1 /* 2 * w1_family.c 3 * 4 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net> 5 * 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 */ 21 22 #include <linux/spinlock.h> 23 #include <linux/list.h> 24 #include <linux/sched.h> /* schedule_timeout() */ 25 #include <linux/delay.h> 26 #include <linux/export.h> 27 28 #include "w1_family.h" 29 #include "w1.h" 30 31 DEFINE_SPINLOCK(w1_flock); 32 static LIST_HEAD(w1_families); 33 34 int w1_register_family(struct w1_family *newf) 35 { 36 struct list_head *ent, *n; 37 struct w1_family *f; 38 int ret = 0; 39 40 spin_lock(&w1_flock); 41 list_for_each_safe(ent, n, &w1_families) { 42 f = list_entry(ent, struct w1_family, family_entry); 43 44 if (f->fid == newf->fid) { 45 ret = -EEXIST; 46 break; 47 } 48 } 49 50 if (!ret) { 51 atomic_set(&newf->refcnt, 0); 52 list_add_tail(&newf->family_entry, &w1_families); 53 } 54 spin_unlock(&w1_flock); 55 56 /* check default devices against the new set of drivers */ 57 w1_reconnect_slaves(newf, 1); 58 59 return ret; 60 } 61 62 void w1_unregister_family(struct w1_family *fent) 63 { 64 struct list_head *ent, *n; 65 struct w1_family *f; 66 67 spin_lock(&w1_flock); 68 list_for_each_safe(ent, n, &w1_families) { 69 f = list_entry(ent, struct w1_family, family_entry); 70 71 if (f->fid == fent->fid) { 72 list_del(&fent->family_entry); 73 break; 74 } 75 } 76 spin_unlock(&w1_flock); 77 78 /* deatch devices using this family code */ 79 w1_reconnect_slaves(fent, 0); 80 81 while (atomic_read(&fent->refcnt)) { 82 printk(KERN_INFO "Waiting for family %u to become free: refcnt=%d.\n", 83 fent->fid, atomic_read(&fent->refcnt)); 84 85 if (msleep_interruptible(1000)) 86 flush_signals(current); 87 } 88 } 89 90 /* 91 * Should be called under w1_flock held. 92 */ 93 struct w1_family * w1_family_registered(u8 fid) 94 { 95 struct list_head *ent, *n; 96 struct w1_family *f = NULL; 97 int ret = 0; 98 99 list_for_each_safe(ent, n, &w1_families) { 100 f = list_entry(ent, struct w1_family, family_entry); 101 102 if (f->fid == fid) { 103 ret = 1; 104 break; 105 } 106 } 107 108 return (ret) ? f : NULL; 109 } 110 111 static void __w1_family_put(struct w1_family *f) 112 { 113 atomic_dec(&f->refcnt); 114 } 115 116 void w1_family_put(struct w1_family *f) 117 { 118 spin_lock(&w1_flock); 119 __w1_family_put(f); 120 spin_unlock(&w1_flock); 121 } 122 123 #if 0 124 void w1_family_get(struct w1_family *f) 125 { 126 spin_lock(&w1_flock); 127 __w1_family_get(f); 128 spin_unlock(&w1_flock); 129 } 130 #endif /* 0 */ 131 132 void __w1_family_get(struct w1_family *f) 133 { 134 smp_mb__before_atomic_inc(); 135 atomic_inc(&f->refcnt); 136 smp_mb__after_atomic_inc(); 137 } 138 139 EXPORT_SYMBOL(w1_unregister_family); 140 EXPORT_SYMBOL(w1_register_family); 141