[109ace3a] | 1 | /** |
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| 2 | * @file timerserver.c |
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| 3 | * |
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[36a63d78] | 4 | * Timer Manager - rtems_timer_initiate_server directive along with |
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[109ace3a] | 5 | * the Timer Server Body and support routines |
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[36a63d78] | 6 | * |
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[109ace3a] | 7 | * @note Data specific to the Timer Server is declared in this |
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| 8 | * file as the Timer Server so it does not have to be in the |
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| 9 | * minimum footprint. It is only really required when |
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| 10 | * task-based timers are used. Since task-based timers can |
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| 11 | * not be started until the server is initiated, this structure |
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| 12 | * does not have to be initialized until then. |
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| 13 | */ |
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| 14 | |
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| 15 | /* COPYRIGHT (c) 1989-2008. |
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[36a63d78] | 16 | * On-Line Applications Research Corporation (OAR). |
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| 17 | * |
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[6e51c4c] | 18 | * Copyright (c) 2009 embedded brains GmbH. |
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| 19 | * |
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[36a63d78] | 20 | * The license and distribution terms for this file may be |
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| 21 | * found in the file LICENSE in this distribution or at |
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[c499856] | 22 | * http://www.rtems.org/license/LICENSE. |
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[36a63d78] | 23 | */ |
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| 24 | |
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[1095ec1] | 25 | #if HAVE_CONFIG_H |
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| 26 | #include "config.h" |
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| 27 | #endif |
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| 28 | |
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[e90b1df] | 29 | #include <rtems/rtems/timerimpl.h> |
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[5618c37a] | 30 | #include <rtems/rtems/tasksimpl.h> |
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[88c74ab] | 31 | #include <rtems/score/isrlevel.h> |
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[5618c37a] | 32 | #include <rtems/score/threadimpl.h> |
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[f031df0e] | 33 | #include <rtems/score/todimpl.h> |
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[4b48ece0] | 34 | #include <rtems/score/watchdogimpl.h> |
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[36a63d78] | 35 | |
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[6e51c4c] | 36 | static Timer_server_Control _Timer_server_Default; |
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[109ace3a] | 37 | |
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[6e51c4c] | 38 | static void _Timer_server_Stop_interval_system_watchdog( |
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| 39 | Timer_server_Control *ts |
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| 40 | ) |
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| 41 | { |
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| 42 | _Watchdog_Remove( &ts->Interval_watchdogs.System_watchdog ); |
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| 43 | } |
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[36a63d78] | 44 | |
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[6e51c4c] | 45 | static void _Timer_server_Reset_interval_system_watchdog( |
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| 46 | Timer_server_Control *ts |
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| 47 | ) |
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| 48 | { |
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| 49 | ISR_Level level; |
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[422289e] | 50 | |
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[6e51c4c] | 51 | _Timer_server_Stop_interval_system_watchdog( ts ); |
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[422289e] | 52 | |
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[6e51c4c] | 53 | _ISR_Disable( level ); |
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| 54 | if ( !_Chain_Is_empty( &ts->Interval_watchdogs.Chain ) ) { |
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| 55 | Watchdog_Interval delta_interval = |
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| 56 | _Watchdog_First( &ts->Interval_watchdogs.Chain )->delta_interval; |
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| 57 | _ISR_Enable( level ); |
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[36a63d78] | 58 | |
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[6e51c4c] | 59 | /* |
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| 60 | * The unit is TICKS here. |
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| 61 | */ |
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| 62 | _Watchdog_Insert_ticks( |
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| 63 | &ts->Interval_watchdogs.System_watchdog, |
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| 64 | delta_interval |
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| 65 | ); |
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| 66 | } else { |
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| 67 | _ISR_Enable( level ); |
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| 68 | } |
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| 69 | } |
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[36a63d78] | 70 | |
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[6e51c4c] | 71 | static void _Timer_server_Stop_tod_system_watchdog( |
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| 72 | Timer_server_Control *ts |
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| 73 | ) |
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| 74 | { |
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| 75 | _Watchdog_Remove( &ts->TOD_watchdogs.System_watchdog ); |
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| 76 | } |
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[109ace3a] | 77 | |
