1 | /* |
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2 | * Clock Tick Device Driver Shell |
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3 | * |
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4 | * COPYRIGHT (c) 1989-2006. |
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5 | * On-Line Applications Research Corporation (OAR). |
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6 | * |
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7 | * The license and distribution terms for this file may be |
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8 | * found in the file LICENSE in this distribution or at |
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9 | * http://www.rtems.com/license/LICENSE. |
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10 | * |
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11 | * $Id$ |
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12 | */ |
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13 | |
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14 | #include <stdlib.h> |
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15 | |
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16 | #include <bsp.h> |
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17 | |
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18 | #if defined(CLOCK_DRIVER_USE_FAST_IDLE) && defined(CLOCK_DRIVER_ISRS_PER_TICK) |
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19 | #error "clockdrv_shell.c: fast idle and N ISRs per tick is not supported" |
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20 | #endif |
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21 | |
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22 | /* |
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23 | * This method is rarely used so default it. |
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24 | */ |
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25 | #ifndef Clock_driver_support_find_timer |
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26 | #define Clock_driver_support_find_timer() |
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27 | #endif |
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28 | |
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29 | /* |
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30 | * ISRs until next clock tick |
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31 | */ |
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32 | #ifdef CLOCK_DRIVER_ISRS_PER_TICK |
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33 | volatile uint32_t Clock_driver_isrs; |
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34 | #endif |
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35 | |
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36 | /* |
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37 | * Clock ticks since initialization |
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38 | */ |
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39 | volatile uint32_t Clock_driver_ticks; |
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40 | |
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41 | /* |
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42 | * ISR formerly installed. |
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43 | */ |
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44 | rtems_isr_entry Old_ticker; |
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45 | |
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46 | void Clock_exit( void ); |
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47 | |
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48 | /* |
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49 | * Clock_isr |
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50 | * |
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51 | * This is the clock tick interrupt handler. |
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52 | * |
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53 | * Input parameters: |
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54 | * vector - vector number |
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55 | * |
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56 | * Output parameters: NONE |
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57 | * |
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58 | * Return values: NONE |
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59 | */ |
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60 | rtems_isr Clock_isr( |
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61 | rtems_vector_number vector |
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62 | ) |
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63 | { |
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64 | /* |
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65 | * Accurate count of ISRs |
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66 | */ |
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67 | Clock_driver_ticks += 1; |
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68 | |
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69 | #ifdef CLOCK_DRIVER_USE_FAST_IDLE |
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70 | do { |
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71 | rtems_clock_tick(); |
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72 | } while ( _Thread_Executing == _Thread_Idle && |
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73 | _Thread_Heir == _Thread_Executing); |
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74 | |
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75 | Clock_driver_support_at_tick(); |
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76 | return; |
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77 | #else |
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78 | /* |
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79 | * Do the hardware specific per-tick action. |
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80 | * |
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81 | * The counter/timer may or may not be set to automatically reload. |
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82 | */ |
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83 | Clock_driver_support_at_tick(); |
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84 | |
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85 | #ifdef CLOCK_DRIVER_ISRS_PER_TICK |
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86 | /* |
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87 | * The driver is multiple ISRs per clock tick. |
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88 | */ |
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89 | if ( !Clock_driver_isrs ) { |
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90 | rtems_clock_tick(); |
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91 | |
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92 | Clock_driver_isrs = CLOCK_DRIVER_ISRS_PER_TICK; |
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93 | } |
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94 | Clock_driver_isrs--; |
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95 | #else |
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96 | /* |
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97 | * The driver is one ISR per clock tick. |
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98 | */ |
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99 | rtems_clock_tick(); |
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100 | #endif |
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101 | #endif |
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102 | } |
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103 | |
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104 | /* |
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105 | * Install_clock |
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106 | * |
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107 | * This routine actually performs the hardware initialization for the clock. |
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108 | * |
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109 | * Input parameters: |
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110 | * clock_isr - clock interrupt service routine entry point |
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111 | * |
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112 | * Output parameters: NONE |
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113 | * |
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114 | * Return values: NONE |
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115 | * |
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116 | */ |
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117 | |
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118 | static void Install_clock( |
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119 | rtems_isr_entry clock_isr |
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120 | ) |
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121 | { |
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122 | Clock_driver_ticks = 0; |
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123 | |
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124 | /* |
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125 | * Find timer -- some BSPs search buses for hardware timer |
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126 | */ |
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127 | Clock_driver_support_find_timer(); |
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128 | |
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129 | /* |
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130 | * Install vector |
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131 | */ |
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132 | Clock_driver_support_install_isr( clock_isr, Old_ticker ); |
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133 | |
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134 | #if defined(Clock_driver_nanoseconds_since_last_tick) |
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135 | rtems_clock_set_nanoseconds_extension( |
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136 | Clock_driver_nanoseconds_since_last_tick |
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137 | ); |
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138 | #endif |
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139 | |
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140 | /* |
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141 | * Now initialize the hardware that is the source of the tick ISR. |
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142 | */ |
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143 | Clock_driver_support_initialize_hardware(); |
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144 | |
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145 | atexit( Clock_exit ); |
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146 | } |
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147 | |
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148 | /* |
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149 | * Clock_exit |
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150 | * |
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151 | * This routine allows the clock driver to exit by masking the interrupt and |
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152 | * disabling the clock's counter. |
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153 | * |
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154 | * Input parameters: NONE |
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155 | * |
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156 | * Output parameters: NONE |
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157 | * |
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158 | * Return values: NONE |
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159 | * |
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160 | */ |
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161 | |
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162 | void Clock_exit( void ) |
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163 | { |
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164 | Clock_driver_support_shutdown_hardware(); |
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165 | |
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166 | /* do not restore old vector */ |
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167 | } |
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168 | |
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169 | /* |
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170 | * Clock_initialize |
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171 | * |
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172 | * This routine initializes the clock driver. |
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173 | * |
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174 | * Input parameters: |
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175 | * major - clock device major number |
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176 | * minor - clock device minor number |
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177 | * parg - pointer to optional device driver arguments |
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178 | * |
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179 | * Output parameters: NONE |
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180 | * |
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181 | * Return values: |
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182 | * rtems_device_driver status code |
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183 | */ |
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184 | |
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185 | rtems_device_driver Clock_initialize( |
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186 | rtems_device_major_number major, |
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187 | rtems_device_minor_number minor, |
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188 | void *pargp |
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189 | ) |
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190 | { |
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191 | Install_clock( Clock_isr ); |
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192 | |
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193 | /* |
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194 | * If we are counting ISRs per tick, then initialize the counter. |
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195 | */ |
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196 | #ifdef CLOCK_DRIVER_ISRS_PER_TICK |
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197 | Clock_driver_isrs = CLOCK_DRIVER_ISRS_PER_TICK; |
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198 | #endif |
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199 | |
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200 | return RTEMS_SUCCESSFUL; |
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201 | } |
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