drivers/char/watchdog/wafer5823wdt.c

   1 /*
   2  *      ICP Wafer 5823 Single Board Computer WDT driver
   3  *      http://www.icpamerica.com/wafer_5823.php
   4  *      May also work on other similar models
   5  *
   6  *      (c) Copyright 2002 Justin Cormack <justin@street-vision.com>
   7  *
   8  *      Release 0.02
   9  *
  10  *      Based on advantechwdt.c which is based on wdt.c.
  11  *      Original copyright messages:
  12  *
  13  *      (c) Copyright 1996-1997 Alan Cox <alan@redhat.com>, All Rights Reserved.
  14  *                              http://www.redhat.com
  15  *
  16  *      This program is free software; you can redistribute it and/or
  17  *      modify it under the terms of the GNU General Public License
  18  *      as published by the Free Software Foundation; either version
  19  *      2 of the License, or (at your option) any later version.
  20  *
  21  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  22  *      warranty for any of this software. This material is provided
  23  *      "AS-IS" and at no charge.
  24  *
  25  *      (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
  26  *
  27  */
  28
  29 #include <linux/module.h>
  30 #include <linux/moduleparam.h>
  31 #include <linux/miscdevice.h>
  32 #include <linux/watchdog.h>
  33 #include <linux/fs.h>
  34 #include <linux/ioport.h>
  35 #include <linux/notifier.h>
  36 #include <linux/reboot.h>
  37 #include <linux/init.h>
  38 #include <linux/spinlock.h>
  39 #include <asm/io.h>
  40 #include <asm/uaccess.h>
  41
  42 #define WATCHDOG_NAME "Wafer 5823 WDT"
  43 #define PFX WATCHDOG_NAME ": "
  44 #define WD_TIMO 60                      /* 60 sec default timeout */
  45
  46 static unsigned long wafwdt_is_open;
  47 static char expect_close;
  48 static spinlock_t wafwdt_lock;
  49
  50 /*
  51  *      You must set these - there is no sane way to probe for this board.
  52  *
  53  *      To enable, write the timeout value in seconds (1 to 255) to I/O
  54  *      port WDT_START, then read the port to start the watchdog. To pat
  55  *      the dog, read port WDT_STOP to stop the timer, then read WDT_START
  56  *      to restart it again.
  57  */
  58
  59 static int wdt_stop = 0x843;
  60 static int wdt_start = 0x443;
  61
  62 static int timeout = WD_TIMO;  /* in seconds */
  63 module_param(timeout, int, 0);
  64 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=255, default=" __MODULE_STRING(WD_TIMO) ".");
  65
  66 static int nowayout = WATCHDOG_NOWAYOUT;
  67 module_param(nowayout, int, 0);
  68 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
  69
  70 static void wafwdt_ping(void)
  71 {
  72         /* pat watchdog */
  73         spin_lock(&wafwdt_lock);
  74         inb_p(wdt_stop);
  75         inb_p(wdt_start);
  76         spin_unlock(&wafwdt_lock);
  77 }
  78
  79 static void wafwdt_start(void)
  80 {
  81         /* start up watchdog */
  82         outb_p(timeout, wdt_start);
  83         inb_p(wdt_start);
  84 }
  85
  86 static void
  87 wafwdt_stop(void)
  88 {
  89         /* stop watchdog */
  90         inb_p(wdt_stop);
  91 }
  92
  93 static ssize_t wafwdt_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos)
  94 {
  95         /* See if we got the magic character 'V' and reload the timer */
  96         if (count) {
  97                 if (!nowayout) {
  98                         size_t i;
  99
 100                         /* In case it was set long ago */
 101                         expect_close = 0;
 102
 103                         /* scan to see whether or not we got the magic character */
 104                         for (i = 0; i != count; i++) {
 105                                 char c;
 106                                 if (get_user(c, buf + i))
 107                                         return -EFAULT;
 108                                 if (c == 'V')
 109                                         expect_close = 42;
 110                         }
 111                 }
 112                 /* Well, anyhow someone wrote to us, we should return that favour */
 113                 wafwdt_ping();
 114         }
 115         return count;
 116 }
 117
 118 static int wafwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 119              unsigned long arg)
 120 {
 121         int new_timeout;
 122         void __user *argp = (void __user *)arg;
 123         int __user *p = argp;
 124         static struct watchdog_info ident = {
 125                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 126                 .firmware_version = 1,
 127                 .identity = "Wafer 5823 WDT",
 128         };
 129
 130         switch (cmd) {
 131         case WDIOC_GETSUPPORT:
 132                 if (copy_to_user(argp, &ident, sizeof (ident)))
 133                         return -EFAULT;
 134                 break;
 135
 136         case WDIOC_GETSTATUS:
 137         case WDIOC_GETBOOTSTATUS:
 138                 return put_user(0, p);
 139
 140         case WDIOC_KEEPALIVE:
 141                 wafwdt_ping();
 142                 break;
 143
 144         case WDIOC_SETTIMEOUT:
 145                 if (get_user(new_timeout, p))
 146                         return -EFAULT;
 147                 if ((new_timeout < 1) || (new_timeout > 255))
 148                         return -EINVAL;
 149                 timeout = new_timeout;
 150                 wafwdt_stop();