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[6e51c4c] | 78 | static void _Timer_server_Reset_tod_system_watchdog( |
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| 79 | Timer_server_Control *ts |
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| 80 | ) |
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| 81 | { |
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| 82 | ISR_Level level; |
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[109ace3a] | 83 | |
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[6e51c4c] | 84 | _Timer_server_Stop_tod_system_watchdog( ts ); |
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[109ace3a] | 85 | |
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[6e51c4c] | 86 | _ISR_Disable( level ); |
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| 87 | if ( !_Chain_Is_empty( &ts->TOD_watchdogs.Chain ) ) { |
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| 88 | Watchdog_Interval delta_interval = |
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| 89 | _Watchdog_First( &ts->TOD_watchdogs.Chain )->delta_interval; |
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| 90 | _ISR_Enable( level ); |
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[109ace3a] | 91 | |
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[6e51c4c] | 92 | /* |
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| 93 | * The unit is SECONDS here. |
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| 94 | */ |
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| 95 | _Watchdog_Insert_seconds( |
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| 96 | &ts->TOD_watchdogs.System_watchdog, |
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| 97 | delta_interval |
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| 98 | ); |
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| 99 | } else { |
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| 100 | _ISR_Enable( level ); |
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| 101 | } |
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| 102 | } |
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| 103 | |
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| 104 | static void _Timer_server_Insert_timer( |
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| 105 | Timer_server_Control *ts, |
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| 106 | Timer_Control *timer |
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| 107 | ) |
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[109ace3a] | 108 | { |
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[6e51c4c] | 109 | if ( timer->the_class == TIMER_INTERVAL_ON_TASK ) { |
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| 110 | _Watchdog_Insert( &ts->Interval_watchdogs.Chain, &timer->Ticker ); |
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| 111 | } else if ( timer->the_class == TIMER_TIME_OF_DAY_ON_TASK ) { |
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| 112 | _Watchdog_Insert( &ts->TOD_watchdogs.Chain, &timer->Ticker ); |
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| 113 | } |
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| 114 | } |
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[109ace3a] | 115 | |
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[6e51c4c] | 116 | static void _Timer_server_Insert_timer_and_make_snapshot( |
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| 117 | Timer_server_Control *ts, |
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| 118 | Timer_Control *timer |
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| 119 | ) |
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| 120 | { |
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| 121 | Watchdog_Control *first_watchdog; |
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| 122 | Watchdog_Interval delta_interval; |
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| 123 | Watchdog_Interval last_snapshot; |
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| 124 | Watchdog_Interval snapshot; |
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| 125 | Watchdog_Interval delta; |
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| 126 | ISR_Level level; |
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[109ace3a] | 127 | |
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[6e51c4c] | 128 | /* |
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| 129 | * We have to update the time snapshots here, because otherwise we may have |
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| 130 | * problems with the integer range of the delta values. The time delta DT |
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| 131 | * from the last snapshot to now may be arbitrarily long. The last snapshot |
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| 132 | * is the reference point for the delta chain. Thus if we do not update the |
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| 133 | * reference point we have to add DT to the initial delta of the watchdog |
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| 134 | * being inserted. This could result in an integer overflow. |
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| 135 | */ |
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| 136 | |
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| 137 | _Thread_Disable_dispatch(); |
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| 138 | |
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| 139 | if ( timer->the_class == TIMER_INTERVAL_ON_TASK ) { |
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| 140 | /* |
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| 141 | * We have to advance the last known ticks value of the server and update |
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| 142 | * the watchdog chain accordingly. |
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| 143 | */ |
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| 144 | _ISR_Disable( level ); |
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| 145 | snapshot = _Watchdog_Ticks_since_boot; |
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| 146 | last_snapshot = ts->Interval_watchdogs.last_snapshot; |
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| 147 | if ( !_Chain_Is_empty( &ts->Interval_watchdogs.Chain ) ) { |
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| 148 | first_watchdog = _Watchdog_First( &ts->Interval_watchdogs.Chain ); |
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| 149 | |
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| 150 | /* |
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| 151 | * We assume adequate unsigned arithmetic here. |
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| 152 | */ |
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| 153 | delta = snapshot - last_snapshot; |
