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/timer.h> 23 #include <linux/miscdevice.h> 24 #include <linux/module.h> 25 #include <linux/mISDNif.h> 26 27 static int *debug; 28 29 30 struct mISDNtimerdev { 31 int next_id; 32 struct list_head pending; 33 struct list_head expired; 34 wait_queue_head_t wait; 35 u_int work; 36 spinlock_t lock; /* protect lists */ 37 }; 38 39 struct mISDNtimer { 40 struct list_head list; 41 struct mISDNtimerdev *dev; 42 struct timer_list tl; 43 int id; 44 }; 45 46 static int 47 mISDN_open(struct inode *ino, struct file *filep) 48 { 49 struct mISDNtimerdev *dev; 50 51 if (*debug & DEBUG_TIMER) 52 printk(KERN_DEBUG "%s(%p,%p)\n", __func__, ino, filep); 53 dev = kmalloc(sizeof(struct mISDNtimerdev) , GFP_KERNEL); 54 if (!dev) 55 return -ENOMEM; 56 dev->next_id = 1; 57 INIT_LIST_HEAD(&dev->pending); 58 INIT_LIST_HEAD(&dev->expired); 59 spin_lock_init(&dev->lock); 60 dev->work = 0; 61 init_waitqueue_head(&dev->wait); 62 filep->private_data = dev; 63 __module_get(THIS_MODULE); 64 return nonseekable_open(ino, filep); 65 } 66 67 static int 68 mISDN_close(struct inode *ino, struct file *filep) 69 { 70 struct mISDNtimerdev *dev = filep->private_data; 71 struct mISDNtimer *timer, *next; 72 73 if (*debug & DEBUG_TIMER) 74 printk(KERN_DEBUG "%s(%p,%p)\n", __func__, ino, filep); 75 list_for_each_entry_safe(timer, next, &dev->pending, list) { 76 del_timer(&timer->tl); 77 kfree(timer); 78 } 79 list_for_each_entry_safe(timer, next, &dev->expired, list) { 80 kfree(timer); 81 } 82 kfree(dev); 83 module_put(THIS_MODULE); 84 return 0; 85 } 86 87 static ssize_t 88 mISDN_read(struct file *filep, char *buf, size_t count, loff_t *off) 89 { 90 struct mISDNtimerdev *dev = filep->private_data; 91 struct mISDNtimer *timer; 92 u_long flags; 93 int ret = 0; 94 95 if (*debug & DEBUG_TIMER) 96 printk(KERN_DEBUG "%s(%p, %p, %d, %p)\n", __func__, 97 filep, buf, (int)count, off); 98 if (*off != filep->f_pos) 99 return -ESPIPE; 100 101 if (list_empty(&dev->expired) && (dev->work == 0)) { 102 if (filep->f_flags & O_NONBLOCK) 103 return -EAGAIN; 104 wait_event_interruptible(dev->wait, (dev->work || 105 !list_empty(&dev->expired))); 106 if (signal_pending(current)) 107 return -ERESTARTSYS; 108 } 109 if (count < sizeof(int)) 110 return -ENOSPC; 111 if (dev->work) 112 dev->work = 0; 113 if (!list_empty(&dev->expired)) { 114 spin_lock_irqsave(&dev->lock, flags); 115 timer = (struct mISDNtimer *)dev->expired.next; 116 list_del(&timer->list); 117 spin_unlock_irqrestore(&dev->lock, flags); 118 if (put_user(timer->id, (int *)buf)) 119 ret = -EFAULT; 120 else 121 ret = sizeof(int); 122 kfree(timer); 123 } 124 return ret; 125 } 126 127 static unsigned int 128 mISDN_poll(struct file *filep, poll_table *wait) 129 { 130 struct mISDNtimerdev *dev = filep->private_data; 131 unsigned int mask = POLLERR; 132 133 if (*debug & DEBUG_TIMER) 134 printk(KERN_DEBUG "%s(%p, %p)\n", __func__, filep, wait); 135 if (dev) { 136 poll_wait(filep, &dev->wait, wait); 137 mask = 0; 138 if (dev->work || !list_empty(&dev->expired)) 139 mask |= (POLLIN | POLLRDNORM); 140 if (*debug & DEBUG_TIMER) 141 printk(KERN_DEBUG "%s work(%d) empty(%d)\n", __func__, 142 dev->work, list_empty(&dev->expired)); 143 } 144 return mask; 145 } 146 147 static void 148 