drivers/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@lxorguk.ukuu.org.uk>,
  14  *                                              All Rights Reserved.
  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 <linux/io.h>
  40 #include <linux/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 DEFINE_SPINLOCK(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,
  65                 "Watchdog timeout in seconds. 1 <= timeout <= 255, default="
  66                                 __MODULE_STRING(WD_TIMO) ".");
  67
  68 static int nowayout = WATCHDOG_NOWAYOUT;
  69 module_param(nowayout, int, 0);
  70 MODULE_PARM_DESC(nowayout,
  71                 "Watchdog cannot be stopped once started (default="
  72                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  73
  74 static void wafwdt_ping(void)
  75 {
  76         /* pat watchdog */
  77         spin_lock(&wafwdt_lock);
  78         inb_p(wdt_stop);
  79         inb_p(wdt_start);
  80         spin_unlock(&wafwdt_lock);
  81 }
  82
  83 static void wafwdt_start(void)
  84 {
  85         /* start up watchdog */
  86         outb_p(timeout, wdt_start);
  87         inb_p(wdt_start);
  88 }
  89
  90 static void wafwdt_stop(void)
  91 {
  92         /* stop watchdog */
  93         inb_p(wdt_stop);
  94 }
  95
  96 static ssize_t wafwdt_write(struct file *file, const char __user *buf,
  97                                                 size_t count, loff_t *ppos)
  98 {
  99         /* See if we got the magic character 'V' and reload the timer */
 100         if (count) {
 101                 if (!nowayout) {
 102                         size_t i;
 103
 104                         /* In case it was set long ago */
 105                         expect_close = 0;
 106
 107                         /* scan to see whether or not we got the magic
 108                            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
 118                    return that favour */
 119                 wafwdt_ping();
 120         }
 121         return count;
 122 }
 123
 124 static long wafwdt_ioctl(struct file *file, unsigned int cmd,
 125                                                         unsigned long arg)
 126 {
 127         int new_timeout;
 128         void __user *argp = (void __user *)arg;
 129         int __user *p = argp;
 130         static const struct watchdog_info ident = {
 131                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
 132                                                         WDIOF_MAGICCLOSE,
 133                 .firmware_version = 1,
 134                 .identity = "Wafer 5823 WDT",
 135         };
 136
 137         switch (cmd) {
 138         case WDIOC_GETSUPPORT:
 139                 if (copy_to_user(argp, &ident, sizeof(ident)))
 140                         return -EFAULT;
 141                 break;
 142
 143         case WDIOC_GETSTATUS:
 144         case WDIOC_GETBOOTSTATUS:
 145                 return put_user(0, p);
 146
 147         case WDIOC_SETOPTIONS:
 148         {
 149                 int options, retval = -EINVAL;
 150
 151                 if (get_user(options, p))
 152                         return -EFAULT;
 153
 154                 if (options & WDIOS_DISABLECARD) {
 155                         wafwdt_start();
 156                         retval = 0;
 157                 }
 158
 159                 if (options & WDIOS_ENABLECARD) {
 160                         wafwdt_stop();
 161                         retval = 0;
 162                 }
 163
 164                 return retval;
 165         }
 166
 167         case WDIOC_KEEPALIVE:
 168                 wafwdt_ping();
 169                 break;
 170
 171         case WDIOC_SETTIMEOUT:
 172                 if (get_user(new_timeout, p))
 173                         return -EFAULT;
 174                 if ((new_timeout < 1) || (new_timeout > 255))
 175                         return -EINVAL;
 176                 timeout = new_timeout;
 177                 wafwdt_stop();
 178                 wafwdt_start();
 179                 /* Fall */
 180         case WDIOC_GETTIMEOUT:
 181                 return put_user(timeout, p);
 182
 183         default:
 184                 return -ENOTTY;
 185         }
 186         return 0;
 187 }
 188
 189 static int wafwdt_open(struct inode *inode, struct file *file)
 190 {
 191         if (test_and_set_bit(0, &wafwdt_is_open))
 192                 return -EBUSY;
 193
 194         /*
 195          *      Activate
 196          */