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| 154 | |
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| 155 | delta_interval = first_watchdog->delta_interval; |
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| 156 | if (delta_interval > delta) { |
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| 157 | delta_interval -= delta; |
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| 158 | } else { |
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| 159 | delta_interval = 0; |
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| 160 | } |
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| 161 | first_watchdog->delta_interval = delta_interval; |
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| 162 | } |
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| 163 | ts->Interval_watchdogs.last_snapshot = snapshot; |
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| 164 | _ISR_Enable( level ); |
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| 165 | |
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| 166 | _Watchdog_Insert( &ts->Interval_watchdogs.Chain, &timer->Ticker ); |
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| 167 | |
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| 168 | if ( !ts->active ) { |
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| 169 | _Timer_server_Reset_interval_system_watchdog( ts ); |
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| 170 | } |
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| 171 | } else if ( timer->the_class == TIMER_TIME_OF_DAY_ON_TASK ) { |
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| 172 | /* |
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| 173 | * We have to advance the last known seconds value of the server and update |
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| 174 | * the watchdog chain accordingly. |
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| 175 | */ |
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| 176 | _ISR_Disable( level ); |
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| 177 | snapshot = (Watchdog_Interval) _TOD_Seconds_since_epoch(); |
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| 178 | last_snapshot = ts->TOD_watchdogs.last_snapshot; |
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| 179 | if ( !_Chain_Is_empty( &ts->TOD_watchdogs.Chain ) ) { |
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| 180 | first_watchdog = _Watchdog_First( &ts->TOD_watchdogs.Chain ); |
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| 181 | delta_interval = first_watchdog->delta_interval; |
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| 182 | if ( snapshot > last_snapshot ) { |
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| 183 | /* |
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| 184 | * We advanced in time. |
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| 185 | */ |
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| 186 | delta = snapshot - last_snapshot; |
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| 187 | if (delta_interval > delta) { |
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| 188 | delta_interval -= delta; |
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| 189 | } else { |
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| 190 | delta_interval = 0; |
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| 191 | } |
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| 192 | } else { |
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| 193 | /* |
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| 194 | * Someone put us in the past. |
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| 195 | */ |
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| 196 | delta = last_snapshot - snapshot; |
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| 197 | delta_interval += delta; |
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| 198 | } |
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| 199 | first_watchdog->delta_interval = delta_interval; |
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| 200 | } |
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| 201 | ts->TOD_watchdogs.last_snapshot = snapshot; |
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| 202 | _ISR_Enable( level ); |
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| 203 | |
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| 204 | _Watchdog_Insert( &ts->TOD_watchdogs.Chain, &timer->Ticker ); |
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| 205 | |
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| 206 | if ( !ts->active ) { |
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| 207 | _Timer_server_Reset_tod_system_watchdog( ts ); |
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[109ace3a] | 208 | } |
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| 209 | } |
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[6e51c4c] | 210 | |
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| 211 | _Thread_Enable_dispatch(); |
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[109ace3a] | 212 | } |
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| 213 | |
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[6e51c4c] | 214 | static void _Timer_server_Schedule_operation_method( |
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| 215 | Timer_server_Control *ts, |
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| 216 | Timer_Control *timer |
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[109ace3a] | 217 | ) |
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| 218 | { |
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[6e51c4c] | 219 | if ( ts->insert_chain == NULL ) { |
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| 220 | _Timer_server_Insert_timer_and_make_snapshot( ts, timer ); |
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| 221 | } else { |
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| 222 | /* |
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| 223 | * We interrupted a critical section of the timer server. The timer |
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| 224 | * server is not preemptible, so we must be in interrupt context here. No |
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| 225 | * thread dispatch will happen until the timer server finishes its |
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| 226 | * critical section. We have to use the protected chain methods because |
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| 227 | * we may be interrupted by a higher priority interrupt. |
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| 228 | */ |
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| 229 | _Chain_Append( ts->insert_chain, &timer->Object.Node ); |
