aboutsummaryrefslogtreecommitdiff
path: root/drivers/isdn/mISDN/timerdev.c
blob: c3243c913ec033b570c04678c6408efa8e13a694 (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
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
/*
 *
 * general timer device for using in ISDN stacks
 *
 * Author	Karsten Keil <kkeil@novell.com>
 *
 * Copyright 2008  by Karsten Keil <kkeil@novell.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * 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.
 *
 */

#include <linux/poll.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/mISDNif.h>
#include <linux/smp_lock.h>
#include "core.h"

static u_int	*debug;


struct mISDNtimerdev {
	int			next_id;
	struct list_head	pending;
	struct list_head	expired;
	wait_queue_head_t	wait;
	u_int			work;
	spinlock_t		lock; /* protect lists */
};

struct mISDNtimer {
	struct list_head	list;
	struct  mISDNtimerdev	*dev;
	struct timer_list	tl;
	int			id;
};

static int
mISDN_open(struct inode *ino, struct file *filep)
{
	struct mISDNtimerdev	*dev;

	if (*debug & DEBUG_TIMER)
		printk(KERN_DEBUG "%s(%p,%p)\n", __func__, ino, filep);
	dev = kmalloc(sizeof(struct mISDNtimerdev) , GFP_KERNEL);
	if (!dev)
		return -ENOMEM;
	dev->next_id = 1;
	INIT_LIST_HEAD(&dev->pending);
	INIT_LIST_HEAD(&dev->expired);
	spin_lock_init(&dev->lock);
	dev->work = 0;
	init_waitqueue_head(&dev->wait);
	filep->private_data = dev;
	__module_get(THIS_MODULE);
	return nonseekable_open(ino, filep);
}

static int
mISDN_close(struct inode *ino, struct file *filep)
{
	struct mISDNtimerdev	*dev = filep->private_data;
	struct mISDNtimer	*timer, *next;

	if (*debug & DEBUG_TIMER)
		printk(KERN_DEBUG "%s(%p,%p)\n", __func__, ino, filep);
	list_for_each_entry_safe(timer, next, &dev->pending, list) {
		del_timer(&timer->tl);
		kfree(timer);
	}
	list_for_each_entry_safe(timer, next, &dev->expired, list) {
		kfree(timer);
	}
	kfree(dev);
	module_put(THIS_MODULE);
	return 0;
}

static ssize_t
mISDN_read(struct file *filep, char __user *buf, size_t count, loff_t *off)
{
	struct mISDNtimerdev	*dev = filep->private_data;
	struct mISDNtimer	*timer;
	u_long	flags;
	int	ret = 0;

	if (*debug & DEBUG_TIMER)
		printk(KERN_DEBUG "%s(%p, %p, %d, %p)\n", __func__,
			filep, buf, (int)count, off);
	if (*off != filep->f_pos)
		return -ESPIPE;

	if (list_empty(&dev->expired) && (dev->work == 0)) {
		if (filep->f_flags & O_NONBLOCK)
			return -EAGAIN;
		wait_event_interruptible(dev->wait, (dev->work ||
		    !list_empty(&dev->expired)));
		if (signal_pending(current))
			return -ERESTARTSYS;
	}
	if (count < sizeof(int))
		return -ENOSPC;
	if (dev->work)
		dev->work = 0;
	if (!list_empty(&dev->expired)) {
		spin_lock_irqsave(&dev->lock, flags);
		timer = (struct mISDNtimer *)dev->expired.next;
		list_del(&timer->list);
		spin_unlock_irqrestore(&dev->lock, flags);
		if (put_user(timer->id, (int __user *)buf))
			ret = -EFAULT;
		else
			ret = sizeof(int);
		kfree(timer);
	}
	return ret;
}

static unsigned int
mISDN_poll(struct file *filep, poll_table *wait)
{
	struct mISDNtimerdev	*dev = filep->private_data;
	unsigned int		mask = POLLERR;

	if (*debug & DEBUG_TIMER)
		printk(KERN_DEBUG "%s(%p, %p)\n", __func__, filep, wait);
	if (dev) {
		poll_wait(filep, &dev->wait, wait);
		mask = 0;
		if (dev->work || !list_empty(&dev->expired))
			mask |= (POLLIN | POLLRDNORM);
		if (*debug & DEBUG_TIMER)
			printk(KERN_DEBUG "%s work(%d) empty(%d)\n", __func__,
				dev->work, list_empty(&dev->expired));
	}
	return mask;
}

