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/**
* @file
*
* @brief rtems_semaphore_create
* @ingroup ClassicSem Semaphores
*/
/*
* COPYRIGHT (c) 1989-2014.
* 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.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/rtems/semimpl.h>
#include <rtems/rtems/attrimpl.h>
#include <rtems/rtems/statusimpl.h>
#include <rtems/rtems/tasksimpl.h>
#include <rtems/score/sysstate.h>
#define SEMAPHORE_KIND_MASK ( RTEMS_SEMAPHORE_CLASS | RTEMS_INHERIT_PRIORITY \
| RTEMS_PRIORITY_CEILING | RTEMS_MULTIPROCESSOR_RESOURCE_SHARING )
rtems_status_code rtems_semaphore_create(
rtems_name name,
uint32_t count,
rtems_attribute attribute_set,
rtems_task_priority priority_ceiling,
rtems_id *id
)
{
Semaphore_Control *the_semaphore;
Thread_Control *executing;
Status_Control status;
rtems_attribute maybe_global;
rtems_attribute mutex_with_protocol;
Semaphore_Variant variant;
if ( !rtems_is_name_valid( name ) )
return RTEMS_INVALID_NAME;
if ( !id )
return RTEMS_INVALID_ADDRESS;
#if defined(RTEMS_MULTIPROCESSING)
if (
_Attributes_Is_global( attribute_set )
&& !_System_state_Is_multiprocessing
) {
return RTEMS_MP_NOT_CONFIGURED;
}
#endif
/* Attribute subset defining a potentially global semaphore variant */
maybe_global = attribute_set & SEMAPHORE_KIND_MASK;
/* Attribute subset defining a mutex variant with a locking protocol */
mutex_with_protocol =
attribute_set & ( SEMAPHORE_KIND_MASK | RTEMS_GLOBAL | RTEMS_PRIORITY );
if ( maybe_global == RTEMS_COUNTING_SEMAPHORE ) {
variant = SEMAPHORE_VARIANT_COUNTING;
} else if ( count > 1 ) {
/*
* The remaining variants are all binary semphores, thus reject an invalid
* count value.
*/
return RTEMS_INVALID_NUMBER;
} else if ( maybe_global == RTEMS_SIMPLE_BINARY_SEMAPHORE ) {
variant = SEMAPHORE_VARIANT_SIMPLE_BINARY;
} else if ( maybe_global == RTEMS_BINARY_SEMAPHORE ) {
variant = SEMAPHORE_VARIANT_MUTEX_NO_PROTOCOL;
} else if (
mutex_with_protocol
== ( RTEMS_BINARY_SEMAPHORE | RTEMS_PRIORITY | RTEMS_INHERIT_PRIORITY )
) {
variant = SEMAPHORE_VARIANT_MUTEX_INHERIT_PRIORITY;
} else if (
mutex_with_protocol
== ( RTEMS_BINARY_SEMAPHORE | RTEMS_PRIORITY | RTEMS_PRIORITY_CEILING )
) {
variant = SEMAPHORE_VARIANT_MUTEX_PRIORITY_CEILING;
} else if (
mutex_with_protocol
== ( RTEMS_BINARY_SEMAPHORE | RTEMS_MULTIPROCESSOR_RESOURCE_SHARING )
) {
#if defined(RTEMS_SMP)
variant = SEMAPHORE_VARIANT_MRSP;
#else
/*
* On uni-processor configurations the Multiprocessor Resource Sharing
* Protocol is equivalent to the Priority Ceiling Protocol.
