drivers/isdn/mISDN/timerdev.c

   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 }