void _Watchdog_Adjust(
Chain_Control *header,
Watchdog_Adjust_directions direction,
Watchdog_Interval units
)
{
ISR_Level level;
_ISR_Disable( level );
/*
* NOTE: It is safe NOT to make 'header' a pointer
* to volatile data (contrast this with watchdoginsert.c)
* because we call _Watchdog_Tickle() below and
* hence the compiler must not assume *header to remain
* unmodified across that call.
*
* Till Straumann, 7/2003
*/
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;
_ISR_Enable( level );
_Watchdog_Tickle( header );
_ISR_Disable( level );
if ( _Chain_Is_empty( header ) )
break;
}
}
break;
}
}
_ISR_Enable( level );
}
static rtems_timer_service_routine test_release_from_isr(
rtems_id timer,
void *arg
)
{
Watchdog_Header *header = &_Watchdog_Ticks_header;
if ( !_Watchdog_Is_empty( header ) ) {
Watchdog_Control *watchdog = _Watchdog_First( header );
if (
watchdog->delta_interval == 0
&& watchdog->routine == _Rate_monotonic_Timeout
) {
Watchdog_States state = _Watchdog_Remove_ticks( watchdog );
rtems_test_assert( state == WATCHDOG_ACTIVE );
(*watchdog->routine)( watchdog->id, watchdog->user_data );
if ( getState() == RATE_MONOTONIC_EXPIRED_WHILE_BLOCKING ) {
case_hit = true;
}
}
}
}
static rtems_timer_service_routine test_release_from_isr(
rtems_id timer,
void *arg
)
{
Watchdog_Header *header = &_Watchdog_Ticks_header;
if ( !_Watchdog_Is_empty( header ) ) {
Watchdog_Control *watchdog = _Watchdog_First( header );
if (
watchdog->delta_interval == 0
&& watchdog->routine == _Thread_queue_Timeout
) {
Watchdog_States state = _Watchdog_Remove( watchdog );
rtems_test_assert( state == WATCHDOG_ACTIVE );
(*watchdog->routine)( watchdog->id, watchdog->user_data );
if ( getState() == THREAD_BLOCKING_OPERATION_TIMEOUT ) {
case_hit = true;
}
}
}
}
static void _Timer_server_Reset_tod_system_watchdog(
Timer_server_Control *ts
)
{
ISR_Level level;
_Timer_server_Stop_tod_system_watchdog( ts );
_ISR_Disable( level );
if ( !_Chain_Is_empty( &ts->TOD_watchdogs.Chain ) ) {
Watchdog_Interval delta_interval =
_Watchdog_First( &ts->TOD_watchdogs.Chain )->delta_interval;
_ISR_Enable( level );
/*
* The unit is SECONDS here.
*/
_Watchdog_Insert_seconds(
&ts->TOD_watchdogs.System_watchdog,
delta_interval
);
} else {
_ISR_Enable( level );
}
}
static rtems_timer_service_routine test_release_from_isr(
rtems_id timer,
void *arg
)
{
Watchdog_Header *header = &_Watchdog_Ticks_header;
if ( !_Watchdog_Is_empty( header ) ) {
Watchdog_Control *watchdog = _Watchdog_First( header );
if (
watchdog->delta_interval == 0
&& watchdog->routine == _Thread_Timeout
) {
Watchdog_States state = _Watchdog_Remove_ticks( watchdog );
rtems_test_assert( state == WATCHDOG_ACTIVE );
(*watchdog->routine)( watchdog->id, watchdog->user_data );
if ( is_interrupt_timeout() ) {
case_hit = true;
}
}
}
}
void _Watchdog_Tickle(
Chain_Control *header
)
{
ISR_Level level;
Watchdog_Control *the_watchdog;
Watchdog_States watchdog_state;
/*
* See the comment in watchdoginsert.c and watchdogadjust.c
* about why it's safe not to declare header a pointer to
* volatile data - till, 2003/7
*/
_ISR_Disable( level );
if ( _Chain_Is_empty( header ) )
goto leave;
the_watchdog = _Watchdog_First( header );
/*
* For some reason, on rare occasions the_watchdog->delta_interval
* of the head of the watchdog chain is 0. Before this test was
* added, on these occasions an event (which usually was supposed
* to have a timeout of 1 tick would have a delta_interval of 0, which
* would be decremented to 0xFFFFFFFF by the unprotected
* "the_watchdog->delta_interval--;" operation.
* This would mean the event would not timeout, and also the chain would
* be blocked, because a timeout with a very high number would be at the
* head, rather than at the end.
* The test "if (the_watchdog->delta_interval != 0)"
* here prevents this from occuring.
*
* We were not able to categorically identify the situation that causes
* this, but proved it to be true empirically. So this check causes
* correct behaviour in this circumstance.
*
* The belief is that a race condition exists whereby an event at the head
* of the chain is removed (by a pending ISR or higher priority task)
* during the _ISR_Flash( level ); in _Watchdog_Insert, but the watchdog
* to be inserted has already had its delta_interval adjusted to 0, and
* so is added to the head of the chain with a delta_interval of 0.
