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/*
 * Project: S.Ha.R.K.
 *
 * Coordinators:
 *   Giorgio Buttazzo    <giorgio@sssup.it>
 *   Paolo Gai           <pj@gandalf.sssup.it>
 *
 * Authors     :
 *   Paolo Gai           <pj@gandalf.sssup.it>
 *   Massimiliano Giorgi <massy@gandalf.sssup.it>
 *   Luca Abeni          <luca@gandalf.sssup.it>
 *   (see the web pages for full authors list)
 *
 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)
 *
 * http://www.sssup.it
 * http://retis.sssup.it
 * http://shark.sssup.it
 */

/***************************************

Mutexs for the kernel

***************************************/

/*
 * CVS :        $Id: mutex.h,v 1.2 2003-03-13 13:37:58 pj Exp $
 *
 * File:        $File$
 * Revision:    $Revision: 1.2 $
 * Last update: $Date: 2003-03-13 13:37:58 $
 */

/*
 * Copyright (C) 1999,2000 Massimiliano Giorgi
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#ifndef _FS_MUTEX_H
#define _FS_MUTEX_H

/*
 * standard mutex    
 */
     
#include <kernel/int_sem.h>
#include "ll/sys/cdefs.h"

__BEGIN_DECLS

/*+ a semaphore object +*/
typedef internal_sem_t __mutex_t;

/*
  The following macros can be used to synchronize events; all
  require a pointer to a semaphore object and return nothing;
  a semaphore can have "val" resource free.
 */

/*+ Initialize a semaphore (to integer val) +*/
#define __mutex_init(ptr,attr) internal_sem_init((ptr),1)

/*+ Wait for a semaphore +*/
#define __mutex_lock(ptr)     (internal_sem_wait(ptr))

/*+ Try to wait for a semaphore (return 0 on success) +*/
#define __mutex_trylock(ptr)  (internal_sem_wait(ptr))

/*+ Signal a semaphore +*/
#define __mutex_unlock(ptr)   (internal_sem_post(ptr))

#if 0
/* start old implementation */

#include <kernel/model.h>
#include <kernel/func.h>
#include <fs/assert.h>
 
/*+ a mutex object +*/
typedef mutex_t  __mutex_t;

/*
  The following macros require a pointer to a mutex object and
  return nothing.
*/

/* Initialize a mutex object +*/
#define __mutex_init(ptr,attr) _assert(mutex_init(ptr,attr)==0)
/*+ Lock a mutex object +*/
#define __mutex_lock(ptr)      _assert(mutex_lock(ptr)==0)
/*+ Try to lock a mutex (return 0 on success locking) +*/
#define __mutex_trylock(ptr)   (mutex_trylock((ptr)))
/*+ Unlock a mutex +*/
#define __mutex_unlock(ptr)    _assert(mutex_unlock(ptr)==0)

/* end old implementation */
#endif

/*
 * fast mutex    
 */

#include <kernel/func.h>

typedef SYS_FLAGS __fastmutex_t;

#define __fastmutex_init(ptr)
#define __fastmutex_lock(ptr)   *ptr=kern_fsave()
#define __fastmutex_unlock(ptr) kern_frestore(*ptr)
 
#if 0

/* Hartik 3.x implemantation */

/*
#include <hartik/const.h>
 
typedef struct {
  QUEUE queue;
  int   value;
} __mutex_t;

void __mutex_init(__mytex_t *);
void __mutex_lock(__mytex_t *);
int  __mutex_trylock(__mytex_t *);
void __mutex_unlock(__mytex_t *);
*/

/*
 * temporary hack
 */

#include <h/sys/kern.h>
#include <h/sys/const.h>

/*+ a mutex object +*/
typedef SEM __mutex_t;

/*
  The following macros require a pointer to a mutex object and
  return nothing.
*/

#ifdef FSCHECKMUTEX
#include <fs/assert.h>
#define checkmutex(x) assert((x)>=0&&(x)<MAX_SEM)
#else
#define checkmutex(x)
#endif

/* Initialize a mutex object +*/
#define __mutex_init(ptr)    { *(ptr)=sem_create(1); checkmutex(*ptr); }

/*+ Lock a mutex object +*/
#define __mutex_lock(ptr)    { checkmutex(*ptr); sem_wait(*(ptr),BLOCK); }

/*+ Try to lock a mutex (return 0 on success locking) +*/
#define __mutex_trylock(ptr) { checkmutex(*ptr); sem_wait(*(ptr),NON_BLOCK); }

/*+ Unlock a mutex +*/
#define __mutex_unlock(ptr)  { checkmutex(*ptr); sem_signal(*(ptr)); }

#endif





__END_DECLS
#endif