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| 230 | } |
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| 231 | } |
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[109ace3a] | 232 | |
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[6e51c4c] | 233 | static void _Timer_server_Process_interval_watchdogs( |
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| 234 | Timer_server_Watchdogs *watchdogs, |
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| 235 | Chain_Control *fire_chain |
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| 236 | ) |
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| 237 | { |
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| 238 | Watchdog_Interval snapshot = _Watchdog_Ticks_since_boot; |
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[109ace3a] | 239 | |
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[6e51c4c] | 240 | /* |
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| 241 | * We assume adequate unsigned arithmetic here. |
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| 242 | */ |
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| 243 | Watchdog_Interval delta = snapshot - watchdogs->last_snapshot; |
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| 244 | |
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| 245 | watchdogs->last_snapshot = snapshot; |
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| 246 | |
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| 247 | _Watchdog_Adjust_to_chain( &watchdogs->Chain, delta, fire_chain ); |
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[109ace3a] | 248 | } |
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| 249 | |
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[6e51c4c] | 250 | static void _Timer_server_Process_tod_watchdogs( |
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| 251 | Timer_server_Watchdogs *watchdogs, |
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| 252 | Chain_Control *fire_chain |
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[109ace3a] | 253 | ) |
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| 254 | { |
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[6e51c4c] | 255 | Watchdog_Interval snapshot = (Watchdog_Interval) _TOD_Seconds_since_epoch(); |
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| 256 | Watchdog_Interval last_snapshot = watchdogs->last_snapshot; |
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| 257 | Watchdog_Interval delta; |
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[109ace3a] | 258 | |
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| 259 | /* |
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| 260 | * Process the seconds chain. Start by checking that the Time |
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| 261 | * of Day (TOD) has not been set backwards. If it has then |
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[6e51c4c] | 262 | * we want to adjust the watchdogs->Chain to indicate this. |
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[109ace3a] | 263 | */ |
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[6e51c4c] | 264 | if ( snapshot > last_snapshot ) { |
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[109ace3a] | 265 | /* |
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| 266 | * This path is for normal forward movement and cases where the |
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| 267 | * TOD has been set forward. |
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| 268 | */ |
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[6e51c4c] | 269 | delta = snapshot - last_snapshot; |
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| 270 | _Watchdog_Adjust_to_chain( &watchdogs->Chain, delta, fire_chain ); |
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[109ace3a] | 271 | |
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[6e51c4c] | 272 | } else if ( snapshot < last_snapshot ) { |
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[109ace3a] | 273 | /* |
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| 274 | * The current TOD is before the last TOD which indicates that |
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| 275 | * TOD has been set backwards. |
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| 276 | */ |
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[6e51c4c] | 277 | delta = last_snapshot - snapshot; |
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| 278 | _Watchdog_Adjust( &watchdogs->Chain, WATCHDOG_BACKWARD, delta ); |
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[109ace3a] | 279 | } |
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[6e51c4c] | 280 | |
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| 281 | watchdogs->last_snapshot = snapshot; |
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[109ace3a] | 282 | } |
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| 283 | |
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[6e51c4c] | 284 | static void _Timer_server_Process_insertions( Timer_server_Control *ts ) |
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[36a63d78] | 285 | { |
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[6e51c4c] | 286 | while ( true ) { |
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| 287 | Timer_Control *timer = (Timer_Control *) _Chain_Get( ts->insert_chain ); |
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[109ace3a] | 288 | |
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[6e51c4c] | 289 | if ( timer == NULL ) { |
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| 290 | break; |
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| 291 | } |
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[109ace3a] | 292 | |
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[6e51c4c] | 293 | _Timer_server_Insert_timer( ts, timer ); |
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| 294 | } |
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| 295 | } |
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[36a63d78] | 296 | |
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[6e51c4c] | 297 | static void _Timer_server_Get_watchdogs_that_fire_now( |
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| 298 | Timer_server_Control *ts, |
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| 299 | Chain_Control *insert_chain, |
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| 300 | Chain_Control *fire_chain |
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| 301 | ) |
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| 302 | { |
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[109ace3a] | 303 | /* |
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[6e51c4c] | 304 | * Afterwards all timer inserts are directed to this chain and the interval |
