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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
*/
/**
------------
CVS : $Id: npp.c,v 1.1.1.1 2002-03-29 14:12:52 pj Exp $
File: $File$
Revision: $Revision: 1.1.1.1 $
Last update: $Date: 2002-03-29 14:12:52 $
------------
Non Preemptive Protocol. see npp.h for more details...
**/
/*
* Copyright (C) 2000 Paolo Gai
*
* 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
*
*/
#include <modules/npp.h>
#include <ll/ll.h>
#include <ll/string.h>
#include <ll/stdio.h>
#include <modules/codes.h>
#include <kernel/const.h>
#include <sys/types.h>
#include <kernel/descr.h>
#include <kernel/var.h>
#include <kernel/func.h>
/* The NPP resource level descriptor */
typedef struct {
mutex_resource_des m
; /*+ the mutex interface +*/
int nlocked
; /*+ how many mutex a task currently locks +*/
} NPP_mutex_resource_des
;
/*+ print resource protocol statistics...+*/
static void NPP_resource_status
(RLEVEL r
)
{
NPP_mutex_resource_des
*m
= (NPP_mutex_resource_des
*)(resource_table
[r
]);
kern_printf
("%d Resources owned by the tasks %d\n", m
->nlocked
, exec_shadow
);
}
static int NPP_level_accept_resource_model
(RLEVEL l
, RES_MODEL
*r
)
{
/* NPP works with all tasks without Resource parameters */
return -1;
}
static void NPP_res_register
(RLEVEL l
, PID p
, RES_MODEL
*r
)
{
/* never called!!! */
}
static void NPP_res_detach
(RLEVEL l
, PID p
)
{
NPP_mutex_resource_des
*m
= (NPP_mutex_resource_des
*)(resource_table
[l
]);
if (m
->nlocked
)
kern_raise
(XMUTEX_OWNER_KILLED
, p
);
}
static int NPP_level_accept_mutexattr
(RLEVEL l
, const mutexattr_t
*a
)
{
if (a
->mclass
== NPP_MCLASS
|| a
->mclass
== (NPP_MCLASS
| l
) )
return 0;
else
return -1;
}
static int NPP_init
(RLEVEL l
, mutex_t
*m
, const mutexattr_t
*a
)
{
m
->mutexlevel
= l
;
m
->opt
= (void *)NIL
;
return 0;
}
static int NPP_destroy
(RLEVEL l
, mutex_t
*m
)
{
// NPP_mutex_resource_des *lev = (NPP_mutex_resource_des *)(resource_table[l]);
if ( ((PID
) m
->opt
) != NIL
)
return (EBUSY
);
return 0;
}
static int NPP_lock
(RLEVEL l
, mutex_t
*m
)
{
NPP_mutex_resource_des
*lev
;
kern_cli
();
if (((PID
)m
->opt
) == exec_shadow
) {
/* the task already owns the mutex */
kern_sti
();
return (EDEADLK
);
}
/* p->opt == NIL (It can't be the case of p->opt != NIL and != exec_shadow
because when a task lock a mutex it become unpreemptable */
/* the mutex is free, We can lock it! */
lev
= (NPP_mutex_resource_des
*)(resource_table
[l
]);
if (!lev
->nlocked
) task_nopreempt
();
lev
->nlocked
++;
m
->opt
= (void *)exec_shadow
;
kern_sti
();
return 0;
}
// static int NPP_trylock(RLEVEL l, mutex_t *m) is a non-sense!
static int NPP_unlock
(RLEVEL l
, mutex_t
*m
)
{
NPP_mutex_resource_des
*lev
;
/* the mutex is mine */
lev
= (NPP_mutex_resource_des
*)(resource_table
[l
]);
lev
->nlocked
--;
m
->opt
= (void *)NIL
;
if (!lev
->nlocked
) task_preempt
();
return 0;
}
void NPP_register_module
(void)
{
RLEVEL l
; /* the level that we register */
NPP_mutex_resource_des
*m
; /* for readableness only */
printk
("NPP_register_module\n");
/* request an entry in the level_table */
l
= resource_alloc_descriptor
();
/* alloc the space needed for the EDF_level_des */
m
= (NPP_mutex_resource_des
*)kern_alloc
(sizeof(NPP_mutex_resource_des
));
/* update the level_table with the new entry */
resource_table
[l
] = (resource_des
*)m
;
/* fill the resource_des descriptor */
strncpy(m
->m.
r.
res_name, NPP_MODULENAME
, MAX_MODULENAME
);
m
->m.
r.
res_code = NPP_MODULE_CODE
;
m
->m.
r.
res_version = NPP_MODULE_VERSION
;
m
->m.
r.
rtype = MUTEX_RTYPE
;
m
->m.
r.
resource_status = NPP_resource_status
;
m
->m.
r.
level_accept_resource_model = NPP_level_accept_resource_model
;
m
->m.
r.
res_register = NPP_res_register
;
m
->m.
r.
res_detach = NPP_res_detach
;
/* fill the mutex_resource_des descriptor */
m
->m.
level_accept_mutexattr = NPP_level_accept_mutexattr
;
m
->m.
init = NPP_init
;
m
->m.
destroy = NPP_destroy
;
m
->m.
lock = NPP_lock
;
m
->m.
trylock = NPP_lock
; // !!!!!!!!!!!!
m
->m.
unlock = NPP_unlock
;
/* fill the NPP_mutex_resource_des descriptor */
m
->nlocked
= 0;
}