2 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
15 #include <linux/kernel.h>
16 #include <linux/list.h>
17 #include <linux/delay.h>
18 #include <linux/kthread.h>
19 #include <linux/slab.h>
20 #include <linux/sched/signal.h>
21 #include <linux/export.h>
22 #include <linux/moduleparam.h>
24 #include "w1_internal.h"
25 #include "w1_netlink.h"
27 static int w1_search_count = -1; /* Default is continual scan */
28 module_param_named(search_count, w1_search_count, int, 0);
30 static int w1_enable_pullup = 1;
31 module_param_named(enable_pullup, w1_enable_pullup, int, 0);
33 static struct w1_master *w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
34 struct device_driver *driver,
35 struct device *device)
37 struct w1_master *dev;
41 * We are in process context(kernel thread), so can sleep.
43 dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
45 pr_err("Failed to allocate %zd bytes for new w1 device.\n",
46 sizeof(struct w1_master));
51 dev->bus_master = (struct w1_bus_master *)(dev + 1);
53 dev->owner = THIS_MODULE;
54 dev->max_slave_count = slave_count;
59 dev->slave_ttl = slave_ttl;
60 dev->search_count = w1_search_count;
61 dev->enable_pullup = w1_enable_pullup;
63 /* For __w1_remove_master_device to decrement
65 atomic_set(&dev->refcnt, 1);
67 INIT_LIST_HEAD(&dev->slist);
68 INIT_LIST_HEAD(&dev->async_list);
69 mutex_init(&dev->mutex);
70 mutex_init(&dev->bus_mutex);
71 mutex_init(&dev->list_mutex);
73 memcpy(&dev->dev, device, sizeof(struct device));
74 dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
75 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
76 dev->dev.init_name = dev->name;
82 err = device_register(&dev->dev);
84 pr_err("Failed to register master device. err=%d\n", err);
85 put_device(&dev->dev);
92 static void w1_free_dev(struct w1_master *dev)
94 device_unregister(&dev->dev);
98 * w1_add_master_device() - registers a new master device
99 * @master: master bus device to register
101 int w1_add_master_device(struct w1_bus_master *master)
103 struct w1_master *dev, *entry;
105 struct w1_netlink_msg msg;
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 pr_err("w1_add_master_device: invalid function set\n");
116 /* Lock until the device is added (or not) to w1_masters. */
117 mutex_lock(&w1_mlock);
118 /* Search for the first available id (starting at 1). */
123 list_for_each_entry(entry, &w1_masters, w1_master_entry) {
124 if (entry->id == id) {
131 dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
132 &w1_master_driver, &w1_master_device);
134 mutex_unlock(&w1_mlock);
138 retval = w1_create_master_attributes(dev);
140 mutex_unlock(&w1_mlock);
141 goto err_out_free_dev;
144 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
146 dev->initialized = 1;
148 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
149 if (IS_ERR(dev->thread)) {
150 retval = PTR_ERR(dev->thread);
152 "Failed to create new kernel thread. err=%d\n",
154 mutex_unlock(&w1_mlock);
155 goto err_out_rm_attr;
158 list_add(&dev->w1_master_entry, &w1_masters);
159 mutex_unlock(&w1_mlock);
161 memset(&msg, 0, sizeof(msg));
162 msg.id.mst.id = dev->id;
163 msg.type = W1_MASTER_ADD;
164 w1_netlink_send(dev, &msg);
168 #if 0 /* Thread cleanup code, not required currently. */
170 set_bit(W1_ABORT_SEARCH, &dev->flags);
171 kthread_stop(dev->thread);
174 w1_destroy_master_attributes(dev);
180 EXPORT_SYMBOL(w1_add_master_device);
182 void __w1_remove_master_device(struct w1_master *dev)
184 struct w1_netlink_msg msg;
185 struct w1_slave *sl, *sln;
187 mutex_lock(&w1_mlock);
188 list_del(&dev->w1_master_entry);
189 mutex_unlock(&w1_mlock);
191 set_bit(W1_ABORT_SEARCH, &dev->flags);
192 kthread_stop(dev->thread);
194 mutex_lock(&dev->mutex);
195 mutex_lock(&dev->list_mutex);
196 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
197 mutex_unlock(&dev->list_mutex);
199 mutex_lock(&dev->list_mutex);
201 w1_destroy_master_attributes(dev);
202 mutex_unlock(&dev->list_mutex);
203 mutex_unlock(&dev->mutex);
204 atomic_dec(&dev->refcnt);
206 while (atomic_read(&dev->refcnt)) {
207 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
208 dev->name, atomic_read(&dev->refcnt));
210 if (msleep_interruptible(1000))
211 flush_signals(current);
212 mutex_lock(&dev->list_mutex);
213 w1_process_callbacks(dev);
214 mutex_unlock(&dev->list_mutex);
216 mutex_lock(&dev->list_mutex);
217 w1_process_callbacks(dev);
218 mutex_unlock(&dev->list_mutex);
220 memset(&msg, 0, sizeof(msg));
221 msg.id.mst.id = dev->id;
222 msg.type = W1_MASTER_REMOVE;
223 w1_netlink_send(dev, &msg);
229 * w1_remove_master_device() - unregister a master device
230 * @bm: master bus device to remove
232 void w1_remove_master_device(struct w1_bus_master *bm)
234 struct w1_master *dev, *found = NULL;
236 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
237 if (!dev->initialized)
240 if (dev->bus_master->data == bm->data) {
247 pr_err("Device doesn't exist.\n");
251 __w1_remove_master_device(found);
253 EXPORT_SYMBOL(w1_remove_master_device);