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> 241da177e4SLinus Torvalds #include <linux/delay.h> 251da177e4SLinus Torvalds 261da177e4SLinus Torvalds #include "w1_family.h" 271da177e4SLinus Torvalds 281da177e4SLinus Torvalds DEFINE_SPINLOCK(w1_flock); 291da177e4SLinus Torvalds static LIST_HEAD(w1_families); 301da177e4SLinus Torvalds 311da177e4SLinus Torvalds static int w1_check_family(struct w1_family *f) 321da177e4SLinus Torvalds { 33ca775c62SEvgeniy Polyakov if (!f->fops->rname || !f->fops->rbin) 341da177e4SLinus Torvalds return -EINVAL; 351da177e4SLinus Torvalds 361da177e4SLinus Torvalds return 0; 371da177e4SLinus Torvalds } 381da177e4SLinus Torvalds 391da177e4SLinus Torvalds int w1_register_family(struct w1_family *newf) 401da177e4SLinus Torvalds { 411da177e4SLinus Torvalds struct list_head *ent, *n; 421da177e4SLinus Torvalds struct w1_family *f; 431da177e4SLinus Torvalds int ret = 0; 441da177e4SLinus Torvalds 451da177e4SLinus Torvalds if (w1_check_family(newf)) 461da177e4SLinus Torvalds return -EINVAL; 471da177e4SLinus Torvalds 481da177e4SLinus Torvalds spin_lock(&w1_flock); 491da177e4SLinus Torvalds list_for_each_safe(ent, n, &w1_families) { 501da177e4SLinus Torvalds f = list_entry(ent, struct w1_family, family_entry); 511da177e4SLinus Torvalds 521da177e4SLinus Torvalds if (f->fid == newf->fid) { 531da177e4SLinus Torvalds ret = -EEXIST; 541da177e4SLinus Torvalds break; 551da177e4SLinus Torvalds } 561da177e4SLinus Torvalds } 571da177e4SLinus Torvalds 581da177e4SLinus Torvalds if (!ret) { 591da177e4SLinus Torvalds atomic_set(&newf->refcnt, 0); 601da177e4SLinus Torvalds newf->need_exit = 0; 611da177e4SLinus Torvalds list_add_tail(&newf->family_entry, &w1_families); 621da177e4SLinus Torvalds } 631da177e4SLinus Torvalds spin_unlock(&w1_flock); 641da177e4SLinus Torvalds 656adf87bdSEvgeniy Polyakov w1_reconnect_slaves(newf); 666adf87bdSEvgeniy Polyakov 671da177e4SLinus Torvalds return ret; 681da177e4SLinus Torvalds } 691da177e4SLinus Torvalds 701da177e4SLinus Torvalds void w1_unregister_family(struct w1_family *fent) 711da177e4SLinus Torvalds { 721da177e4SLinus Torvalds struct list_head *ent, *n; 731da177e4SLinus Torvalds struct w1_family *f; 741da177e4SLinus Torvalds 751da177e4SLinus Torvalds spin_lock(&w1_flock); 761da177e4SLinus Torvalds list_for_each_safe(ent, n, &w1_families) { 771da177e4SLinus Torvalds f = list_entry(ent, struct w1_family, family_entry); 781da177e4SLinus Torvalds 791da177e4SLinus Torvalds if (f->fid == fent->fid) { 801da177e4SLinus Torvalds list_del(&fent->family_entry); 811da177e4SLinus Torvalds break; 821da177e4SLinus Torvalds } 831da177e4SLinus Torvalds } 841da177e4SLinus Torvalds 851da177e4SLinus Torvalds fent->need_exit = 1; 861da177e4SLinus Torvalds 871da177e4SLinus Torvalds spin_unlock(&w1_flock); 881da177e4SLinus Torvalds 891da177e4SLinus Torvalds while (atomic_read(&fent->refcnt)) { 901da177e4SLinus Torvalds printk(KERN_INFO "Waiting for family %u to become free: refcnt=%d.