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Diffstat (limited to 'cpukit/score/src/watchdog.c')
| -rw-r--r-- | cpukit/score/src/watchdog.c | 273 |
1 files changed, 273 insertions, 0 deletions
diff --git a/cpukit/score/src/watchdog.c b/cpukit/score/src/watchdog.c new file mode 100644 index 0000000000..67aaf267e9 --- /dev/null +++ b/cpukit/score/src/watchdog.c @@ -0,0 +1,273 @@ +/* + * Watchdog Handler + * + * + * COPYRIGHT (c) 1989-1997. + * On-Line Applications Research Corporation (OAR). + * Copyright assigned to U.S. Government, 1994. + * + * The license and distribution terms for this file may in + * the file LICENSE in this distribution or at + * http://www.OARcorp.com/rtems/license.html. + * + * $Id$ + */ + +#include <rtems/system.h> +#include <rtems/score/isr.h> +#include <rtems/score/watchdog.h> + +/*PAGE + * + * _Watchdog_Handler_initialization + * + * This routine initializes the watchdog handler. + * + * Input parameters: NONE + * + * Output parameters: NONE + */ + +void _Watchdog_Handler_initialization( void ) +{ + _Watchdog_Sync_count = 0; + _Watchdog_Sync_level = 0; + _Watchdog_Ticks_since_boot = 0; + + _Chain_Initialize_empty( &_Watchdog_Ticks_chain ); + _Chain_Initialize_empty( &_Watchdog_Seconds_chain ); +} + +/*PAGE + * + * _Watchdog_Remove + * + * The routine removes a watchdog from a delta chain and updates + * the delta counters of the remaining watchdogs. + */ + +Watchdog_States _Watchdog_Remove( + Watchdog_Control *the_watchdog +) +{ + ISR_Level level; + Watchdog_States previous_state; + Watchdog_Control *next_watchdog; + + _ISR_Disable( level ); + previous_state = the_watchdog->state; + switch ( previous_state ) { + case WATCHDOG_INACTIVE: + break; + + case WATCHDOG_BEING_INSERTED: + + /* + * It is not actually on the chain so just change the state and + * the Insert operation we interrupted will be aborted. + */ + the_watchdog->state = WATCHDOG_INACTIVE; + break; + + case WATCHDOG_ACTIVE: + case WATCHDOG_REMOVE_IT: + + the_watchdog->state = WATCHDOG_INACTIVE; + next_watchdog = _Watchdog_Next( the_watchdog ); + + if ( _Watchdog_Next(next_watchdog) ) + next_watchdog->delta_interval += the_watchdog->delta_interval; + + if ( _Watchdog_Sync_count ) + _Watchdog_Sync_level = _ISR_Nest_level; + + _Chain_Extract_unprotected( &the_watchdog->Node ); + break; + } + the_watchdog->stop_time = _Watchdog_Ticks_since_boot; + + _ISR_Enable( level ); + return( previous_state ); +} + +/*PAGE + * + * _Watchdog_Adjust + * + * This routine adjusts the delta chain backward or forward in response + * to a time change. + * + * Input parameters: + * header - pointer to the delta chain to be adjusted + * direction - forward or backward adjustment to delta chain + * units - units to adjust + * + * Output parameters: + */ + +void _Watchdog_Adjust( + Chain_Control *header, + Watchdog_Adjust_directions direction, + Watchdog_Interval units +) +{ + if ( !_Chain_Is_empty( header ) ) { + switch ( direction ) { + case WATCHDOG_BACKWARD: + _Watchdog_First( header )->delta_interval += units; + break; + case WATCHDOG_FORWARD: + while ( units ) { + if ( units < _Watchdog_First( header )->delta_interval ) { + _Watchdog_First( header )->delta_interval -= units; + break; + } else { + units -= _Watchdog_First( header )->delta_interval; + _Watchdog_First( header )->delta_interval = 1; + _Watchdog_Tickle( header ); + if ( _Chain_Is_empty( header ) ) + break; + } + } + break; + } + } +} + +/*PAGE + * + * _Watchdog_Insert + * + * This routine inserts a watchdog timer on to the appropriate delta + * chain while updating the delta interval counters. + */ + +void _Watchdog_Insert( + Chain_Control *header, + Watchdog_Control *the_watchdog +) +{ + ISR_Level level; + Watchdog_Control *after; + unsigned32 insert_isr_nest_level; + Watchdog_Interval delta_interval; + + + insert_isr_nest_level = _ISR_Nest_level; + the_watchdog->state = WATCHDOG_BEING_INSERTED; + + _Watchdog_Sync_count++; +restart: + delta_interval = the_watchdog->initial; + + _ISR_Disable( level ); + + for ( after = _Watchdog_First( header ) ; + ; + after = _Watchdog_Next( after ) ) { + + if ( delta_interval == 0 || !_Watchdog_Next( after ) ) + break; + + if ( delta_interval < after->delta_interval ) { + after->delta_interval -= delta_interval; + break; + } + + delta_interval -= after->delta_interval; + + /* + * If you experience problems comment out the _ISR_Flash line. + * 3.2.0 was the first release with this critical section redesigned. + * Under certain circumstances, the PREVIOUS critical section algorithm + * used around this flash point allowed interrupts to execute + * which violated the design assumptions. The critical section + * mechanism used here WAS redesigned to address this. + */ + + _ISR_Flash( level ); + + if ( the_watchdog->state != WATCHDOG_BEING_INSERTED ) { + goto exit_insert; + } + + if ( _Watchdog_Sync_level > insert_isr_nest_level ) { + _Watchdog_Sync_level = insert_isr_nest_level; + _ISR_Enable( level ); + goto restart; + } + } + + _Watchdog_Activate( the_watchdog ); + + the_watchdog->delta_interval = delta_interval; + + _Chain_Insert_unprotected( after->Node.previous, &the_watchdog->Node ); + + the_watchdog->start_time = _Watchdog_Ticks_since_boot; + +exit_insert: + _Watchdog_Sync_level = insert_isr_nest_level; + _Watchdog_Sync_count--; + _ISR_Enable( level ); +} + +/*PAGE + * + * _Watchdog_Tickle + * + * This routine decrements the delta counter in response to a tick. The + * delta chain is updated accordingly. + * + * Input parameters: + * header - pointer to the delta chain to be tickled + * + * Output parameters: NONE + */ + +void _Watchdog_Tickle( + Chain_Control *header +) +{ + Watchdog_Control *the_watchdog; + + if ( _Chain_Is_empty( header ) ) + return; + + the_watchdog = _Watchdog_First( header ); + the_watchdog->delta_interval--; + if ( the_watchdog->delta_interval != 0 ) + return; + + do { + switch( _Watchdog_Remove( the_watchdog ) ) { + case WATCHDOG_ACTIVE: + (*the_watchdog->routine)( + the_watchdog->id, + the_watchdog->user_data + ); + break; + + case WATCHDOG_INACTIVE: + /* + * This state indicates that the watchdog is not on any chain. + * Thus, it is NOT on a chain being tickled. This case should + * never occur. + */ + break; + + case WATCHDOG_BEING_INSERTED: + /* + * This state indicates that the watchdog is in the process of + * BEING inserted on the chain. Thus, it can NOT be on a chain + * being tickled. This case should never occur. + */ + break; + + case WATCHDOG_REMOVE_IT: + break; + } + the_watchdog = _Watchdog_First( header ); + } while ( !_Chain_Is_empty( header ) && + (the_watchdog->delta_interval == 0) ); +} |