/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @ingroup RTEMSScore
*
* @brief This source file contains the implementation of
* _Semaphore_Wait(), _Semaphore_Wait_timed_ticks(), _Semaphore_Try_wait(),
* _Semaphore_Post(), and _Semaphore_Post_binary().
*/
/*
* Copyright (C) 2015, 2017 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 <rtems/score/semaphoreimpl.h>
#include <rtems/score/statesimpl.h>
#include <rtems/score/threadimpl.h>
#include <errno.h>
RTEMS_STATIC_ASSERT(
offsetof( Sem_Control, Queue )
== offsetof( struct _Semaphore_Control, _Queue ),
SEMAPHORE_CONTROL_QUEUE
);
RTEMS_STATIC_ASSERT(
offsetof( Sem_Control, count )
== offsetof( struct _Semaphore_Control, _count ),
SEMAPHORE_CONTROL_COUNT
);
RTEMS_STATIC_ASSERT(
sizeof( Sem_Control ) == sizeof( struct _Semaphore_Control ),
SEMAPHORE_CONTROL_SIZE
);
void _Semaphore_Wait( struct _Semaphore_Control *_sem )
{
Sem_Control *sem;
ISR_Level level;
Thread_queue_Context queue_context;
Thread_Control *executing;
unsigned int count;
sem = _Sem_Get( _sem );
_Thread_queue_Context_initialize( &queue_context );
_Thread_queue_Context_ISR_disable( &queue_context, level );
executing = _Sem_Queue_acquire_critical( sem, &queue_context );
count = sem->count;
if ( RTEMS_PREDICT_TRUE( count > 0 ) ) {
sem->count = count - 1;
_Sem_Queue_release( sem, level, &queue_context );
} else {
_Thread_queue_Context_set_thread_state(
&queue_context,
STATES_WAITING_FOR_SEMAPHORE
);
_Thread_queue_Context_set_enqueue_do_nothing_extra( &queue_context );
_Thread_queue_Context_set_ISR_level( &queue_context, level );
_Thread_queue_Enqueue(
&sem->Queue.Queue,
SEMAPHORE_TQ_OPERATIONS,
executing,
&queue_context
);
}
}
int _Semaphore_Wait_timed_ticks( struct _Semaphore_Control *_sem, uint32_t ticks )
{
Sem_Control *sem;
ISR_Level level;
Thread_queue_Context queue_context;
Thread_Control *executing;
unsigned int count;
sem = _Sem_Get( _sem );
_Thread_queue_Context_initialize( &queue_context );
_Thread_queue_Context_ISR_disable( &queue_context, level );
executing = _Sem_Queue_acquire_critical( sem, &queue_context );
count = sem->count;
if ( RTEMS_PREDICT_TRUE( count > 0 ) ) {
sem->count = count - 1;
_Sem_Queue_release( sem, level, &queue_context );
return 0;
} else {
_Thread_queue_Context_set_thread_state(
&queue_context,
STATES_WAITING_FOR_SEMAPHORE
);
_Thread_queue_Context_set_enqueue_timeout_ticks( &queue_context, ticks );
_Thread_queue_Context_set_ISR_level( &queue_context, level );
_Thread_queue_Enqueue(
&sem->Queue.Queue,
SEMAPHORE_TQ_OPERATIONS,
executing,
&queue_context
);
return STATUS_GET_POSIX( _Thread_Wait_get_status( executing ) );
}
}
int _Semaphore_Try_wait( struct _Semaphore_Control *_sem )
{
Sem_Control *sem;
ISR_Level level;
Thread_queue_Context queue_context;
unsigned int count;
int eno;
sem = _Sem_Get( _sem );
_Thread_queue_Context_initialize( &queue_context );
_Thread_queue_Context_ISR_disable( &queue_context, level );
_Sem_Queue_acquire_critical( sem, &queue_context );
count = sem->count;
if ( RTEMS_PREDICT_TRUE( count > 0 ) ) {
sem->count = count - 1;
eno = 0;
} else {
eno = EAGAIN;
}
_Sem_Queue_release( sem, level, &queue_context );
return eno;
}
void _Semaphore_Post( struct _Semaphore_Control *_sem )
{
Sem_Control *sem;
ISR_Level level;
Thread_queue_Context queue_context;
Thread_queue_Heads *heads;
sem = _Sem_Get( _sem );
_Thread_queue_Context_initialize( &queue_context );
_Thread_queue_Context_ISR_disable( &queue_context, level );
_Sem_Queue_acquire_critical( sem, &queue_context );
heads = sem->Queue.Queue.heads;
if ( RTEMS_PREDICT_TRUE( heads == NULL ) ) {
++sem->count;
_Sem_Queue_release( sem, level, &queue_context );
} else {
_Thread_queue_Context_set_ISR_level( &queue_context, level );
_Thread_queue_Surrender_no_priority(
&sem->Queue.Queue,
heads,
&queue_context,
SEMAPHORE_TQ_OPERATIONS
);
}
}
void _Semaphore_Post_binary( struct _Semaphore_Control *_sem )
{
Sem_Control *sem;
ISR_Level level;
Thread_queue_Context queue_context;
Thread_queue_Heads *heads;
sem = _Sem_Get( _sem );
_Thread_queue_Context_initialize( &queue_context );
_Thread_queue_Context_ISR_disable( &queue_context, level );
_Sem_Queue_acquire_critical( sem, &queue_context );
heads = sem->Queue.Queue.heads;
if ( RTEMS_PREDICT_TRUE( heads == NULL ) ) {
sem->count = 1;
_Sem_Queue_release( sem, level, &queue_context );
} else {
_Thread_queue_Context_set_ISR_level( &queue_context, level );
_Thread_queue_Surrender_no_priority(
&sem->Queue.Queue,
heads,
&queue_context,
SEMAPHORE_TQ_OPERATIONS
);
}
}