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