eventseize.c

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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.
 */

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

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

rtems_status_code _Event_Seize(
  rtems_event_set    event_in,
  rtems_option       option_set,
  rtems_interval     ticks,
  rtems_event_set   *event_out,
  Thread_Control    *executing,
  Event_Control     *event,
  Thread_Wait_flags  wait_class,
  States_Control     block_state,
  ISR_lock_Context  *lock_context
)
{
  rtems_event_set    seized_events;
  rtems_event_set    pending_events;
  bool               success;
  Thread_Wait_flags  intend_to_block;
  Per_CPU_Control   *cpu_self;

  pending_events = event->pending_events;
  seized_events  = _Event_sets_Get( pending_events, event_in );

  if ( !_Event_sets_Is_empty( seized_events ) &&
       (seized_events == event_in || _Options_Is_any( option_set )) ) {
    event->pending_events =
      _Event_sets_Clear( pending_events, seized_events );
    _Thread_Wait_release_default( executing, lock_context );
    *event_out = seized_events;
    return RTEMS_SUCCESSFUL;
  }

  if ( _Options_Is_no_wait( option_set ) ) {
    _Thread_Wait_release_default( executing, lock_context );
    *event_out = seized_events;
    return RTEMS_UNSATISFIED;
  }

  intend_to_block = wait_class | THREAD_WAIT_STATE_INTEND_TO_BLOCK;

  /*
   *  Note what we are waiting for BEFORE we enter the critical section.
   *  The interrupt critical section management code needs this to be
   *  set properly when we are marked as in the event critical section.
   *
   *  NOTE: Since interrupts are disabled, this isn't that much of an
   *        issue but better safe than sorry.
   */
  executing->Wait.return_code     = STATUS_SUCCESSFUL;
  executing->Wait.option          = option_set;
  executing->Wait.count           = event_in;
  executing->Wait.return_argument = event_out;
  _Thread_Wait_flags_set( executing, intend_to_block );

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

  if ( ticks ) {
    _Thread_Add_timeout_ticks( executing, cpu_self, ticks );
  }

  _Thread_Set_state( executing, block_state );

  success = _Thread_Wait_flags_try_change_acquire(
    executing,
    intend_to_block,
    wait_class | THREAD_WAIT_STATE_BLOCKED
  );
  if ( !success ) {
    _Thread_Timer_remove( executing );
    _Thread_Unblock( executing );
  }

  _Thread_Dispatch_direct( cpu_self );
  return _Status_Get_after_wait( executing );
}

#if defined(RTEMS_MULTIPROCESSING)
static void _Event_MP_Initialize( void )
{
  _MPCI_Register_packet_processor( MP_PACKET_EVENT, _Event_MP_Process_packet );
}

RTEMS_SYSINIT_ITEM(
  _Event_MP_Initialize,
  RTEMS_SYSINIT_CLASSIC_EVENT_MP,
  RTEMS_SYSINIT_ORDER_MIDDLE
);
#endif