dev_expire_timer(unsigned long data) 149 { 150 struct mISDNtimer *timer = (void *)data; 151 u_long flags; 152 153 spin_lock_irqsave(&timer->dev->lock, flags); 154 list_del(&timer->list); 155 list_add_tail(&timer->list, &timer->dev->expired); 156 spin_unlock_irqrestore(&timer->dev->lock, flags); 157 wake_up_interruptible(&timer->dev->wait); 158 } 159 160 static int 161 misdn_add_timer(struct mISDNtimerdev *dev, int timeout) 162 { 163 int id; 164 u_long flags; 165 struct mISDNtimer *timer; 166 167 if (!timeout) { 168 dev->work = 1; 169 wake_up_interruptible(&dev->wait); 170 id = 0; 171 } else { 172 timer = kzalloc(sizeof(struct mISDNtimer), GFP_KERNEL); 173 if (!timer) 174 return -ENOMEM; 175 spin_lock_irqsave(&dev->lock, flags); 176 timer->id = dev->next_id++; 177 if (dev->next_id < 0) 178 dev->next_id = 1; 179 list_add_tail(&timer->list, &dev->pending); 180 spin_unlock_irqrestore(&dev->lock, flags); 181 timer->dev = dev; 182 timer->tl.data = (long)timer; 183 timer->tl.function = dev_expire_timer; 184 init_timer(&timer->tl); 185 timer->tl.expires = jiffies + ((HZ * (u_long)timeout) / 1000); 186 add_timer(&timer->tl); 187 id = timer->id; 188 } 189 return id; 190 } 191 192 static int 193 misdn_del_timer(struct mISDNtimerdev *dev, int id) 194 { 195 u_long flags; 196 struct mISDNtimer *timer; 197 int ret = 0; 198 199 spin_lock_irqsave(&dev->lock, flags); 200 list_for_each_entry(timer, &dev->pending, list) { 201 if (timer->id == id) { 202 list_del_init(&timer->list); 203 /* RED-PEN AK: race -- timer can be still running on 204 * other CPU. Needs reference count I think 205 */ 206 del_timer(&timer->tl); 207 ret = timer->id; 208 kfree(timer); 209 goto unlock; 210 } 211 } 212 unlock: 213 spin_unlock_irqrestore(&dev->lock, flags); 214 return ret; 215 } 216 217 static int 218 mISDN_ioctl(struct inode *inode, struct file *filep, unsigned int cmd, 219 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 switch (cmd) { 229 case IMADDTIMER: 230 if (get_user(tout, (int __user *)arg)) { 231 ret = -EFAULT; 232 break; 233 } 234 id = misdn_add_timer(dev, tout); 235 if (*debug & DEBUG_TIMER) 236 printk(KERN_DEBUG "%s add %d id %d\n", __func__, 237 tout, id); 238 if (id < 0) { 239 ret = id; 240 break; 241 } 242 if (put_user(id, (int __user *)arg)) 243 ret = -EFAULT; 244 break; 245 case IMDELTIMER: 246 if (get_user(id, (int __user *)arg)) { 247 ret = -EFAULT; 248 break; 249 } 250 if (*debug & DEBUG_TIMER) 251 printk(KERN_DEBUG "%s del id %d\n", __func__, id); 252 id = misdn_del_timer(dev, id); 253 if (put_user(id, (int __user *)arg)) 254 ret = -EFAULT; 255 break; 256 default: 257 ret = -EINVAL; 258 } 259 return ret; 260 } 261 262 static struct file_operations mISDN_fops = { 263 .read = mISDN_read, 264 .poll = mISDN_poll, 265 .ioctl = mISDN_ioctl, 266 .open = mISDN_open, 267 .release = mISDN_close, 268 }; 269 270 static struct miscdevice mISDNtimer = { 271 .minor = MISC_DYNAMIC_MINOR, 272 .name = "mISDNtimer", 273 .fops = &mISDN_fops, 274 }; 275 276 int 277 mISDN_inittimer(int *deb) 278 { 279 int err; 280 281 debug = deb; 282 err = misc_register(&mISDNtimer); 283 if (err) 284 printk(KERN_WARNING "mISDN: Could not register timer device\n"); 285 return err; 286 } 287 288 void mISDN_timer_cleanup(void) 289 { 290 misc_deregister(&mISDNtimer); 291 } 292