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/*  mutex.h

 *

 *  This include file contains all the constants and structures associated

 *  with the Mutex Handler.  A mutex is an enhanced version of the standard

 *  Dijkstra binary semaphore used to provide synchronization and mutual

 *  exclusion capabilities.

 *

 *  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: coremutex.h,v 1.2 2001-09-27 11:59:32 chris Exp $

 */

#ifndef __RTEMS_CORE_MUTEX_h

#define __RTEMS_CORE_MUTEX_h

#ifdef __cplusplus

extern "C" {

#endif

#include <rtems/score/thread.h>

#include <rtems/score/threadq.h>

#include <rtems/score/priority.h>

#include <rtems/score/watchdog.h>

/*

 *  The following type defines the callout which the API provides

 *  to support global/multiprocessor operations on mutexes.

 */

typedef void ( *CORE_mutex_API_mp_support_callout )(

                 Thread_Control *,

                 Objects_Id

             );

/*

 *  Blocking disciplines for a mutex.

 */

typedef enum {

  CORE_MUTEX_DISCIPLINES_FIFO,

  CORE_MUTEX_DISCIPLINES_PRIORITY,

  CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT,

  CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING

}   CORE_mutex_Disciplines;

/*

 *  Mutex handler return statuses.

 */

typedef enum {

  CORE_MUTEX_STATUS_SUCCESSFUL,

  CORE_MUTEX_STATUS_UNSATISFIED_NOWAIT,

  CORE_MUTEX_STATUS_NESTING_NOT_ALLOWED,

  CORE_MUTEX_STATUS_NOT_OWNER_OF_RESOURCE,

  CORE_MUTEX_WAS_DELETED,

  CORE_MUTEX_TIMEOUT,

  CORE_MUTEX_STATUS_CEILING_VIOLATED

}   CORE_mutex_Status;

/*

 *  Mutex lock nesting behavior

 *

 *  CORE_MUTEX_NESTING_ACQUIRES:

 *    This sequence has no blocking or errors:

 *         lock(m)

 *         lock(m)

 *         unlock(m)

 *         unlock(m)

 *

 *  CORE_MUTEX_NESTING_IS_ERROR

 *    This sequence returns an error at the indicated point:

 *        lock(m)

 *        lock(m)   - already locked error

 *        unlock(m)

 *

 *  CORE_MUTEX_NESTING_BLOCKS

 *    This sequence performs as indicated:

 *        lock(m)

 *        lock(m)   - deadlocks or timeouts

 *        unlock(m) - releases

 */

typedef enum {

  CORE_MUTEX_NESTING_ACQUIRES,

  CORE_MUTEX_NESTING_IS_ERROR,

  CORE_MUTEX_NESTING_BLOCKS

}  CORE_mutex_Nesting_behaviors;

/*

 *  Locked and unlocked values

 */

#define CORE_MUTEX_UNLOCKED 1

#define CORE_MUTEX_LOCKED   0

/*

 *  The following defines the control block used to manage the

 *  attributes of each mutex.

 */

typedef struct {

  CORE_mutex_Nesting_behaviors lock_nesting_behavior;

  boolean                      only_owner_release;

  CORE_mutex_Disciplines       discipline;

  Priority_Control             priority_ceiling;

}   CORE_mutex_Attributes;

/*

 *  The following defines the control block used to manage each mutex.

 */

typedef struct {

  Thread_queue_Control    Wait_queue;

  CORE_mutex_Attributes   Attributes;

  unsigned32              lock;

  unsigned32              nest_count;

  Thread_Control         *holder;

  Objects_Id              holder_id;

}   CORE_mutex_Control;

/*

 *  _CORE_mutex_Initialize

 *

 *  DESCRIPTION:

 *

 *  This routine initializes the mutex based on the parameters passed.

 */

void _CORE_mutex_Initialize(

  CORE_mutex_Control           *the_mutex,

  Objects_Classes               the_class,

  CORE_mutex_Attributes        *the_mutex_attributes,

  unsigned32                    initial_lock,

  Thread_queue_Extract_callout  proxy_extract_callout

);

/*

 *  _CORE_mutex_Seize

 *

 *  DESCRIPTION:

 *

 *  This routine attempts to receive a unit from the_mutex.

 *  If a unit is available or if the wait flag is FALSE, then the routine

 *  returns.  Otherwise, the calling task is blocked until a unit becomes

 *  available.

 */

void _CORE_mutex_Seize(

  CORE_mutex_Control  *the_mutex,

  Objects_Id           id,

  boolean              wait,

  Watchdog_Interval    timeout

);

/*

 *  _CORE_mutex_Surrender

 *

 *  DESCRIPTION:

 *

 *  This routine frees a unit to the mutex.  If a task was blocked waiting for

 *  a unit from this mutex, then that task will be readied and the unit

 *  given to that task.  Otherwise, the unit will be returned to the mutex.

 */

CORE_mutex_Status _CORE_mutex_Surrender(

  CORE_mutex_Control                *the_mutex,

  Objects_Id                         id,

  CORE_mutex_API_mp_support_callout  api_mutex_mp_support

);

/*

 *  _CORE_mutex_Flush

 *

 *  DESCRIPTION:

 *

 *  This routine assists in the deletion of a mutex by flushing the associated

 *  wait queue.

 */

void _CORE_mutex_Flush(

  CORE_mutex_Control         *the_mutex,

  Thread_queue_Flush_callout  remote_extract_callout,

  unsigned32                  status

);

#ifndef __RTEMS_APPLICATION__

#include <rtems/score/coremutex.inl>

#endif

#ifdef __cplusplus

}

#endif

#endif

/*  end of include file */