rtems_status_code rtems_timer_server_fire_when(
rtems_id id,
rtems_time_of_day *wall_time,
rtems_timer_service_routine_entry routine,
void *user_data
)
{
Timer_Control *the_timer;
Objects_Locations location;
rtems_interval seconds;
Timer_server_Control *timer_server = _Timer_server;
if ( !timer_server )
return RTEMS_INCORRECT_STATE;
if ( !_TOD.is_set )
return RTEMS_NOT_DEFINED;
if ( !routine )
return RTEMS_INVALID_ADDRESS;
if ( !_TOD_Validate( wall_time ) )
return RTEMS_INVALID_CLOCK;
seconds = _TOD_To_seconds( wall_time );
if ( seconds <= _TOD_Seconds_since_epoch() )
return RTEMS_INVALID_CLOCK;
the_timer = _Timer_Get( id, &location );
switch ( location ) {
case OBJECTS_LOCAL:
(void) _Watchdog_Remove( &the_timer->Ticker );
the_timer->the_class = TIMER_TIME_OF_DAY_ON_TASK;
_Watchdog_Initialize( &the_timer->Ticker, routine, id, user_data );
the_timer->Ticker.initial = seconds - _TOD_Seconds_since_epoch();
(*timer_server->schedule_operation)( timer_server, the_timer );
_Thread_Enable_dispatch();
return RTEMS_SUCCESSFUL;
#if defined(RTEMS_MULTIPROCESSING)
case OBJECTS_REMOTE: /* should never return this */
#endif
case OBJECTS_ERROR:
break;
}
return RTEMS_INVALID_ID;
}
void _TOD_Set_with_timestamp(
const Timestamp_Control *tod_as_timestamp
)
{
TOD_Control *tod = &_TOD;
uint32_t nanoseconds = _Timestamp_Get_nanoseconds( tod_as_timestamp );
Watchdog_Interval seconds_next = _Timestamp_Get_seconds( tod_as_timestamp );
Watchdog_Interval seconds_now;
ISR_lock_Context lock_context;
_Thread_Disable_dispatch();
seconds_now = _TOD_Seconds_since_epoch();
if ( seconds_next < seconds_now )
_Watchdog_Adjust_seconds( WATCHDOG_BACKWARD, seconds_now - seconds_next );
else
_Watchdog_Adjust_seconds( WATCHDOG_FORWARD, seconds_next - seconds_now );
_TOD_Acquire( tod, &lock_context );
tod->now = *tod_as_timestamp;
_TOD_Release( tod, &lock_context );
tod->seconds_trigger = nanoseconds;
tod->is_set = true;
_Thread_Enable_dispatch();
}
rtems_status_code _Timer_Fire_when(
rtems_id id,
const rtems_time_of_day *wall_time,
rtems_timer_service_routine_entry routine,
void *user_data,
Timer_Classes the_class,
Watchdog_Service_routine_entry adaptor
)
{
rtems_interval seconds;
if ( !_TOD_Is_set() )
return RTEMS_NOT_DEFINED;
if ( !routine )
return RTEMS_INVALID_ADDRESS;
if ( !_TOD_Validate( wall_time ) )
return RTEMS_INVALID_CLOCK;
seconds = _TOD_To_seconds( wall_time );
if ( seconds <= _TOD_Seconds_since_epoch() )
return RTEMS_INVALID_CLOCK;
return _Timer_Fire(
id,
seconds,
routine,
user_data,
the_class,
adaptor
);
}
static void _Timer_server_Process_tod_watchdogs(
Timer_server_Watchdogs *watchdogs,
Chain_Control *fire_chain
)
{
Watchdog_Interval snapshot = (Watchdog_Interval) _TOD_Seconds_since_epoch();
Watchdog_Interval last_snapshot = watchdogs->last_snapshot;
Watchdog_Interval delta;
/*
* Process the seconds chain. Start by checking that the Time
* of Day (TOD) has not been set backwards. If it has then
* we want to adjust the watchdogs->Chain to indicate this.
*/
if ( snapshot > last_snapshot ) {
/*
* This path is for normal forward movement and cases where the
* TOD has been set forward.
