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 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 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 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 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 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 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 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 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 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 } 290 291 void mISDN_timer_cleanup(void) 292 { 293 misc_deregister(&mISDNtimer); 294 } 295