1/*
2 *	w1_int.c
3 *
4 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
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
27#include "w1.h"
28#include "w1_log.h"
29#include "w1_netlink.h"
30#include "w1_int.h"
31
32static u32 w1_ids = 1;
33
34static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
35				       struct device_driver *driver,
36				       struct device *device)
37{
38	struct w1_master *dev;
39	int err;
40
41	/*
42	 * We are in process context(kernel thread), so can sleep.
43	 */
44	dev = kmalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
45	if (!dev) {
46		printk(KERN_ERR
47			"Failed to allocate %zd bytes for new w1 device.\n",
48			sizeof(struct w1_master));
49		return NULL;
50	}
51
52	memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
53
54	dev->bus_master = (struct w1_bus_master *)(dev + 1);
55
56	dev->owner		= THIS_MODULE;
57	dev->max_slave_count	= slave_count;
58	dev->slave_count	= 0;
59	dev->attempts		= 0;
60	dev->initialized	= 0;
61	dev->id			= id;
62	dev->slave_ttl		= slave_ttl;
63        dev->search_count	= -1; /* continual scan */
64
65	atomic_set(&dev->refcnt, 2);
66
67	INIT_LIST_HEAD(&dev->slist);
68	mutex_init(&dev->mutex);
69
70	memcpy(&dev->dev, device, sizeof(struct device));
71	snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
72		  "w1_bus_master%u", dev->id);
73	snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
74
75	dev->driver = driver;
76
77	dev->seq = 1;
78
79	err = device_register(&dev->dev);
80	if (err) {
81		printk(KERN_ERR "Failed to register master device. err=%d\n", err);
82		memset(dev, 0, sizeof(struct w1_master));
83		kfree(dev);
84		dev = NULL;
85	}
86
87	return dev;
88}
89
90static void w1_free_dev(struct w1_master *dev)
91{
92	device_unregister(&dev->dev);
93}
94
95int w1_add_master_device(struct w1_bus_master *master)
96{
97	struct w1_master *dev;
98	int retval = 0;
99	struct w1_netlink_msg msg;
100
101        /* validate minimum functionality */
102        if (!(master->touch_bit && master->reset_bus) &&
103            !(master->write_bit && master->read_bit) &&
104	    !(master->write_byte && master->read_byte && master->reset_bus)) {
105		printk(KERN_ERR "w1_add_master_device: invalid function set\n");
106		return(-EINVAL);
107        }
108
109	dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device);
110	if (!dev)
111		return -ENOMEM;
112
113	dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
114	if (IS_ERR(dev->thread)) {
115		retval = PTR_ERR(dev->thread);
116		dev_err(&dev->dev,
117			 "Failed to create new kernel thread. err=%d\n",
118			 retval);
119		goto err_out_free_dev;
120	}
121
122	retval =  w1_create_master_attributes(dev);
123	if (retval)
124		goto err_out_kill_thread;
125
126	memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
127
128	dev->initialized = 1;
129
130	mutex_lock(&w1_mlock);
131	list_add(&dev->w1_master_entry, &w1_masters);
132	mutex_unlock(&w1_mlock);
133
134	memset(&msg, 0, sizeof(msg));
135	msg.id.mst.id = dev->id;
136	msg.type = W1_MASTER_ADD;
137	w1_netlink_send(dev, &msg);
138
139	return 0;
140
141err_out_kill_thread:
142	kthread_stop(dev->thread);
143err_out_free_dev:
144	w1_free_dev(dev);
145
146	return retval;
147}
148
149void __w1_remove_master_device(struct w1_master *dev)
150{
151	struct w1_netlink_msg msg;
152
153	set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
154	kthread_stop(dev->thread);
155
156	while (atomic_read(&dev->refcnt)) {
157		dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
158				dev->name, atomic_read(&dev->refcnt));
159
160		if (msleep_interruptible(1000))
161			flush_signals(current);
162	}
163
164	memset(&msg, 0, sizeof(msg));
165	msg.id.mst.id = dev->id;
166	msg.type = W1_MASTER_REMOVE;
167	w1_netlink_send(dev, &msg);
168
169	w1_free_dev(dev);
170}
171
172void w1_remove_master_device(struct w1_bus_master *bm)
173{
174	struct w1_master *dev = NULL;
175
176	list_for_each_entry(dev, &w1_masters, w1_master_entry) {
177		if (!dev->initialized)
178			continue;
179
180		if (dev->bus_master->data == bm->data)
181			break;
182	}
183
184	if (!dev) {
185		printk(KERN_ERR "Device doesn't exist.\n");
186		return;
187	}
188
189	__w1_remove_master_device(dev);
190}
191
192EXPORT_SYMBOL(w1_add_master_device);
193EXPORT_SYMBOL(w1_remove_master_device);
194