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/**
* @file rtems/score/corebarrier.h
*
* This include file contains all the constants and structures associated
* with the Barrier Handler.
*/
/*
* COPYRIGHT (c) 1989-2007.
* 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.
*/
#ifndef _RTEMS_SCORE_COREBARRIER_H
#define _RTEMS_SCORE_COREBARRIER_H
/**
* @defgroup ScoreBarrier Barrier Handler
*
* @ingroup Score
*
* This handler encapsulates functionality which provides the foundation
* Barrier services used in all of the APIs supported by RTEMS.
*/
/**@{*/
#ifdef __cplusplus
extern "C" {
#endif
#include <rtems/score/thread.h>
#include <rtems/score/threadq.h>
#include <rtems/score/priority.h>
#include <rtems/score/watchdog.h>
/**
* The following type defines the callout which the API provides
* to support global/multiprocessor operations on barriers.
*/
typedef void ( *CORE_barrier_API_mp_support_callout )(
Thread_Control *,
Objects_Id
);
/**
* Flavors of barriers.
*/
typedef enum {
/** This specifies that the barrier will automatically release when
* the user specified number of threads have arrived at the barrier.
*/
CORE_BARRIER_AUTOMATIC_RELEASE,
/** This specifies that the user will have to manually release the barrier
* in order to release the waiting threads.
*/
CORE_BARRIER_MANUAL_RELEASE
} CORE_barrier_Disciplines;
/**
* Core Barrier handler return statuses.
*/
typedef enum {
/** This status indicates that the operation completed successfully. */
CORE_BARRIER_STATUS_SUCCESSFUL,
/** This status indicates that the barrier is configured for automatic
* release and the caller tripped the automatic release. The caller
* thus did not block.
*/
CORE_BARRIER_STATUS_AUTOMATICALLY_RELEASED,
/** This status indicates that the thread was blocked waiting for an
* operation to complete and the barrier was deleted.
*/
CORE_BARRIER_WAS_DELETED,
/** This status indicates that the calling task was willing to block
* but the operation was unable to complete within the time allotted
* because the resource never became available.
*/
CORE_BARRIER_TIMEOUT
} CORE_barrier_Status;
/**
* @brief Core Barrier Last Status
*
* This is the last status value.
*/
#define CORE_BARRIER_STATUS_LAST CORE_BARRIER_TIMEOUT
/**
* The following defines the control block used to manage the
* attributes of each barrier.
*/
typedef struct {
/** This field indicates whether the barrier is automatic or manual.
*/
CORE_barrier_Disciplines discipline;
/** This element indicates the number of threads which must arrive at the
* barrier to trip the automatic release.
*/
uint32_t maximum_count;
} CORE_barrier_Attributes;
/**
* The following defines the control block used to manage each
* barrier.
*/
typedef struct {
/** This field is the Waiting Queue used to manage the set of tasks
* which are blocked waiting for the barrier to be released.
*/
Thread_queue_Control Wait_queue;
/** This element is the set of attributes which define this instance's
* behavior.
*/
CORE_barrier_Attributes Attributes;
/** This element contains the current number of thread waiting for this
* barrier to be released. */
uint32_t number_of_waiting_threads;
} CORE_barrier_Control;
/**
* This routine initializes the barrier based on the parameters passed.
*
* @param[in] the_barrier is the barrier to initialize
* @param[in] the_barrier_attributes define the behavior of this instance
*/
void _CORE_barrier_Initialize(
CORE_barrier_Control *the_barrier,
CORE_barrier_Attributes *the_barrier_attributes
);
/**
* This routine wait for the barrier to be released. If the barrier
* is set to automatic and this is the appropriate thread, then it returns
* immediately. Otherwise, the calling thread is blocked until the barrier
* is released.
*
* @param[in] the_barrier is the barrier to wait for
* @param[in] id is the id of the object being waited upon
* @param[in] wait is true if the calling thread is willing to wait
* @param[in] timeout is the number of ticks the calling thread is willing
* to wait if @a wait is true.
* @param[in] api_barrier_mp_support is the routine to invoke if the
* thread unblocked is remote
*
* @note Status is returned via the thread control block.
*/
void _CORE_barrier_Wait(
CORE_barrier_Control *the_barrier,
Objects_Id id,
bool wait,
Watchdog_Interval timeout,
CORE_barrier_API_mp_support_callout api_barrier_mp_support
);
/**
* This routine manually releases the barrier. All of the threads waiting
* for the barrier will be readied.
*
* @param[in] the_barrier is the barrier to surrender
* @param[in] id is the id of the object for a remote unblock
* @param[in] api_barrier_mp_support is the routine to invoke if the
* thread unblocked is remote
*
* @return the number of unblocked threads
*/
uint32_t _CORE_barrier_Release(
CORE_barrier_Control *the_barrier,
Objects_Id id,
CORE_barrier_API_mp_support_callout api_barrier_mp_support
);
/**
* This routine assists in the deletion of a barrier by flushing the
* associated wait queue.
*
* @param[in] _the_barrier is the barrier to flush
* @param[in] _remote_extract_callout is the routine to invoke if the
* thread unblocked is remote
* @param[in] _status is the status to be returned to the unblocked thread
*/
#define _CORE_barrier_Flush( _the_barrier, _remote_extract_callout, _status) \
_Thread_queue_Flush( \
&((_the_barrier)->Wait_queue), \
(_remote_extract_callout), \
(_status) \
)
#ifndef __RTEMS_APPLICATION__
#include <rtems/score/corebarrier.inl>
#endif
#ifdef __cplusplus
}
#endif
/**@}*/
#endif
/* end of include file */
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