xref: /linux/drivers/w1/w1_family.c (revision fe3cb82364332b9db3b574e9e41de9c27eff470a)
11da177e4SLinus Torvalds /*
21da177e4SLinus Torvalds  *	w1_family.c
31da177e4SLinus Torvalds  *
41da177e4SLinus Torvalds  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
51da177e4SLinus Torvalds  *
61da177e4SLinus Torvalds  *
71da177e4SLinus Torvalds  * This program is free software; you can redistribute it and/or modify
81da177e4SLinus Torvalds  * it under the terms of the GNU General Public License as published by
91da177e4SLinus Torvalds  * the Free Software Foundation; either version 2 of the License, or
101da177e4SLinus Torvalds  * (at your option) any later version.
111da177e4SLinus Torvalds  *
121da177e4SLinus Torvalds  * This program is distributed in the hope that it will be useful,
131da177e4SLinus Torvalds  * but WITHOUT ANY WARRANTY; without even the implied warranty of
141da177e4SLinus Torvalds  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
151da177e4SLinus Torvalds  * GNU General Public License for more details.
161da177e4SLinus Torvalds  *
171da177e4SLinus Torvalds  * You should have received a copy of the GNU General Public License
181da177e4SLinus Torvalds  * along with this program; if not, write to the Free Software
191da177e4SLinus Torvalds  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
201da177e4SLinus Torvalds  */
211da177e4SLinus Torvalds 
221da177e4SLinus Torvalds #include <linux/spinlock.h>
231da177e4SLinus Torvalds #include <linux/list.h>
244e57b681STim Schmielau #include <linux/sched.h>	/* schedule_timeout() */
251da177e4SLinus Torvalds #include <linux/delay.h>
261da177e4SLinus Torvalds 
271da177e4SLinus Torvalds #include "w1_family.h"
28a9fb1c7bSAdrian Bunk #include "w1.h"
291da177e4SLinus Torvalds 
301da177e4SLinus Torvalds DEFINE_SPINLOCK(w1_flock);
311da177e4SLinus Torvalds static LIST_HEAD(w1_families);
321da177e4SLinus Torvalds 
331da177e4SLinus Torvalds int w1_register_family(struct w1_family *newf)
341da177e4SLinus Torvalds {
351da177e4SLinus Torvalds 	struct list_head *ent, *n;
361da177e4SLinus Torvalds 	struct w1_family *f;
371da177e4SLinus Torvalds 	int ret = 0;
381da177e4SLinus Torvalds 
391da177e4SLinus Torvalds 	spin_lock(&w1_flock);
401da177e4SLinus Torvalds 	list_for_each_safe(ent, n, &w1_families) {
411da177e4SLinus Torvalds 		f = list_entry(ent, struct w1_family, family_entry);
421da177e4SLinus Torvalds 
431da177e4SLinus Torvalds 		if (f->fid == newf->fid) {
441da177e4SLinus Torvalds 			ret = -EEXIST;
451da177e4SLinus Torvalds 			break;
461da177e4SLinus Torvalds 		}
471da177e4SLinus Torvalds 	}
481da177e4SLinus Torvalds 
491da177e4SLinus Torvalds 	if (!ret) {
501da177e4SLinus Torvalds 		atomic_set(&newf->refcnt, 0);
511da177e4SLinus Torvalds 		list_add_tail(&newf->family_entry, &w1_families);
521da177e4SLinus Torvalds 	}
531da177e4SLinus Torvalds 	spin_unlock(&w1_flock);
541da177e4SLinus Torvalds 
55c30c9b15SDavid Fries 	/* check default devices against the new set of drivers */
56c30c9b15SDavid Fries 	w1_reconnect_slaves(newf, 1);
576adf87bdSEvgeniy Polyakov 
581da177e4SLinus Torvalds 	return ret;
591da177e4SLinus Torvalds }
601da177e4SLinus Torvalds 
611da177e4SLinus Torvalds void w1_unregister_family(struct w1_family *fent)
621da177e4SLinus Torvalds {
631da177e4SLinus Torvalds 	struct list_head *ent, *n;
641da177e4SLinus Torvalds 	struct w1_family *f;
651da177e4SLinus Torvalds 
