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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Evgeniy Polyakov77859252005-05-20 22:33:25 +04002 * w1_int.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
4 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Evgeniy Polyakov77859252005-05-20 22:33:25 +04005 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 *
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>
Evgeniy Polyakov674a396c2006-02-20 11:15:37 +030025#include <linux/kthread.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090026#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
28#include "w1.h"
29#include "w1_log.h"
30#include "w1_netlink.h"
Evgeniy Polyakov70d484b2006-04-24 10:46:14 +040031#include "w1_int.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
David Fries9141f572008-10-15 22:04:45 -070033static int w1_search_count = -1; /* Default is continual scan */
34module_param_named(search_count, w1_search_count, int, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
David Fries6a158c02008-10-15 22:04:42 -070036static int w1_enable_pullup = 1;
37module_param_named(enable_pullup, w1_enable_pullup, int, 0);
38
Evgeniy Polyakov77859252005-05-20 22:33:25 +040039static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
40 struct device_driver *driver,
41 struct device *device)
Linus Torvalds1da177e2005-04-16 15:20:36 -070042{
43 struct w1_master *dev;
44 int err;
45
46 /*
47 * We are in process context(kernel thread), so can sleep.
48 */
Yoann Padioleaudd00cc42007-07-19 01:49:03 -070049 dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070057
58 dev->bus_master = (struct w1_bus_master *)(dev + 1);
59
Evgeniy Polyakov77859252005-05-20 22:33:25 +040060 dev->owner = THIS_MODULE;
61 dev->max_slave_count = slave_count;
62 dev->slave_count = 0;
63 dev->attempts = 0;
Evgeniy Polyakov77859252005-05-20 22:33:25 +040064 dev->initialized = 0;
65 dev->id = id;
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 dev->slave_ttl = slave_ttl;
David Fries9141f572008-10-15 22:04:45 -070067 dev->search_count = w1_search_count;
David Fries6a158c02008-10-15 22:04:42 -070068 dev->enable_pullup = w1_enable_pullup;
Linus Torvalds1da177e2005-04-16 15:20:36 -070069
David Fries01e14d62008-10-15 22:04:40 -070070 /* 1 for w1_process to decrement
71 * 1 for __w1_remove_master_device to decrement
72 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 atomic_set(&dev->refcnt, 2);
74
75 INIT_LIST_HEAD(&dev->slist);
Evgeniy Polyakovabd52a12006-04-03 12:04:27 +040076 mutex_init(&dev->mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 memcpy(&dev->dev, device, sizeof(struct device));
Kay Sievers40f91de2009-01-06 10:44:34 -080079 dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
81
82 dev->driver = driver;
83
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 dev->seq = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070085
86 err = device_register(&dev->dev);
87 if (err) {
88 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 memset(dev, 0, sizeof(struct w1_master));
90 kfree(dev);
91 dev = NULL;
92 }
93
94 return dev;
95}
96
Evgeniy Polyakov2c5bfda2006-04-04 20:35:22 +040097static void w1_free_dev(struct w1_master *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -070098{
99 device_unregister(&dev->dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100}
101
102int w1_add_master_device(struct w1_bus_master *master)
103{
David Friesaf00a2d2008-10-15 22:04:53 -0700104 struct w1_master *dev, *entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 int retval = 0;
106 struct w1_netlink_msg msg;
David Friesaf00a2d2008-10-15 22:04:53 -0700107 int id, found;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108
Evgeniy Polyakovbe57ce22005-06-04 01:21:46 +0400109 /* validate minimum functionality */
110 if (!(master->touch_bit && master->reset_bus) &&
Evgeniy Polyakovc1f858b2007-05-08 00:31:20 -0700111 !(master->write_bit && master->read_bit) &&
112 !(master->write_byte && master->read_byte && master->reset_bus)) {
Evgeniy Polyakov6adf87b2005-06-04 01:29:25 +0400113 printk(KERN_ERR "w1_add_master_device: invalid function set\n");
114 return(-EINVAL);
Evgeniy Polyakovbe57ce22005-06-04 01:21:46 +0400115 }
David Fries6a158c02008-10-15 22:04:42 -0700116 /* 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 }
Evgeniy Polyakovbe57ce22005-06-04 01:21:46 +0400128
David Friesaf00a2d2008-10-15 22:04:53 -0700129 /* Lock until the device is added (or not) to w1_masters. */
130 mutex_lock(&w1_mlock);
131 /* Search for the first available id (starting at 1). */
132 id = 0;
133 do {
134 ++id;
135 found = 0;
136 list_for_each_entry(entry, &w1_masters, w1_master_entry) {
137 if (entry->id == id) {
138 found = 1;
139 break;
140 }
141 }
142 } while (found);