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| 305 | * and TOD chains will be no more modified by other parties. |
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[109ace3a] | 306 | */ |
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[6e51c4c] | 307 | ts->insert_chain = insert_chain; |
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[36a63d78] | 308 | |
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[6e51c4c] | 309 | while ( true ) { |
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| 310 | ISR_Level level; |
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[109ace3a] | 311 | |
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[894d01c] | 312 | /* |
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[6e51c4c] | 313 | * Remove all the watchdogs that need to fire so we can invoke them. |
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[894d01c] | 314 | */ |
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[6e51c4c] | 315 | _Timer_server_Process_interval_watchdogs( |
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| 316 | &ts->Interval_watchdogs, |
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| 317 | fire_chain |
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| 318 | ); |
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| 319 | _Timer_server_Process_tod_watchdogs( &ts->TOD_watchdogs, fire_chain ); |
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[50f32b11] | 320 | |
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[109ace3a] | 321 | /* |
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[6e51c4c] | 322 | * The insertions have to take place here, because they reference the |
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| 323 | * current time. The previous process methods take a snapshot of the |
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| 324 | * current time. In case someone inserts a watchdog with an initial value |
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| 325 | * of zero it will be processed in the next iteration of the timer server |
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| 326 | * body loop. |
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[109ace3a] | 327 | */ |
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[6e51c4c] | 328 | _Timer_server_Process_insertions( ts ); |
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[36a63d78] | 329 | |
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[6e51c4c] | 330 | _ISR_Disable( level ); |
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| 331 | if ( _Chain_Is_empty( insert_chain ) ) { |
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| 332 | ts->insert_chain = NULL; |
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[109ace3a] | 333 | _ISR_Enable( level ); |
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| 334 | |
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[6e51c4c] | 335 | break; |
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| 336 | } else { |
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| 337 | _ISR_Enable( level ); |
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[109ace3a] | 338 | } |
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[36a63d78] | 339 | } |
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| 340 | } |
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| 341 | |
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[a1ccc40] | 342 | /* FIXME: This locking approach for SMP is improvable! */ |
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| 343 | |
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| 344 | static void _Timer_server_SMP_lock_aquire( void ) |
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| 345 | { |
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| 346 | #if defined( RTEMS_SMP ) |
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| 347 | _Thread_Disable_dispatch(); |
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| 348 | #endif |
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| 349 | } |
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| 350 | |
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| 351 | static void _Timer_server_SMP_lock_release( void ) |
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| 352 | { |
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| 353 | #if defined( RTEMS_SMP ) |
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| 354 | _Thread_Enable_dispatch(); |
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| 355 | #endif |
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| 356 | } |
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| 357 | |
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[109ace3a] | 358 | /** |
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[6e51c4c] | 359 | * @brief Timer server body. |
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[109ace3a] | 360 | * |
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[6e51c4c] | 361 | * This is the server for task based timers. This task executes whenever a |
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| 362 | * task-based timer should fire. It services both "after" and "when" timers. |
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| 363 | * It is not created automatically but must be created explicitly by the |
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| 364 | * application before task-based timers may be initiated. The parameter |
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| 365 | * @a arg points to the corresponding timer server control block. |
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[109ace3a] | 366 | */ |
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[6e51c4c] | 367 | static rtems_task _Timer_server_Body( |
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| 368 | rtems_task_argument arg |
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[109ace3a] | 369 | ) |
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| 370 | { |
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[6e51c4c] | 371 | Timer_server_Control *ts = (Timer_server_Control *) arg; |
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| 372 | Chain_Control insert_chain; |
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| 373 | Chain_Control fire_chain; |
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| 374 | |
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| 375 | _Chain_Initialize_empty( &insert_chain ); |
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| 376 | _Chain_Initialize_empty( &fire_chain ); |
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| 377 | |
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[a1ccc40] | 378 | _Timer_server_SMP_lock_aquire(); |
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| 379 | |
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[6e51c4c] | 380 | while ( true ) { |
