[PATCH] w1: Adds a sysfs entry (w1_master_search) that allows you to disable/enable...
[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 = 23;
90         dev->seq = 1;
91         dev->nls = netlink_kernel_create(NETLINK_NFLOG, NULL);
92         if (!dev->nls) {
93                 printk(KERN_ERR "Failed to create new netlink socket(%u) for w1 master %s.\n",
94                         NETLINK_NFLOG, dev->dev.bus_id);
95         }
96
97         err = device_register(&dev->dev);
98         if (err) {
99                 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
100                 if (dev->nls && dev->nls->sk_socket)
101                         sock_release(dev->nls->sk_socket);
102                 memset(dev, 0, sizeof(struct w1_master));
103                 kfree(dev);
104                 dev = NULL;
105         }
106
107         return dev;
108 }
109
110 static void w1_free_dev(struct w1_master *dev)
111 {
112         device_unregister(&dev->dev);
113         if (dev->nls && dev->nls->sk_socket)
114                 sock_release(dev->nls->sk_socket);
115         memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
116         kfree(dev);
117 }
118
119 int w1_add_master_device(struct w1_bus_master *master)
120 {
121         struct w1_master *dev;
122         int retval = 0;
123         struct w1_netlink_msg msg;
124
125         /* validate minimum functionality */
126         if (!(master->touch_bit && master->reset_bus) &&
127             !(master->write_bit && master->read_bit))
128         {
129            printk(KERN_ERR "w1_add_master_device: invalid function set\n");
130            return(-EINVAL);
131         }
132
133         dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_driver, &w1_device);
134         if (!dev)
135                 return -ENOMEM;
136
137         dev->kpid = kernel_thread(&w1_process, dev, 0);
138         if (dev->kpid < 0) {
139                 dev_err(&dev->dev,
140                          "Failed to create new kernel thread. err=%d\n",
141                          dev->kpid);
142                 retval = dev->kpid;
143                 goto err_out_free_dev;
144         }
145
146         retval =  w1_create_master_attributes(dev);
147         if (retval)
148                 goto err_out_kill_thread;
149
150         memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
151
152         dev->initialized = 1;
153
154         spin_lock(&w1_mlock);
155         list_add(&dev->w1_master_entry, &w1_masters);
156         spin_unlock(&w1_mlock);
157
158         msg.id.mst.id = dev->id;
159         msg.id.mst.pid = dev->kpid;
160         msg.type = W1_MASTER_ADD;
161         w1_netlink_send(dev, &msg);
162
163         return 0;
164
165 err_out_kill_thread:
166         dev->need_exit = 1;
167         if (kill_proc(dev->kpid, SIGTERM, 1))
168                 dev_err(&dev->dev,
169                          "Failed to send signal to w1 kernel thread %d.\n",
170                          dev->kpid);
171         wait_for_completion(&dev->dev_exited);
172
173 err_out_free_dev:
174         w1_free_dev(dev);
175
176         return retval;
177 }
178
179 void __w1_remove_master_device(struct w1_master *dev)
180 {
181         int err;
182         struct w1_netlink_msg msg;
183
184         dev->need_exit = 1;
185         err = kill_proc(dev->kpid, SIGTERM, 1);
186         if (err)
187                 dev_err(&dev->dev,
188                          "%s: Failed to send signal to w1 kernel thread %d.\n",
189                          __func__, dev->kpid);
190
191         while (atomic_read(&dev->refcnt)) {
192                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
193                                 dev->name, atomic_read(&dev->refcnt));
194
195                 if (msleep_interruptible(1000))
196                         flush_signals(current);
197         }
198
199         msg.id.mst.id = dev->id;
200         msg.id.mst.pid = dev->kpid;
201         msg.type = W1_MASTER_REMOVE;
202         w1_netlink_send(dev, &msg);
203
204         w1_free_dev(dev);
205 }
206
207 void w1_remove_master_device(struct w1_bus_master *bm)
208 {
209         struct w1_master *dev = NULL;
210
211         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
212                 if (!dev->initialized)
213                         continue;
214
215                 if (dev->bus_master->data == bm->data)
216                         break;
217         }
218
219         if (!dev) {
220                 printk(KERN_ERR "Device doesn't exist.\n");
221                 return;
222         }
223
224         __w1_remove_master_device(dev);
225 }
226
227 EXPORT_SYMBOL(w1_add_master_device);
228 EXPORT_SYMBOL(w1_remove_master_device);