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/*
* Watchdog Handler
*
*
* COPYRIGHT (c) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* $Id$
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/system.h>
#include <rtems/score/isr.h>
#include <rtems/score/watchdog.h>
/*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;
uint32_t insert_isr_nest_level;
Watchdog_Interval delta_interval;
insert_isr_nest_level = _ISR_Nest_level;
_ISR_Disable( level );
/*
* Check to see if the watchdog has just been inserted by a
* higher priority interrupt. If so, abandon this insert.
*/
if ( the_watchdog->state != WATCHDOG_INACTIVE ) {
_ISR_Enable( level );
return;
}
the_watchdog->state = WATCHDOG_BEING_INSERTED;
_Watchdog_Sync_count++;
restart:
delta_interval = the_watchdog->initial;
/*
* We CANT use _Watchdog_First() here, because a TICK interrupt
* could modify the chain during the _ISR_Flash() below. Hence,
* the header is pointing to volatile data. The _Watchdog_First()
* INLINE routine (but not the macro - note the subtle difference)
* casts away the 'volatile'...
*
* Also, this is only necessary because we call no other routine
* from this piece of code, hence the compiler thinks it's safe to
* cache *header!!
*
* Till Straumann, 7/2003 (gcc-3.2.2 -O4 on powerpc)
*
*/
for ( after = (Watchdog_Control *) ((volatile Chain_Control *)header)->first ;
;
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;
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 );
}
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