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 /* SPDX-License-Identifier: BSD-2-Clause */
 
 /**
  * @file
  *
  * @ingroup RTEMSScore
  *
  * @brief This source file contains the implementation of
  *   _Condition_Wait(), _Condition_Wait_timed(), _Condition_Wait_recursive(),
  *   _Condition_Wait_recursive_timed(),
  *   _Condition_Wait_recursive_timed_ticks(), _Condition_Signal(), and
  *   _Condition_Broadcast().
  */
 
 /*
  * Copyright (C) 2015, 2016 embedded brains GmbH & Co. KG
  *
  * 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 <sys/lock.h>
 #include <errno.h>
 #include <limits.h>
 
 #include <rtems/score/atomic.h>
 #include <rtems/score/chainimpl.h>
 #include <rtems/score/threadimpl.h>
 #include <rtems/score/threadqimpl.h>
 #include <rtems/score/todimpl.h>
 #include <rtems/score/watchdogimpl.h>
 
 #define CONDITION_TQ_OPERATIONS &_Thread_queue_Operations_FIFO
 
 typedef struct {
   Thread_queue_Syslock_queue Queue;
 } Condition_Control;
 
 RTEMS_STATIC_ASSERT(
   offsetof( Condition_Control, Queue )
     == offsetof( struct _Condition_Control, _Queue ),
   CONDITION_CONTROL_QUEUE
 );
 
 RTEMS_STATIC_ASSERT(
   sizeof( Condition_Control ) == sizeof( struct _Condition_Control ),
   CONDITION_CONTROL_SIZE
 );
 
 static Condition_Control *_Condition_Get(
   struct _Condition_Control *_condition
 )
 {
   return (Condition_Control *) _condition;
 }
 
 static Thread_Control *_Condition_Queue_acquire_critical(
   Condition_Control    *condition,
   Thread_queue_Context *queue_context
 )
 {
   Thread_Control *executing;
 
   executing = _Thread_Executing;
   _Thread_queue_Queue_acquire_critical(
     &condition->Queue.Queue,
     &executing->Potpourri_stats,
     &queue_context->Lock_context.Lock_context
   );
 
   return executing;
 }
 
 static void _Condition_Queue_release(
   Condition_Control    *condition,
   Thread_queue_Context *queue_context
 )
 {
   _Thread_queue_Queue_release(
     &condition->Queue.Queue,
     &queue_context->Lock_context.Lock_context
   );
 }
 
 typedef struct {
   Thread_queue_Context   Base;
   struct _Mutex_Control *mutex;
 } Condition_Enqueue_context;
 
 static void _Condition_Mutex_release( Thread_queue_Context *queue_context )
 {
   Condition_Enqueue_context *context;
 
   context = (Condition_Enqueue_context *) queue_context;
   _Mutex_Release( context->mutex );
 }
 
 static void _Condition_Enqueue_no_timeout(
   Thread_queue_Queue   *queue,
   Thread_Control       *the_thread,
   Per_CPU_Control      *cpu_self,
   Thread_queue_Context *queue_context
 )
 {
   _Condition_Mutex_release( queue_context );
 }
 
 static void _Condition_Enqueue_with_timeout(
   Thread_queue_Queue   *queue,
   Thread_Control       *the_thread,
   Per_CPU_Control      *cpu_self,
   Thread_queue_Context *queue_context
 )
 {
   _Thread_queue_Add_timeout_realtime_timespec(
     queue,
     the_thread,
     cpu_self,
     queue_context
   );
   _Condition_Mutex_release( queue_context );
 }
 
 static Thread_Control *_Condition_Do_wait(
   struct _Condition_Control *_condition,
   struct _Mutex_Control     *_mutex,
   Condition_Enqueue_context *context
 )
 {
   Condition_Control *condition;
   Thread_Control    *executing;
 
   context->mutex = _mutex;
   condition = _Condition_Get( _condition );
   _ISR_lock_ISR_disable( &context->Base.Lock_context.Lock_context );
   executing = _Condition_Queue_acquire_critical( condition, &context->Base );
   _Thread_queue_Context_set_thread_state(
     &context->Base,
     STATES_WAITING_FOR_CONDITION_VARIABLE
   );
   _Thread_queue_Enqueue(
     &condition->Queue.Queue,
     CONDITION_TQ_OPERATIONS,
     executing,
     &context->Base
   );
 
   return executing;
 }
 
 void _Condition_Wait(
   struct _Condition_Control *_condition,
   struct _Mutex_Control     *_mutex
 )
 {
   Condition_Enqueue_context context;
 
