corerwlockimpl.h

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/*
 *  COPYRIGHT (c) 1989-2008.
 *  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_CORERWLOCKIMPL_H
#define _RTEMS_SCORE_CORERWLOCKIMPL_H

#include <rtems/score/percpu.h>
#include <rtems/score/status.h>
#include <rtems/score/thread.h>
#include <rtems/score/threadqimpl.h>
#include <rtems/score/watchdog.h>

#ifdef __cplusplus
extern "C" {
#endif

#define CORE_RWLOCK_TQ_OPERATIONS &_Thread_queue_Operations_FIFO

#define CORE_RWLOCK_THREAD_WAITING_FOR_READ  0

#define CORE_RWLOCK_THREAD_WAITING_FOR_WRITE 1

typedef enum {
  CORE_RWLOCK_UNLOCKED,
  CORE_RWLOCK_LOCKED_FOR_READING,
  CORE_RWLOCK_LOCKED_FOR_WRITING
}   CORE_RWLock_States;

typedef struct {
  Thread_queue_Syslock_queue Queue;

  CORE_RWLock_States current_state;

  unsigned int number_of_readers;
}   CORE_RWLock_Control;

void _CORE_RWLock_Initialize(
  CORE_RWLock_Control *the_rwlock
);

RTEMS_INLINE_ROUTINE void _CORE_RWLock_Destroy(
  CORE_RWLock_Control *the_rwlock
)
{
  (void) the_rwlock;
}

RTEMS_INLINE_ROUTINE Thread_Control *_CORE_RWLock_Acquire(
  CORE_RWLock_Control  *the_rwlock,
  Thread_queue_Context *queue_context
)
{
  ISR_Level       level;
  Thread_Control *executing;

  _Thread_queue_Context_ISR_disable( queue_context, level );
  _Thread_queue_Context_set_ISR_level( queue_context, level );
  executing = _Thread_Executing;
  _Thread_queue_Queue_acquire_critical(
    &the_rwlock->Queue.Queue,
    &executing->Potpourri_stats,
    &queue_context->Lock_context.Lock_context
  );

  return executing;
}

RTEMS_INLINE_ROUTINE void _CORE_RWLock_Release(
  CORE_RWLock_Control  *the_rwlock,
  Thread_queue_Context *queue_context
)
{
  _Thread_queue_Queue_release(
    &the_rwlock->Queue.Queue,
    &queue_context->Lock_context.Lock_context
  );
}

Status_Control _CORE_RWLock_Seize_for_reading(
  CORE_RWLock_Control  *the_rwlock,
  bool                  wait,
  Thread_queue_Context *queue_context
);

Status_Control _CORE_RWLock_Seize_for_writing(
  CORE_RWLock_Control  *the_rwlock,
  bool                  wait,
  Thread_queue_Context *queue_context
);

Status_Control _CORE_RWLock_Surrender( CORE_RWLock_Control *the_rwlock );

#ifdef __cplusplus
}
#endif

#endif
/* end of include file */