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 #ifdef CONFIG_WATCHDOG_NOWAYOUT
  67 static int nowayout = 1;
  68 #else
  69 static int nowayout = 0;
  70 #endif
  71
  72 module_param(nowayout, int, 0);
  73 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
  74
  75 static void wafwdt_ping(void)
  76 {
  77         /* pat watchdog */
  78         spin_lock(&wafwdt_lock);
  79         inb_p(wdt_stop);
  80         inb_p(wdt_start);
  81         spin_unlock(&wafwdt_lock);
  82 }
  83
  84 static void wafwdt_start(void)
  85 {
  86         /* start up watchdog */
  87         outb_p(timeout, wdt_start);
  88         inb_p(wdt_start);
  89 }
  90
  91 static void
  92 wafwdt_stop(void)
  93 {
  94         /* stop watchdog */
  95         inb_p(wdt_stop);
  96 }
  97
  98 static ssize_t wafwdt_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos)
  99 {
 100         /* See if we got the magic character 'V' and reload the timer */
 101         if (count) {
 102                 if (!nowayout) {
 103                         size_t i;
 104
 105                         /* In case it was set long ago */
 106                         expect_close = 0;
 107
 108                         /* scan to see whether or not we got the magic character */
 109                         for (i = 0; i != count; i++) {
 110                                 char c;
 111                                 if (get_user(c, buf + i))
 112                                         return -EFAULT;
 113                                 if (c == 'V')
 114                                         expect_close = 42;
 115                         }
 116                 }
 117                 /* Well, anyhow someone wrote to us, we should return that favour */
 118                 wafwdt_ping();
 119         }
 120         return count;
 121 }
 122
 123 static int wafwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 124              unsigned long arg)
 125 {
 126         int new_timeout;
 127         void __user *argp = (void __user *)arg;
 128         int __user *p = argp;
 129         static struct watchdog_info ident = {
 130                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 131                 .firmware_version = 1,
 132                 .identity = "Wafer 5823 WDT",
 133         };
 134
 135         switch (cmd) {
 136         case WDIOC_GETSUPPORT:
 137                 if (copy_to_user(argp, &ident, sizeof (ident)))
 138                         return -EFAULT;
 139                 break;
 140
 141         case WDIOC_GETSTATUS:
 142         case WDIOC_GETBOOTSTATUS:
 143                 return put_user(0, p);
 144
 145         case WDIOC_KEEPALIVE:
 146                 wafwdt_ping();
 147                 break;
 148
 149         case WDIOC_SETTIMEOUT:
 150                 if (get_user(new_timeout, p))
 151                         return -EFAULT;
 152                 if ((new_timeout < 1) || (new_timeout > 255))
 153                         return -EINVAL;
 154                 timeout = new_timeout;
 155                 wafwdt_stop();
 156                 wafwdt_start();
 157                 /* Fall */
 158         case WDIOC_GETTIMEOUT:
 159                 return put_user(timeout, p);
 160
 161         case WDIOC_SETOPTIONS:
 162         {
 163                 int options, retval = -EINVAL;
 164
 165                 if (get_user(options, p))
 166                         return -EFAULT;
 167
 168                 if (options & WDIOS_DISABLECARD) {
 169                         wafwdt_start();
 170                         retval = 0;
 171                 }
 172
 173                 if (options & WDIOS_ENABLECARD) {
 174                         wafwdt_stop();
 175                         retval = 0;
 176                 }
 177
 178                 return retval;
 179         }
 180
 181         default:
 182                 return -ENOIOCTLCMD;
 183         }
 184         return 0;
 185 }
 186
 187 static int wafwdt_open(struct inode *inode, struct file *file)
 188 {
 189         if (test_and_set_bit(0, &wafwdt_is_open))
 190                 return -EBUSY;
 191
 192         /*
 193          *      Activate
 194          */
 195         wafwdt_start();
 196         return nonseekable_open(inode, file);
