Loading...
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
4 */
5
6#include <linux/kernel.h>
7#include <linux/list.h>
8#include <linux/delay.h>
9#include <linux/kthread.h>
10#include <linux/slab.h>
11#include <linux/sched/signal.h>
12#include <linux/export.h>
13#include <linux/moduleparam.h>
14
15#include "w1_internal.h"
16#include "w1_netlink.h"
17
18static int w1_search_count = -1; /* Default is continual scan */
19module_param_named(search_count, w1_search_count, int, 0);
20
21static int w1_enable_pullup = 1;
22module_param_named(enable_pullup, w1_enable_pullup, int, 0);
23
24static struct w1_master *w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
25 struct device_driver *driver,
26 struct device *device)
27{
28 struct w1_master *dev;
29 int err;
30
31 /*
32 * We are in process context(kernel thread), so can sleep.
33 */
34 dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
35 if (!dev) {
36 pr_err("Failed to allocate %zd bytes for new w1 device.\n",
37 sizeof(struct w1_master));
38 return NULL;
39 }
40
41
42 dev->bus_master = (struct w1_bus_master *)(dev + 1);
43
44 dev->owner = THIS_MODULE;
45 dev->max_slave_count = slave_count;
46 dev->slave_count = 0;
47 dev->attempts = 0;
48 dev->initialized = 0;
49 dev->id = id;
50 dev->slave_ttl = slave_ttl;
51 dev->search_count = w1_search_count;
52 dev->enable_pullup = w1_enable_pullup;
53
54 /* 1 for w1_process to decrement
55 * 1 for __w1_remove_master_device to decrement
56 */
57 atomic_set(&dev->refcnt, 2);
58
59 INIT_LIST_HEAD(&dev->slist);
60 INIT_LIST_HEAD(&dev->async_list);
61 mutex_init(&dev->mutex);
62 mutex_init(&dev->bus_mutex);
63 mutex_init(&dev->list_mutex);
64
65 memcpy(&dev->dev, device, sizeof(struct device));
66 dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
67 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
68 dev->dev.init_name = dev->name;
69
70 dev->driver = driver;
71
72 dev->seq = 1;
73
74 err = device_register(&dev->dev);
75 if (err) {
76 pr_err("Failed to register master device. err=%d\n", err);
77 put_device(&dev->dev);
78 dev = NULL;
79 }
80
81 return dev;
82}
83
84static void w1_free_dev(struct w1_master *dev)
85{
86 device_unregister(&dev->dev);
87}
88
89/**
90 * w1_add_master_device() - registers a new master device
91 * @master: master bus device to register
92 */
93int w1_add_master_device(struct w1_bus_master *master)
94{
95 struct w1_master *dev, *entry;
96 int retval = 0;
97 struct w1_netlink_msg msg;
98 int id, found;
99
100 /* validate minimum functionality */
101 if (!(master->touch_bit && master->reset_bus) &&
102 !(master->write_bit && master->read_bit) &&
103 !(master->write_byte && master->read_byte && master->reset_bus)) {
104 pr_err("w1_add_master_device: invalid function set\n");
105 return(-EINVAL);
106 }
107
108 /* Lock until the device is added (or not) to w1_masters. */
109 mutex_lock(&w1_mlock);
110 /* Search for the first available id (starting at 1). */
111 id = 0;
112 do {
113 ++id;
114 found = 0;
115 list_for_each_entry(entry, &w1_masters, w1_master_entry) {
116 if (entry->id == id) {
117 found = 1;
118 break;
119 }
120 }
121 } while (found);
122
123 dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
124 &w1_master_driver, &w1_master_device);
125 if (!dev) {
126 mutex_unlock(&w1_mlock);
127 return -ENOMEM;
128 }
129
130 retval = w1_create_master_attributes(dev);
131 if (retval) {
132 mutex_unlock(&w1_mlock);
133 goto err_out_free_dev;
134 }
135
136 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
137
138 dev->initialized = 1;
139
140 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
