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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 1.1.1.1 2002-03-29 14:12:51 pj Exp $

 *

 * File:        $File$

 * Revision:    $Revision: 1.1.1.1 $

 * Last update: $Date: 2002-03-29 14:12:51 $

 */

/*

 * 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>

/*+ 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

#endif