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 return nonseekable_open(ino, filep); 68 } 69 70 static int 71 mISDN_close(struct inode *ino, struct file *filep) 72 { 73 struct mISDNtimerdev *dev = filep->private_data; 74 struct list_head *list = &dev->pending; 75 struct mISDNtimer *timer, *next; 76 77 if (*debug & DEBUG_TIMER) 78 printk(KERN_DEBUG "%s(%p,%p)\n", __func__, ino, filep); 79 80 spin_lock_irq(&dev->lock); 81 while (!list_empty(list)) { 82 timer = list_first_entry(list, struct mISDNtimer, list); 83 spin_unlock_irq(&dev->lock); 84 del_timer_sync(&timer->tl); 85 spin_lock_irq(&dev->lock); 86 /* it might have been moved to ->expired */ 87 list_del(&timer->list); 88 kfree(timer); 89 } 90 spin_unlock_irq(&dev->lock); 91 92 list_for_each_entry_safe(timer, next, &dev->expired, list) { 93 kfree(timer); 94 } 95 kfree(dev); 96 return 0; 97 } 98 99 static ssize_t 100 mISDN_read(struct file *filep, char __user *buf, size_t count, loff_t *off) 101 { 102 struct mISDNtimerdev *dev = filep->private_data; 103 struct list_head *list = &dev->expired; 104 struct mISDNtimer *timer; 105 int ret = 0; 106 107 if (*debug & DEBUG_TIMER) 108 printk(KERN_DEBUG "%s(%p, %p, %d, %p)\n", __func__, 109 filep, buf, (int)count, off); 110 111 if (count < sizeof(int)) 112 return -ENOSPC; 113 114 spin_lock_irq(&dev->lock); 115 while (list_empty(list) && (dev->work == 0)) { 116 spin_unlock_irq(&dev->lock); 117 if (filep->f_flags & O_NONBLOCK) 118 return -EAGAIN; 119 wait_event_interruptible(dev->wait, (dev->work || 120 !list_empty(list))); 121 if (signal_pending(current)) 122 return -ERESTARTSYS; 123 spin_lock_irq(&dev->lock); 124 } 125 if (dev->work) 126 dev->work = 0; 127 if (!list_empty(list)) { 128 timer = list_first_entry(list, struct mISDNtimer, list); 129 list_del(&timer->list); 130 spin_unlock_irq(&dev->lock); 131 if (put_user(timer->id, (int __user *)buf)) 132 ret = -EFAULT; 133 else 134 ret = sizeof(int); 135 kfree(timer); 136 } else { 137 spin_unlock_irq(&dev->lock); 138 } 139 return ret; 140 } 141 142 static unsigned int 143 mISDN_poll(struct file *filep, poll_table *wait) 144 { 145 struct mISDNtimerdev *dev = filep->private_data; 146 unsigned int mask = POLLERR; 147 148 if (*debug & DEBUG_TIMER) 149 printk(KERN_DEBUG "%s(%p, %p)\n", __func__, filep, wait); 150 if (dev) { 151 poll_wait(filep, &dev->wait, wait); 152 mask = 0; 153 if (dev->work || !list_empty(&dev->expired)) 154 mask |= (POLLIN | POLLRDNORM); 155 if (*debug & DEBUG_TIMER) 156 printk(KERN_DEBUG "%s work(%d) empty(%d)\n", __func__, 157 dev->work, list_empty(&dev->expired)); 158 } 159 return mask; 160 } 161 162 static void 163 dev_expire_timer(unsigned long data) 164 { 165 struct mISDNtimer *timer = (void *)data; 166 u_long flags; 167 168 spin_lock_irqsave(&timer->dev->lock, flags); 169 if (timer->id >= 0) 170 list_move_tail(&timer->list, &timer->dev->expired); 171 spin_unlock_irqrestore(&timer->dev->lock, flags); 172 wake_up_interruptible(&timer->dev->wait); 