1 /*
2 *
3 * general timer device for using in ISDN stacks
4 *
5 * Author Karsten Keil <kkeil@novell.com>
6 *
7 * Copyright 2008 by Karsten Keil <kkeil@novell.com>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 */
19
20 #include <linux/poll.h>
21 #include <linux/vmalloc.h>
22 #include <linux/slab.h>
23 #include <linux/timer.h>
24 #include <linux/miscdevice.h>
25 #include <linux/module.h>
26 #include <linux/mISDNif.h>
27 #include <linux/mutex.h>
28 #include "core.h"
29
30 static DEFINE_MUTEX(mISDN_mutex);
31 static u_int *debug;
32
33
34 struct mISDNtimerdev {
35 int next_id;
36 struct list_head pending;
37 struct list_head expired;
38 wait_queue_head_t wait;
39 u_int work;
40 spinlock_t lock; /* protect lists */
41 };
42
43 struct mISDNtimer {
44 struct list_head list;
45 struct mISDNtimerdev *dev;
46 struct timer_list tl;
47 int id;
48 };
49
50 static int
mISDN_open(struct inode * ino,struct file * filep)51 mISDN_open(struct inode *ino, struct file *filep)
52 {
53 struct mISDNtimerdev *dev;
54
55 if (*debug & DEBUG_TIMER)
56 printk(KERN_DEBUG "%s(%p,%p)\n", __func__, ino, filep);
57 dev = kmalloc(sizeof(struct mISDNtimerdev) , GFP_KERNEL);
58 if (!dev)
59 return -ENOMEM;
60 dev->next_id = 1;
61 INIT_LIST_HEAD(&dev->pending);
62 INIT_LIST_HEAD(&dev->expired);
63 spin_lock_init(&dev->lock);
64 dev->work = 0;
65 init_waitqueue_head(&dev->wait);
66 filep->private_data = dev;
67 __module_get(THIS_MODULE);
68 return nonseekable_open(ino, filep);
69 }
70
71 static int
mISDN_close(struct inode * ino,struct file * filep)72 mISDN_close(struct inode *ino, struct file *filep)
73 {
74 struct mISDNtimerdev *dev = filep->private_data;
75 struct mISDNtimer *timer, *next;
76
77 if (*debug & DEBUG_TIMER)
78 printk(KERN_DEBUG "%s(%p,%p)\n", __func__, ino, filep);
79 list_for_each_entry_safe(timer, next, &dev->pending, list) {
80 del_timer(&timer->tl);
81 kfree(timer);
82 }
83 list_for_each_entry_safe(timer, next, &dev->expired, list) {
84 kfree(timer);
85 }
86 kfree(dev);
87 module_put(THIS_MODULE);
88 return 0;
89 }
90
91 static ssize_t
mISDN_read(struct file * filep,char __user * buf,size_t count,loff_t * off)92 mISDN_read(struct file *filep, char __user *buf, size_t count, loff_t *off)
93 {
94 struct mISDNtimerdev *dev = filep->private_data;
95 struct mISDNtimer *timer;
96 u_long flags;
97 int ret = 0;
98
99 if (*debug & DEBUG_TIMER)
100 printk(KERN_DEBUG "%s(%p, %p, %d, %p)\n", __func__,
101 filep, buf, (int)count, off);
102
103 if (list_empty(&dev->expired) && (dev->work == 0)) {
104 if (filep->f_flags & O_NONBLOCK)
105 return -EAGAIN;
106 wait_event_interruptible(dev->wait, (dev->work ||
107 !list_empty(&dev->expired)));
108 if (signal_pending(current))
109 return -ERESTARTSYS;
110 }
111 if (count < sizeof(int))
112 return -ENOSPC;
113 if (dev->work)
114 dev->work = 0;
115 if (!list_empty(&dev->expired)) {
116 spin_lock_irqsave(&dev->lock, flags);
117 timer = (struct mISDNtimer *)dev->expired.next;
118 list_del(&timer->list);
119 spin_unlock_irqrestore(&dev->lock, flags);
120 if (put_user(timer->id, (int __user *)buf))
121 ret = -EFAULT;
122 else
123 ret = sizeof(int);
124 kfree(timer);
125 }
126 return ret;
127 }
128
129 static unsigned int
mISDN_poll(struct file * filep,poll_table * wait)130 mISDN_poll(struct file *filep, poll_table *wait)
131 {
132 struct mISDNtimerdev *dev = filep->private_data;
133 unsigned int mask = POLLERR;
134
135 if (*debug & DEBUG_TIMER)
136 printk(KERN_DEBUG "%s(%p, %p)\n", __func__, filep, wait);
137 if (dev) {
138 poll_wait(filep, &dev->wait, wait);
139 mask = 0;
140 if (dev->work || !list_empty(&dev->expired))
141 mask |= (POLLIN | POLLRDNORM);
142 if (*debug & DEBUG_TIMER)
143 printk(KERN_DEBUG "%s work(%d) empty(%d)\n", __func__,
144 dev->work, list_empty(&dev->expired));
145 }
146 return mask;
