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/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 }