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| 381 | _Timer_server_Get_watchdogs_that_fire_now( ts, &insert_chain, &fire_chain ); |
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| 382 | |
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| 383 | if ( !_Chain_Is_empty( &fire_chain ) ) { |
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| 384 | /* |
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| 385 | * Fire the watchdogs. |
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| 386 | */ |
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| 387 | while ( true ) { |
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| 388 | Watchdog_Control *watchdog; |
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| 389 | ISR_Level level; |
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| 390 | |
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| 391 | /* |
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| 392 | * It is essential that interrupts are disable here since an interrupt |
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| 393 | * service routine may remove a watchdog from the chain. |
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| 394 | */ |
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| 395 | _ISR_Disable( level ); |
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| 396 | watchdog = (Watchdog_Control *) _Chain_Get_unprotected( &fire_chain ); |
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| 397 | if ( watchdog != NULL ) { |
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| 398 | watchdog->state = WATCHDOG_INACTIVE; |
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| 399 | _ISR_Enable( level ); |
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| 400 | } else { |
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| 401 | _ISR_Enable( level ); |
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| 402 | |
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| 403 | break; |
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| 404 | } |
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| 405 | |
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[a1ccc40] | 406 | _Timer_server_SMP_lock_release(); |
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| 407 | |
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[6e51c4c] | 408 | /* |
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| 409 | * The timer server may block here and wait for resources or time. |
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| 410 | * The system watchdogs are inactive and will remain inactive since |
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| 411 | * the active flag of the timer server is true. |
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| 412 | */ |
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| 413 | (*watchdog->routine)( watchdog->id, watchdog->user_data ); |
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[a1ccc40] | 414 | |
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| 415 | _Timer_server_SMP_lock_aquire(); |
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[6e51c4c] | 416 | } |
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| 417 | } else { |
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| 418 | ts->active = false; |
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| 419 | |
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| 420 | /* |
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| 421 | * Block until there is something to do. |
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| 422 | */ |
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[a1ccc40] | 423 | #if !defined( RTEMS_SMP ) |
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[6e51c4c] | 424 | _Thread_Disable_dispatch(); |
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[a1ccc40] | 425 | #endif |
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[6e51c4c] | 426 | _Thread_Set_state( ts->thread, STATES_DELAYING ); |
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| 427 | _Timer_server_Reset_interval_system_watchdog( ts ); |
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| 428 | _Timer_server_Reset_tod_system_watchdog( ts ); |
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[a1ccc40] | 429 | #if !defined( RTEMS_SMP ) |
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[6e51c4c] | 430 | _Thread_Enable_dispatch(); |
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[a1ccc40] | 431 | #endif |
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| 432 | |
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| 433 | _Timer_server_SMP_lock_release(); |
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| 434 | _Timer_server_SMP_lock_aquire(); |
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[6e51c4c] | 435 | |
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| 436 | ts->active = true; |
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| 437 | |
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| 438 | /* |
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| 439 | * Maybe an interrupt did reset the system timers, so we have to stop |
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| 440 | * them here. Since we are active now, there will be no more resets |
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| 441 | * until we are inactive again. |
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| 442 | */ |
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| 443 | _Timer_server_Stop_interval_system_watchdog( ts ); |
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| 444 | _Timer_server_Stop_tod_system_watchdog( ts ); |
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| 445 | } |
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| 446 | } |
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[109ace3a] | 447 | } |
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| 448 | |
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| 449 | /** |
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| 450 | * @brief rtems_timer_initiate_server |
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[36a63d78] | 451 | * |
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| 452 | * This directive creates and starts the server for task-based timers. |
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| 453 | * It must be invoked before any task-based timers can be initiated. |
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| 454 | * |
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[109ace3a] | 455 | * @param[in] priority is the timer server priority |
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| 456 | * @param[in] stack_size is the stack size in bytes |
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| 457 | * @param[in] attribute_set is the timer server attributes |
