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/*
* Rate Monotonic Manager
*
*
* 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.OARcorp.com/rtems/license.html.
*
* $Id$
*/
#include <rtems/system.h>
#include <rtems/rtems/status.h>
#include <rtems/rtems/support.h>
#include <rtems/score/isr.h>
#include <rtems/score/object.h>
#include <rtems/rtems/ratemon.h>
#include <rtems/score/thread.h>
/*PAGE
*
* rtems_rate_monotonic_period
*
* This directive allows a thread to manipulate a rate monotonic timer.
*
* Input parameters:
* id - rate monotonic id
* length - length of period (in ticks)
*
* Output parameters:
* RTEMS_SUCCESSFUL - if successful
* error code - if unsuccessful
*/
rtems_status_code rtems_rate_monotonic_period(
Objects_Id id,
rtems_interval length
)
{
Rate_monotonic_Control *the_period;
Objects_Locations location;
rtems_status_code return_value;
rtems_rate_monotonic_period_states local_state;
ISR_Level level;
the_period = _Rate_monotonic_Get( id, &location );
switch ( location ) {
case OBJECTS_REMOTE: /* should never return this */
return RTEMS_INTERNAL_ERROR;
case OBJECTS_ERROR:
return RTEMS_INVALID_ID;
case OBJECTS_LOCAL:
if ( !_Thread_Is_executing( the_period->owner ) ) {
_Thread_Enable_dispatch();
return RTEMS_NOT_OWNER_OF_RESOURCE;
}
if ( length == RTEMS_PERIOD_STATUS ) {
switch ( the_period->state ) {
case RATE_MONOTONIC_INACTIVE:
return_value = RTEMS_NOT_DEFINED;
break;
case RATE_MONOTONIC_ACTIVE:
return_value = RTEMS_SUCCESSFUL;
break;
case RATE_MONOTONIC_EXPIRED:
return_value = RTEMS_TIMEOUT;
break;
default: /* unreached -- only to remove warnings */
return_value = RTEMS_INTERNAL_ERROR;
break;
}
_Thread_Enable_dispatch();
return( return_value );
}
_ISR_Disable( level );
switch ( the_period->state ) {
case RATE_MONOTONIC_INACTIVE:
_ISR_Enable( level );
the_period->state = RATE_MONOTONIC_ACTIVE;
_Watchdog_Initialize(
&the_period->Timer,
_Rate_monotonic_Timeout,
id,
NULL
);
the_period->owner_ticks_executed_at_period =
_Thread_Executing->ticks_executed;
the_period->time_at_period = _Watchdog_Ticks_since_boot;
the_period->next_length = length;
_Watchdog_Insert_ticks( &the_period->Timer, length );
_Thread_Enable_dispatch();
return RTEMS_SUCCESSFUL;
case RATE_MONOTONIC_ACTIVE:
/*
* This tells the _Rate_monotonic_Timeout that this task is
* in the process of blocking on the period and that we
* may be changing the length of the next period.
*/
the_period->state = RATE_MONOTONIC_OWNER_IS_BLOCKING;
the_period->next_length = length;
_ISR_Enable( level );
_Thread_Executing->Wait.id = the_period->Object.id;
_Thread_Set_state( _Thread_Executing, STATES_WAITING_FOR_PERIOD );
/*
* Did the watchdog timer expire while we were actually blocking
* on it?
*/
_ISR_Disable( level );
local_state = the_period->state;
the_period->state = RATE_MONOTONIC_ACTIVE;
_ISR_Enable( level );
/*
* If it did, then we want to unblock ourself and continue as
* if nothing happen. The period was reset in the timeout routine.
*/
if ( local_state == RATE_MONOTONIC_EXPIRED_WHILE_BLOCKING )
_Thread_Clear_state( _Thread_Executing, STATES_WAITING_FOR_PERIOD );
_Thread_Enable_dispatch();
return RTEMS_SUCCESSFUL;
break;
case RATE_MONOTONIC_EXPIRED:
_ISR_Enable( level );
the_period->state = RATE_MONOTONIC_ACTIVE;
the_period->owner_ticks_executed_at_period =
_Thread_Executing->ticks_executed;
the_period->time_at_period = _Watchdog_Ticks_since_boot;
the_period->next_length = length;
_Watchdog_Insert_ticks( &the_period->Timer, length );
_Thread_Enable_dispatch();
return RTEMS_TIMEOUT;
case RATE_MONOTONIC_OWNER_IS_BLOCKING:
case RATE_MONOTONIC_EXPIRED_WHILE_BLOCKING:
/*
* These should never happen.
*/
break;
}
}
return RTEMS_INTERNAL_ERROR; /* unreached - only to remove warnings */
}
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