*/
variant = SEMAPHORE_VARIANT_MUTEX_PRIORITY_CEILING;
#endif
} else {
return RTEMS_NOT_DEFINED;
}
the_semaphore = _Semaphore_Allocate();
if ( !the_semaphore ) {
_Objects_Allocator_unlock();
return RTEMS_TOO_MANY;
}
#if defined(RTEMS_MULTIPROCESSING)
the_semaphore->is_global = _Attributes_Is_global( attribute_set );
if ( _Attributes_Is_global( attribute_set ) &&
! ( _Objects_MP_Allocate_and_open( &_Semaphore_Information, name,
the_semaphore->Object.id, false ) ) ) {
_Semaphore_Free( the_semaphore );
_Objects_Allocator_unlock();
return RTEMS_TOO_MANY;
}
#endif
priority_ceiling = _RTEMS_tasks_Priority_to_Core( priority_ceiling );
executing = _Thread_Get_executing();
the_semaphore->variant = variant;
if ( _Attributes_Is_priority( attribute_set ) ) {
the_semaphore->discipline = SEMAPHORE_DISCIPLINE_PRIORITY;
} else {
the_semaphore->discipline = SEMAPHORE_DISCIPLINE_FIFO;
}
switch ( the_semaphore->variant ) {
case SEMAPHORE_VARIANT_MUTEX_NO_PROTOCOL:
case SEMAPHORE_VARIANT_MUTEX_INHERIT_PRIORITY:
_CORE_recursive_mutex_Initialize(
&the_semaphore->Core_control.Mutex.Recursive
);
if ( count == 0 ) {
_CORE_mutex_Set_owner(
&the_semaphore->Core_control.Mutex.Recursive.Mutex,
executing
);
if ( variant == SEMAPHORE_VARIANT_MUTEX_INHERIT_PRIORITY ) {
++executing->resource_count;
}
}
status = STATUS_SUCCESSFUL;
break;
case SEMAPHORE_VARIANT_MUTEX_PRIORITY_CEILING:
_CORE_ceiling_mutex_Initialize(
&the_semaphore->Core_control.Mutex,
priority_ceiling
);
if ( count == 0 ) {
Thread_queue_Context queue_context;
_Thread_queue_Context_initialize( &queue_context );
_ISR_lock_ISR_disable( &queue_context.Lock_context );
_CORE_mutex_Acquire_critical(
&the_semaphore->Core_control.Mutex.Recursive.Mutex,
&queue_context
);
status = _CORE_ceiling_mutex_Set_owner(
&the_semaphore->Core_control.Mutex,
executing,
&queue_context
);
if ( status != STATUS_SUCCESSFUL ) {
_Thread_queue_Destroy( &the_semaphore->Core_control.Wait_queue );
}
} else {
status = STATUS_SUCCESSFUL;
}
break;
#if defined(RTEMS_SMP)
case SEMAPHORE_VARIANT_MRSP:
status = _MRSP_Initialize(
&the_semaphore->Core_control.MRSP,
priority_ceiling,
executing,
count == 0
);
break;
#endif
default:
_Assert(
the_semaphore->variant == SEMAPHORE_VARIANT_SIMPLE_BINARY
|| the_semaphore->variant == SEMAPHORE_VARIANT_COUNTING
);
_CORE_semaphore_Initialize(
&the_semaphore->Core_control.Semaphore,
count
);
status = STATUS_SUCCESSFUL;
break;
}
if ( status != STATUS_SUCCESSFUL ) {
_Semaphore_Free( the_semaphore );
_Objects_Allocator_unlock();
return _Status_Get( status );
}
/*
* Whether we initialized it as a mutex or counting semaphore, it is
* now ready to be "offered" for use as a Classic API Semaphore.
*/
_Objects_Open(
&_Semaphore_Information,
&the_semaphore->Object,
(Objects_Name) name
);
*id = the_semaphore->Object.id;
#if defined(RTEMS_MULTIPROCESSING)
if ( _Attributes_Is_global( attribute_set ) )
_Semaphore_MP_Send_process_packet(
SEMAPHORE_MP_ANNOUNCE_CREATE,
the_semaphore->Object.id,
name,
0 /* Not used */
);
#endif
_Objects_Allocator_unlock();
return RTEMS_SUCCESSFUL;
}
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