143
144 dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
145 &w1_master_driver, &w1_master_device);
146 if (!dev) {
147 mutex_unlock(&w1_mlock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 return -ENOMEM;
David Friesaf00a2d2008-10-15 22:04:53 -0700149 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150
David Fries01e14d62008-10-15 22:04:40 -0700151 retval = w1_create_master_attributes(dev);
David Friesaf00a2d2008-10-15 22:04:53 -0700152 if (retval) {
153 mutex_unlock(&w1_mlock);
David Fries01e14d62008-10-15 22:04:40 -0700154 goto err_out_free_dev;
David Friesaf00a2d2008-10-15 22:04:53 -0700155 }
David Fries01e14d62008-10-15 22:04:40 -0700156
157 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
158
159 dev->initialized = 1;
160
Evgeniy Polyakov674a396c2006-02-20 11:15:37 +0300161 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
162 if (IS_ERR(dev->thread)) {
163 retval = PTR_ERR(dev->thread);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 dev_err(&dev->dev,
165 "Failed to create new kernel thread. err=%d\n",
Evgeniy Polyakov674a396c2006-02-20 11:15:37 +0300166 retval);
David Friesaf00a2d2008-10-15 22:04:53 -0700167 mutex_unlock(&w1_mlock);
David Fries01e14d62008-10-15 22:04:40 -0700168 goto err_out_rm_attr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 }
170
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 list_add(&dev->w1_master_entry, &w1_masters);
Evgeniy Polyakovabd52a12006-04-03 12:04:27 +0400172 mutex_unlock(&w1_mlock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173
Evgeniy Polyakov12003372006-03-23 19:11:58 +0300174 memset(&msg, 0, sizeof(msg));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 msg.id.mst.id = dev->id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 msg.type = W1_MASTER_ADD;
177 w1_netlink_send(dev, &msg);
178
179 return 0;
180
David Fries01e14d62008-10-15 22:04:40 -0700181#if 0 /* Thread cleanup code, not required currently. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182err_out_kill_thread:
Evgeniy Polyakov674a396c2006-02-20 11:15:37 +0300183 kthread_stop(dev->thread);
David Fries01e14d62008-10-15 22:04:40 -0700184#endif
185err_out_rm_attr:
186 w1_destroy_master_attributes(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187err_out_free_dev:
188 w1_free_dev(dev);
189
190 return retval;
191}
192
193void __w1_remove_master_device(struct w1_master *dev)
194{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 struct w1_netlink_msg msg;
David Friesc30c9b12008-10-15 22:04:38 -0700196 struct w1_slave *sl, *sln;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197
Evgeniy Polyakov674a396c2006-02-20 11:15:37 +0300198 kthread_stop(dev->thread);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199
David Friesc30c9b12008-10-15 22:04:38 -0700200 mutex_lock(&w1_mlock);
201 list_del(&dev->w1_master_entry);
202 mutex_unlock(&w1_mlock);
203
204 mutex_lock(&dev->mutex);
205 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry)
206 w1_slave_detach(sl);
207 w1_destroy_master_attributes(dev);
208 mutex_unlock(&dev->mutex);
209 atomic_dec(&dev->refcnt);
210
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 while (atomic_read(&dev->refcnt)) {
Evgeniy Polyakov674a396c2006-02-20 11:15:37 +0300212 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 dev->name, atomic_read(&dev->refcnt));
214
215 if (msleep_interruptible(1000))
216 flush_signals(current);
217 }
218
Evgeniy Polyakov12003372006-03-23 19:11:58 +0300219 memset(&msg, 0, sizeof(msg));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 msg.id.mst.id = dev->id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 msg.type = W1_MASTER_REMOVE;
222 w1_netlink_send(dev, &msg);
223
224 w1_free_dev(dev);
225}
226
227void w1_remove_master_device(struct w1_bus_master *bm)
228{
Evgeniy Polyakov59d94452007-08-22 14:01:51 -0700229 struct w1_master *dev, *found = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
Evgeniy Polyakov77859252005-05-20 22:33:25 +0400231 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 if (!dev->initialized)
233 continue;
234
Evgeniy Polyakov59d94452007-08-22 14:01:51 -0700235 if (dev->bus_master->data == bm->data) {
236 found = dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 break;
Evgeniy Polyakov59d94452007-08-22 14:01:51 -0700238 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 }
240
Evgeniy Polyakov59d94452007-08-22 14:01:51 -0700241 if (!found) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 printk(KERN_ERR "Device doesn't exist.\n");
243 return;
244 }
245
Evgeniy Polyakov59d94452007-08-22 14:01:51 -0700246 __w1_remove_master_device(found);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247}
248
249EXPORT_SYMBOL(w1_add_master_device);
250EXPORT_SYMBOL(w1_remove_master_device);