 197         wafwdt_start();
 198         return nonseekable_open(inode, file);
 199 }
 200
 201 static int wafwdt_close(struct inode *inode, struct file *file)
 202 {
 203         if (expect_close == 42)
 204                 wafwdt_stop();
 205         else {
 206                 printk(KERN_CRIT PFX
 207                     "WDT device closed unexpectedly.  WDT will not stop!\n");
 208                 wafwdt_ping();
 209         }
 210         clear_bit(0, &wafwdt_is_open);
 211         expect_close = 0;
 212         return 0;
 213 }
 214
 215 /*
 216  *      Notifier for system down
 217  */
 218
 219 static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code,
 220                                                                 void *unused)
 221 {
 222         if (code == SYS_DOWN || code == SYS_HALT)
 223                 wafwdt_stop();
 224         return NOTIFY_DONE;
 225 }
 226
 227 /*
 228  *      Kernel Interfaces
 229  */
 230
 231 static const struct file_operations wafwdt_fops = {
 232         .owner          = THIS_MODULE,
 233         .llseek         = no_llseek,
 234         .write          = wafwdt_write,
 235         .unlocked_ioctl = wafwdt_ioctl,
 236         .open           = wafwdt_open,
 237         .release        = wafwdt_close,
 238 };
 239
 240 static struct miscdevice wafwdt_miscdev = {
 241         .minor  = WATCHDOG_MINOR,
 242         .name   = "watchdog",
 243         .fops   = &wafwdt_fops,
 244 };
 245
 246 /*
 247  *      The WDT needs to learn about soft shutdowns in order to
 248  *      turn the timebomb registers off.
 249  */
 250
 251 static struct notifier_block wafwdt_notifier = {
 252         .notifier_call = wafwdt_notify_sys,
 253 };
 254
 255 static int __init wafwdt_init(void)
 256 {
 257         int ret;
 258
 259         printk(KERN_INFO
 260           "WDT driver for Wafer 5823 single board computer initialising.\n");
 261
 262         if (timeout < 1 || timeout > 255) {
 263                 timeout = WD_TIMO;
 264                 printk(KERN_INFO PFX
 265                         "timeout value must be 1 <= x <= 255, using %d\n",
 266                                                                 timeout);
 267         }
 268
 269         if (wdt_stop != wdt_start) {
 270                 if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
 271                         printk(KERN_ERR PFX
 272                                 "I/O address 0x%04x already in use\n",
 273                                                                 wdt_stop);
 274                         ret = -EIO;
 275                         goto error;
 276                 }
 277         }
 278
 279         if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
 280                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 281                         wdt_start);
 282                 ret = -EIO;
 283                 goto error2;
 284         }
 285
 286         ret = register_reboot_notifier(&wafwdt_notifier);
 287         if (ret != 0) {
 288                 printk(KERN_ERR PFX
 289                         "cannot register reboot notifier (err=%d)\n", ret);
 290                 goto error3;
 291         }
 292
 293         ret = misc_register(&wafwdt_miscdev);
 294         if (ret != 0) {
 295                 printk(KERN_ERR PFX
 296                         "cannot register miscdev on minor=%d (err=%d)\n",
 297                                                 WATCHDOG_MINOR, ret);
 298                 goto error4;
 299         }
 300
 301         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 302                 timeout, nowayout);
 303
 304         return ret;
 305 error4:
 306         unregister_reboot_notifier(&wafwdt_notifier);
 307 error3:
 308         release_region(wdt_start, 1);
 309 error2:
 310         if (wdt_stop != wdt_start)
 311                 release_region(wdt_stop, 1);
 312 error:
 313         return ret;
 314 }
 315
 316 static void __exit wafwdt_exit(void)
 317 {
 318         misc_deregister(&wafwdt_miscdev);
 319         unregister_reboot_notifier(&wafwdt_notifier);
 320         if (wdt_stop != wdt_start)
 321                 release_region(wdt_stop, 1);
 322         release_region(wdt_start, 1);
 323 }
 324
 325 module_init(wafwdt_init);
 326 module_exit(wafwdt_exit);
 327
 328 MODULE_AUTHOR("Justin Cormack");
 329 MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
 330 MODULE_LICENSE("GPL");
 331 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 332
 333 /* end of wafer5823wdt.c */