 197 }
 198
 199 static int
 200 wafwdt_close(struct inode *inode, struct file *file)
 201 {
 202         if (expect_close == 42) {
 203                 wafwdt_stop();
 204         } else {
 205                 printk(KERN_CRIT PFX "WDT device closed unexpectedly.  WDT will not stop!\n");
 206                 wafwdt_ping();
 207         }
 208         clear_bit(0, &wafwdt_is_open);
 209         expect_close = 0;
 210         return 0;
 211 }
 212
 213 /*
 214  *      Notifier for system down
 215  */
 216
 217 static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
 218 {
 219         if (code == SYS_DOWN || code == SYS_HALT) {
 220                 /* Turn the WDT off */
 221                 wafwdt_stop();
 222         }
 223         return NOTIFY_DONE;
 224 }
 225
 226 /*
 227  *      Kernel Interfaces
 228  */
 229
 230 static struct file_operations wafwdt_fops = {
 231         .owner          = THIS_MODULE,
 232         .llseek         = no_llseek,
 233         .write          = wafwdt_write,
 234         .ioctl          = wafwdt_ioctl,
 235         .open           = wafwdt_open,
 236         .release        = wafwdt_close,
 237 };
 238
 239 static struct miscdevice wafwdt_miscdev = {
 240         .minor  = WATCHDOG_MINOR,
 241         .name   = "watchdog",
 242         .fops   = &wafwdt_fops,
 243 };
 244
 245 /*
 246  *      The WDT needs to learn about soft shutdowns in order to
 247  *      turn the timebomb registers off.
 248  */
 249
 250 static struct notifier_block wafwdt_notifier = {
 251         .notifier_call = wafwdt_notify_sys,
 252 };
 253
 254 static int __init wafwdt_init(void)
 255 {
 256         int ret;
 257
 258         printk(KERN_INFO "WDT driver for Wafer 5823 single board computer initialising.\n");
 259
 260         spin_lock_init(&wafwdt_lock);
 261
 262         if (timeout < 1 || timeout > 255) {
 263                 timeout = WD_TIMO;
 264                 printk (KERN_INFO PFX "timeout value must be 1<=x<=255, using %d\n",
 265                         timeout);
 266         }
 267
 268         if (wdt_stop != wdt_start) {
 269                 if(!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
 270                         printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
 271                         wdt_stop);
 272                         ret = -EIO;
 273                         goto error;
 274                 }
 275         }
 276
 277         if(!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
 278                 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
 279                         wdt_start);
 280                 ret = -EIO;
 281                 goto error2;
 282         }
 283
 284         ret = register_reboot_notifier(&wafwdt_notifier);
 285         if (ret != 0) {
 286                 printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 287                         ret);
 288                 goto error3;
 289         }
 290
 291         ret = misc_register(&wafwdt_miscdev);
 292         if (ret != 0) {
 293                 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 294                         WATCHDOG_MINOR, ret);
 295                 goto error4;
 296         }
 297
 298         printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 299                 timeout, nowayout);
 300
 301         return ret;
 302 error4:
 303         unregister_reboot_notifier(&wafwdt_notifier);
 304 error3:
 305         release_region(wdt_start, 1);
 306 error2:
 307         if (wdt_stop != wdt_start)
 308                 release_region(wdt_stop, 1);
 309 error:
 310         return ret;
 311 }
 312
 313 static void __exit wafwdt_exit(void)
 314 {
 315         misc_deregister(&wafwdt_miscdev);
 316         unregister_reboot_notifier(&wafwdt_notifier);
 317         if(wdt_stop != wdt_start)
 318                 release_region(wdt_stop, 1);
 319         release_region(wdt_start, 1);
 320 }
 321
 322 module_init(wafwdt_init);
 323 module_exit(wafwdt_exit);
 324
 325 MODULE_AUTHOR("Justin Cormack");
 326 MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
 327 MODULE_LICENSE("GPL");
 328 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 329
 330 /* end of wafer5823wdt.c */