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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.

 *

 *  ratemonperiod.c,v 1.3 2000/09/29 14:48:17 joel Exp

 */

#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 */

}