147 }
148
149 static void
dev_expire_timer(unsigned long data)150 dev_expire_timer(unsigned long data)
151 {
152 struct mISDNtimer *timer = (void *)data;
153 u_long flags;
154
155 spin_lock_irqsave(&timer->dev->lock, flags);
156 list_move_tail(&timer->list, &timer->dev->expired);
157 spin_unlock_irqrestore(&timer->dev->lock, flags);
158 wake_up_interruptible(&timer->dev->wait);
159 }
160
161 static int
misdn_add_timer(struct mISDNtimerdev * dev,int timeout)162 misdn_add_timer(struct mISDNtimerdev *dev, int timeout)
163 {
164 int id;
165 u_long flags;
166 struct mISDNtimer *timer;
167
168 if (!timeout) {
169 dev->work = 1;
170 wake_up_interruptible(&dev->wait);
171 id = 0;
172 } else {
173 timer = kzalloc(sizeof(struct mISDNtimer), GFP_KERNEL);
174 if (!timer)
175 return -ENOMEM;
176 spin_lock_irqsave(&dev->lock, flags);
177 timer->id = dev->next_id++;
178 if (dev->next_id < 0)
179 dev->next_id = 1;
180 list_add_tail(&timer->list, &dev->pending);
181 spin_unlock_irqrestore(&dev->lock, flags);
182 timer->dev = dev;
183 timer->tl.data = (long)timer;
184 timer->tl.function = dev_expire_timer;
185 init_timer(&timer->tl);
186 timer->tl.expires = jiffies + ((HZ * (u_long)timeout) / 1000);
187 add_timer(&timer->tl);
188 id = timer->id;
189 }
190 return id;
191 }
192
193 static int
misdn_del_timer(struct mISDNtimerdev * dev,int id)194 misdn_del_timer(struct mISDNtimerdev *dev, int id)
195 {
196 u_long flags;
197 struct mISDNtimer *timer;
198 int ret = 0;
199
200 spin_lock_irqsave(&dev->lock, flags);
201 list_for_each_entry(timer, &dev->pending, list) {
202 if (timer->id == id) {
203 list_del_init(&timer->list);
204 /* RED-PEN AK: race -- timer can be still running on
205 * other CPU. Needs reference count I think
206 */
207 del_timer(&timer->tl);
208 ret = timer->id;
209 kfree(timer);
210 goto unlock;
211 }
212 }
213 unlock:
214 spin_unlock_irqrestore(&dev->lock, flags);
215 return ret;
216 }
217
218 static long
mISDN_ioctl(struct file * filep,unsigned int cmd,unsigned long arg)219 mISDN_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
220 {
221 struct mISDNtimerdev *dev = filep->private_data;
222 int id, tout, ret = 0;
223
224
225 if (*debug & DEBUG_TIMER)
226 printk(KERN_DEBUG "%s(%p, %x, %lx)\n", __func__,
227 filep, cmd, arg);
228 mutex_lock(&mISDN_mutex);
229 switch (cmd) {
230 case IMADDTIMER:
231 if (get_user(tout, (int __user *)arg)) {
232 ret = -EFAULT;
233 break;
234 }
235 id = misdn_add_timer(dev, tout);
236 if (*debug & DEBUG_TIMER)
237 printk(KERN_DEBUG "%s add %d id %d\n", __func__,
238 tout, id);
239 if (id < 0) {
240 ret = id;
241 break;
242 }
243 if (put_user(id, (int __user *)arg))
244 ret = -EFAULT;
245 break;
246 case IMDELTIMER:
247 if (get_user(id, (int __user *)arg)) {
248 ret = -EFAULT;
249 break;
250 }
251 if (*debug & DEBUG_TIMER)
252 printk(KERN_DEBUG "%s del id %d\n", __func__, id);
253 id = misdn_del_timer(dev, id);
254 if (put_user(id, (int __user *)arg))
255 ret = -EFAULT;
256 break;
257 default:
258 ret = -EINVAL;
259 }
260 mutex_unlock(&mISDN_mutex);
261 return ret;
262 }
263
264 static const struct file_operations mISDN_fops = {
265 .read = mISDN_read,
266 .poll = mISDN_poll,
267 .unlocked_ioctl = mISDN_ioctl,
268 .open = mISDN_open,
269 .release = mISDN_close,
270 .llseek = no_llseek,
271 };
272
273 static struct miscdevice mISDNtimer = {
274 .minor = MISC_DYNAMIC_MINOR,
275 .name = "mISDNtimer",
276 .fops = &mISDN_fops,
277 };
278
279 int
mISDN_inittimer(u_int * deb)280 mISDN_inittimer(u_int *deb)
281 {
282 int err;
283
284 debug = deb;
285 err = misc_register(&mISDNtimer);
286 if (err)
287 printk(KERN_WARNING "mISDN: Could not register timer device\n");
288 return err;
289 }
290
mISDN_timer_cleanup(void)291 void mISDN_timer_cleanup(void)
292 {
293 misc_deregister(&mISDNtimer);
294 }
295