[PATCH] w1: cleanups.
[linux-2.6.git] / drivers / w1 / w1_int.c
1 /*
2  *      w1_int.c
3  *
4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
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/kernel.h>
23 #include <linux/list.h>
24 #include <linux/delay.h>
25
26 #include "w1.h"
27 #include "w1_log.h"
28 #include "w1_netlink.h"
29
30 static u32 w1_ids = 1;
31
32 extern struct device_driver w1_driver;
33 extern struct bus_type w1_bus_type;
34 extern struct device w1_device;
35 extern int w1_max_slave_count;
36 extern int w1_max_slave_ttl;
37 extern struct list_head w1_masters;
38 extern spinlock_t w1_mlock;
39
40 extern int w1_process(void *);
41
42 static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
43                                        struct device_driver *driver,
44                                        struct device *device)
45 {
46         struct w1_master *dev;
47         int err;
48
49         /*
50          * We are in process context(kernel thread), so can sleep.
51          */
52         dev = kmalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
53         if (!dev) {
54                 printk(KERN_ERR
55                         "Failed to allocate %zd bytes for new w1 device.\n",
56                         sizeof(struct w1_master));
57                 return NULL;
58         }
59
60         memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
61
62         dev->bus_master = (struct w1_bus_master *)(dev + 1);
63
64         dev->owner              = THIS_MODULE;
65         dev->max_slave_count    = slave_count;
66         dev->slave_count        = 0;
67         dev->attempts           = 0;
68         dev->kpid               = -1;
69         dev->initialized        = 0;
70         dev->id                 = id;
71         dev->slave_ttl          = slave_ttl;
72
73         atomic_set(&dev->refcnt, 2);
74
75         INIT_LIST_HEAD(&dev->slist);
76         init_MUTEX(&dev->mutex);
77
78         init_completion(&dev->dev_released);
79         init_completion(&dev->dev_exited);
80
81         memcpy(&dev->dev, device, sizeof(struct device));
82         snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
83                   "w1_bus_master%u", dev->id);
84         snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
85
86         dev->driver = driver;
87
88         dev->groups = 23;
89         dev->seq = 1;
90         dev->nls = netlink_kernel_create(NETLINK_NFLOG, NULL);
91         if (!dev->nls) {
92                 printk(KERN_ERR "Failed to create new netlink socket(%u) for w1 master %s.\n",
93                         NETLINK_NFLOG, dev->dev.bus_id);
94         }
95
96         err = device_register(&dev->dev);
97         if (err) {
98                 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
99                 if (dev->nls && dev->nls->sk_socket)
100                         sock_release(dev->nls->sk_socket);
101                 memset(dev, 0, sizeof(struct w1_master));
102                 kfree(dev);
103                 dev = NULL;
104         }
105
106         return dev;
107 }
108
109 static void w1_free_dev(struct w1_master *dev)
110 {
111         device_unregister(&dev->dev);
112         if (dev->nls && dev->nls->sk_socket)
113                 sock_release(dev->nls->sk_socket);
114         memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
115         kfree(dev);
116 }
117
118 int w1_add_master_device(struct w1_bus_master *master)
119 {
120         struct w1_master *dev;
121         int retval = 0;
122         struct w1_netlink_msg msg;
123
124         dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_driver, &w1_device);
125         if (!dev)
126                 return -ENOMEM;
127
128         dev->kpid = kernel_thread(&w1_process, dev, 0);
129         if (dev->kpid < 0) {
130                 dev_err(&dev->dev,
131                          "Failed to create new kernel thread. err=%d\n",
132                          dev->kpid);
133                 retval = dev->kpid;
134                 goto err_out_free_dev;
135         }
136
137         retval =  w1_create_master_attributes(dev);
138         if (retval)
139                 goto err_out_kill_thread;
140
141         memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
142
143         dev->initialized = 1;
144
145         spin_lock(&w1_mlock);
146         list_add(&dev->w1_master_entry, &w1_masters);
147         spin_unlock(&w1_mlock);
148
149         msg.id.mst.id = dev->id;
150         msg.id.mst.pid = dev->kpid;
151         msg.type = W1_MASTER_ADD;
152         w1_netlink_send(dev, &msg);
153
154         return 0;
155
156 err_out_kill_thread:
157         dev->need_exit = 1;
158         if (kill_proc(dev->kpid, SIGTERM, 1))
159                 dev_err(&dev->dev,
160                          "Failed to send signal to w1 kernel thread %d.\n",
161                          dev->kpid);
162         wait_for_completion(&dev->dev_exited);
163
164 err_out_free_dev:
165         w1_free_dev(dev);
166
167         return retval;
168 }
169
170 void __w1_remove_master_device(struct w1_master *dev)
171 {
172         int err;
173         struct w1_netlink_msg msg;
174
175         dev->need_exit = 1;
176         err = kill_proc(dev->kpid, SIGTERM, 1);
177         if (err)
178                 dev_err(&dev->dev,
179                          "%s: Failed to send signal to w1 kernel thread %d.\n",
180                          __func__, dev->kpid);
181
182         while (atomic_read(&dev->refcnt)) {
183                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
184                                 dev->name, atomic_read(&dev->refcnt));
185
186                 if (msleep_interruptible(1000))
187                         flush_signals(current);
188         }
189
190         msg.id.mst.id = dev->id;
191         msg.id.mst.pid = dev->kpid;
192         msg.type = W1_MASTER_REMOVE;
193         w1_netlink_send(dev, &msg);
194
195         w1_free_dev(dev);
196 }
197
198 void w1_remove_master_device(struct w1_bus_master *bm)
199 {
200         struct w1_master *dev = NULL;
201
202         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
203                 if (!dev->initialized)
204                         continue;
205
206                 if (dev->bus_master->data == bm->data)
207                         break;
208         }
209
210         if (!dev) {
211                 printk(KERN_ERR "Device doesn't exist.\n");
212                 return;
213         }
214
215         __w1_remove_master_device(dev);
216 }
217
218 EXPORT_SYMBOL(w1_add_master_device);
219 EXPORT_SYMBOL(w1_remove_master_device);