Subversion Repositories openrisc

/*

 *  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.

 *

 *  $Id: semcreate.c,v 1.2 2001-09-27 11:59:19 chris 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_create

 *

 *  This directive creates a semaphore and sets the initial value based

 *  on the given count.  A semaphore id is returned.

 *

 *  Input parameters:

 *    name             - user defined semaphore name

 *    count            - initial count of semaphore

 *    attribute_set    - semaphore attributes

 *    priority_ceiling - semaphore's ceiling priority

 *    id               - pointer to semaphore id

 *

 *  Output parameters:

 *    id       - semaphore id

 *    RTEMS_SUCCESSFUL - if successful

 *    error code - if unsuccessful

 */

rtems_status_code rtems_semaphore_create(

  rtems_name           name,

  unsigned32           count,

  rtems_attribute      attribute_set,

  rtems_task_priority  priority_ceiling,

  Objects_Id          *id

)

{

  register Semaphore_Control *the_semaphore;

  CORE_mutex_Attributes       the_mutex_attributes;

  CORE_semaphore_Attributes   the_semaphore_attributes;

  unsigned32                  lock;

  if ( !rtems_is_name_valid( name ) )

    return RTEMS_INVALID_NAME;

#if defined(RTEMS_MULTIPROCESSING)

  if ( _Attributes_Is_global( attribute_set ) ) {

    if ( !_System_state_Is_multiprocessing )

      return RTEMS_MP_NOT_CONFIGURED;

    if ( _Attributes_Is_inherit_priority( attribute_set ) )

      return RTEMS_NOT_DEFINED;

  } else

#endif

  if ( _Attributes_Is_inherit_priority( attribute_set ) ||

              _Attributes_Is_priority_ceiling( attribute_set ) ) {

    if ( ! ( (_Attributes_Is_binary_semaphore( attribute_set ) ||

              _Attributes_Is_simple_binary_semaphore( attribute_set )) &&

             _Attributes_Is_priority( attribute_set ) ) )

      return RTEMS_NOT_DEFINED;

  }

  if ( !_Attributes_Is_counting_semaphore( attribute_set ) && ( count > 1 ) )

    return RTEMS_INVALID_NUMBER;

  _Thread_Disable_dispatch();             /* prevents deletion */

  the_semaphore = _Semaphore_Allocate();

  if ( !the_semaphore ) {

    _Thread_Enable_dispatch();

    return RTEMS_TOO_MANY;

  }

#if defined(RTEMS_MULTIPROCESSING)

  if ( _Attributes_Is_global( attribute_set ) &&

       ! ( _Objects_MP_Allocate_and_open( &_Semaphore_Information, name,

                            the_semaphore->Object.id, FALSE ) ) ) {

    _Semaphore_Free( the_semaphore );

    _Thread_Enable_dispatch();

    return RTEMS_TOO_MANY;

  }

#endif

  the_semaphore->attribute_set = attribute_set;

  /*

   *  If it is not a counting semaphore, then it is either a

   *  simple binary semaphore or a more powerful mutex style binary

   *  semaphore.

   */

  if ( !_Attributes_Is_counting_semaphore( attribute_set ) ) {

    if ( _Attributes_Is_inherit_priority( attribute_set ) )

      the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT;

    else if ( _Attributes_Is_priority_ceiling( attribute_set ) )

      the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING;

    else if ( _Attributes_Is_priority( attribute_set ) )

      the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY;

    else

      the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_FIFO;

    if ( _Attributes_Is_binary_semaphore( attribute_set ) ) {

      the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_ACQUIRES;

      switch ( the_mutex_attributes.discipline ) {

        case CORE_MUTEX_DISCIPLINES_FIFO:

        case CORE_MUTEX_DISCIPLINES_PRIORITY:

          the_mutex_attributes.only_owner_release = FALSE;

          break;

        case CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING:

        case CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT:

          the_mutex_attributes.only_owner_release = TRUE;

          break;

      }

    } else {

      the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_BLOCKS;

      the_mutex_attributes.only_owner_release = FALSE;

    }

    the_mutex_attributes.priority_ceiling = priority_ceiling;

    if ( count == 1 )

      lock = CORE_MUTEX_UNLOCKED;

    else

      lock = CORE_MUTEX_LOCKED;

    _CORE_mutex_Initialize(

      &the_semaphore->Core_control.mutex,

      OBJECTS_RTEMS_SEMAPHORES,

      &the_mutex_attributes,

      lock,

#if defined(RTEMS_MULTIPROCESSING)

      _Semaphore_MP_Send_extract_proxy

#else

      NULL

#endif

    );

  } else {

    if ( _Attributes_Is_priority( attribute_set ) )

      the_semaphore_attributes.discipline = CORE_SEMAPHORE_DISCIPLINES_PRIORITY;

    else

      the_semaphore_attributes.discipline = CORE_SEMAPHORE_DISCIPLINES_FIFO;

    /*

     *  This effectively disables limit checking.

     */

    the_semaphore_attributes.maximum_count = 0xFFFFFFFF;

    /*

     *  The following are just to make Purify happy.

     */

    the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_ACQUIRES;

    the_mutex_attributes.priority_ceiling = PRIORITY_MINIMUM;

    _CORE_semaphore_Initialize(

      &the_semaphore->Core_control.semaphore,

      OBJECTS_RTEMS_SEMAPHORES,

      &the_semaphore_attributes,

      count,

#if defined(RTEMS_MULTIPROCESSING)

      _Semaphore_MP_Send_extract_proxy

#else

      NULL

#endif

    );

  }

  _Objects_Open( &_Semaphore_Information, &the_semaphore->Object, &name );

  *id = the_semaphore->Object.id;

#if defined(RTEMS_MULTIPROCESSING)

  if ( _Attributes_Is_global( attribute_set ) )

    _Semaphore_MP_Send_process_packet(

      SEMAPHORE_MP_ANNOUNCE_CREATE,

      the_semaphore->Object.id,

      name,

    );

#endif

  _Thread_Enable_dispatch();

  return RTEMS_SUCCESSFUL;

}