coresemimpl.h

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/*
 *  COPYRIGHT (c) 1989-2006.
 *  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.rtems.org/license/LICENSE.
 */

#ifndef _RTEMS_SCORE_CORESEMIMPL_H
#define _RTEMS_SCORE_CORESEMIMPL_H

#include <rtems/score/coresem.h>
#include <rtems/score/objectimpl.h>
#include <rtems/score/threaddispatch.h>
#include <rtems/score/threadqimpl.h>
#include <rtems/score/statesimpl.h>

#ifdef __cplusplus
extern "C" {
#endif

typedef enum {
  CORE_SEMAPHORE_STATUS_SUCCESSFUL,
  CORE_SEMAPHORE_STATUS_UNSATISFIED_NOWAIT,
  CORE_SEMAPHORE_WAS_DELETED,
  CORE_SEMAPHORE_TIMEOUT,
  CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED
}   CORE_semaphore_Status;

#define CORE_SEMAPHORE_STATUS_LAST CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED

typedef void ( *CORE_semaphore_API_mp_support_callout )(
                 Thread_Control *,
                 Objects_Id
             );

void _CORE_semaphore_Initialize(
  CORE_semaphore_Control          *the_semaphore,
  const CORE_semaphore_Attributes *the_semaphore_attributes,
  uint32_t                         initial_value
);

RTEMS_INLINE_ROUTINE void _CORE_semaphore_Destroy(
  CORE_semaphore_Control *the_semaphore
)
{
  _Thread_queue_Destroy( &the_semaphore->Wait_queue );
}

RTEMS_INLINE_ROUTINE CORE_semaphore_Status _CORE_semaphore_Surrender(
  CORE_semaphore_Control                *the_semaphore,
  Objects_Id                             id,
  CORE_semaphore_API_mp_support_callout  api_semaphore_mp_support,
  ISR_lock_Context                      *lock_context
)
{
  Thread_Control *the_thread;
  CORE_semaphore_Status status;

  status = CORE_SEMAPHORE_STATUS_SUCCESSFUL;

  _Thread_queue_Acquire_critical( &the_semaphore->Wait_queue, lock_context );

  the_thread = _Thread_queue_First_locked( &the_semaphore->Wait_queue );
  if ( the_thread != NULL ) {
#if defined(RTEMS_MULTIPROCESSING)
    _Thread_Dispatch_disable();
#endif

    _Thread_queue_Extract_critical(
      &the_semaphore->Wait_queue,
      the_thread,
      lock_context
    );

#if defined(RTEMS_MULTIPROCESSING)
    if ( !_Objects_Is_local_id( the_thread->Object.id ) )
      (*api_semaphore_mp_support) ( the_thread, id );

    _Thread_Dispatch_enable( _Per_CPU_Get() );
#endif
  } else {
    if ( the_semaphore->count < the_semaphore->Attributes.maximum_count )
      the_semaphore->count += 1;
    else
      status = CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED;

    _Thread_queue_Release( &the_semaphore->Wait_queue, lock_context );
  }

  return status;
}

RTEMS_INLINE_ROUTINE void _CORE_semaphore_Flush(
  CORE_semaphore_Control         *the_semaphore,
  Thread_queue_Flush_callout      remote_extract_callout,
  uint32_t                        status
)
{
  _Thread_queue_Flush(
    &the_semaphore->Wait_queue,
    remote_extract_callout,
    status
  );
}

RTEMS_INLINE_ROUTINE bool _CORE_semaphore_Is_priority(
  const CORE_semaphore_Attributes *the_attribute
)
{
   return ( the_attribute->discipline == CORE_SEMAPHORE_DISCIPLINES_PRIORITY );
}

RTEMS_INLINE_ROUTINE uint32_t  _CORE_semaphore_Get_count(
  CORE_semaphore_Control  *the_semaphore
)
{
  return the_semaphore->count;
}

RTEMS_INLINE_ROUTINE void _CORE_semaphore_Seize(
  CORE_semaphore_Control  *the_semaphore,
  Thread_Control          *executing,
  Objects_Id               id,
  bool                     wait,
  Watchdog_Interval        timeout,
  ISR_lock_Context        *lock_context
)
{
  /* disabled when you get here */

  executing->Wait.return_code = CORE_SEMAPHORE_STATUS_SUCCESSFUL;
  _Thread_queue_Acquire_critical( &the_semaphore->Wait_queue, lock_context );
  if ( the_semaphore->count != 0 ) {
    the_semaphore->count -= 1;
    _Thread_queue_Release( &the_semaphore->Wait_queue, lock_context );
    return;
  }

  if ( !wait ) {
    _Thread_queue_Release( &the_semaphore->Wait_queue, lock_context );
    executing->Wait.return_code = CORE_SEMAPHORE_STATUS_UNSATISFIED_NOWAIT;
    return;
  }

  executing->Wait.id = id;
  _Thread_queue_Enqueue_critical(
    &the_semaphore->Wait_queue,
    executing,
    STATES_WAITING_FOR_SEMAPHORE,
    timeout,
    CORE_SEMAPHORE_TIMEOUT,
    lock_context
  );
}

#ifdef __cplusplus
}
#endif

#endif
/* end of include file */