*/
delta = snapshot - last_snapshot;
_Watchdog_Adjust_to_chain( &watchdogs->Chain, delta, fire_chain );
} else if ( snapshot < last_snapshot ) {
/*
* The current TOD is before the last TOD which indicates that
* TOD has been set backwards.
*/
delta = last_snapshot - snapshot;
_Watchdog_Adjust( &watchdogs->Chain, WATCHDOG_BACKWARD, delta );
}
watchdogs->last_snapshot = snapshot;
}
void _TOD_Set_with_timestamp(
const Timestamp_Control *tod
)
{
uint32_t nanoseconds = _Timestamp_Get_nanoseconds( tod );
Watchdog_Interval seconds_next = _Timestamp_Get_seconds( tod );
Watchdog_Interval seconds_now;
_Thread_Disable_dispatch();
_TOD_Deactivate();
seconds_now = _TOD_Seconds_since_epoch();
if ( seconds_next < seconds_now )
_Watchdog_Adjust_seconds( WATCHDOG_BACKWARD, seconds_now - seconds_next );
else
_Watchdog_Adjust_seconds( WATCHDOG_FORWARD, seconds_next - seconds_now );
_TOD.now = *tod;
_TOD.seconds_trigger = nanoseconds;
_TOD.is_set = true;
_TOD_Activate();
_Thread_Enable_dispatch();
}
rtems_status_code rtems_clock_get_seconds_since_epoch(
rtems_interval *the_interval
)
{
if ( !the_interval )
return RTEMS_INVALID_ADDRESS;
if ( !_TOD_Is_set )
return RTEMS_NOT_DEFINED;
*the_interval = _TOD_Seconds_since_epoch();
return RTEMS_SUCCESSFUL;
}
rtems_status_code rtems_task_wake_when(
rtems_time_of_day *time_buffer
)
{
Watchdog_Interval seconds;
if ( !_TOD_Is_set() )
return RTEMS_NOT_DEFINED;
if ( !time_buffer )
return RTEMS_INVALID_ADDRESS;
time_buffer->ticks = 0;
if ( !_TOD_Validate( time_buffer ) )
return RTEMS_INVALID_CLOCK;
seconds = _TOD_To_seconds( time_buffer );
if ( seconds <= _TOD_Seconds_since_epoch() )
return RTEMS_INVALID_CLOCK;
_Thread_Disable_dispatch();
_Thread_Set_state( _Thread_Executing, STATES_WAITING_FOR_TIME );
_Watchdog_Initialize(
&_Thread_Executing->Timer,
_Thread_Delay_ended,
_Thread_Executing->Object.id,
NULL
);
_Watchdog_Insert_seconds(
&_Thread_Executing->Timer,
seconds - _TOD_Seconds_since_epoch()
);
_Thread_Enable_dispatch();
return RTEMS_SUCCESSFUL;
}
void _TOD_Set(
const struct timespec *time
)
{
long seconds;
_Thread_Disable_dispatch();
_TOD_Deactivate();
seconds = _TOD_Seconds_since_epoch();
if ( time->tv_sec < seconds )
_Watchdog_Adjust_seconds( WATCHDOG_BACKWARD, seconds - time->tv_sec );
else
_Watchdog_Adjust_seconds( WATCHDOG_FORWARD, time->tv_sec - seconds );
/* POSIX format TOD (timespec) */
_Timestamp_Set( &_TOD_Now, time->tv_sec, time->tv_nsec );
_TOD_Is_set = true;
_TOD_Activate();
_Thread_Enable_dispatch();
}
/**
* @brief rtems_timer_initiate_server
*
* This directive creates and starts the server for task-based timers.
* It must be invoked before any task-based timers can be initiated.
*
* @param[in] priority is the timer server priority
* @param[in] stack_size is the stack size in bytes
* @param[in] attribute_set is the timer server attributes
*
* @return This method returns RTEMS_SUCCESSFUL if successful and an
* error code otherwise.