173 } 174 175 static int 176 misdn_add_timer(struct mISDNtimerdev *dev, int timeout) 177 { 178 int id; 179 struct mISDNtimer *timer; 180 181 if (!timeout) { 182 dev->work = 1; 183 wake_up_interruptible(&dev->wait); 184 id = 0; 185 } else { 186 timer = kzalloc(sizeof(struct mISDNtimer), GFP_KERNEL); 187 if (!timer) 188 return -ENOMEM; 189 timer->dev = dev; 190 setup_timer(&timer->tl, dev_expire_timer, (long)timer); 191 spin_lock_irq(&dev->lock); 192 id = timer->id = dev->next_id++; 193 if (dev->next_id < 0) 194 dev->next_id = 1; 195 list_add_tail(&timer->list, &dev->pending); 196 timer->tl.expires = jiffies + ((HZ * (u_long)timeout) / 1000); 197 add_timer(&timer->tl); 198 spin_unlock_irq(&dev->lock); 199 } 200 return id; 201 } 202 203 static int 204 misdn_del_timer(struct mISDNtimerdev *dev, int id) 205 { 206 struct mISDNtimer *timer; 207 208 spin_lock_irq(&dev->lock); 209 list_for_each_entry(timer, &dev->pending, list) { 210 if (timer->id == id) { 211 list_del_init(&timer->list); 212 timer->id = -1; 213 spin_unlock_irq(&dev->lock); 214 del_timer_sync(&timer->tl); 215 kfree(timer); 216 return id; 217 } 218 } 219 spin_unlock_irq(&dev->lock); 220 return 0; 221 } 222 223 static long 224 mISDN_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) 225 { 226 struct mISDNtimerdev *dev = filep->private_data; 227 int id, tout, ret = 0; 228 229 230 if (*debug & DEBUG_TIMER) 231 printk(KERN_DEBUG "%s(%p, %x, %lx)\n", __func__, 232 filep, cmd, arg); 233 mutex_lock(&mISDN_mutex); 234 switch (cmd) { 235 case IMADDTIMER: 236 if (get_user(tout, (int __user *)arg)) { 237 ret = -EFAULT; 238 break; 239 } 240 id = misdn_add_timer(dev, tout); 241 if (*debug & DEBUG_TIMER) 242 printk(KERN_DEBUG "%s add %d id %d\n", __func__, 243 tout, id); 244 if (id < 0) { 245 ret = id; 246 break; 247 } 248 if (put_user(id, (int __user *)arg)) 249 ret = -EFAULT; 250 break; 251 case IMDELTIMER: 252 if (get_user(id, (int __user *)arg)) { 253 ret = -EFAULT; 254 break; 255 } 256 if (*debug & DEBUG_TIMER) 257 printk(KERN_DEBUG "%s del id %d\n", __func__, id); 258 id = misdn_del_timer(dev, id); 259 if (put_user(id, (int __user *)arg)) 260 ret = -EFAULT; 261 break; 262 default: 263 ret = -EINVAL; 264 } 265 mutex_unlock(&mISDN_mutex); 266 return ret; 267 } 268 269 static const struct file_operations mISDN_fops = { 270 .owner = THIS_MODULE, 271 .read = mISDN_read, 272 .poll = mISDN_poll, 273 .unlocked_ioctl = mISDN_ioctl, 274 .open = mISDN_open, 275 .release = mISDN_close, 276 .llseek = no_llseek, 277 }; 278 279 static struct miscdevice mISDNtimer = { 280 .minor = MISC_DYNAMIC_MINOR, 281 .name = "mISDNtimer", 282 .fops = &mISDN_fops, 283 }; 284 285 int 286 mISDN_inittimer(u_int *deb) 287 { 288 int err; 289 290 debug = deb; 291 err = misc_register(&mISDNtimer); 292 if (err) 293 printk(KERN_WARNING "mISDN: Could not register timer device\n"); 294 return err; 295 } 296 297 void mISDN_timer_cleanup(void) 298 { 299 misc_deregister(&mISDNtimer); 300 } 301