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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
4 */
5
6#include <linux/spinlock.h>
7#include <linux/list.h>
8#include <linux/sched/signal.h>
9#include <linux/delay.h>
10#include <linux/export.h>
11
12#include "w1_internal.h"
13
14DEFINE_SPINLOCK(w1_flock);
15static LIST_HEAD(w1_families);
16
17/**
18 * w1_register_family() - register a device family driver
19 * @newf: family to register
20 */
21int w1_register_family(struct w1_family *newf)
22{
23 struct list_head *ent, *n;
24 struct w1_family *f;
25 int ret = 0;
26
27 spin_lock(&w1_flock);
28 list_for_each_safe(ent, n, &w1_families) {
29 f = list_entry(ent, struct w1_family, family_entry);
30
31 if (f->fid == newf->fid) {
32 ret = -EEXIST;
33 break;
34 }
35 }
36
37 if (!ret) {
38 atomic_set(&newf->refcnt, 0);
39 list_add_tail(&newf->family_entry, &w1_families);
40 }
41 spin_unlock(&w1_flock);
42
43 /* check default devices against the new set of drivers */
44 w1_reconnect_slaves(newf, 1);
45
46 return ret;
47}
48EXPORT_SYMBOL(w1_register_family);
49
50/**
51 * w1_unregister_family() - unregister a device family driver
52 * @fent: family to unregister
53 */
54void w1_unregister_family(struct w1_family *fent)
55{
56 struct list_head *ent, *n;
57 struct w1_family *f;
58
59 spin_lock(&w1_flock);
60 list_for_each_safe(ent, n, &w1_families) {
61 f = list_entry(ent, struct w1_family, family_entry);
62
63 if (f->fid == fent->fid) {
64 list_del(&fent->family_entry);
65 break;
66 }
67 }
68 spin_unlock(&w1_flock);
69
70 /* deatch devices using this family code */
71 w1_reconnect_slaves(fent, 0);
72
73 while (atomic_read(&fent->refcnt)) {
74 pr_info("Waiting for family %u to become free: refcnt=%d.\n",
75 fent->fid, atomic_read(&fent->refcnt));
76
77 if (msleep_interruptible(1000))
78 flush_signals(current);
79 }
80}
81EXPORT_SYMBOL(w1_unregister_family);
82
83/*
84 * Should be called under w1_flock held.
85 */
86struct w1_family * w1_family_registered(u8 fid)
87{
88 struct list_head *ent, *n;
89 struct w1_family *f = NULL;
90 int ret = 0;
91
92 list_for_each_safe(ent, n, &w1_families) {
93 f = list_entry(ent, struct w1_family, family_entry);
94
95 if (f->fid == fid) {
96 ret = 1;
97 break;
98 }
99 }
100
101 return (ret) ? f : NULL;
102}
103
104static void __w1_family_put(struct w1_family *f)
105{
106 atomic_dec(&f->refcnt);
107}
108
109void w1_family_put(struct w1_family *f)
110{
111 spin_lock(&w1_flock);
112 __w1_family_put(f);
113 spin_unlock(&w1_flock);
114}
115
116#if 0
117void w1_family_get(struct w1_family *f)
118{
119 spin_lock(&w1_flock);
120 __w1_family_get(f);
121 spin_unlock(&w1_flock);
122}
123#endif /* 0 */
124
125void __w1_family_get(struct w1_family *f)
126{
127 smp_mb__before_atomic();
128 atomic_inc(&f->refcnt);
129 smp_mb__after_atomic();
130}
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
34/**
35 * w1_register_family() - register a device family driver
36 * @newf: family to register
37 */
38int w1_register_family(struct w1_family *newf)
39{
40 struct list_head *ent, *n;
41 struct w1_family *f;
42 int ret = 0;
43
44 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);
56 list_add_tail(&newf->family_entry, &w1_families);
57 }
58 spin_unlock(&w1_flock);
59
60 /* check default devices against the new set of drivers */
61 w1_reconnect_slaves(newf, 1);
62
63 return ret;
64}
65
66/**
67 * w1_unregister_family() - unregister a device family driver
68 * @fent: family to unregister
69 */
70void 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 }
84 spin_unlock(&w1_flock);
85
86 /* deatch devices using this family code */
87 w1_reconnect_slaves(fent, 0);
88
89 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
119static void __w1_family_put(struct w1_family *f)
120{
121 atomic_dec(&f->refcnt);
122}
123
124void 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
131#if 0
132void w1_family_get(struct w1_family *f)
133{
134 spin_lock(&w1_flock);
135 __w1_family_get(f);
136 spin_unlock(&w1_flock);
137}
138#endif /* 0 */
139
140void __w1_family_get(struct w1_family *f)
141{
142 smp_mb__before_atomic_inc();
143 atomic_inc(&f->refcnt);
144 smp_mb__after_atomic_inc();
145}
146
147EXPORT_SYMBOL(w1_unregister_family);
148EXPORT_SYMBOL(w1_register_family);