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/*
* Copyright (c) 2015 embedded brains GmbH. All rights reserved.
*
* embedded brains GmbH
* Dornierstr. 4
* 82178 Puchheim
* Germany
* <rtems@embedded-brains.de>
*
* 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.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#if HAVE_STRUCT__THREAD_QUEUE_QUEUE
#include <sys/lock.h>
#include <rtems/score/assert.h>
#include <rtems/score/threadimpl.h>
#include <rtems/score/threadqimpl.h>
#define SEMAPHORE_TQ_OPERATIONS &_Thread_queue_Operations_priority
typedef struct {
Thread_queue_Syslock_queue Queue;
unsigned int count;
} Semaphore_Control;
RTEMS_STATIC_ASSERT(
offsetof( Semaphore_Control, Queue )
== offsetof( struct _Semaphore_Control, _Queue ),
SEMAPHORE_CONTROL_QUEUE
);
RTEMS_STATIC_ASSERT(
offsetof( Semaphore_Control, count )
== offsetof( struct _Semaphore_Control, _count ),
SEMAPHORE_CONTROL_COUNT
);
RTEMS_STATIC_ASSERT(
sizeof( Semaphore_Control ) == sizeof( struct _Semaphore_Control ),
SEMAPHORE_CONTROL_SIZE
);
static Semaphore_Control *_Semaphore_Get(
struct _Semaphore_Control *_sem
)
{
return (Semaphore_Control *) _sem;
}
static Thread_Control *_Semaphore_Queue_acquire(
Semaphore_Control *sem,
ISR_lock_Context *lock_context
)
{
Thread_Control *executing;
_ISR_lock_ISR_disable( lock_context );
executing = _Thread_Executing;
_Thread_queue_Queue_acquire_critical(
&sem->Queue.Queue,
&executing->Potpourri_stats,
lock_context
);
return executing;
}
static void _Semaphore_Queue_release(
Semaphore_Control *sem,
ISR_lock_Context *lock_context
)
{
_Thread_queue_Queue_release( &sem->Queue.Queue, lock_context );
}
void _Semaphore_Wait( struct _Semaphore_Control *_sem )
{
Semaphore_Control *sem ;
ISR_lock_Context lock_context;
Thread_Control *executing;
unsigned int count;
sem = _Semaphore_Get( _sem );
executing = _Semaphore_Queue_acquire( sem, &lock_context );
count = sem->count;
if ( count > 0 ) {
sem->count = count - 1;
_Semaphore_Queue_release( sem, &lock_context );
} else {
_Thread_queue_Enqueue_critical(
&sem->Queue.Queue,
SEMAPHORE_TQ_OPERATIONS,
executing,
STATES_WAITING_FOR_SYS_LOCK_SEMAPHORE,
0,
0,
&lock_context
);
}
}
void _Semaphore_Post( struct _Semaphore_Control *_sem )
{
Semaphore_Control *sem;
ISR_lock_Context lock_context;
Thread_queue_Heads *heads;
sem = _Semaphore_Get( _sem );
_Semaphore_Queue_acquire( sem, &lock_context );
heads = sem->Queue.Queue.heads;
if ( heads == NULL ) {
_Assert( sem->count < UINT_MAX );
++sem->count;
_Semaphore_Queue_release( sem, &lock_context );
} else {
const Thread_queue_Operations *operations;
Thread_Control *first;
operations = SEMAPHORE_TQ_OPERATIONS;
first = ( *operations->first )( heads );
_Thread_queue_Extract_critical(
&sem->Queue.Queue,
operations,
first,
&lock_context
);
}
}
#endif /* HAVE_STRUCT__THREAD_QUEUE_QUEUE */
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