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         __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 }