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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 return NULL;
37
38 dev->bus_master = (struct w1_bus_master *)(dev + 1);
39
40 dev->owner = THIS_MODULE;
41 dev->max_slave_count = slave_count;
42 dev->slave_count = 0;
43 dev->attempts = 0;
44 dev->initialized = 0;
45 dev->id = id;
46 dev->slave_ttl = slave_ttl;
47 dev->search_count = w1_search_count;
48 dev->enable_pullup = w1_enable_pullup;
49
50 /* For __w1_remove_master_device to decrement
51 */
52 atomic_set(&dev->refcnt, 1);
53
54 INIT_LIST_HEAD(&dev->slist);
55 INIT_LIST_HEAD(&dev->async_list);
56 mutex_init(&dev->mutex);
57 mutex_init(&dev->bus_mutex);
58 mutex_init(&dev->list_mutex);
59
60 memcpy(&dev->dev, device, sizeof(struct device));
61 dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
62 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
63 dev->dev.init_name = dev->name;
64
65 dev->driver = driver;
66
67 dev->seq = 1;
68
69 err = device_register(&dev->dev);
70 if (err) {
71 pr_err("Failed to register master device. err=%d\n", err);
72 put_device(&dev->dev);
73 dev = NULL;
74 }
75
76 return dev;
77}
78
79static void w1_free_dev(struct w1_master *dev)
80{
81 device_unregister(&dev->dev);
82}
83
84/**
85 * w1_add_master_device() - registers a new master device
86 * @master: master bus device to register
87 */
88int w1_add_master_device(struct w1_bus_master *master)
89{
90 struct w1_master *dev, *entry;
91 int retval = 0;
92 struct w1_netlink_msg msg;
93 int id, found;
94
95 /* validate minimum functionality */
96 if (!(master->touch_bit && master->reset_bus) &&
97 !(master->write_bit && master->read_bit) &&
98 !(master->write_byte && master->read_byte && master->reset_bus)) {
99 pr_err("w1_add_master_device: invalid function set\n");
100 return(-EINVAL);
101 }
102
103 /* Lock until the device is added (or not) to w1_masters. */
104 mutex_lock(&w1_mlock);
105 /* Search for the first available id (starting at 1). */
106 id = 0;
107 do {
108 ++id;
109 found = 0;
110 list_for_each_entry(entry, &w1_masters, w1_master_entry) {
111 if (entry->id == id) {
112 found = 1;
113 break;
114 }
115 }
116 } while (found);
117
118 dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
119 &w1_master_driver, &w1_master_device);
120 if (!dev) {
121 mutex_unlock(&w1_mlock);
122 return -ENOMEM;
123 }
124
125 retval = w1_create_master_attributes(dev);
126 if (retval) {
127 mutex_unlock(&w1_mlock);
128 goto err_out_free_dev;
129 }
130
131 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
132
133 dev->initialized = 1;
134
135 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
136 if (IS_ERR(dev->thread)) {
137 retval = PTR_ERR(dev->thread);
138 dev_err(&dev->dev,
139 "Failed to create new kernel thread. err=%d\n",
140 retval);
141 mutex_unlock(&w1_mlock);
142 goto err_out_rm_attr;
143 }
144
145 list_add(&dev->w1_master_entry, &w1_masters);
146 mutex_unlock(&w1_mlock);
147
148 memset(&msg, 0, sizeof(msg));
149 msg.id.mst.id = dev->id;
150 msg.type = W1_MASTER_ADD;
151 w1_netlink_send(dev, &msg);
152
153 return 0;
154
155#if 0 /* Thread cleanup code, not required currently. */
156err_out_kill_thread:
157 set_bit(W1_ABORT_SEARCH, &dev->flags);
158 kthread_stop(dev->thread);
159#endif
160err_out_rm_attr:
161 w1_destroy_master_attributes(dev);
