/**
* @file rtems/rtems/sem.h
*
* This include file contains all the constants and structures associated
* with the Semaphore Manager. This manager utilizes standard Dijkstra
* counting semaphores to provide synchronization and mutual exclusion
* capabilities.
*
* Directives provided are:
*
* - create a semaphore
* - get an ID of a semaphore
* - delete a semaphore
* - acquire a semaphore
* - release a semaphore
*/
/* 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.com/license/LICENSE.
*
* $Id$
*/
#ifndef _RTEMS_RTEMS_SEM_H
#define _RTEMS_RTEMS_SEM_H
/**
* This constant is defined to extern most of the time when using
* this header file. However by defining it to nothing, the data
* declared in this header file can be instantiated. This is done
* in a single per manager file.
*/
#ifndef RTEMS_SEM_EXTERN
#define RTEMS_SEM_EXTERN extern
#endif
#ifdef __cplusplus
extern "C" {
#endif
#include <rtems/rtems/types.h>
#include <rtems/rtems/options.h>
#include <rtems/rtems/support.h>
#include <rtems/rtems/tasks.h>
#include <rtems/rtems/attr.h>
#include <rtems/score/coremutex.h>
#include <rtems/score/object.h>
#include <rtems/score/coresem.h>
/**
* @defgroup ClassicSem Semaphores
*
* @ingroup ClassicRTEMS
*
* This encapsulates functionality related to the Classic API
* Semaphore Manager.
*/
/**@{*/
/**
* The following defines the control block used to manage each semaphore.
*/
typedef struct {
/** This field is the object management portion of a Semaphore instance. */
Objects_Control Object;
/**
* This is the Classic API attribute provided to the create directive.
* It is translated into behavioral attributes on the SuperCore Semaphore
* or Mutex instance.
*/
rtems_attribute attribute_set;
/**
* This contains the memory associated with the SuperCore Semaphore or
* Mutex instance that provides the primary functionality of each
* Classic API Semaphore instance. The structure used is dependent
* on the attributes specified by the user on the create directive.
*
* @note Only one of these has meaning in a particular Classic API
* Semaphore instance.
*/
union {
/**
* This is the SuperCore Mutex instance associated with this Classic
* API Semaphore instance.
*/
CORE_mutex_Control mutex;
/**
* This is the SuperCore Semaphore instance associated with this Classic
* API Semaphore instance.
*/
CORE_semaphore_Control semaphore;
} Core_control;
} Semaphore_Control;
/**
* The following defines the information control block used to manage
* this class of objects.
*/
RTEMS_SEM_EXTERN Objects_Information _Semaphore_Information;
/**
* @brief Semaphore_Manager_initialization
*
* This routine performs the initialization necessary for this manager.
*/
void _Semaphore_Manager_initialization(void);
/**
* @brief rtems_semaphore_create
*
* This routine implements the rtems_semaphore_create directive. The
* semaphore will have the name name. The starting count for
* the semaphore is count. The attribute_set determines if
* the semaphore is global or local and the thread queue
* discipline. It returns the id of the created semaphore in ID.
*/
rtems_status_code rtems_semaphore_create(
rtems_name name,
uint32_t count,
rtems_attribute attribute_set,
rtems_task_priority priority_ceiling,
rtems_id *id
);
/**
* @brief rtems_semaphore_ident
*
* This routine implements the rtems_semaphore_ident directive.
* This directive returns the semaphore ID associated with name.
* If more than one semaphore is named name, then the semaphore
* to which the ID belongs is arbitrary. node indicates the
* extent of the search for the ID of the semaphore named name.
* The search can be limited to a particular node or allowed to
* encompass all nodes.
*/
rtems_status_code rtems_semaphore_ident(
rtems_name name,
uint32_t node,
rtems_id *id
);
/**
* @brief rtems_semaphore_delete
*
* This routine implements the rtems_semaphore_delete directive. The
* semaphore indicated by ID is deleted.
*/
rtems_status_code rtems_semaphore_delete(
rtems_id id
);
/**
* @brief rtems_semaphore_obtain
*
* This routine implements the rtems_semaphore_obtain directive. It
* attempts to obtain a unit from the semaphore associated with ID.
* If a unit can be allocated, the calling task will return immediately.
* If no unit is available, then the task may return immediately or
* block waiting for a unit with an optional timeout of timeout
* clock ticks. Whether the task blocks or returns immediately
* is based on the RTEMS_NO_WAIT option in the option_set.
*/
rtems_status_code rtems_semaphore_obtain(
rtems_id id,
rtems_option option_set,
rtems_interval timeout
);
/**
* @brief rtems_semaphore_release
*
* This routine implements the rtems_semaphore_release directive. It
* frees a unit to the semaphore associated with ID. If a task was
* blocked waiting for a unit from this semaphore, then that task will
* be readied and the unit given to that task. Otherwise, the unit
* will be returned to the semaphore.
*/
rtems_status_code rtems_semaphore_release(
rtems_id id
);
/**
* @brief rtems_semaphore_flush
* pending on the semaphore.
*/
rtems_status_code rtems_semaphore_flush(
rtems_id id
);
/**
* @brief _Semaphore_Seize
*
* This routine attempts to receive a unit from the_semaphore.
* If a unit is available or if the RTEMS_NO_WAIT option is enabled in
* option_set, then the routine returns. Otherwise, the calling task
* is blocked until a unit becomes available.
*/
bool _Semaphore_Seize(
Semaphore_Control *the_semaphore,
uint32_t option_set
);
/**
* @brief _Semaphore_Translate_core_mutex_return_code
*
* This function returns a RTEMS status code based on the mutex
* status code specified.
*/
rtems_status_code _Semaphore_Translate_core_mutex_return_code (
uint32_t the_mutex_status
);
/**
* @brief _Semaphore_Translate_core_semaphore_return_code
*
* This function returns a RTEMS status code based on the semaphore
* status code specified.
*/
rtems_status_code _Semaphore_Translate_core_semaphore_return_code (
uint32_t the_mutex_status
);
#ifndef __RTEMS_APPLICATION__
#include <rtems/rtems/sem.inl>
#endif
#if defined(RTEMS_MULTIPROCESSING)
#include <rtems/rtems/semmp.h>
#endif
#ifdef __cplusplus
}
#endif
/**@}*/
#endif
/* end of include file */