 151                 wafwdt_start();
 152                 /* Fall */
 153         case WDIOC_GETTIMEOUT:
 154                 return put_user(timeout, p);
 155
 156         case WDIOC_SETOPTIONS:
 157         {
 158                 int options, retval = -EINVAL;
 159
 160                 if (get_user(options, p))
 161                         return -EFAULT;
 162
 163                 if (options & WDIOS_DISABLECARD) {
 164                         wafwdt_start();
 165                         retval = 0;
 166                 }
 167
 168                 if (options & WDIOS_ENABLECARD) {
 169                         wafwdt_stop();
 170                         retval = 0;
 171                 }
 172
 173                 return retval;
 174         }
 175
 176         default:
 177                 return -ENOIOCTLCMD;
 178         }
 179         return 0;
 180 }
 181
 182 static int wafwdt_open(struct inode *inode, struct file *file)
 183 {
 184         if (test_and_set_bit(0, &wafwdt_is_open))
 185                 return -EBUSY;
 186
 187         /*
 188          *      Activate
 189          */
 190         wafwdt_start();
 191         return nonseekable_open(inode, file);
 192 }
 193
 194 static int
 195 wafwdt_close(struct inode *inode, struct file *file)
 196 {
 197         if (expect_close == 42) {
 198                 wafwdt_stop();
 199         } else {
 200                 printk(KERN_CRIT PFX "WDT device closed unexpectedly.  WDT will not stop!\n");
 201                 wafwdt_ping();
 202         }
 203         clear_bit(0, &wafwdt_is_open);
 204         expect_close = 0;
 205         return 0;
 206 }
 207
 208 /*
 209  *      Notifier for system down
 210  */
 211
 212 static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
 213 {
 214         if (code == SYS_DOWN || code == SYS_HALT) {
 215                 /* Turn the WDT off */
 216                 wafwdt_stop();
 217         }
 218         return NOTIFY_DONE;
 219 }
 220
 221 /*
 222  *      Kernel Interfaces
 223  */
 224
 225 static struct file_operations wafwdt_fops = {
 226         .owner          = THIS_MODULE,
 227         .llseek         = no_llseek,
 228         .write          = wafwdt_write,
 229         .ioctl          = wafwdt_ioctl,
 230         .open           = wafwdt_open,
 231         .release        = wafwdt_close,
 232 };
 233
 234 static struct miscdevice wafwdt_miscdev = {
 235         .minor  = WATCHDOG_MINOR,
 236         .name   = "watchdog",
 237         .fops   = &wafwdt_fops,
 238 };
 239
 240 /*
 241  *      The WDT needs to learn about soft shutdowns in order to
 242  *      turn the timebomb registers off.
 243  */
 244
 245 static struct notifier_block wafwdt_notifier = {
 246         .notifier_call = wafwdt_notify_sys,
 247 };
 248
 249 static int __init wafwdt_init(void)
 250 {
 251         int ret;
 252
 253         printk(KERN_INFO "WDT driver for Wafer 5823 single board computer initialising.\n");
 254
 255         spin_lock_init(&wafwdt_lock);
 256
 257         if (timeout < 1 || timeout > 255) {
 258                 timeout = WD_TIMO;
 259                 printk (KERN_INFO PFX "timeout value must be 1<=x<=255, using %d\n",
 260                         timeout);
 261         }
 262
 263         if (wdt_stop != wdt_start) {
 264                 if(!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
 265                         printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
 266                         wdt_stop);
 267                         ret = -EIO;
 268                         goto error;
 269                 }
 270         }
 271
 272         if(!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
 273                 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
 274                         wdt_start);
 275                 ret = -EIO;
 276                 goto error2;
 277         }
 278
 279         ret = register_reboot_notifier(&wafwdt_notifier);
 280         if (ret != 0) {
 281                 printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 282                         ret);
 283                 goto error3;
 284         }
 285
 286         ret = misc_register(&wafwdt_miscdev);
 287         if (ret != 0) {
 288                 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 289                         WATCHDOG_MINOR, ret);
 290                 goto error4;
 291         }
 292
 293         printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 294                 timeout, nowayout);
 295
 296         return ret;
 297 error4:
 298         unregister_reboot_notifier(&wafwdt_notifier);
 299 error3:
 300         release_region(wdt_start, 1);
 301 error2:
 302         if (wdt_stop != wdt_start)
 303                 release_region(wdt_stop, 1);
 304 error:
 305         return ret;
 306 }
 307
 308 static void __exit wafwdt_exit(void)
 309 {
 310         misc_deregister(&wafwdt_miscdev);
 311         unregister_reboot_notifier(&wafwdt_notifier);
 312         if(wdt_stop != wdt_start)
 313                 release_region(wdt_stop, 1);
 314         release_region(wdt_start, 1);
 315 }
 316
 317 module_init(wafwdt_init);
 318 module_exit(wafwdt_exit);
 319
 320 MODULE_AUTHOR("Justin Cormack");
 321 MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
 322 MODULE_LICENSE("GPL");
 323 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 324
 325 /* end of wafer5823wdt.c */