3fd6e6651fbebaa44f17de0e04ff539a9496ee71
[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 static int w1_search_count = -1; /* Default is continual scan */
34 module_param_named(search_count, w1_search_count, int, 0);
35
36 static int w1_enable_pullup = 1;
37 module_param_named(enable_pullup, w1_enable_pullup, int, 0);
38
39 static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
40                                        struct device_driver *driver,
41                                        struct device *device)
42 {
43         struct w1_master *dev;
44         int err;
45
46         /*
47          * We are in process context(kernel thread), so can sleep.
48          */
49         dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
50         if (!dev) {
51                 printk(KERN_ERR
52                         "Failed to allocate %zd bytes for new w1 device.\n",
53                         sizeof(struct w1_master));
54                 return NULL;
55         }
56
57
58         dev->bus_master = (struct w1_bus_master *)(dev + 1);
59
60         dev->owner              = THIS_MODULE;
61         dev->max_slave_count    = slave_count;
62         dev->slave_count        = 0;
63         dev->attempts           = 0;
64         dev->initialized        = 0;
65         dev->id                 = id;
66         dev->slave_ttl          = slave_ttl;
67         dev->search_count       = w1_search_count;
68         dev->enable_pullup      = w1_enable_pullup;
69
70         /* 1 for w1_process to decrement
71          * 1 for __w1_remove_master_device to decrement
72          */
73         atomic_set(&dev->refcnt, 2);
74
75         INIT_LIST_HEAD(&dev->slist);
76         mutex_init(&dev->mutex);
77
78         memcpy(&dev->dev, device, sizeof(struct device));
79         snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
80                   "w1_bus_master%u", dev->id);
81         snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
82
83         dev->driver = driver;
84
85         dev->seq = 1;
86
87         err = device_register(&dev->dev);
88         if (err) {
89                 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
90                 memset(dev, 0, sizeof(struct w1_master));
91                 kfree(dev);
92                 dev = NULL;
93         }
94
95         return dev;
96 }
97
98 static void w1_free_dev(struct w1_master *dev)
99 {
100         device_unregister(&dev->dev);
101 }
102
103 int w1_add_master_device(struct w1_bus_master *master)
104 {
105         struct w1_master *dev;
106         int retval = 0;
107         struct w1_netlink_msg msg;
108
109         /* validate minimum functionality */
110         if (!(master->touch_bit && master->reset_bus) &&
111             !(master->write_bit && master->read_bit) &&
112             !(master->write_byte && master->read_byte && master->reset_bus)) {
113                 printk(KERN_ERR "w1_add_master_device: invalid function set\n");
114                 return(-EINVAL);
115         }
116         /* While it would be electrically possible to make a device that
117          * generated a strong pullup in bit bang mode, only hardare that
118          * controls 1-wire time frames are even expected to support a strong
119          * pullup.  w1_io.c would need to support calling set_pullup before
120          * the last write_bit operation of a w1_write_8 which it currently
121          * doesn't.
122          */
123         if (!master->write_byte && !master->touch_bit && master->set_pullup) {
124                 printk(KERN_ERR "w1_add_master_device: set_pullup requires "
125                         "write_byte or touch_bit, disabling\n");
126                 master->set_pullup = NULL;
127         }
128
129         dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device);
130         if (!dev)
131                 return -ENOMEM;
132
133         retval =  w1_create_master_attributes(dev);
134         if (retval)
135                 goto err_out_free_dev;
136
137         memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
138
139         dev->initialized = 1;
140
141         dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
142         if (IS_ERR(dev->thread)) {
143                 retval = PTR_ERR(dev->thread);
144                 dev_err(&dev->dev,
145                          "Failed to create new kernel thread. err=%d\n",
146                          retval);
147                 goto err_out_rm_attr;
148         }
149
150         mutex_lock(&w1_mlock);
151         list_add(&dev->w1_master_entry, &w1_masters);
152         mutex_unlock(&w1_mlock);
153
154         memset(&msg, 0, sizeof(msg));
155         msg.id.mst.id = dev->id;
156         msg.type = W1_MASTER_ADD;
157         w1_netlink_send(dev, &msg);
158
159         return 0;
160
161 #if 0 /* Thread cleanup code, not required currently. */
162 err_out_kill_thread:
163         kthread_stop(dev->thread);
164 #endif
165 err_out_rm_attr:
166         w1_destroy_master_attributes(dev);
167 err_out_free_dev:
168         w1_free_dev(dev);
169
170         return retval;
171 }
172
173 void __w1_remove_master_device(struct w1_master *dev)
174 {
175         struct w1_netlink_msg msg;
176         struct w1_slave *sl, *sln;
177
178         kthread_stop(dev->thread);
179
180         mutex_lock(&w1_mlock);
181         list_del(&dev->w1_master_entry);
182         mutex_unlock(&w1_mlock);
183
184         mutex_lock(&dev->mutex);
185         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry)
186                 w1_slave_detach(sl);
187         w1_destroy_master_attributes(dev);
188         mutex_unlock(&dev->mutex);
189         atomic_dec(&dev->refcnt);
190
191         while (atomic_read(&dev->refcnt)) {
192                 dev_info(&dev->dev, "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         memset(&msg, 0, sizeof(msg));
200         msg.id.mst.id = dev->id;
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, *found = 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                         found = dev;
217                         break;
218                 }
219         }
220
221         if (!found) {
222                 printk(KERN_ERR "Device doesn't exist.\n");
223                 return;
224         }
225
226         __w1_remove_master_device(found);
227 }
228
229 EXPORT_SYMBOL(w1_add_master_device);
230 EXPORT_SYMBOL(w1_remove_master_device);