/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @ingroup RTEMSScoreSMPBarrier
*
* @brief This header file provides the interfaces of the
* @ref RTEMSScoreSMPBarrier.
*/
/*
* Copyright (C) 2013, 2014 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.
*/
#ifndef _RTEMS_SCORE_SMPBARRIER_H
#define _RTEMS_SCORE_SMPBARRIER_H
#include <rtems/score/cpuopts.h>
#include <rtems/score/atomic.h>
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
/**
* @defgroup RTEMSScoreSMPBarrier SMP Barriers
*
* @ingroup RTEMSScore
*
* @brief This group contains the SMP barrier implementation.
*
* The SMP barrier provides barrier synchronization for SMP systems at the
* lowest level.
*
* The SMP barrier is implemented as a sense barrier, see also Herlihy and
* Shavit, "The Art of Multiprocessor Programming", 17.3 Sense-Reversing
* Barrier.
*
* @{
*/
/**
* @brief SMP barrier control.
*/
typedef struct {
Atomic_Uint value;
Atomic_Uint sense;
} SMP_barrier_Control;
/**
* @brief SMP barrier per-thread state.
*
* Each user of the barrier must provide this per-thread state.
*/
typedef struct {
unsigned int sense;
} SMP_barrier_State;
/**
* @brief SMP barrier control initializer for static initialization.
*/
#define SMP_BARRIER_CONTROL_INITIALIZER \
{ ATOMIC_INITIALIZER_UINT( 0U ), ATOMIC_INITIALIZER_UINT( 0U ) }
/**
* @brief SMP barrier per-thread state initializer for static initialization.
*/
#define SMP_BARRIER_STATE_INITIALIZER { 0U }
/**
* @brief Initializes a SMP barrier control.
*
* Concurrent initialization leads to unpredictable results.
*
* @param[out] control The SMP barrier control.
*/
static inline void _SMP_barrier_Control_initialize(
SMP_barrier_Control *control
)
{
_Atomic_Init_uint( &control->value, 0U );
_Atomic_Init_uint( &control->sense, 0U );
}
/**
* @brief Initializes a SMP barrier per-thread state.
*
* @param[out] state The SMP barrier control.
*/
static inline void _SMP_barrier_State_initialize(
SMP_barrier_State *state
)
{
state->sense = 0U;
}
/**
* @brief Waits on the SMP barrier until count threads rendezvoused.
*
* @param[in, out] control The SMP barrier control.
* @param[in, out] state The SMP barrier per-thread state.
* @param count The thread count bound to rendezvous.
*
* @retval true This processor performed the barrier release.
* @retval false This processor did not performe the barrier release.
*/
bool _SMP_barrier_Wait(
SMP_barrier_Control *control,
SMP_barrier_State *state,
unsigned int count
);
/** @} */
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* _RTEMS_SCORE_SMPBARRIER_H */