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[36a63d78] | 458 | * |
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[6e51c4c] | 459 | * @return This method returns RTEMS_SUCCESSFUL if successful and an |
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[109ace3a] | 460 | * error code otherwise. |
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[36a63d78] | 461 | */ |
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| 462 | rtems_status_code rtems_timer_initiate_server( |
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[1d496f6] | 463 | uint32_t priority, |
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| 464 | uint32_t stack_size, |
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[36a63d78] | 465 | rtems_attribute attribute_set |
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| 466 | ) |
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| 467 | { |
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[6e51c4c] | 468 | rtems_id id; |
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| 469 | rtems_status_code status; |
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| 470 | rtems_task_priority _priority; |
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| 471 | static bool initialized = false; |
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| 472 | bool tmpInitialized; |
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| 473 | Timer_server_Control *ts = &_Timer_server_Default; |
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[1ad83eb] | 474 | |
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| 475 | /* |
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[109ace3a] | 476 | * Make sure the requested priority is valid. The if is |
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[115fb76] | 477 | * structured so we check it is invalid before looking for |
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| 478 | * a specific invalid value as the default. |
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[1ad83eb] | 479 | */ |
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| 480 | _priority = priority; |
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[115fb76] | 481 | if ( !_RTEMS_tasks_Priority_is_valid( priority ) ) { |
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| 482 | if ( priority != RTEMS_TIMER_SERVER_DEFAULT_PRIORITY ) |
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| 483 | return RTEMS_INVALID_PRIORITY; |
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[1ad83eb] | 484 | _priority = 0; |
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[115fb76] | 485 | } |
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[36a63d78] | 486 | |
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| 487 | /* |
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[5088d97] | 488 | * Just to make sure this is only called once. |
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[36a63d78] | 489 | */ |
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| 490 | _Thread_Disable_dispatch(); |
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[5088d97] | 491 | tmpInitialized = initialized; |
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[484a769] | 492 | initialized = true; |
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[5088d97] | 493 | _Thread_Enable_dispatch(); |
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[36a63d78] | 494 | |
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[5088d97] | 495 | if ( tmpInitialized ) |
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[36a63d78] | 496 | return RTEMS_INCORRECT_STATE; |
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| 497 | |
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| 498 | /* |
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[1ad83eb] | 499 | * Create the Timer Server with the name the name of "TIME". The attribute |
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| 500 | * RTEMS_SYSTEM_TASK allows us to set a priority to 0 which will makes it |
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| 501 | * higher than any other task in the system. It can be viewed as a low |
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| 502 | * priority interrupt. It is also always NO_PREEMPT so it looks like |
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| 503 | * an interrupt to other tasks. |
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| 504 | * |
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| 505 | * We allow the user to override the default priority because the Timer |
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[50f32b11] | 506 | * Server can invoke TSRs which must adhere to language run-time or |
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[1ad83eb] | 507 | * other library rules. For example, if using a TSR written in Ada the |
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| 508 | * Server should run at the same priority as the priority Ada task. |
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| 509 | * Otherwise, the priority ceiling for the mutex used to protect the |
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| 510 | * GNAT run-time is violated. |
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[36a63d78] | 511 | */ |
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| 512 | status = rtems_task_create( |
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[6c06288] | 513 | _Objects_Build_name('T','I','M','E'), /* "TIME" */ |
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[1ad83eb] | 514 | _priority, /* create with priority 1 since 0 is illegal */ |
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[36a63d78] | 515 | stack_size, /* let user specify stack size */ |
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| 516 | RTEMS_NO_PREEMPT, /* no preempt is like an interrupt */ |
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[1ad83eb] | 517 | /* user may want floating point but we need */ |
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| 518 | /* system task specified for 0 priority */ |
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| 519 | attribute_set | RTEMS_SYSTEM_TASK, |
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[36a63d78] | 520 | &id /* get the id back */ |
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| 521 | ); |
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| 522 | if (status) { |
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[484a769] | 523 | initialized = false; |
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[36a63d78] | 524 | return status; |
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| 525 | } |
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| 526 | |
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[5088d97] | 527 | /* |
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| 528 | * Do all the data structure initialization before starting the |
