atomic locks |
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7 | * which can be used in multiprocessor configurations. |
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8 | */ |
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9 | |
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10 | /* |
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11 | * COPYRIGHT (c) 1989-2011. |
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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.com/license/LICENSE. |
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17 | */ |
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18 | |
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19 | #ifndef _RTEMS_LOCK_H |
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20 | #define _RTEMS_LOCK_H |
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21 | |
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22 | #include <rtems/score/isr.h> |
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23 | |
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24 | /** |
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25 | * @defgroup RTEMS Lock Interface |
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26 | * |
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27 | * @ingroup Score |
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28 | * |
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29 | */ |
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30 | |
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31 | /**@{*/ |
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32 | |
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33 | #ifdef __cplusplus |
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34 | extern "C" { |
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35 | #endif |
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36 | |
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37 | /** |
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38 | * This type is used to lock elements for atomic access. |
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39 | * This spinlock is a simple non-nesting spinlock, and |
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40 | * may be used for short non-nesting accesses. |
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41 | */ |
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42 | typedef uint32_t SMP_lock_spinlock_simple_Control; |
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43 | |
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44 | /** |
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45 | * This type is used to lock elements for atomic access. |
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46 | * This spinlock supports nesting, but is slightly more |
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47 | * complicated to use. Please see the descriptions of |
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48 | * obtain and release prior to using in order to understand |
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49 | * the callers responsibilty of managing short interupt disable |
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50 | * times. |
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51 | */ |
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52 | typedef struct { |
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53 | SMP_lock_spinlock_simple_Control lock; |
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54 | uint32_t count; |
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55 | int cpu_id; |
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56 | } SMP_lock_spinlock_nested_Control; |
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57 | |
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58 | /** |
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59 | * @brief Initialize a lock. |
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60 | * |
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61 | * This method is used to initialize the lock at @a lock. |
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62 | * |
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63 | * @param [in] lock is the address of the lock to obtain. |
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64 | */ |
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65 | void _SMP_lock_spinlock_simple_Initialize( |
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66 | SMP_lock_spinlock_simple_Control *lock |
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67 | ); |
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68 | |
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69 | /** |
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70 | * @brief Obtain a lock. |
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71 | * |
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72 | * This method is used to obtain the lock at @a lock. |
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73 | * |
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74 | * @param [in] lock is the address of the lock to obtain. |
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75 | * |
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76 | * @retval This method returns with processor interrupts disabled. |
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77 | * The previous level is returned. |
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78 | */ |
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79 | ISR_Level _SMP_lock_spinlock_simple_Obtain( |
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80 | SMP_lock_spinlock_simple_Control *lock |
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81 | ); |
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82 | |
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83 | /** |
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84 | * @brief Release a lock. |
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85 | * |
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86 | * This method is used to release the lock at @a lock. |
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87 | * |
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88 | * @param [in] lock is the address of the lock to obtain. |
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89 | */ |
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90 | void _SMP_lock_spinlock_simple_Release( |
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91 | SMP_lock_spinlock_simple_Control *lock, |
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92 | ISR_Level level |
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93 | ); |
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94 | |
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95 | /** |
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96 | * @brief Initialize a lock. |
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97 | * |
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98 | * This method is used to initialize the lock at @a lock. |
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99 | * |
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100 | * @param [in] lock is the address of the lock to obtain. |
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101 | */ |
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102 | void _SMP_lock_spinlock_nested_Initialize( |
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103 | SMP_lock_spinlock_nested_Control *lock |
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104 | ); |
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105 | |
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106 | /** |
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107 | * @brief Obtain a lock. |
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108 | * |
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109 | * This method is used to obtain the lock at @a lock. ISR's are |
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110 | * disabled when this routine returns and it is the callers responsibility |
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111 | * to either: |
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112 | * |
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113 | * # Do something very short and then call |
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114 | * _SMP_lock_spinlock_nested_Release or |
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115 | * # Do something very sort, call isr enable, then when ready |
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116 | * call isr_disable and _SMP_lock_spinlock_nested_Release |
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117 | * |
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118 | * @param [in] lock is the address of the lock to obtain. |
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119 | * |
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120 | * @retval This method returns with processor interrupts disabled. |
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121 | * The previous level is returned. |
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122 | */ |
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123 | ISR_Level _SMP_lock_spinlock_nested_Obtain( |
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124 | SMP_lock_spinlock_nested_Control *lock |
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125 | ); |
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126 | |
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127 | /** |
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128 | * @brief Release a lock. |
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129 | * |
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130 | * This method is used to release the lock at @a lock. |
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131 | * |
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132 | * @note ISR's are reenabled by this method and are expected to be |
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133 | * disabled upon entry to the method. |
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134 | * |
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135 | * @param [in] lock is the address of the lock to obtain. |
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136 | */ |
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137 | void _SMP_lock_spinlock_nested_Release( |
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138 | SMP_lock_spinlock_nested_Control *lock, |
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139 | ISR_Level level |
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140 | ); |
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141 | |
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142 | #ifdef __cplusplus |
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143 | } |
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144 | #endif |
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145 | |
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146 | /**@}*/ |
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147 | |
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148 | #endif |
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149 | /* end of include file */ |
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