Linux Kernel  3.7.1
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w1_family.c
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1 /*
2  * w1_family.c
3  *
4  * Copyright (c) 2004 Evgeniy Polyakov <[email protected]>
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))
87  }
88 }
89 
90 /*
91  * Should be called under w1_flock held.
92  */
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 
133 {
135  atomic_inc(&f->refcnt);
137 }
138