162err_out_free_dev:
163 w1_free_dev(dev);
164
165 return retval;
166}
167EXPORT_SYMBOL(w1_add_master_device);
168
169void __w1_remove_master_device(struct w1_master *dev)
170{
171 struct w1_netlink_msg msg;
172 struct w1_slave *sl, *sln;
173
174 mutex_lock(&w1_mlock);
175 list_del(&dev->w1_master_entry);
176 mutex_unlock(&w1_mlock);
177
178 set_bit(W1_ABORT_SEARCH, &dev->flags);
179 kthread_stop(dev->thread);
180
181 mutex_lock(&dev->mutex);
182 mutex_lock(&dev->list_mutex);
183 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
184 mutex_unlock(&dev->list_mutex);
185 w1_slave_detach(sl);
186 mutex_lock(&dev->list_mutex);
187 }
188 w1_destroy_master_attributes(dev);
189 mutex_unlock(&dev->list_mutex);
190 mutex_unlock(&dev->mutex);
191 atomic_dec(&dev->refcnt);
192
193 while (atomic_read(&dev->refcnt)) {
194 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
195 dev->name, atomic_read(&dev->refcnt));
196
197 if (msleep_interruptible(1000))
198 flush_signals(current);
199 mutex_lock(&dev->list_mutex);
200 w1_process_callbacks(dev);
201 mutex_unlock(&dev->list_mutex);
202 }
203 mutex_lock(&dev->list_mutex);
204 w1_process_callbacks(dev);
205 mutex_unlock(&dev->list_mutex);
206
207 memset(&msg, 0, sizeof(msg));
208 msg.id.mst.id = dev->id;
209 msg.type = W1_MASTER_REMOVE;
210 w1_netlink_send(dev, &msg);
211
212 w1_free_dev(dev);
213}
214
215/**
216 * w1_remove_master_device() - unregister a master device
217 * @bm: master bus device to remove
218 */
219void w1_remove_master_device(struct w1_bus_master *bm)
220{
221 struct w1_master *dev, *found = NULL;
222
223 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
224 if (!dev->initialized)
225 continue;
226
227 if (dev->bus_master->data == bm->data) {
228 found = dev;
229 break;
230 }
231 }
232
233 if (!found) {
234 pr_err("Device doesn't exist.\n");
235 return;
236 }
237
238 __w1_remove_master_device(found);
239}
240EXPORT_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 INIT_LIST_HEAD(&dev->async_list);
79 mutex_init(&dev->mutex);
80 mutex_init(&dev->bus_mutex);
81 mutex_init(&dev->list_mutex);
82
83 memcpy(&dev->dev, device, sizeof(struct device));
84 dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
85 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
86 dev->dev.init_name = dev->name;
87
88 dev->driver = driver;
89
90 dev->seq = 1;
91
92 err = device_register(&dev->dev);
93 if (err) {
94 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
95 memset(dev, 0, sizeof(struct w1_master));
96 kfree(dev);
97 dev = NULL;
98 }
99
100 return dev;
101}
102
103static void w1_free_dev(struct w1_master *dev)
104{
105 device_unregister(&dev->dev);
106}
107
108/**
109 * w1_add_master_device() - registers a new master device
110 * @master: master bus device to register
111 */
112int w1_add_master_device(struct w1_bus_master *master)
113{
114 struct w1_master *dev, *entry;
115 int retval = 0;
116 struct w1_netlink_msg msg;
117 int id, found;
118
119 /* validate minimum functionality */
120 if (!(master->touch_bit && master->reset_bus) &&
121 !(master->write_bit && master->read_bit) &&
122 !(master->write_byte && master->read_byte && master->reset_bus)) {
123 printk(KERN_ERR "w1_add_master_device: invalid function set\n");
124 return(-EINVAL);
125 }
126