*
* Steven Johnson - 12/2005 (gcc-3.2.3 -O3 on powerpc)
*/
if (the_watchdog->delta_interval != 0) {
the_watchdog->delta_interval--;
if ( the_watchdog->delta_interval != 0 )
goto leave;
}
do {
watchdog_state = _Watchdog_Remove( the_watchdog );
_ISR_Enable( level );
switch( watchdog_state ) {
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;
}
_ISR_Disable( level );
the_watchdog = _Watchdog_First( header );
} while ( !_Chain_Is_empty( header ) &&
(the_watchdog->delta_interval == 0) );
leave:
_ISR_Enable(level);
}
void _Watchdog_Tickle(
Watchdog_Header *header
)
{
ISR_lock_Context lock_context;
_Watchdog_Acquire( header, &lock_context );
if ( !_Watchdog_Is_empty( header ) ) {
Watchdog_Control *first;
Watchdog_Interval delta;
first = _Watchdog_First( header );
delta = first->delta_interval;
/*
* Although it is forbidden to insert watchdogs with a delta interval of
* zero it is possible to observe watchdogs with a delta interval of zero
* at this point. For example lets have a watchdog chain of one watchdog
* with a delta interval of one and insert a new one with an initial value
* of one. At the start of the insert procedure it will advance one step
* and reduce its delta interval by one yielding zero. Now a tick happens.
* This will remove the watchdog on the chain and update the insert
* iterator. Now the insert operation continues and will insert the new
* watchdog with a delta interval of zero.
*/
if ( delta > 0 ) {
--delta;
first->delta_interval = delta;
}
while ( delta == 0 ) {
bool run;
Watchdog_Service_routine_entry routine;
Objects_Id id;
void *user_data;
run = ( first->state == WATCHDOG_ACTIVE );
_Watchdog_Remove_it( header, first );
routine = first->routine;
id = first->id;
user_data = first->user_data;
_Watchdog_Release( header, &lock_context );
if ( run ) {
(*routine)( id, user_data );
}
_Watchdog_Acquire( header, &lock_context );
if ( _Watchdog_Is_empty( header ) ) {
break;
}
first = _Watchdog_First( header );
delta = first->delta_interval;
}
}
_Watchdog_Release( header, &lock_context );
}
static void _Timer_server_Insert_timer_and_make_snapshot(
Timer_server_Control *ts,
Timer_Control *timer
)
{
Watchdog_Control *first_watchdog;
Watchdog_Interval delta_interval;
Watchdog_Interval last_snapshot;
Watchdog_Interval snapshot;
Watchdog_Interval delta;
ISR_Level level;
/*
* We have to update the time snapshots here, because otherwise we may have
* problems with the integer range of the delta values. The time delta DT
* from the last snapshot to now may be arbitrarily long. The last snapshot
* is the reference point for the delta chain. Thus if we do not update the
* reference point we have to add DT to the initial delta of the watchdog
* being inserted. This could result in an integer overflow.
*/
_Thread_Disable_dispatch();
if ( timer->the_class == TIMER_INTERVAL_ON_TASK ) {
/*
* We have to advance the last known ticks value of the server and update
* the watchdog chain accordingly.
*/
_ISR_Disable( level );
snapshot = _Watchdog_Ticks_since_boot;
last_snapshot = ts->Interval_watchdogs.last_snapshot;
if ( !_Chain_Is_empty( &ts->Interval_watchdogs.Chain ) ) {
first_watchdog = _Watchdog_First( &ts->Interval_watchdogs.Chain );
/*
* We assume adequate unsigned arithmetic here.
*/
delta = snapshot - last_snapshot;
delta_interval = first_watchdog->delta_interval;
if (delta_interval > delta) {
delta_interval -= delta;
} else {
delta_interval = 0;
}
first_watchdog->delta_interval = delta_interval;
}
ts->Interval_watchdogs.last_snapshot = snapshot;
_ISR_Enable( level );
_Watchdog_Insert( &ts->Interval_watchdogs.Chain, &timer->Ticker );
if ( !ts->active ) {
_Timer_server_Reset_interval_system_watchdog( ts );
}
} else if ( timer->the_class == TIMER_TIME_OF_DAY_ON_TASK ) {
/*
* We have to advance the last known seconds value of the server and update
* the watchdog chain accordingly.
*/
_ISR_Disable( level );
snapshot = (Watchdog_Interval) _TOD_Seconds_since_epoch();
last_snapshot = ts->TOD_watchdogs.last_snapshot;
if ( !_Chain_Is_empty( &ts->TOD_watchdogs.Chain ) ) {
first_watchdog = _Watchdog_First( &ts->TOD_watchdogs.Chain );
delta_interval = first_watchdog->delta_interval;
if ( snapshot > last_snapshot ) {
/*
* We advanced in time.
*/
delta = snapshot - last_snapshot;
if (delta_interval > delta) {
delta_interval -= delta;
} else {
delta_interval = 0;
}
} else {
/*
* Someone put us in the past.
*/
delta = last_snapshot - snapshot;
delta_interval += delta;
}
first_watchdog->delta_interval = delta_interval;
}
ts->TOD_watchdogs.last_snapshot = snapshot;
_ISR_Enable( level );
_Watchdog_Insert( &ts->TOD_watchdogs.Chain, &timer->Ticker );
if ( !ts->active ) {
_Timer_server_Reset_tod_system_watchdog( ts );
}
}
_Thread_Enable_dispatch();
}
void _Watchdog_Insert(
Watchdog_Header *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;
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;
_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 );
}
