Subversion Repositories or1k

/*

 *  Semaphore Manager

 *

 *  DESCRIPTION:

 *

 *  This package is the implementation of the Semaphore Manager.

 *  This manager utilizes standard Dijkstra counting semaphores to provide

 *  synchronization and mutual exclusion capabilities.

 *

 *  Directives provided are:

 *

 *     + create a semaphore

 *     + get an ID of a semaphore

 *     + delete a semaphore

 *     + acquire a semaphore

 *     + release a semaphore

 *

 *  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.

 *

 *  semobtain.c,v 1.4 2000/07/06 19:40:58 joel Exp

 */

#include <rtems/system.h>

#include <rtems/rtems/status.h>

#include <rtems/rtems/support.h>

#include <rtems/rtems/attr.h>

#include <rtems/score/isr.h>

#include <rtems/score/object.h>

#include <rtems/rtems/options.h>

#include <rtems/rtems/sem.h>

#include <rtems/score/coremutex.h>

#include <rtems/score/coresem.h>

#include <rtems/score/states.h>

#include <rtems/score/thread.h>

#include <rtems/score/threadq.h>

#if defined(RTEMS_MULTIPROCESSING)

#include <rtems/score/mpci.h>

#endif

#include <rtems/score/sysstate.h>

#include <rtems/score/interr.h>

/*PAGE

 *

 *  rtems_semaphore_obtain

 *

 *  This directive allows a thread to acquire a semaphore.

 *

 *  Input parameters:

 *    id         - semaphore id

 *    option_set - wait option

 *    timeout    - number of ticks to wait (0 means wait forever)

 *

 *  Output parameters:

 *    RTEMS_SUCCESSFUL - if successful

 *    error code        - if unsuccessful

 */

rtems_status_code rtems_semaphore_obtain(

  Objects_Id      id,

  unsigned32      option_set,

  rtems_interval  timeout

)

{

  register Semaphore_Control *the_semaphore;

  Objects_Locations           location;

  boolean                     wait;

  ISR_Level                   level;

  the_semaphore = _Semaphore_Get_interrupt_disable( id, &location, &level );

  switch ( location ) {

    case OBJECTS_REMOTE:

#if defined(RTEMS_MULTIPROCESSING)

      return _Semaphore_MP_Send_request_packet(

          SEMAPHORE_MP_OBTAIN_REQUEST,

          id,

          option_set,

          timeout

      );

#endif

    case OBJECTS_ERROR:

      return RTEMS_INVALID_ID;

    case OBJECTS_LOCAL:

      if ( _Options_Is_no_wait( option_set ) )

        wait = FALSE;

      else

        wait = TRUE;

      if ( !_Attributes_Is_counting_semaphore(the_semaphore->attribute_set) ) {

        _CORE_mutex_Seize(

          &the_semaphore->Core_control.mutex,

          id,

          wait,

          timeout,

          level

        );

        return _Semaphore_Translate_core_mutex_return_code(

                  _Thread_Executing->Wait.return_code );

      }

      /* must be a counting semaphore */

      _CORE_semaphore_Seize_isr_disable(

        &the_semaphore->Core_control.semaphore,

        id,

        wait,

        timeout,

        &level

      );

      return _Semaphore_Translate_core_semaphore_return_code(

                  _Thread_Executing->Wait.return_code );

  }

  return RTEMS_INTERNAL_ERROR;   /* unreached - only to remove warnings */

}