*/
rtems_status_code rtems_timer_initiate_server(
uint32_t priority,
uint32_t stack_size,
rtems_attribute attribute_set
)
{
rtems_id id;
rtems_status_code status;
rtems_task_priority _priority;
static bool initialized = false;
bool tmpInitialized;
Timer_server_Control *ts = &_Timer_server_Default;
/*
* Make sure the requested priority is valid. The if is
* structured so we check it is invalid before looking for
* a specific invalid value as the default.
*/
_priority = priority;
if ( !_RTEMS_tasks_Priority_is_valid( priority ) ) {
if ( priority != RTEMS_TIMER_SERVER_DEFAULT_PRIORITY )
return RTEMS_INVALID_PRIORITY;
_priority = 0;
}
/*
* Just to make sure this is only called once.
*/
_Thread_Disable_dispatch();
tmpInitialized = initialized;
initialized = true;
_Thread_Enable_dispatch();
if ( tmpInitialized )
return RTEMS_INCORRECT_STATE;
/*
* Create the Timer Server with the name the name of "TIME". The attribute
* RTEMS_SYSTEM_TASK allows us to set a priority to 0 which will makes it
* higher than any other task in the system. It can be viewed as a low
* priority interrupt. It is also always NO_PREEMPT so it looks like
* an interrupt to other tasks.
*
* We allow the user to override the default priority because the Timer
* Server can invoke TSRs which must adhere to language run-time or
* other library rules. For example, if using a TSR written in Ada the
* Server should run at the same priority as the priority Ada task.
* Otherwise, the priority ceiling for the mutex used to protect the
* GNAT run-time is violated.
*/
status = rtems_task_create(
_Objects_Build_name('T','I','M','E'), /* "TIME" */
_priority, /* create with priority 1 since 0 is illegal */
stack_size, /* let user specify stack size */
RTEMS_NO_PREEMPT, /* no preempt is like an interrupt */
/* user may want floating point but we need */
/* system task specified for 0 priority */
attribute_set | RTEMS_SYSTEM_TASK,
&id /* get the id back */
);
if (status) {
initialized = false;
return status;
}
/*
* Do all the data structure initialization before starting the
* Timer Server so we do not have to have a critical section.
*/
/*
* We work with the TCB pointer, not the ID, so we need to convert
* to a TCB pointer from here out.
*/
ts->thread = (Thread_Control *)_Objects_Get_local_object(
&_RTEMS_tasks_Information,
_Objects_Get_index(id)
);
/*
* Initialize the timer lists that the server will manage.
*/
_Chain_Initialize_empty( &ts->Interval_watchdogs.Chain );
_Chain_Initialize_empty( &ts->TOD_watchdogs.Chain );
/*
* Initialize the timers that will be used to control when the
* Timer Server wakes up and services the task-based timers.
*/
_Watchdog_Initialize(
&ts->Interval_watchdogs.System_watchdog,
_Thread_Delay_ended,
id,
NULL
);
_Watchdog_Initialize(
&ts->TOD_watchdogs.System_watchdog,
_Thread_Delay_ended,
id,
NULL
);
/*
* Initialize the pointer to the timer schedule method so applications that
* do not use the Timer Server do not have to pull it in.
*/
ts->schedule_operation = _Timer_server_Schedule_operation_method;
ts->Interval_watchdogs.last_snapshot = _Watchdog_Ticks_since_boot;
ts->TOD_watchdogs.last_snapshot = (Watchdog_Interval) _TOD_Seconds_since_epoch();
ts->insert_chain = NULL;
ts->active = false;
/*
* The default timer server is now available.
*/
_Timer_server = ts;
/*
* Start the timer server
*/
status = rtems_task_start(
id,
_Timer_server_Body,
(rtems_task_argument) ts
);
#if defined(RTEMS_DEBUG)
/*
* One would expect a call to rtems_task_delete() here to clean up
* but there is actually no way (in normal circumstances) that the
* start can fail. The id and starting address are known to be
* be good. If this service fails, something is weirdly wrong on the
* target such as a stray write in an ISR or incorrect memory layout.
*/
if (status) {
initialized = false;
}
#endif
return status;
}
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();
}
