drivers/w1: Add export.h for EXPORT_SYMBOL/THIS_MODULE
[linux-2.6.git] / drivers / w1 / w1_int.c
1 /*
2  *      w1_int.c
3  *
4  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
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 #include <linux/slab.h>
27 #include <linux/export.h>
28
29 #include "w1.h"
30 #include "w1_log.h"
31 #include "w1_netlink.h"
32 #include "w1_int.h"
33
34 static int w1_search_count = -1; /* Default is continual scan */
35 module_param_named(search_count, w1_search_count, int, 0);
36
37 static int w1_enable_pullup = 1;
38 module_param_named(enable_pullup, w1_enable_pullup, int, 0);
39
40 static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
41                                        struct device_driver *driver,
42                                        struct device *device)
43 {
44         struct w1_master *dev;
45         int err;
46
47         /*
48          * We are in process context(kernel thread), so can sleep.
49          */
50         dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
51         if (!dev) {
52                 printk(KERN_ERR
53                         "Failed to allocate %zd bytes for new w1 device.\n",
54                         sizeof(struct w1_master));
55                 return NULL;
56         }
57
58
59         dev->bus_master = (struct w1_bus_master *)(dev + 1);
60
61         dev->owner              = THIS_MODULE;
62         dev->max_slave_count    = slave_count;
63         dev->slave_count        = 0;
64         dev->attempts           = 0;
65         dev->initialized        = 0;
66         dev->id                 = id;
67         dev->slave_ttl          = slave_ttl;
68         dev->search_count       = w1_search_count;
69         dev->enable_pullup      = w1_enable_pullup;
70
71         /* 1 for w1_process to decrement
72          * 1 for __w1_remove_master_device to decrement
73          */
74         atomic_set(&dev->refcnt, 2);
75
76         INIT_LIST_HEAD(&dev->slist);
77         mutex_init(&dev->mutex);
78
79         memcpy(&dev->dev, device, sizeof(struct device));
80         dev_set_name(&dev->dev, "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, *entry;
106         int retval = 0;
107         struct w1_netlink_msg msg;
108         int id, found;
109
110         /* validate minimum functionality */
111         if (!(master->touch_bit && master->reset_bus) &&
112             !(master->write_bit && master->read_bit) &&
113             !(master->write_byte && master->read_byte && master->reset_bus)) {
114                 printk(KERN_ERR "w1_add_master_device: invalid function set\n");
115                 return(-EINVAL);
116         }
117         /* While it would be electrically possible to make a device that
118          * generated a strong pullup in bit bang mode, only hardare that
119          * controls 1-wire time frames are even expected to support a strong
120          * pullup.  w1_io.c would need to support calling set_pullup before
121          * the last write_bit operation of a w1_write_8 which it currently
122          * doesn't.
123          */
124         if (!master->write_byte && !master->touch_bit && master->set_pullup) {
125                 printk(KERN_ERR "w1_add_master_device: set_pullup requires "
126                         "write_byte or touch_bit, disabling\n");
127                 master->set_pullup = NULL;
128         }
129
130         /* Lock until the device is added (or not) to w1_masters. */
131         mutex_lock(&w1_mlock);
132         /* Search for the first available id (starting at 1). */
133         id = 0;
134         do {
135                 ++id;
136                 found = 0;
137                 list_for_each_entry(entry, &w1_masters, w1_master_entry) {
138                         if (entry->id == id) {
139                                 found = 1;
140                                 break;
141                         }
142                 }
143         } while (found);
144
145         dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
146                 &w1_master_driver, &w1_master_device);
147         if (!dev) {
148                 mutex_unlock(&w1_mlock);
149                 return -ENOMEM;
150         }
151
152         retval =  w1_create_master_attributes(dev);
153         if (retval) {
154                 mutex_unlock(&w1_mlock);
155                 goto err_out_free_dev;
156         }
157
158         memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
159
160         dev->initialized = 1;
161
162         dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
163         if (IS_ERR(dev->thread)) {
164                 retval = PTR_ERR(dev->thread);
165                 dev_err(&dev->dev,
166                          "Failed to create new kernel thread. err=%d\n",
167                          retval);
168                 mutex_unlock(&w1_mlock);
169                 goto err_out_rm_attr;
170         }
171
172         list_add(&dev->w1_master_entry, &w1_masters);
173         mutex_unlock(&w1_mlock);
174
175         memset(&msg, 0, sizeof(msg));
176         msg.id.mst.id = dev->id;
177         msg.type = W1_MASTER_ADD;
178         w1_netlink_send(dev, &msg);
179
180         return 0;
181
182 #if 0 /* Thread cleanup code, not required currently. */
183 err_out_kill_thread:
184         kthread_stop(dev->thread);
185 #endif
186 err_out_rm_attr:
187         w1_destroy_master_attributes(dev);
188 err_out_free_dev:
189         w1_free_dev(dev);
190
191         return retval;
192 }
193
194 void __w1_remove_master_device(struct w1_master *dev)
195 {
196         struct w1_netlink_msg msg;
197         struct w1_slave *sl, *sln;
198
199         kthread_stop(dev->thread);
200
201         mutex_lock(&w1_mlock);
202         list_del(&dev->w1_master_entry);
203         mutex_unlock(&w1_mlock);
204
205         mutex_lock(&dev->mutex);
206         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry)
207                 w1_slave_detach(sl);
208         w1_destroy_master_attributes(dev);
209         mutex_unlock(&dev->mutex);
210         atomic_dec(&dev->refcnt);
211
212         while (atomic_read(&dev->refcnt)) {
213                 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
214                                 dev->name, atomic_read(&dev->refcnt));
215
216                 if (msleep_interruptible(1000))
217                         flush_signals(current);
218         }
219
220         memset(&msg, 0, sizeof(msg));
221         msg.id.mst.id = dev->id;
222         msg.type = W1_MASTER_REMOVE;
223         w1_netlink_send(dev, &msg);
224
225         w1_free_dev(dev);
226 }
227
228 void w1_remove_master_device(struct w1_bus_master *bm)
229 {
230         struct w1_master *dev, *found = NULL;
231
232         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
233                 if (!dev->initialized)
234                         continue;
235
236                 if (dev->bus_master->data == bm->data) {
237                         found = dev;
238                         break;
239                 }
240         }
241
242         if (!found) {
243                 printk(KERN_ERR "Device doesn't exist.\n");
244                 return;
245         }
246
247         __w1_remove_master_device(found);
248 }
249
250 EXPORT_SYMBOL(w1_add_master_device);
251 EXPORT_SYMBOL(w1_remove_master_device);