Revert "ARM: tegra: tegratab: dummy change"
[linux-2.6.git] / drivers / w1 / w1_family.c
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);