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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 *
Evgeniy Polyakova8018762011-08-25 15:59:06 -07004 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
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 Polyakov674a3962006-02-20 11:15:37 +030025#include <linux/kthread.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090026#include <linux/slab.h>
Paul Gortmaker96239322011-07-10 13:21:52 -040027#include <linux/export.h>
Paul Gortmaker4d184122011-09-15 23:09:52 -040028#include <linux/moduleparam.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
30#include "w1.h"
31#include "w1_log.h"
32#include "w1_netlink.h"
Evgeniy Polyakov70d484b2006-04-24 10:46:14 +040033#include "w1_int.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
David Fries9141f572008-10-15 22:04:45 -070035static int w1_search_count = -1; /* Default is continual scan */
36module_param_named(search_count, w1_search_count, int, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
David Fries6a158c02008-10-15 22:04:42 -070038static int w1_enable_pullup = 1;
39module_param_named(enable_pullup, w1_enable_pullup, int, 0);
40
Evgeniy Polyakov77859252005-05-20 22:33:25 +040041static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
42 struct device_driver *driver,
43 struct device *device)
Linus Torvalds1da177e2005-04-16 15:20:36 -070044{
45 struct w1_master *dev;
46 int err;
47
48 /*
49 * We are in process context(kernel thread), so can sleep.
50 */
Yoann Padioleaudd00cc42007-07-19 01:49:03 -070051 dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070059
60 dev->bus_master = (struct w1_bus_master *)(dev + 1);
61
Evgeniy Polyakov77859252005-05-20 22:33:25 +040062 dev->owner = THIS_MODULE;
63 dev->max_slave_count = slave_count;
64 dev->slave_count = 0;
65 dev->attempts = 0;
Evgeniy Polyakov77859252005-05-20 22:33:25 +040066 dev->initialized = 0;
67 dev->id = id;
Linus Torvalds1da177e2005-04-16 15:20:36 -070068 dev->slave_ttl = slave_ttl;
David Fries9141f572008-10-15 22:04:45 -070069 dev->search_count = w1_search_count;
David Fries6a158c02008-10-15 22:04:42 -070070 dev->enable_pullup = w1_enable_pullup;
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
David Fries01e14d62008-10-15 22:04:40 -070072 /* 1 for w1_process to decrement
73 * 1 for __w1_remove_master_device to decrement
74 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070075 atomic_set(&dev->refcnt, 2);
76
77 INIT_LIST_HEAD(&dev->slist);
Evgeniy Polyakovabd52a12006-04-03 12:04:27 +040078 mutex_init(&dev->mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 memcpy(&dev->dev, device, sizeof(struct device));
Kay Sievers40f91de2009-01-06 10:44:34 -080081 dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
Florian Faber68a436a2011-11-02 13:39:59 -070083 dev->dev.init_name = dev->name;
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
85 dev->driver = driver;
86
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 dev->seq = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070088
89 err = device_register(&dev->dev);
90 if (err) {
91 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 memset(dev, 0, sizeof(struct w1_master));
93 kfree(dev);
94 dev = NULL;
95 }
96
97 return dev;
98}
99
Evgeniy Polyakov2c5bfda2006-04-04 20:35:22 +0400100static void w1_free_dev(struct w1_master *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101{
102 device_unregister(&dev->dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103}
104
105int w1_add_master_device(struct w1_bus_master *master)
106{
David Friesaf00a2d2008-10-15 22:04:53 -0700107 struct w1_master *dev, *entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 int retval = 0;
109 struct w1_netlink_msg msg;
David Friesaf00a2d2008-10-15 22:04:53 -0700110 int id, found;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111
Evgeniy Polyakovbe57ce22005-06-04 01:21:46 +0400112 /* validate minimum functionality */
113 if (!(master->touch_bit && master->reset_bus) &&
Evgeniy Polyakovc1f858b2007-05-08 00:31:20 -0700114 !(master->write_bit && master->read_bit) &&
115 !(master->write_byte && master->read_byte && master->reset_bus)) {
Evgeniy Polyakov6adf87b2005-06-04 01:29:25 +0400116 printk(KERN_ERR "w1_add_master_device: invalid function set\n");
117 return(-EINVAL);
Evgeniy Polyakovbe57ce22005-06-04 01:21:46 +0400118 }
David Fries6a158c02008-10-15 22:04:42 -0700119 /* 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 }