static void
dev_expire_timer(unsigned long data)
{
	struct mISDNtimer *timer = (void *)data;
	u_long			flags;

	spin_lock_irqsave(&timer->dev->lock, flags);
	list_move_tail(&timer->list, &timer->dev->expired);
	spin_unlock_irqrestore(&timer->dev->lock, flags);
	wake_up_interruptible(&timer->dev->wait);
}

static int
misdn_add_timer(struct mISDNtimerdev *dev, int timeout)
{
	int 			id;
	u_long			flags;
	struct mISDNtimer	*timer;

	if (!timeout) {
		dev->work = 1;
		wake_up_interruptible(&dev->wait);
		id = 0;
	} else {
		timer = kzalloc(sizeof(struct mISDNtimer), GFP_KERNEL);
		if (!timer)
			return -ENOMEM;
		spin_lock_irqsave(&dev->lock, flags);
		timer->id = dev->next_id++;
		if (dev->next_id < 0)
			dev->next_id = 1;
		list_add_tail(&timer->list, &dev->pending);
		spin_unlock_irqrestore(&dev->lock, flags);
		timer->dev = dev;
		timer->tl.data = (long)timer;
		timer->tl.function = dev_expire_timer;
		init_timer(&timer->tl);
		timer->tl.expires = jiffies + ((HZ * (u_long)timeout) / 1000);
		add_timer(&timer->tl);
		id = timer->id;
	}
	return id;
}

static int
misdn_del_timer(struct mISDNtimerdev *dev, int id)
{
	u_long			flags;
	struct mISDNtimer	*timer;
	int			ret = 0;

	spin_lock_irqsave(&dev->lock, flags);
	list_for_each_entry(timer, &dev->pending, list) {
		if (timer->id == id) {
			list_del_init(&timer->list);
			/* RED-PEN AK: race -- timer can be still running on
			 * other CPU. Needs reference count I think
			 */
			del_timer(&timer->tl);
			ret = timer->id;
			kfree(timer);
			goto unlock;
		}
	}
unlock:
	spin_unlock_irqrestore(&dev->lock, flags);
	return ret;
}

static long
mISDN_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
{
	struct mISDNtimerdev	*dev = filep->private_data;
	int			id, tout, ret = 0;


	if (*debug & DEBUG_TIMER)
		printk(KERN_DEBUG "%s(%p, %x, %lx)\n", __func__,
		    filep, cmd, arg);
	lock_kernel();
	switch (cmd) {
	case IMADDTIMER:
		if (get_user(tout, (int __user *)arg)) {
			ret = -EFAULT;
			break;
		}
		id = misdn_add_timer(dev, tout);
		if (*debug & DEBUG_TIMER)
			printk(KERN_DEBUG "%s add %d id %d\n", __func__,
			    tout, id);
		if (id < 0) {
			ret = id;
			break;
		}
		if (put_user(id, (int __user *)arg))
			ret = -EFAULT;
		break;
	case IMDELTIMER:
		if (get_user(id, (int __user *)arg)) {
			ret = -EFAULT;
			break;
		}
		if (*debug & DEBUG_TIMER)
			printk(KERN_DEBUG "%s del id %d\n", __func__, id);
		id = misdn_del_timer(dev, id);
		if (put_user(id, (int __user *)arg))
			ret = -EFAULT;
		break;
	default:
		ret = -EINVAL;
	}
	unlock_kernel();
	return ret;
}

static const struct file_operations mISDN_fops = {
	.read		= mISDN_read,
	.poll		= mISDN_poll,
	.unlocked_ioctl	= mISDN_ioctl,
	.open		= mISDN_open,
	.release	= mISDN_close,
};

static struct miscdevice mISDNtimer = {
	.minor	= MISC_DYNAMIC_MINOR,
	.name	= "mISDNtimer",
	.fops	= &mISDN_fops,
};

int
mISDN_inittimer(u_int *deb)
{
	int	err;

	debug = deb;
	err = misc_register(&mISDNtimer);
	if (err)
		printk(KERN_WARNING "mISDN: Could not register timer device\n");
	return err;
}

void mISDN_timer_cleanup(void)
{
	misc_deregister(&mISDNtimer);
}