[PATCH] W1: w1_netlink: New init/fini netlink callbacks.
[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         dev->search_count       = -1; /* continual scan */
73
74         atomic_set(&dev->refcnt, 2);
75
76         INIT_LIST_HEAD(&dev->slist);
77         init_MUTEX(&dev->mutex);
78
79         init_completion(&dev->dev_released);
80         init_completion(&dev->dev_exited);
81
82         memcpy(&dev->dev, device, sizeof(struct device));
83         snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
84                   "w1_bus_master%u", dev->id);
85         snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
86
87         dev->driver = driver;
88
89         dev->groups = 1;
90         dev->seq = 1;
91         dev_init_netlink(dev);
92
93         err = device_register(&dev->dev);
94         if (err) {
95                 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
96
97                 dev_fini_netlink(dev);
98
99                 memset(dev, 0, sizeof(struct w1_master));
100                 kfree(dev);
101                 dev = NULL;
102         }
103
104         return dev;
105 }
106
107 void w1_free_dev(struct w1_master *dev)
108 {
109         device_unregister(&dev->dev);
110         dev_fini_netlink(dev);
111         memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
112         kfree(dev);
113 }
114
115 int w1_add_master_device(struct w1_bus_master *master)
116 {
117         struct w1_master *dev;
118         int retval = 0;
119         struct w1_netlink_msg msg;
120
121         /* validate minimum functionality */
122         if (!(master->touch_bit && master->reset_bus) &&
123             !(master->write_bit && master->read_bit)) {
124                 printk(KERN_ERR "w1_add_master_device: invalid function set\n");
125                 return(-EINVAL);
126         }
127
128         dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_driver, &w1_device);
129         if (!dev)
130                 return -ENOMEM;
131
132         dev->kpid = kernel_thread(&w1_process, dev, 0);
133         if (dev->kpid < 0) {
134                 dev_err(&dev->dev,
135                          "Failed to create new kernel thread. err=%d\n",
136                          dev->kpid);
137                 retval = dev->kpid;
138                 goto err_out_free_dev;
139         }
140
141         retval =  w1_create_master_attributes(dev);
142         if (retval)
143                 goto err_out_kill_thread;
144
145         memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
146
147         dev->initialized = 1;
148
149         spin_lock(&w1_mlock);
150         list_add(&dev->w1_master_entry, &w1_masters);
151         spin_unlock(&w1_mlock);
152
153         msg.id.mst.id = dev->id;
154         msg.id.mst.pid = dev->kpid;
155         msg.type = W1_MASTER_ADD;
156         w1_netlink_send(dev, &msg);
157
158         return 0;
159
160 err_out_kill_thread:
161         set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
162         if (kill_proc(dev->kpid, SIGTERM, 1))
163                 dev_err(&dev->dev,
164                          "Failed to send signal to w1 kernel thread %d.\n",
165                          dev->kpid);
166         wait_for_completion(&dev->dev_exited);
167
168 err_out_free_dev:
169         w1_free_dev(dev);
170
171         return retval;
172 }
173
174 void __w1_remove_master_device(struct w1_master *dev)
175 {
176         int err;
177         struct w1_netlink_msg msg;
178
179         set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
180         err = kill_proc(dev->kpid, SIGTERM, 1);
181         if (err)
182                 dev_err(&dev->dev,
183                          "%s: Failed to send signal to w1 kernel thread %d.\n",
184                          __func__, dev->kpid);
185
186         while (atomic_read(&dev->refcnt)) {
187                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
188                                 dev->name, atomic_read(&dev->refcnt));
189
190                 if (msleep_interruptible(1000))
191                         flush_signals(current);
192         }
193
194         msg.id.mst.id = dev->id;
195         msg.id.mst.pid = dev->kpid;
196         msg.type = W1_MASTER_REMOVE;
197         w1_netlink_send(dev, &msg);
198
199         w1_free_dev(dev);
200 }
201
202 void w1_remove_master_device(struct w1_bus_master *bm)
203 {
204         struct w1_master *dev = NULL;
205
206         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
207                 if (!dev->initialized)
208                         continue;
209
210                 if (dev->bus_master->data == bm->data)
211                         break;
212         }
213
214         if (!dev) {
215                 printk(KERN_ERR "Device doesn't exist.\n");
216                 return;
217         }
218
219         __w1_remove_master_device(dev);
220 }
221
222 EXPORT_SYMBOL(w1_add_master_device);
223 EXPORT_SYMBOL(w1_remove_master_device);
224
225 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_W1);