661da177e4SLinus Torvalds 	spin_lock(&w1_flock);
671da177e4SLinus Torvalds 	list_for_each_safe(ent, n, &w1_families) {
681da177e4SLinus Torvalds 		f = list_entry(ent, struct w1_family, family_entry);
691da177e4SLinus Torvalds 
701da177e4SLinus Torvalds 		if (f->fid == fent->fid) {
711da177e4SLinus Torvalds 			list_del(&fent->family_entry);
721da177e4SLinus Torvalds 			break;
731da177e4SLinus Torvalds 		}
741da177e4SLinus Torvalds 	}
751da177e4SLinus Torvalds 	spin_unlock(&w1_flock);
761da177e4SLinus Torvalds 
77c30c9b15SDavid Fries 	/* deatch devices using this family code */
78c30c9b15SDavid Fries 	w1_reconnect_slaves(fent, 0);
79c30c9b15SDavid Fries 
801da177e4SLinus Torvalds 	while (atomic_read(&fent->refcnt)) {
811da177e4SLinus Torvalds 		printk(KERN_INFO "Waiting for family %u to become free: refcnt=%d.\n",
821da177e4SLinus Torvalds 				fent->fid, atomic_read(&fent->refcnt));
831da177e4SLinus Torvalds 
841da177e4SLinus Torvalds 		if (msleep_interruptible(1000))
851da177e4SLinus Torvalds 			flush_signals(current);
861da177e4SLinus Torvalds 	}
871da177e4SLinus Torvalds }
881da177e4SLinus Torvalds 
891da177e4SLinus Torvalds /*
901da177e4SLinus Torvalds  * Should be called under w1_flock held.
911da177e4SLinus Torvalds  */
921da177e4SLinus Torvalds struct w1_family * w1_family_registered(u8 fid)
931da177e4SLinus Torvalds {
941da177e4SLinus Torvalds 	struct list_head *ent, *n;
951da177e4SLinus Torvalds 	struct w1_family *f = NULL;
961da177e4SLinus Torvalds 	int ret = 0;
971da177e4SLinus Torvalds 
981da177e4SLinus Torvalds 	list_for_each_safe(ent, n, &w1_families) {
991da177e4SLinus Torvalds 		f = list_entry(ent, struct w1_family, family_entry);
1001da177e4SLinus Torvalds 
1011da177e4SLinus Torvalds 		if (f->fid == fid) {
1021da177e4SLinus Torvalds 			ret = 1;
1031da177e4SLinus Torvalds 			break;
1041da177e4SLinus Torvalds 		}
1051da177e4SLinus Torvalds 	}
1061da177e4SLinus Torvalds 
1071da177e4SLinus Torvalds 	return (ret) ? f : NULL;
1081da177e4SLinus Torvalds }
1091da177e4SLinus Torvalds 
11070d484bfSEvgeniy Polyakov static void __w1_family_put(struct w1_family *f)
11170d484bfSEvgeniy Polyakov {
112*fe3cb823SDavid Fries 	atomic_dec(&f->refcnt);
11370d484bfSEvgeniy Polyakov }
11470d484bfSEvgeniy Polyakov 
1151da177e4SLinus Torvalds void w1_family_put(struct w1_family *f)
1161da177e4SLinus Torvalds {
1171da177e4SLinus Torvalds 	spin_lock(&w1_flock);
1181da177e4SLinus Torvalds 	__w1_family_put(f);
1191da177e4SLinus Torvalds 	spin_unlock(&w1_flock);
1201da177e4SLinus Torvalds }
1211da177e4SLinus Torvalds 
12270d484bfSEvgeniy Polyakov #if 0
1231da177e4SLinus Torvalds void w1_family_get(struct w1_family *f)
1241da177e4SLinus Torvalds {
1251da177e4SLinus Torvalds 	spin_lock(&w1_flock);
1261da177e4SLinus Torvalds 	__w1_family_get(f);
1271da177e4SLinus Torvalds 	spin_unlock(&w1_flock);
1281da177e4SLinus Torvalds }
12970d484bfSEvgeniy Polyakov #endif  /*  0  */
1301da177e4SLinus Torvalds 
1311da177e4SLinus Torvalds void __w1_family_get(struct w1_family *f)
1321da177e4SLinus Torvalds {
1331da177e4SLinus Torvalds 	smp_mb__before_atomic_inc();
1341da177e4SLinus Torvalds 	atomic_inc(&f->refcnt);
1351da177e4SLinus Torvalds 	smp_mb__after_atomic_inc();
1361da177e4SLinus Torvalds }
1371da177e4SLinus Torvalds 
1381da177e4SLinus Torvalds EXPORT_SYMBOL(w1_unregister_family);
1391da177e4SLinus Torvalds EXPORT_SYMBOL(w1_register_family);
140