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/*
* Watchdog Handler
*
*
* COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994.
* On-Line Applications Research Corporation (OAR).
* All rights assigned to U.S. Government, 1994.
*
* This material may be reproduced by or for the U.S. Government pursuant
* to the copyright license under the clause at DFARS 252.227-7013. This
* notice must appear in all copies of this file and its derivatives.
*
* $Id$
*/
#include <rtems/system.h>
#include <rtems/isr.h>
#include <rtems/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;
_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_REINSERT:
/*
* 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;
}
_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,
rtems_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,
Watchdog_Insert_modes insert_mode
)
{
ISR_Level level;
Watchdog_Control *after;
unsigned32 insert_isr_nest_level;
rtems_interval delta_interval;
insert_isr_nest_level = _ISR_Nest_level;
the_watchdog->state = WATCHDOG_REINSERT;
_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. This
* (3.2.0) is the first release with this critical section redesigned.
* Under certain circumstances, the PREVIOUS critical section algorithm
* used around this flash point allows 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_REINSERT ) {
goto exit_insert;
}
if ( _Watchdog_Sync_level > insert_isr_nest_level ) {
_Watchdog_Sync_level = insert_isr_nest_level;
_ISR_Enable( level );
goto restart;
}
}
if ( insert_mode == WATCHDOG_ACTIVATE_NOW )
_Watchdog_Activate( the_watchdog );
the_watchdog->delta_interval = delta_interval;
_Chain_Insert_unprotected( after->Node.previous, &the_watchdog->Node );
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_REINSERT:
_Watchdog_Insert( header, the_watchdog, WATCHDOG_ACTIVATE_NOW );
break;
case WATCHDOG_INACTIVE:
case WATCHDOG_REMOVE_IT:
break;
}
the_watchdog = _Watchdog_First( header );
} while ( !_Chain_Is_empty( header ) &&
(the_watchdog->delta_interval == 0) );
}
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