WebSVN - shark - Blame - Rev 38 - /shark/trunk/kernel/modules/npp.c

Rev	Author	Line No.	Line
2	pj	1	/*
		2	* Project: S.Ha.R.K.
		3	*
		4	* Coordinators:
		5	* Giorgio Buttazzo <giorgio@sssup.it>
		6	* Paolo Gai <pj@gandalf.sssup.it>
		7	*
		8	* Authors :
		9	* Paolo Gai <pj@gandalf.sssup.it>
		10	* Massimiliano Giorgi <massy@gandalf.sssup.it>
		11	* Luca Abeni <luca@gandalf.sssup.it>
		12	* (see the web pages for full authors list)
		13	*
		14	* ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)
		15	*
		16	* http://www.sssup.it
		17	* http://retis.sssup.it
		18	* http://shark.sssup.it
		19	*/
		20
		21	/**
		22	------------
38	pj	23	CVS : $Id: npp.c,v 1.2 2003-01-07 17:07:50 pj Exp $
2	pj	24
		25	File: $File$
38	pj	26	Revision: $Revision: 1.2 $
		27	Last update: $Date: 2003-01-07 17:07:50 $
2	pj	28	------------
		29
		30	Non Preemptive Protocol. see npp.h for more details...
		31
		32	**/
		33
		34	/*
		35	* Copyright (C) 2000 Paolo Gai
		36	*
		37	* This program is free software; you can redistribute it and/or modify
		38	* it under the terms of the GNU General Public License as published by
		39	* the Free Software Foundation; either version 2 of the License, or
		40	* (at your option) any later version.
		41	*
		42	* This program is distributed in the hope that it will be useful,
		43	* but WITHOUT ANY WARRANTY; without even the implied warranty of
		44	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		45	* GNU General Public License for more details.
		46	*
		47	* You should have received a copy of the GNU General Public License
		48	* along with this program; if not, write to the Free Software
		49	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
		50	*
		51	*/
		52
		53
		54	#include <modules/npp.h>
		55
		56	#include <ll/ll.h>
		57	#include <ll/string.h>
		58	#include <ll/stdio.h>
		59	#include <kernel/const.h>
		60	#include <sys/types.h>
		61	#include <kernel/descr.h>
		62	#include <kernel/var.h>
		63	#include <kernel/func.h>
		64
		65	/* The NPP resource level descriptor */
		66	typedef struct {
		67	mutex_resource_des m; /+ the mutex interface +/
		68
		69	int nlocked; /+ how many mutex a task currently locks +/
		70	} NPP_mutex_resource_des;
		71
		72
38	pj	73	#if 0
2	pj	74	/+ print resource protocol statistics...+/
		75	static void NPP_resource_status(RLEVEL r)
		76	{
		77	NPP_mutex_resource_des m = (NPP_mutex_resource_des )(resource_table[r]);
		78
		79	kern_printf("%d Resources owned by the tasks %d\n", m->nlocked, exec_shadow);
		80	}
38	pj	81	#endif
2	pj	82
38	pj	83	static int NPP_res_register(RLEVEL l, PID p, RES_MODEL *r)
2	pj	84	{
		85	/* NPP works with all tasks without Resource parameters */
		86	return -1;
		87	}
		88
		89	static void NPP_res_detach(RLEVEL l, PID p)
		90	{
		91	NPP_mutex_resource_des m = (NPP_mutex_resource_des )(resource_table[l]);
		92
		93	if (m->nlocked)
		94	kern_raise(XMUTEX_OWNER_KILLED, p);
		95	}
		96
38	pj	97	static int NPP_init(RLEVEL l, mutex_t m, const mutexattr_t a)
2	pj	98	{
38	pj	99	if (a->mclass != NPP_MCLASS)
2	pj	100	return -1;
		101
		102	m->mutexlevel = l;
		103	m->opt = (void *)NIL;
		104
		105	return 0;
		106	}
		107
		108
		109	static int NPP_destroy(RLEVEL l, mutex_t *m)
		110	{
		111	// NPP_mutex_resource_des lev = (NPP_mutex_resource_des )(resource_table[l]);
		112
		113	if ( ((PID) m->opt) != NIL)
		114	return (EBUSY);
		115
		116	return 0;
		117	}
		118
		119	static int NPP_lock(RLEVEL l, mutex_t *m)
		120	{
		121	NPP_mutex_resource_des *lev;
		122
		123	kern_cli();
		124
		125	if (((PID)m->opt) == exec_shadow) {
		126	/* the task already owns the mutex */
		127	kern_sti();
		128	return (EDEADLK);
		129	}
		130
		131	/* p->opt == NIL (It can't be the case of p->opt != NIL and != exec_shadow
		132	because when a task lock a mutex it become unpreemptable */
		133
		134	/* the mutex is free, We can lock it! */
		135	lev = (NPP_mutex_resource_des *)(resource_table[l]);
		136
		137	if (!lev->nlocked) task_nopreempt();
		138	lev->nlocked++;
		139
		140	m->opt = (void *)exec_shadow;
		141
		142	kern_sti();
		143
		144	return 0;
		145	}
		146
		147	// static int NPP_trylock(RLEVEL l, mutex_t *m) is a non-sense!
		148
		149	static int NPP_unlock(RLEVEL l, mutex_t *m)
		150	{
		151	NPP_mutex_resource_des *lev;
		152
		153	/* the mutex is mine */
		154	lev = (NPP_mutex_resource_des *)(resource_table[l]);
		155	lev->nlocked--;
		156
		157	m->opt = (void *)NIL;
		158
		159	if (!lev->nlocked) task_preempt();
		160
		161	return 0;
		162	}
		163
		164	void NPP_register_module(void)
		165	{
		166	RLEVEL l; /* the level that we register */
		167	NPP_mutex_resource_des m; / for readableness only */
		168
		169	printk("NPP_register_module\n");
		170
		171	/* request an entry in the level_table */
		172	l = resource_alloc_descriptor();
		173
		174	/* alloc the space needed for the EDF_level_des */
		175	m = (NPP_mutex_resource_des *)kern_alloc(sizeof(NPP_mutex_resource_des));
		176
		177	/* update the level_table with the new entry */
		178	resource_table[l] = (resource_des *)m;
		179
		180	/* fill the resource_des descriptor */
		181	m->m.r.rtype = MUTEX_RTYPE;
		182	m->m.r.res_register = NPP_res_register;
		183	m->m.r.res_detach = NPP_res_detach;
		184
		185	/* fill the mutex_resource_des descriptor */
		186	m->m.init = NPP_init;
		187	m->m.destroy = NPP_destroy;
		188	m->m.lock = NPP_lock;
		189	m->m.trylock = NPP_lock; // !!!!!!!!!!!!
		190	m->m.unlock = NPP_unlock;
		191
		192	/* fill the NPP_mutex_resource_des descriptor */
		193	m->nlocked = 0;
		194	}
		195

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