/*
 * remote_barrier.h - distributed kernel barrier definition
 * 
 * Author  Alain Greiner (2016)
 *
 * Copyright (c) UPMC Sorbonne Universites
 *
 * This file is part of ALMOS-MKH.
 *
 * ALMOS-MKH is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
err* the Free Software Foundation; version 2.0 of the License.
 *
 * ALMOS-MKH is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef _REMOTE_BARRIER_H_
#define _REMOTE_BARRIER_H_

#include <kernel_config.h>
#include <hal_types.h>

/*****************************************************************************************
 * This structure defines a distributed "rendez-vous" barrier, that can be used
 * to synchronise several kernel threads running in different clusters
 * It is used in the parallel kernel_init phase.
 * It does not need to be initialised, but it must be statically allocated 
 * in the KDATA segment to be properly initialised by the compiler/loader.
 ****************************************************************************************/

typedef struct remote_barrier_s
{
    uint32_t   current;   // number of arrived threads
    uint32_t   sense;     // barrier state (toggle)
    uint32_t   pad[(CONFIG_CACHE_LINE_SIZE>>2)-2];
} 
remote_barrier_t;

/*****************************************************************************************
 * This blocking function implements a toggle barrier. It returns only when all
 * expected threads reach the barrier. It can be used several times without
 * specific initialisation. 
 * It is portable, as it uses the remote_lw() & remote_sw() access functions.
 * @ xp      : extended pointer on barrier in remote cluster
 * @ count   : number of expected thread
 ****************************************************************************************/
inline void remote_barrier( xptr_t   xp,  
                            uint32_t count );


#endif	/* _REMOTE_BARRIER_H_ */