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| 529 | * Timer Server so we do not have to have a critical section. |
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| 530 | */ |
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[36a63d78] | 531 | |
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| 532 | /* |
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| 533 | * We work with the TCB pointer, not the ID, so we need to convert |
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| 534 | * to a TCB pointer from here out. |
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| 535 | */ |
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[6e51c4c] | 536 | ts->thread = (Thread_Control *)_Objects_Get_local_object( |
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[36a63d78] | 537 | &_RTEMS_tasks_Information, |
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| 538 | _Objects_Get_index(id) |
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| 539 | ); |
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| 540 | |
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| 541 | /* |
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| 542 | * Initialize the timer lists that the server will manage. |
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| 543 | */ |
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[6e51c4c] | 544 | _Chain_Initialize_empty( &ts->Interval_watchdogs.Chain ); |
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| 545 | _Chain_Initialize_empty( &ts->TOD_watchdogs.Chain ); |
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[36a63d78] | 546 | |
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[50f32b11] | 547 | /* |
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| 548 | * Initialize the timers that will be used to control when the |
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[36a63d78] | 549 | * Timer Server wakes up and services the task-based timers. |
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| 550 | */ |
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[6e51c4c] | 551 | _Watchdog_Initialize( |
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| 552 | &ts->Interval_watchdogs.System_watchdog, |
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| 553 | _Thread_Delay_ended, |
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[f6b7b7ba] | 554 | 0, |
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| 555 | ts->thread |
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[6e51c4c] | 556 | ); |
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| 557 | _Watchdog_Initialize( |
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| 558 | &ts->TOD_watchdogs.System_watchdog, |
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| 559 | _Thread_Delay_ended, |
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[f6b7b7ba] | 560 | 0, |
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| 561 | ts->thread |
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[6e51c4c] | 562 | ); |
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[109ace3a] | 563 | |
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[5088d97] | 564 | /* |
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[6e51c4c] | 565 | * Initialize the pointer to the timer schedule method so applications that |
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| 566 | * do not use the Timer Server do not have to pull it in. |
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[5088d97] | 567 | */ |
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[6e51c4c] | 568 | ts->schedule_operation = _Timer_server_Schedule_operation_method; |
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| 569 | |
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| 570 | ts->Interval_watchdogs.last_snapshot = _Watchdog_Ticks_since_boot; |
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| 571 | ts->TOD_watchdogs.last_snapshot = (Watchdog_Interval) _TOD_Seconds_since_epoch(); |
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| 572 | |
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| 573 | ts->insert_chain = NULL; |
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| 574 | ts->active = false; |
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| 575 | |
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| 576 | /* |
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| 577 | * The default timer server is now available. |
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| 578 | */ |
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| 579 | _Timer_server = ts; |
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[36a63d78] | 580 | |
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[109ace3a] | 581 | /* |
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| 582 | * Start the timer server |
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| 583 | */ |
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[5088d97] | 584 | status = rtems_task_start( |
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[6e51c4c] | 585 | id, |
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| 586 | _Timer_server_Body, |
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| 587 | (rtems_task_argument) ts |
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[5088d97] | 588 | ); |
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[6e51c4c] | 589 | |
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[1de98d97] | 590 | #if defined(RTEMS_DEBUG) |
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[5088d97] | 591 | /* |
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| 592 | * One would expect a call to rtems_task_delete() here to clean up |
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| 593 | * but there is actually no way (in normal circumstances) that the |
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| 594 | * start can fail. The id and starting address are known to be |
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| 595 | * be good. If this service fails, something is weirdly wrong on the |
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| 596 | * target such as a stray write in an ISR or incorrect memory layout. |
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| 597 | */ |
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[1de98d97] | 598 | if (status) { |
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| 599 | initialized = false; |
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| 600 | } |
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| 601 | #endif |
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[5088d97] | 602 | |
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| 603 | return status; |
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[36a63d78] | 604 | } |
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