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 0; 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 loff_t 128 mISDN_llseek(struct file *filep, loff_t offset, int orig) 129 { 130 return -ESPIPE; 131 } 132 133 static ssize_t 134 mISDN_write(struct file *filep, const char *buf, size_t count, loff_t *off) 135 { 136 return -EOPNOTSUPP; 137 } 138 139 static unsigned int 140 mISDN_poll(struct file *filep, poll_table *wait) 141 { 142 struct mISDNtimerdev *dev = filep->private_data; 143 unsigned int mask = POLLERR; 144 145 if (*debug & DEBUG_TIMER) 146 printk(KERN_DEBUG "%s(%p, %p)\n", __func__, filep, wait); 147 if (dev) { 148 poll_wait(filep, &dev->wait, wait); 149 mask = 0; 150 if (dev->work || !list_empty(&dev->expired)) 151 mask |= (POLLIN | POLLRDNORM); 152 if (*debug & DEBUG_TIMER) 153 printk(KERN_DEBUG "%s work(%d) empty(%d)\n", __func__, 154 dev->work, list_empty(&dev->expired)); 155 } 156 return mask; 157 } 158 159 static void 160 dev_expire_timer(struct mISDNtimer *timer) 161 { 162 u_long flags; 163 164 spin_lock_irqsave(&timer->dev->lock, flags); 165 list_del(&timer->list); 166 list_add_tail(&timer->list, &timer->dev->expired); 167 spin_unlock_irqrestore(&timer->dev->lock, flags); 168 wake_up_interruptible(&timer->dev->wait); 169 } 170 171 static int 172 misdn_add_timer(struct mISDNtimerdev *dev, int timeout) 173 { 174 int id; 175 u_long flags; 176 struct mISDNtimer *timer; 177 178 if (!timeout) { 179 dev->work = 1; 180 wake_up_interruptible(&dev->wait); 181 id = 0; 182 } else { 183 timer = kzalloc(sizeof(struct mISDNtimer), GFP_KERNEL); 184 if (!timer) 185 return -ENOMEM; 186 spin_lock_irqsave(&dev->lock, flags); 187 timer->id = dev->next_id++; 188 if (dev->next_id < 0) 189 dev->next_id = 1; 190 list_add_tail(&timer->list, &dev->pending); 191 spin_unlock_irqrestore(&dev->lock, flags); 192 timer->dev = dev; 193 timer->tl.data = (long)timer; 194 timer->tl.function = (void *) dev_expire_timer; 195 init_timer(&timer->tl); 196 timer->tl.expires = jiffies + ((HZ * (u_long)timeout) / 1000); 197 add_timer(&timer->tl); 198 id = timer->id; 199 } 200 return id; 201 } 202 203 static int 204 misdn_del_timer(struct mISDNtimerdev *dev, int id) 205 { 206 u_long flags; 207 struct mISDNtimer *timer; 208 int ret = 0; 209 210 spin_lock_irqsave(&dev->lock, flags); 211 list_for_each_entry(timer, &dev->pending, list) { 212 if (timer->id == id) { 213 list_del_init(&timer->list); 214 del_timer(&timer->tl); 215 ret = timer->id; 216 kfree(timer); 217 goto unlock; 218 } 219 } 220 unlock: 221 spin_unlock_irqrestore(&dev->lock, flags); 222 return ret; 223 } 224 225 static int 226 mISDN_ioctl(struct inode *inode, struct file *filep, unsigned int cmd, 227 unsigned long arg) 228 { 229 struct mISDNtimerdev *dev = filep->private_data; 230 int id, tout, ret = 0; 231 232 233 if (*debug & DEBUG_TIMER) 234 printk(KERN_DEBUG "%s(%p, %x, %lx)\n", __func__, 235 filep, cmd, arg); 236 switch (cmd) { 237 case IMADDTIMER: 238 if (get_user(tout, (int __user *)arg)) { 239 ret = -EFAULT; 240 break; 241 } 242 id = misdn_add_timer(dev, tout); 243 if (*debug & DEBUG_TIMER) 244 printk(KERN_DEBUG "%s add %d id %d\n", __func__, 245 tout, id); 246 if (id < 0) { 247 ret = id; 248 break; 249 } 250 if (put_user(id, (int __user *)arg)) 251 ret = -EFAULT; 252 break; 253 case IMDELTIMER: 254 if (get_user(id, (int __user *)arg)) { 255 ret = -EFAULT; 256 break; 257 } 258 if (*debug & DEBUG_TIMER) 259 printk(KERN_DEBUG "%s del id %d\n", __func__, id); 260 id = misdn_del_timer(dev, id); 261 if (put_user(id, (int __user *)arg)) 262 ret = -EFAULT; 263 break; 264 default: 265 ret = -EINVAL; 266 } 267 return ret; 268 } 269 270 static struct file_operations mISDN_fops = { 271 .llseek = mISDN_llseek, 272 .read = mISDN_read, 273 .write = mISDN_write, 274 .poll = mISDN_poll, 275 .ioctl = mISDN_ioctl, 276 .open = mISDN_open, 277 .release = mISDN_close, 278 }; 279 280 static struct miscdevice mISDNtimer = { 281 .minor = MISC_DYNAMIC_MINOR, 282 .name = "mISDNtimer", 283 .fops = &mISDN_fops, 284 }; 285 286 int 287 mISDN_inittimer(int *deb) 288 { 289 int err; 290 291 debug = deb; 292 err = misc_register(&mISDNtimer); 293 if (err) 294 printk(KERN_WARNING "mISDN: Could not register timer device\n"); 295 return err; 296 } 297 298 void mISDN_timer_cleanup(void) 299 { 300 misc_deregister(&mISDNtimer); 301 } 302