\n", 911da177e4SLinus Torvalds fent->fid, atomic_read(&fent->refcnt)); 921da177e4SLinus Torvalds 931da177e4SLinus Torvalds if (msleep_interruptible(1000)) 941da177e4SLinus Torvalds flush_signals(current); 951da177e4SLinus Torvalds } 961da177e4SLinus Torvalds } 971da177e4SLinus Torvalds 981da177e4SLinus Torvalds /* 991da177e4SLinus Torvalds * Should be called under w1_flock held. 1001da177e4SLinus Torvalds */ 1011da177e4SLinus Torvalds struct w1_family * w1_family_registered(u8 fid) 1021da177e4SLinus Torvalds { 1031da177e4SLinus Torvalds struct list_head *ent, *n; 1041da177e4SLinus Torvalds struct w1_family *f = NULL; 1051da177e4SLinus Torvalds int ret = 0; 1061da177e4SLinus Torvalds 1071da177e4SLinus Torvalds list_for_each_safe(ent, n, &w1_families) { 1081da177e4SLinus Torvalds f = list_entry(ent, struct w1_family, family_entry); 1091da177e4SLinus Torvalds 1101da177e4SLinus Torvalds if (f->fid == fid) { 1111da177e4SLinus Torvalds ret = 1; 1121da177e4SLinus Torvalds break; 1131da177e4SLinus Torvalds } 1141da177e4SLinus Torvalds } 1151da177e4SLinus Torvalds 1161da177e4SLinus Torvalds return (ret) ? f : NULL; 1171da177e4SLinus Torvalds } 1181da177e4SLinus Torvalds 1191da177e4SLinus Torvalds void w1_family_put(struct w1_family *f) 1201da177e4SLinus Torvalds { 1211da177e4SLinus Torvalds spin_lock(&w1_flock); 1221da177e4SLinus Torvalds __w1_family_put(f); 1231da177e4SLinus Torvalds spin_unlock(&w1_flock); 1241da177e4SLinus Torvalds } 1251da177e4SLinus Torvalds 1261da177e4SLinus Torvalds void __w1_family_put(struct w1_family *f) 1271da177e4SLinus Torvalds { 1281da177e4SLinus Torvalds if (atomic_dec_and_test(&f->refcnt)) 1291da177e4SLinus Torvalds f->need_exit = 1; 1301da177e4SLinus Torvalds } 1311da177e4SLinus Torvalds 1321da177e4SLinus Torvalds void w1_family_get(struct w1_family *f) 1331da177e4SLinus Torvalds { 1341da177e4SLinus Torvalds spin_lock(&w1_flock); 1351da177e4SLinus Torvalds __w1_family_get(f); 1361da177e4SLinus Torvalds spin_unlock(&w1_flock); 1371da177e4SLinus Torvalds 1381da177e4SLinus Torvalds } 1391da177e4SLinus Torvalds 1401da177e4SLinus Torvalds void __w1_family_get(struct w1_family *f) 1411da177e4SLinus Torvalds { 1421da177e4SLinus Torvalds smp_mb__before_atomic_inc(); 1431da177e4SLinus Torvalds atomic_inc(&f->refcnt); 1441da177e4SLinus Torvalds smp_mb__after_atomic_inc(); 1451da177e4SLinus Torvalds } 1461da177e4SLinus Torvalds 1471da177e4SLinus Torvalds EXPORT_SYMBOL(w1_family_get); 1481da177e4SLinus Torvalds EXPORT_SYMBOL(w1_family_put); 1491da177e4SLinus Torvalds EXPORT_SYMBOL(w1_family_registered); 1501da177e4SLinus Torvalds EXPORT_SYMBOL(w1_unregister_family); 1511da177e4SLinus Torvalds EXPORT_SYMBOL(w1_register_family); 152