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 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 }