path: root/cpukit/rtems/src/eventsurrender.c

/* SPDX-License-Identifier: BSD-2-Clause */

/**
 * @file
 *
 * @ingroup RTEMSImplClassicEvent
 *
 * @brief This source file contains the implementation of
 *   _Event_Surrender().
 */

/*
 *  COPYRIGHT (c) 1989-2008.
 *  On-Line Applications Research Corporation (OAR).
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <rtems/rtems/eventimpl.h>
#include <rtems/rtems/optionsimpl.h>
#include <rtems/score/threadimpl.h>
#include <rtems/score/watchdogimpl.h>

static void _Event_Satisfy(
  Thread_Control  *the_thread,
  Event_Control   *event,
  rtems_event_set  pending_events,
  rtems_event_set  seized_events
)
{
  event->pending_events = _Event_sets_Clear( pending_events, seized_events );
  *(rtems_event_set *) the_thread->Wait.return_argument = seized_events;
}

static bool _Event_Is_blocking_on_event(
  const Thread_Control *the_thread,
  Thread_Wait_flags     wait_class
)
{
  Thread_Wait_flags wait_flags;

  wait_flags = _Thread_Wait_flags_get( the_thread );

  return ( wait_flags & THREAD_WAIT_CLASS_MASK ) == wait_class;
}

static bool _Event_Is_satisfied(
  const Thread_Control *the_thread,
  rtems_event_set       pending_events,
  rtems_event_set      *seized_events
)
{
  rtems_option    option_set;
  rtems_event_set event_condition;

  option_set = the_thread->Wait.option;
  event_condition = the_thread->Wait.count;
  *seized_events = _Event_sets_Get( pending_events, event_condition );

  return !_Event_sets_Is_empty( *seized_events )
    && ( *seized_events == event_condition || _Options_Is_any( option_set ) );
}

rtems_status_code _Event_Surrender(
  Thread_Control    *the_thread,
  rtems_event_set    event_in,
  Event_Control     *event,
  Thread_Wait_flags  wait_class,
  ISR_lock_Context  *lock_context
)
{
  rtems_event_set pending_events;
  rtems_event_set seized_events;
  bool            unblock;

  _Thread_Wait_acquire_default_critical( the_thread, lock_context );

  _Event_sets_Post( event_in, &event->pending_events );
  pending_events = event->pending_events;

  if (
    _Event_Is_blocking_on_event( the_thread, wait_class )
      && _Event_Is_satisfied( the_thread, pending_events, &seized_events )
  ) {
    bool success;

    _Event_Satisfy( the_thread, event, pending_events, seized_events );

    success = _Thread_Wait_flags_try_change_release(
      the_thread,
      wait_class | THREAD_WAIT_STATE_INTEND_TO_BLOCK,
      THREAD_WAIT_STATE_READY
    );

    if ( success ) {
      unblock = false;
    } else {
      _Assert(
        _Thread_Wait_flags_get( the_thread )
          == ( wait_class | THREAD_WAIT_STATE_BLOCKED )
      );
      _Thread_Wait_flags_set( the_thread, THREAD_WAIT_STATE_READY );
      unblock = true;
    }
  } else {
    unblock = false;
  }

  if ( unblock ) {
    Per_CPU_Control *cpu_self;

    cpu_self = _Thread_Dispatch_disable_critical( lock_context );
    _Thread_Wait_release_default( the_thread, lock_context );

    _Thread_Timer_remove( the_thread );
    _Thread_Unblock( the_thread );

    _Thread_Dispatch_enable( cpu_self );
  } else {
    _Thread_Wait_release_default( the_thread, lock_context );
  }

  return RTEMS_SUCCESSFUL;
}