Revert "ARM: tegra: tegratab: dummy change"
[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 #include <linux/moduleparam.h>
29
30 #include "w1.h"
31 #include "w1_log.h"
32 #include "w1_netlink.h"
33 #include "w1_int.h"
34
35 static int w1_search_count = -1; /* Default is continual scan */
36 module_param_named(search_count, w1_search_count, int, 0);
37
38 static int w1_enable_pullup = 1;
39 module_param_named(enable_pullup, w1_enable_pullup, int, 0);
40
41 static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
42                                        struct device_driver *driver,
43                                        struct device *device)
44 {
45         struct w1_master *dev;
46         int err;
47
48         /*
49          * We are in process context(kernel thread), so can sleep.
50          */
51         dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
52         if (!dev) {
53                 printk(KERN_ERR
54                         "Failed to allocate %zd bytes for new w1 device.\n",
55                         sizeof(struct w1_master));
56                 return NULL;
57         }
58
59
60         dev->bus_master = (struct w1_bus_master *)(dev + 1);
61
62         dev->owner              = THIS_MODULE;
63         dev->max_slave_count    = slave_count;
64         dev->slave_count        = 0;
65         dev->attempts           = 0;
66         dev->initialized        = 0;
67         dev->id                 = id;
68         dev->slave_ttl          = slave_ttl;
69         dev->search_count       = w1_search_count;
70         dev->enable_pullup      = w1_enable_pullup;
71
72         /* 1 for w1_process to decrement
73          * 1 for __w1_remove_master_device to decrement
74          */
75         atomic_set(&dev->refcnt, 2);
76
77         INIT_LIST_HEAD(&dev->slist);
78         mutex_init(&dev->mutex);
79
80         memcpy(&dev->dev, device, sizeof(struct device));
81         dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
82         snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
83         dev->dev.init_name = dev->name;
84
85         dev->driver = driver;
86
87         dev->seq = 1;
88
89         err = device_register(&dev->dev);
90         if (err) {
91                 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
92                 memset(dev, 0, sizeof(struct w1_master));
93                 kfree(dev);
94                 dev = NULL;
95         }
96
97         return dev;
98 }
99
100 static void w1_free_dev(struct w1_master *dev)
101 {
102         device_unregister(&dev->dev);
103 }
104
105 int w1_add_master_device(struct w1_bus_master *master)
106 {
107         struct w1_master *dev, *entry;
108         int retval = 0;
109         struct w1_netlink_msg msg;
110         int id, found;
111
112         /* validate minimum functionality */
113         if (!(master->touch_bit && master->reset_bus) &&
114             !(master->write_bit && master->read_bit) &&
115             !(master->write_byte && master->read_byte && master->reset_bus)) {
116                 printk(KERN_ERR "w1_add_master_device: invalid function set\n");
117                 return(-EINVAL);
118         }
119         /* While it would be electrically possible to make a device that
120          * generated a strong pullup in bit bang mode, only hardare that
121          * controls 1-wire time frames are even expected to support a strong
122          * pullup.  w1_io.c would need to support calling set_pullup before
123          * the last write_bit operation of a w1_write_8 which it currently
124          * doesn't.
125          */
126         if (!master->write_byte && !master->touch_bit && master->set_pullup) {
127                 printk(KERN_ERR "w1_add_master_device: set_pullup requires "
128                         "write_byte or touch_bit, disabling\n");
129                 master->set_pullup = NULL;
130         }
131
132         /* Lock until the device is added (or not) to w1_masters. */
133         mutex_lock(&w1_mlock);
134         /* Search for the first available id (starting at 1). */
135         id = 0;
136         do {
137                 ++id;
138                 found = 0;
139                 list_for_each_entry(entry, &w1_masters, w1_master_entry) {
140                         if (entry->id == id) {
141                                 found = 1;
142                                 break;
143                         }
144                 }
145         } while (found);
146
147         dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
148                 &w1_master_driver, &w1_master_device);
149         if (!dev) {
150                 mutex_unlock(&w1_mlock);
151                 return -ENOMEM;
152         }
153
154         retval =  w1_create_master_attributes(dev);
155         if (retval) {
156                 mutex_unlock(&w1_mlock);
157                 goto err_out_free_dev;
158         }
159
160         memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
161
162         dev->initialized = 1;
163
164         dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
165         if (IS_ERR(dev->thread)) {
166                 retval = PTR_ERR(dev->thread);
167                 dev_err(&dev->dev,
168                          "Failed to create new kernel thread. err=%d\n",
169                          retval);
170                 mutex_unlock(&w1_mlock);
171                 goto err_out_rm_attr;
172         }
173
174         list_add(&dev->w1_master_entry, &w1_masters);
175         mutex_unlock(&w1_mlock);
176
177         memset(&msg, 0, sizeof(msg));
178         msg.id.mst.id = dev->id;
179         msg.type = W1_MASTER_ADD;
180         w1_netlink_send(dev, &msg);
181
182         return 0;
183
184 #if 0 /* Thread cleanup code, not required currently. */
185 err_out_kill_thread:
186         kthread_stop(dev->thread);
187 #endif
188 err_out_rm_attr:
189         w1_destroy_master_attributes(dev);
190 err_out_free_dev:
191         w1_free_dev(dev);
192
193         return retval;
194 }
195
196 void __w1_remove_master_device(struct w1_master *dev)
197 {
198         struct w1_netlink_msg msg;
199         struct w1_slave *sl, *sln;
200
201         kthread_stop(dev->thread);
202
203         mutex_lock(&w1_mlock);
204         list_del(&dev->w1_master_entry);
205         mutex_unlock(&w1_mlock);
206
207         mutex_lock(&dev->mutex);
208         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry)
209                 w1_slave_detach(sl);
210         w1_destroy_master_attributes(dev);
211         mutex_unlock(&dev->mutex);
212         atomic_dec(&dev->refcnt);
213
214         while (atomic_read(&dev->refcnt)) {
215                 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
216                                 dev->name, atomic_read(&dev->refcnt));
217
218                 if (msleep_interruptible(1000))
219                         flush_signals(current);
220         }
221
222         memset(&msg, 0, sizeof(msg));
223         msg.id.mst.id = dev->id;
224         msg.type = W1_MASTER_REMOVE;
225         w1_netlink_send(dev, &msg);
226
227         w1_free_dev(dev);
228 }
229
230 void w1_remove_master_device(struct w1_bus_master *bm)
231 {
232         struct w1_master *dev, *found = NULL;
233
234         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
235                 if (!dev->initialized)
236                         continue;
237
238                 if (dev->bus_master->data == bm->data) {
239                         found = dev;
240                         break;
241                 }
242         }
243
244         if (!found) {
245                 printk(KERN_ERR "Device doesn't exist.\n");
246                 return;
247         }
248
249         __w1_remove_master_device(found);
250 }
251
252 EXPORT_SYMBOL(w1_add_master_device);
253 EXPORT_SYMBOL(w1_remove_master_device);