Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/w1-2.6
[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 #include <linux/kthread.h>
26
27 #include "w1.h"
28 #include "w1_log.h"
29 #include "w1_netlink.h"
30 #include "w1_int.h"
31
32 static u32 w1_ids = 1;
33
34 static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
35                                        struct device_driver *driver,
36                                        struct device *device)
37 {
38         struct w1_master *dev;
39         int err;
40
41         /*
42          * We are in process context(kernel thread), so can sleep.
43          */
44         dev = kmalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
45         if (!dev) {
46                 printk(KERN_ERR
47                         "Failed to allocate %zd bytes for new w1 device.\n",
48                         sizeof(struct w1_master));
49                 return NULL;
50         }
51
52         memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
53
54         dev->bus_master = (struct w1_bus_master *)(dev + 1);
55
56         dev->owner              = THIS_MODULE;
57         dev->max_slave_count    = slave_count;
58         dev->slave_count        = 0;
59         dev->attempts           = 0;
60         dev->initialized        = 0;
61         dev->id                 = id;
62         dev->slave_ttl          = slave_ttl;
63         dev->search_count       = -1; /* continual scan */
64
65         atomic_set(&dev->refcnt, 2);
66
67         INIT_LIST_HEAD(&dev->slist);
68         mutex_init(&dev->mutex);
69
70         memcpy(&dev->dev, device, sizeof(struct device));
71         snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
72                   "w1_bus_master%u", dev->id);
73         snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
74
75         dev->driver = driver;
76
77         dev->seq = 1;
78
79         err = device_register(&dev->dev);
80         if (err) {
81                 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
82                 memset(dev, 0, sizeof(struct w1_master));
83                 kfree(dev);
84                 dev = NULL;
85         }
86
87         return dev;
88 }
89
90 static void w1_free_dev(struct w1_master *dev)
91 {
92         device_unregister(&dev->dev);
93 }
94
95 int w1_add_master_device(struct w1_bus_master *master)
96 {
97         struct w1_master *dev;
98         int retval = 0;
99         struct w1_netlink_msg msg;
100
101         /* validate minimum functionality */
102         if (!(master->touch_bit && master->reset_bus) &&
103             !(master->write_bit && master->read_bit)) {
104                 printk(KERN_ERR "w1_add_master_device: invalid function set\n");
105                 return(-EINVAL);
106         }
107
108         dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device);
109         if (!dev)
110                 return -ENOMEM;
111
112         dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
113         if (IS_ERR(dev->thread)) {
114                 retval = PTR_ERR(dev->thread);
115                 dev_err(&dev->dev,
116                          "Failed to create new kernel thread. err=%d\n",
117                          retval);
118                 goto err_out_free_dev;
119         }
120
121         retval =  w1_create_master_attributes(dev);
122         if (retval)
123                 goto err_out_kill_thread;
124
125         memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
126
127         dev->initialized = 1;
128
129         mutex_lock(&w1_mlock);
130         list_add(&dev->w1_master_entry, &w1_masters);
131         mutex_unlock(&w1_mlock);
132
133         memset(&msg, 0, sizeof(msg));
134         msg.id.mst.id = dev->id;
135         msg.type = W1_MASTER_ADD;
136         w1_netlink_send(dev, &msg);
137
138         return 0;
139
140 err_out_kill_thread:
141         kthread_stop(dev->thread);
142 err_out_free_dev:
143         w1_free_dev(dev);
144
145         return retval;
146 }
147
148 void __w1_remove_master_device(struct w1_master *dev)
149 {
150         struct w1_netlink_msg msg;
151
152         set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
153         kthread_stop(dev->thread);
154
155         while (atomic_read(&dev->refcnt)) {
156                 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
157                                 dev->name, atomic_read(&dev->refcnt));
158
159                 if (msleep_interruptible(1000))
160                         flush_signals(current);
161         }
162
163         memset(&msg, 0, sizeof(msg));
164         msg.id.mst.id = dev->id;
165         msg.type = W1_MASTER_REMOVE;
166         w1_netlink_send(dev, &msg);
167
168         w1_free_dev(dev);
169 }
170
171 void w1_remove_master_device(struct w1_bus_master *bm)
172 {
173         struct w1_master *dev = NULL;
174
175         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
176                 if (!dev->initialized)
177                         continue;
178
179                 if (dev->bus_master->data == bm->data)
180                         break;
181         }
182
183         if (!dev) {
184                 printk(KERN_ERR "Device doesn't exist.\n");
185                 return;
186         }
187
188         __w1_remove_master_device(dev);
189 }
190
191 EXPORT_SYMBOL(w1_add_master_device);
192 EXPORT_SYMBOL(w1_remove_master_device);