summaryrefslogtreecommitdiff
path: root/drivers/w1/w1_int.c
blob: f79e62e54e8d25bf21b6bba2850ae9b4b9e6c184 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
/*
 *	w1_int.c
 *
 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/slab.h>

#include "w1.h"
#include "w1_log.h"
#include "w1_netlink.h"
#include "w1_int.h"

static int w1_search_count = -1; /* Default is continual scan */
module_param_named(search_count, w1_search_count, int, 0);

static int w1_enable_pullup = 1;
module_param_named(enable_pullup, w1_enable_pullup, int, 0);

static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
				       struct device_driver *driver,
				       struct device *device)
{
	struct w1_master *dev;
	int err;

	/*
	 * We are in process context(kernel thread), so can sleep.
	 */
	dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
	if (!dev) {
		printk(KERN_ERR
			"Failed to allocate %zd bytes for new w1 device.\n",
			sizeof(struct w1_master));
		return NULL;
	}


	dev->bus_master = (struct w1_bus_master *)(dev + 1);

	dev->owner		= THIS_MODULE;
	dev->max_slave_count	= slave_count;
	dev->slave_count	= 0;
	dev->attempts		= 0;
	dev->initialized	= 0;
	dev->id			= id;
	dev->slave_ttl		= slave_ttl;
	dev->search_count	= w1_search_count;
	dev->enable_pullup	= w1_enable_pullup;

	/* 1 for w1_process to decrement
	 * 1 for __w1_remove_master_device to decrement
	 */
	atomic_set(&dev->refcnt, 2);

	INIT_LIST_HEAD(&dev->slist);
	mutex_init(&dev->mutex);

	memcpy(&dev->dev, device, sizeof(struct device));
	dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
	snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
	dev->dev.init_name = dev->name;

	dev->driver = driver;

	dev->seq = 1;

	err = device_register(&dev->dev);
	if (err) {
		printk(KERN_ERR "Failed to register master device. err=%d\n", err);
		memset(dev, 0, sizeof(struct w1_master));
		kfree(dev);
		dev = NULL;
	}

	return dev;
}

static void w1_free_dev(struct w1_master *dev)
{
	device_unregister(&dev->dev);
}

int w1_add_master_device(struct w1_bus_master *master)
{
	struct w1_master *dev, *entry;
	int retval = 0;
	struct w1_netlink_msg msg;
	int id, found;

        /* validate minimum functionality */
        if (!(master->touch_bit && master->reset_bus) &&
            !(master->write_bit && master->read_bit) &&
	    !(master->write_byte && master->read_byte && master->reset_bus)) {
		printk(KERN_ERR "w1_add_master_device: invalid function set\n");
		return(-EINVAL);
        }
	/* While it would be electrically possible to make a device that
	 * generated a strong pullup in bit bang mode, only hardare that
	 * controls 1-wire time frames are even expected to support a strong
	 * pullup.  w1_io.c would need to support calling set_pullup before
	 * the last write_bit operation of a w1_write_8 which it currently
	 * doesn't.
	 */
	if (!master->write_byte && !master->touch_bit && master->set_pullup) {
		printk(KERN_ERR "w1_add_master_device: set_pullup requires "
			"write_byte or touch_bit, disabling\n");
		master->set_pullup = NULL;
	}

	/* Lock until the device is added (or not) to w1_masters. */
	mutex_lock(&w1_mlock);
	/* Search for the first available id (starting at 1). */
	id = 0;
	do {
		++id;
		found = 0;
		list_for_each_entry(entry, &w1_masters, w1_master_entry) {
			if (entry->id == id) {
				found = 1;
				break;
			}
		}
	} while (found);

	dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
		&w1_master_driver, &w1_master_device);
	if (!dev) {
		mutex_unlock(&w1_mlock);
		return -ENOMEM;
	}

	retval =  w1_create_master_attributes(dev);
	if (retval) {
		mutex_unlock(&w1_mlock);
		goto err_out_free_dev;
	}

	memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));

	dev->initialized = 1;

	dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
	if (IS_ERR(dev->thread)) {
		retval = PTR_ERR(dev->thread);
		dev_err(&dev->dev,
			 "Failed to create new kernel thread. err=%d\n",
			 retval);
		mutex_unlock(&w1_mlock);
		goto err_out_rm_attr;
	}

	list_add(&dev->w1_master_entry, &w1_masters);
	mutex_unlock(&w1_mlock);

	memset(&msg, 0, sizeof(msg));
	msg.id.mst.id = dev->id;
	msg.type = W1_MASTER_ADD;
	w1_netlink_send(dev, &msg);

	return 0;

#if 0 /* Thread cleanup code, not required currently. */
err_out_kill_thread:
	kthread_stop(dev->thread);
#endif
err_out_rm_attr:
	w1_destroy_master_attributes(dev);
err_out_free_dev:
	w1_free_dev(dev);

	return retval;
}

void __w1_remove_master_device(struct w1_master *dev)
{
	struct w1_netlink_msg msg;
	struct w1_slave *sl, *sln;

	kthread_stop(dev->thread);

	mutex_lock(&w1_mlock);
	list_del(&dev->w1_master_entry);
	mutex_unlock(&w1_mlock);

	mutex_lock(&dev->mutex);
	list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry)
		w1_slave_detach(sl);
	w1_destroy_master_attributes(dev);
	mutex_unlock(&dev->mutex);
	atomic_dec(&dev->refcnt);

	while (atomic_read(&dev->refcnt)) {
		dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
				dev->name, atomic_read(&dev->refcnt));

		if (msleep_interruptible(1000))
			flush_signals(current);
	}

	memset(&msg, 0, sizeof(msg));
	msg.id.mst.id = dev->id;
	msg.type = W1_MASTER_REMOVE;
	w1_netlink_send(dev, &msg);

	w1_free_dev(dev);
}

void w1_remove_master_device(struct w1_bus_master *bm)
{
	struct w1_master *dev, *found = NULL;

	list_for_each_entry(dev, &w1_masters, w1_master_entry) {
		if (!dev->initialized)
			continue;

		if (dev->bus_master->data == bm->data) {
			found = dev;
			break;
		}
	}

	if (!found) {
		printk(KERN_ERR "Device doesn't exist.\n");
		return;
	}

	__w1_remove_master_device(found);
}

EXPORT_SYMBOL(w1_add_master_device);
EXPORT_SYMBOL(w1_remove_master_device);