127 /* Lock until the device is added (or not) to w1_masters. */
128 mutex_lock(&w1_mlock);
129 /* Search for the first available id (starting at 1). */
130 id = 0;
131 do {
132 ++id;
133 found = 0;
134 list_for_each_entry(entry, &w1_masters, w1_master_entry) {
135 if (entry->id == id) {
136 found = 1;
137 break;
138 }
139 }
140 } while (found);
141
142 dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
143 &w1_master_driver, &w1_master_device);
144 if (!dev) {
145 mutex_unlock(&w1_mlock);
146 return -ENOMEM;
147 }
148
149 retval = w1_create_master_attributes(dev);
150 if (retval) {
151 mutex_unlock(&w1_mlock);
152 goto err_out_free_dev;
153 }
154
155 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
156
157 dev->initialized = 1;
158
159 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
160 if (IS_ERR(dev->thread)) {
161 retval = PTR_ERR(dev->thread);
162 dev_err(&dev->dev,
163 "Failed to create new kernel thread. err=%d\n",
164 retval);
165 mutex_unlock(&w1_mlock);
166 goto err_out_rm_attr;
167 }
168
169 list_add(&dev->w1_master_entry, &w1_masters);
170 mutex_unlock(&w1_mlock);
171
172 memset(&msg, 0, sizeof(msg));
173 msg.id.mst.id = dev->id;
174 msg.type = W1_MASTER_ADD;
175 w1_netlink_send(dev, &msg);
176
177 return 0;
178
179#if 0 /* Thread cleanup code, not required currently. */
180err_out_kill_thread:
181 set_bit(W1_ABORT_SEARCH, &dev->flags);
182 kthread_stop(dev->thread);
183#endif
184err_out_rm_attr:
185 w1_destroy_master_attributes(dev);
186err_out_free_dev:
187 w1_free_dev(dev);
188
189 return retval;
190}
191
192void __w1_remove_master_device(struct w1_master *dev)
193{
194 struct w1_netlink_msg msg;
195 struct w1_slave *sl, *sln;
196
197 mutex_lock(&w1_mlock);
198 list_del(&dev->w1_master_entry);
199 mutex_unlock(&w1_mlock);
200
201 set_bit(W1_ABORT_SEARCH, &dev->flags);
202 kthread_stop(dev->thread);
203
204 mutex_lock(&dev->mutex);
205 mutex_lock(&dev->list_mutex);
206 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
207 mutex_unlock(&dev->list_mutex);
208 w1_slave_detach(sl);
209 mutex_lock(&dev->list_mutex);
210 }
211 w1_destroy_master_attributes(dev);
212 mutex_unlock(&dev->list_mutex);
213 mutex_unlock(&dev->mutex);
214 atomic_dec(&dev->refcnt);
215
216 while (atomic_read(&dev->refcnt)) {
217 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
218 dev->name, atomic_read(&dev->refcnt));
219
220 if (msleep_interruptible(1000))
221 flush_signals(current);
222 w1_process_callbacks(dev);
223 }
224 w1_process_callbacks(dev);
225
226 memset(&msg, 0, sizeof(msg));
227 msg.id.mst.id = dev->id;
228 msg.type = W1_MASTER_REMOVE;
229 w1_netlink_send(dev, &msg);
230
231 w1_free_dev(dev);
232}
233
234/**
235 * w1_remove_master_device() - unregister a master device
236 * @bm: master bus device to remove
237 */
238void w1_remove_master_device(struct w1_bus_master *bm)
239{
240 struct w1_master *dev, *found = NULL;
241
242 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
243 if (!dev->initialized)
244 continue;
245
246 if (dev->bus_master->data == bm->data) {
247 found = dev;
248 break;
249 }
250 }
251
252 if (!found) {
253 printk(KERN_ERR "Device doesn't exist.\n");
254 return;
255 }
256
257 __w1_remove_master_device(found);
258}
259
260EXPORT_SYMBOL(w1_add_master_device);
261EXPORT_SYMBOL(w1_remove_master_device);