   _Thread_queue_Context_initialize( &context.Base );
   _Thread_queue_Context_set_enqueue_callout(
     &context.Base,
     _Condition_Enqueue_no_timeout
   );
   _Condition_Do_wait( _condition, _mutex, &context );
   _Mutex_Acquire( _mutex );
 }
 
 int _Condition_Wait_timed(
   struct _Condition_Control *_condition,
   struct _Mutex_Control     *_mutex,
   const struct timespec     *abstime
 )
 {
   Condition_Enqueue_context  context;
   Thread_Control            *executing;
   int                        eno;
 
   _Thread_queue_Context_initialize( &context.Base );
   _Thread_queue_Context_set_enqueue_callout(
     &context.Base,
     _Condition_Enqueue_with_timeout
   );
   _Thread_queue_Context_set_timeout_argument( &context.Base, abstime, true );
   executing = _Condition_Do_wait( _condition, _mutex, &context );
   eno = STATUS_GET_POSIX( _Thread_Wait_get_status( executing ) );
   _Mutex_Acquire( _mutex );
 
   return eno;
 }
 
 static unsigned int _Condition_Unnest_mutex(
   struct _Mutex_recursive_Control *_mutex
 )
 {
   unsigned int nest_level;
 
   nest_level = _mutex->_nest_level;
   _mutex->_nest_level = 0;
 
   return nest_level;
 }
 
 void _Condition_Wait_recursive(
   struct _Condition_Control       *_condition,
   struct _Mutex_recursive_Control *_mutex
 )
 {
   Condition_Enqueue_context context;
   unsigned int              nest_level;
 
   _Thread_queue_Context_initialize( &context.Base );
   _Thread_queue_Context_set_enqueue_callout(
     &context.Base,
     _Condition_Enqueue_no_timeout
   );
   nest_level = _Condition_Unnest_mutex( _mutex );
   _Condition_Do_wait( _condition, &_mutex->_Mutex, &context );
   _Mutex_recursive_Acquire( _mutex );
   _mutex->_nest_level = nest_level;
 }
 
 int _Condition_Wait_recursive_timed(
   struct _Condition_Control       *_condition,
   struct _Mutex_recursive_Control *_mutex,
   const struct timespec           *abstime
 )
 {
   Condition_Enqueue_context  context;
   Thread_Control            *executing;
   int                        eno;
   unsigned int               nest_level;
 
   _Thread_queue_Context_initialize( &context.Base );
   _Thread_queue_Context_set_enqueue_callout(
     &context.Base,
     _Condition_Enqueue_with_timeout
   );
   _Thread_queue_Context_set_timeout_argument( &context.Base, abstime, true );
   nest_level = _Condition_Unnest_mutex( _mutex );
   executing = _Condition_Do_wait( _condition, &_mutex->_Mutex, &context );
   eno = STATUS_GET_POSIX( _Thread_Wait_get_status( executing ) );
   _Mutex_recursive_Acquire( _mutex );
   _mutex->_nest_level = nest_level;
 
   return eno;
 }
 
 typedef struct {
   Thread_queue_Context Base;
   int                  count;
 } Condition_Flush_context;
 
 static Thread_Control *_Condition_Flush_filter(
   Thread_Control       *the_thread,
   Thread_queue_Queue   *queue,
   Thread_queue_Context *queue_context
 )
 {
   Condition_Flush_context *context;
 
   context = (Condition_Flush_context *) queue_context;
 
   if ( context->count <= 0 ) {
     return NULL;
   }
 
   --context->count;
 
   return the_thread;
 }
 
 static void _Condition_Wake( struct _Condition_Control *_condition, int count )
 {
   Condition_Control       *condition;
   Condition_Flush_context  context;
 
   condition = _Condition_Get( _condition );
   _Thread_queue_Context_initialize( &context.Base );
   _ISR_lock_ISR_disable( &context.Base.Lock_context.Lock_context );
   _Condition_Queue_acquire_critical( condition, &context.Base );
 
   /*
    * In common uses cases of condition variables there are normally no threads
    * on the queue, so check this condition early.
    */
   if (
     RTEMS_PREDICT_TRUE( _Thread_queue_Is_empty( &condition->Queue.Queue ) )
   ) {
     _Condition_Queue_release( condition, &context.Base );
     return;
   }
 
   context.count = count;
   _Thread_queue_Flush_critical(
     &condition->Queue.Queue,
     CONDITION_TQ_OPERATIONS,
     _Condition_Flush_filter,
     &context.Base
   );
 }
 
 void _Condition_Signal( struct _Condition_Control *_condition )
 {
   _Condition_Wake( _condition, 1 );
 }
 
 void _Condition_Broadcast( struct _Condition_Control *_condition )
 {
   _Condition_Wake( _condition, INT_MAX );
 }

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