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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Evgeniy Polyakov77859252005-05-20 22:33:25 +04002 * w1_family.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
Evgeniy Polyakova8018762011-08-25 15:59:06 -07004 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
Evgeniy Polyakov77859252005-05-20 22:33:25 +04005 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 *
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>
Tim Schmielau4e57b682005-10-30 15:03:48 -080024#include <linux/sched.h> /* schedule_timeout() */
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/delay.h>
Paul Gortmaker96239322011-07-10 13:21:52 -040026#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
28#include "w1_family.h"
Adrian Bunka9fb1c72005-12-13 14:04:33 -080029#include "w1.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
31DEFINE_SPINLOCK(w1_flock);
32static LIST_HEAD(w1_families);
33
David Friesb3be1772014-01-15 22:29:25 -060034/**
35 * w1_register_family() - register a device family driver
36 * @newf: family to register
37 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070038int w1_register_family(struct w1_family *newf)
39{
40 struct list_head *ent, *n;
41 struct w1_family *f;
42 int ret = 0;
43
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 spin_lock(&w1_flock);
45 list_for_each_safe(ent, n, &w1_families) {
46 f = list_entry(ent, struct w1_family, family_entry);
47
48 if (f->fid == newf->fid) {
49 ret = -EEXIST;
50 break;
51 }
52 }
53
54 if (!ret) {
55 atomic_set(&newf->refcnt, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 list_add_tail(&newf->family_entry, &w1_families);
57 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 spin_unlock(&w1_flock);
59
David Friesc30c9b12008-10-15 22:04:38 -070060 /* check default devices against the new set of drivers */
61 w1_reconnect_slaves(newf, 1);
Evgeniy Polyakov6adf87b2005-06-04 01:29:25 +040062
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 return ret;
64}
65
David Friesb3be1772014-01-15 22:29:25 -060066/**
67 * w1_unregister_family() - unregister a device family driver
68 * @fent: family to unregister
69 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070070void w1_unregister_family(struct w1_family *fent)
71{
72 struct list_head *ent, *n;
73 struct w1_family *f;
74
75 spin_lock(&w1_flock);
76 list_for_each_safe(ent, n, &w1_families) {
77 f = list_entry(ent, struct w1_family, family_entry);
78
79 if (f->fid == fent->fid) {
80 list_del(&fent->family_entry);
81 break;
82 }
83 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 spin_unlock(&w1_flock);
85
David Friesc30c9b12008-10-15 22:04:38 -070086 /* deatch devices using this family code */
87 w1_reconnect_slaves(fent, 0);
88
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 while (atomic_read(&fent->refcnt)) {
90 printk(KERN_INFO "Waiting for family %u to become free: refcnt=%d.\n",
91 fent->fid, atomic_read(&fent->refcnt));
92
93 if (msleep_interruptible(1000))
94 flush_signals(current);
95 }
96}
97
98/*
99 * Should be called under w1_flock held.
100 */
101struct w1_family * w1_family_registered(u8 fid)
102{
103 struct list_head *ent, *n;
104 struct w1_family *f = NULL;
105 int ret = 0;
106
107 list_for_each_safe(ent, n, &w1_families) {
108 f = list_entry(ent, struct w1_family, family_entry);
109
110 if (f->fid == fid) {
111 ret = 1;
112 break;
113 }
114 }
115
116 return (ret) ? f : NULL;
117}
118
Evgeniy Polyakov70d484b2006-04-24 10:46:14 +0400119static void __w1_family_put(struct w1_family *f)
120{
David Friesfe3cb822008-10-15 22:04:52 -0700121 atomic_dec(&f->refcnt);
Evgeniy Polyakov70d484b2006-04-24 10:46:14 +0400122}
123
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124void w1_family_put(struct w1_family *f)
125{
126 spin_lock(&w1_flock);
127 __w1_family_put(f);
128 spin_unlock(&w1_flock);
129}
130
Evgeniy Polyakov70d484b2006-04-24 10:46:14 +0400131#if 0
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132void w1_family_get(struct w1_family *f)
133{
134 spin_lock(&w1_flock);
135 __w1_family_get(f);
136 spin_unlock(&w1_flock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137}
Evgeniy Polyakov70d484b2006-04-24 10:46:14 +0400138#endif /* 0 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139
140void __w1_family_get(struct w1_family *f)
141{
Peter Zijlstra4e857c52014-03-17 18:06:10 +0100142 smp_mb__before_atomic();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 atomic_inc(&f->refcnt);
Peter Zijlstra4e857c52014-03-17 18:06:10 +0100144 smp_mb__after_atomic();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145}
146
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147EXPORT_SYMBOL(w1_unregister_family);
148EXPORT_SYMBOL(w1_register_family);