Evgeniy Polyakovbe57ce22005-06-04 01:21:46 +0400131
David Friesaf00a2d2008-10-15 22:04:53 -0700132 /* 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 return -ENOMEM;
David Friesaf00a2d2008-10-15 22:04:53 -0700152 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
David Fries01e14d62008-10-15 22:04:40 -0700154 retval = w1_create_master_attributes(dev);
David Friesaf00a2d2008-10-15 22:04:53 -0700155 if (retval) {
156 mutex_unlock(&w1_mlock);
David Fries01e14d62008-10-15 22:04:40 -0700157 goto err_out_free_dev;
David Friesaf00a2d2008-10-15 22:04:53 -0700158 }
David Fries01e14d62008-10-15 22:04:40 -0700159
160 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
161
162 dev->initialized = 1;
163
Evgeniy Polyakov674a3962006-02-20 11:15:37 +0300164 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
165 if (IS_ERR(dev->thread)) {
166 retval = PTR_ERR(dev->thread);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 dev_err(&dev->dev,
168 "Failed to create new kernel thread. err=%d\n",
Evgeniy Polyakov674a3962006-02-20 11:15:37 +0300169 retval);
David Friesaf00a2d2008-10-15 22:04:53 -0700170 mutex_unlock(&w1_mlock);
David Fries01e14d62008-10-15 22:04:40 -0700171 goto err_out_rm_attr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 }
173
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 list_add(&dev->w1_master_entry, &w1_masters);
Evgeniy Polyakovabd52a12006-04-03 12:04:27 +0400175 mutex_unlock(&w1_mlock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176
Evgeniy Polyakov12003372006-03-23 19:11:58 +0300177 memset(&msg, 0, sizeof(msg));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 msg.id.mst.id = dev->id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 msg.type = W1_MASTER_ADD;
180 w1_netlink_send(dev, &msg);
181
182 return 0;
183
David Fries01e14d62008-10-15 22:04:40 -0700184#if 0 /* Thread cleanup code, not required currently. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185err_out_kill_thread:
Evgeniy Polyakov674a3962006-02-20 11:15:37 +0300186 kthread_stop(dev->thread);
David Fries01e14d62008-10-15 22:04:40 -0700187#endif
188err_out_rm_attr:
189 w1_destroy_master_attributes(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190err_out_free_dev:
191 w1_free_dev(dev);
192
193 return retval;
194}
195
196void __w1_remove_master_device(struct w1_master *dev)
197{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 struct w1_netlink_msg msg;
David Friesc30c9b12008-10-15 22:04:38 -0700199 struct w1_slave *sl, *sln;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200
Evgeniy Polyakov674a3962006-02-20 11:15:37 +0300201 kthread_stop(dev->thread);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202
David Friesc30c9b12008-10-15 22:04:38 -0700203 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 while (atomic_read(&dev->refcnt)) {
Evgeniy Polyakov674a3962006-02-20 11:15:37 +0300215 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 dev->name, atomic_read(&dev->refcnt));
217
218 if (msleep_interruptible(1000))
219 flush_signals(current);
220 }
221
Evgeniy Polyakov12003372006-03-23 19:11:58 +0300222 memset(&msg, 0, sizeof(msg));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 msg.id.mst.id = dev->id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 msg.type = W1_MASTER_REMOVE;
225 w1_netlink_send(dev, &msg);
226
227 w1_free_dev(dev);
228}
229
230void w1_remove_master_device(struct w1_bus_master *bm)
231{
Evgeniy Polyakov59d94452007-08-22 14:01:51 -0700232 struct w1_master *dev, *found = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233
Evgeniy Polyakov77859252005-05-20 22:33:25 +0400234 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 if (!dev->initialized)
236 continue;
237
Evgeniy Polyakov59d94452007-08-22 14:01:51 -0700238 if (dev->bus_master->data == bm->data) {
239 found = dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 break;
Evgeniy Polyakov59d94452007-08-22 14:01:51 -0700241 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 }
243
Evgeniy Polyakov59d94452007-08-22 14:01:51 -0700244 if (!found) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 printk(KERN_ERR "Device doesn't exist.\n");
246 return;
247 }
248
Evgeniy Polyakov59d94452007-08-22 14:01:51 -0700249 __w1_remove_master_device(found);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250}
251
252EXPORT_SYMBOL(w1_add_master_device);
253EXPORT_SYMBOL(w1_remove_master_device);