tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
31DEFINE_SPINLOCK(w1_flock);
32static LIST_HEAD(w1_families);
33
34int 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
62void 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 */
93struct 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
111static void __w1_family_put(struct w1_family *f)
112{
113 atomic_dec(&f->refcnt);
114}
115
116void 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
124void 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
132void __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
139EXPORT_SYMBOL(w1_unregister_family);
140EXPORT_SYMBOL(w1_register_family);