141 if (IS_ERR(dev->thread)) {
142 retval = PTR_ERR(dev->thread);
143 dev_err(&dev->dev,
144 "Failed to create new kernel thread. err=%d\n",
145 retval);
146 mutex_unlock(&w1_mlock);
147 goto err_out_rm_attr;
148 }
149
150 list_add(&dev->w1_master_entry, &w1_masters);
151 mutex_unlock(&w1_mlock);
152
153 memset(&msg, 0, sizeof(msg));
154 msg.id.mst.id = dev->id;
155 msg.type = W1_MASTER_ADD;
156 w1_netlink_send(dev, &msg);
157
158 return 0;
159
160#if 0 /* Thread cleanup code, not required currently. */
161err_out_kill_thread:
162 set_bit(W1_ABORT_SEARCH, &dev->flags);
163 kthread_stop(dev->thread);
164#endif
165err_out_rm_attr:
166 w1_destroy_master_attributes(dev);
167err_out_free_dev:
168 w1_free_dev(dev);
169
170 return retval;
171}
172EXPORT_SYMBOL(w1_add_master_device);
173
174void __w1_remove_master_device(struct w1_master *dev)
175{
176 struct w1_netlink_msg msg;
177 struct w1_slave *sl, *sln;
178
179 mutex_lock(&w1_mlock);
180 list_del(&dev->w1_master_entry);
181 mutex_unlock(&w1_mlock);
182
183 set_bit(W1_ABORT_SEARCH, &dev->flags);
184 kthread_stop(dev->thread);
185
186 mutex_lock(&dev->mutex);
187 mutex_lock(&dev->list_mutex);
188 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
189 mutex_unlock(&dev->list_mutex);
190 w1_slave_detach(sl);
191 mutex_lock(&dev->list_mutex);
192 }
193 w1_destroy_master_attributes(dev);
194 mutex_unlock(&dev->list_mutex);
195 mutex_unlock(&dev->mutex);
196 atomic_dec(&dev->refcnt);
197
198 while (atomic_read(&dev->refcnt)) {
199 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
200 dev->name, atomic_read(&dev->refcnt));
201
202 if (msleep_interruptible(1000))
203 flush_signals(current);
204 mutex_lock(&dev->list_mutex);
205 w1_process_callbacks(dev);
206 mutex_unlock(&dev->list_mutex);
207 }
208 mutex_lock(&dev->list_mutex);
209 w1_process_callbacks(dev);
210 mutex_unlock(&dev->list_mutex);
211
212 memset(&msg, 0, sizeof(msg));
213 msg.id.mst.id = dev->id;
214 msg.type = W1_MASTER_REMOVE;
215 w1_netlink_send(dev, &msg);
216
217 w1_free_dev(dev);
218}
219
220/**
221 * w1_remove_master_device() - unregister a master device
222 * @bm: master bus device to remove
223 */
224void w1_remove_master_device(struct w1_bus_master *bm)
225{
226 struct w1_master *dev, *found = NULL;
227
228 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
229 if (!dev->initialized)
230 continue;
231
232 if (dev->bus_master->data == bm->data) {
233 found = dev;
234 break;
235 }
236 }
237
238 if (!found) {
239 pr_err("Device doesn't exist.\n");
240 return;
241 }
242
243 __w1_remove_master_device(found);
244}
245EXPORT_SYMBOL(w1_remove_master_device);
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
35static int w1_search_count = -1; /* Default is continual scan */
36module_param_named(search_count, w1_search_count, int, 0);
37
38static int w1_enable_pullup = 1;
39module_param_named(enable_pullup, w1_enable_pullup, int, 0);
40
41static 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
100static void w1_free_dev(struct w1_master *dev)
101{
102 device_unregister(&dev->dev);
103}
104
105int 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. */
185err_out_kill_thread:
186 kthread_stop(dev->thread);
187#endif
188err_out_rm_attr:
189 w1_destroy_master_attributes(dev);
190err_out_free_dev:
191 w1_free_dev(dev);
192
193 return retval;
194}
195
196void __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
230void 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
252EXPORT_SYMBOL(w1_add_master_device);
253EXPORT_SYMBOL(w1_remove_master_device);