bd877b24ce421ba4ef6a5357571cdc818fb00a50
[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 = kzalloc(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
53         dev->bus_master = (struct w1_bus_master *)(dev + 1);
54
55         dev->owner              = THIS_MODULE;
56         dev->max_slave_count    = slave_count;
57         dev->slave_count        = 0;
58         dev->attempts           = 0;
59         dev->initialized        = 0;
60         dev->id                 = id;
61         dev->slave_ttl          = slave_ttl;
62         dev->search_count       = -1; /* continual scan */
63
64         /* 1 for w1_process to decrement
65          * 1 for __w1_remove_master_device to decrement
66          */
67         atomic_set(&dev->refcnt, 2);
68
69         INIT_LIST_HEAD(&dev->slist);
70         mutex_init(&dev->mutex);
71
72         memcpy(&dev->dev, device, sizeof(struct device));
73         snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
74                   "w1_bus_master%u", dev->id);
75         snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
76
77         dev->driver = driver;
78
79         dev->seq = 1;
80
81         err = device_register(&dev->dev);
82         if (err) {
83                 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
84                 memset(dev, 0, sizeof(struct w1_master));
85                 kfree(dev);
86                 dev = NULL;
87         }
88
89         return dev;
90 }
91
92 static void w1_free_dev(struct w1_master *dev)
93 {
94         device_unregister(&dev->dev);
95 }
96
97 int w1_add_master_device(struct w1_bus_master *master)
98 {
99         struct w1_master *dev;
100         int retval = 0;
101         struct w1_netlink_msg msg;
102
103         /* validate minimum functionality */
104         if (!(master->touch_bit && master->reset_bus) &&
105             !(master->write_bit && master->read_bit) &&
106             !(master->write_byte && master->read_byte && master->reset_bus)) {
107                 printk(KERN_ERR "w1_add_master_device: invalid function set\n");
108                 return(-EINVAL);
109         }
110
111         dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device);
112         if (!dev)
113                 return -ENOMEM;
114
115         retval =  w1_create_master_attributes(dev);
116         if (retval)
117                 goto err_out_free_dev;
118
119         memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
120
121         dev->initialized = 1;
122
123         dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
124         if (IS_ERR(dev->thread)) {
125                 retval = PTR_ERR(dev->thread);
126                 dev_err(&dev->dev,
127                          "Failed to create new kernel thread. err=%d\n",
128                          retval);
129                 goto err_out_rm_attr;
130         }
131
132         mutex_lock(&w1_mlock);
133         list_add(&dev->w1_master_entry, &w1_masters);
134         mutex_unlock(&w1_mlock);
135
136         memset(&msg, 0, sizeof(msg));
137         msg.id.mst.id = dev->id;
138         msg.type = W1_MASTER_ADD;
139         w1_netlink_send(dev, &msg);
140
141         return 0;
142
143 #if 0 /* Thread cleanup code, not required currently. */
144 err_out_kill_thread:
145         kthread_stop(dev->thread);
146 #endif
147 err_out_rm_attr:
148         w1_destroy_master_attributes(dev);
149 err_out_free_dev:
150         w1_free_dev(dev);
151
152         return retval;
153 }
154
155 void __w1_remove_master_device(struct w1_master *dev)
156 {
157         struct w1_netlink_msg msg;
158         struct w1_slave *sl, *sln;
159
160         kthread_stop(dev->thread);
161
162         mutex_lock(&w1_mlock);
163         list_del(&dev->w1_master_entry);
164         mutex_unlock(&w1_mlock);
165
166         mutex_lock(&dev->mutex);
167         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry)
168                 w1_slave_detach(sl);
169         w1_destroy_master_attributes(dev);
170         mutex_unlock(&dev->mutex);
171         atomic_dec(&dev->refcnt);
172
173         while (atomic_read(&dev->refcnt)) {
174                 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
175                                 dev->name, atomic_read(&dev->refcnt));
176
177                 if (msleep_interruptible(1000))
178                         flush_signals(current);
179         }
180
181         memset(&msg, 0, sizeof(msg));
182         msg.id.mst.id = dev->id;
183         msg.type = W1_MASTER_REMOVE;
184         w1_netlink_send(dev, &msg);
185
186         w1_free_dev(dev);
187 }
188
189 void w1_remove_master_device(struct w1_bus_master *bm)
190 {
191         struct w1_master *dev, *found = NULL;
192
193         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
194                 if (!dev->initialized)
195                         continue;
196
197                 if (dev->bus_master->data == bm->data) {
198                         found = dev;
199                         break;
200                 }
201         }
202
203         if (!found) {
204                 printk(KERN_ERR "Device doesn't exist.\n");
205                 return;
206         }
207
208         __w1_remove_master_device(found);
209 }
210
211 EXPORT_SYMBOL(w1_add_master_device);
212 EXPORT_SYMBOL(w1_remove_master_device);