drivers/char/watchdog/advantechwdt.c

   1 /*
   2  *      Advantech Single Board Computer WDT driver
   3  *
   4  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
   5  *
   6  *      Based on acquirewdt.c which is based on wdt.c.
   7  *      Original copyright messages:
   8  *
   9  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
  10  *                              http://www.redhat.com
  11  *
  12  *      This program is free software; you can redistribute it and/or
  13  *      modify it under the terms of the GNU General Public License
  14  *      as published by the Free Software Foundation; either version
  15  *      2 of the License, or (at your option) any later version.
  16  *
  17  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  18  *      warranty for any of this software. This material is provided
  19  *      "AS-IS" and at no charge.
  20  *
  21  *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
  22  *
  23  *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  24  *          Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  25  *
  26  *      16-Oct-2002 Rob Radez <rob@osinvestor.com>
  27  *          Clean up ioctls, clean up init + exit, add expect close support,
  28  *          add wdt_start and wdt_stop as parameters.
  29  */
  30
  31 #include <linux/module.h>
  32 #include <linux/moduleparam.h>
  33 #include <linux/types.h>
  34 #include <linux/miscdevice.h>
  35 #include <linux/watchdog.h>
  36 #include <linux/fs.h>
  37 #include <linux/ioport.h>
  38 #include <linux/notifier.h>
  39 #include <linux/reboot.h>
  40 #include <linux/init.h>
  41
  42 #include <asm/io.h>
  43 #include <asm/uaccess.h>
  44 #include <asm/system.h>
  45
  46 #define WATCHDOG_NAME "Advantech WDT"
  47 #define PFX WATCHDOG_NAME ": "
  48 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  49
  50 static unsigned long advwdt_is_open;
  51 static char adv_expect_close;
  52
  53 /*
  54  *      You must set these - there is no sane way to probe for this board.
  55  *
  56  *      To enable or restart, write the timeout value in seconds (1 to 63)
  57  *      to I/O port wdt_start.  To disable, read I/O port wdt_stop.
  58  *      Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
  59  *      check your manual (at least the PCA-6159 seems to be different -
  60  *      the manual says wdt_stop is 0x43, not 0x443).
  61  *      (0x43 is also a write-only control register for the 8254 timer!)
  62  */
  63
  64 static int wdt_stop = 0x443;
  65 module_param(wdt_stop, int, 0);
  66 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
  67
  68 static int wdt_start = 0x443;
  69 module_param(wdt_start, int, 0);
  70 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
  71
  72 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  73 module_param(timeout, int, 0);
  74 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=63, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  75
  76 #ifdef CONFIG_WATCHDOG_NOWAYOUT
  77 static int nowayout = 1;
  78 #else
  79 static int nowayout = 0;
  80 #endif
  81
  82 module_param(nowayout, int, 0);
  83 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
  84
  85 /*
  86  *      Kernel methods.
  87  */
  88
  89 static void
  90 advwdt_ping(void)
  91 {
  92         /* Write a watchdog value */
  93         outb_p(timeout, wdt_start);
  94 }
  95
  96 static void
  97 advwdt_disable(void)
  98 {
  99         inb_p(wdt_stop);
 100 }
 101
 102 static ssize_t
 103 advwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 104 {
 105         if (count) {
 106                 if (!nowayout) {
 107                         size_t i;
 108
 109                         adv_expect_close = 0;
 110
 111                         for (i = 0; i != count; i++) {
 112                                 char c;
 113                                 if (get_user(c, buf+i))
 114                                         return -EFAULT;
 115                                 if (c == 'V')
 116                                         adv_expect_close = 42;
 117                         }
 118                 }
 119                 advwdt_ping();
 120         }
 121         return count;
 122 }
 123
 124 static int
 125 advwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 126           unsigned long arg)
 127 {
 128         int new_timeout;
 129         void __user *argp = (void __user *)arg;
 130         int __user *p = argp;
 131         static struct watchdog_info ident = {
 132                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 133                 .firmware_version = 1,
 134                 .identity = "Advantech 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_KEEPALIVE:
 148           advwdt_ping();
 149           break;
 150
 151         case WDIOC_SETTIMEOUT:
 152           if (get_user(new_timeout, p))
 153                   return -EFAULT;
 154           if ((new_timeout < 1) || (new_timeout > 63))
 155                   return -EINVAL;
 156           timeout = new_timeout;
 157           advwdt_ping();
 158           /* Fall */
 159
 160         case WDIOC_GETTIMEOUT:
 161           return put_user(timeout, p);
 162
 163         case WDIOC_SETOPTIONS:
 164         {
 165           int options, retval = -EINVAL;
 166
 167           if (get_user(options, p))
 168             return -EFAULT;
 169
 170           if (options & WDIOS_DISABLECARD) {
 171             advwdt_disable();
 172             retval = 0;
 173           }
 174
 175           if (options & WDIOS_ENABLECARD) {
 176             advwdt_ping();
 177             retval = 0;
 178           }
 179
 180           return retval;
 181         }
 182
 183         default:
 184           return -ENOIOCTLCMD;
 185         }
 186         return 0;
 187 }
 188
 189 static int
 190 advwdt_open(struct inode *inode, struct file *file)
 191 {
 192         if (test_and_set_bit(0, &advwdt_is_open))
 193                 return -EBUSY;
 194         /*
 195          *      Activate
 196          */
 197
 198         advwdt_ping();
 199         return nonseekable_open(inode, file);
 200 }
 201
 202 static int
 203 advwdt_close(struct inode *inode, struct file *file)
 204 {
 205         if (adv_expect_close == 42) {
 206                 advwdt_disable();
 207         } else {
 208                 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
 209                 advwdt_ping();
 210         }
 211         clear_bit(0, &advwdt_is_open);
 212         adv_expect_close = 0;
 213         return 0;
 214 }
 215
 216 /*
 217  *      Notifier for system down
 218  */
 219
 220 static int
 221 advwdt_notify_sys(struct notifier_block *this, unsigned long code,
 222         void *unused)
 223 {
 224         if (code == SYS_DOWN || code == SYS_HALT) {
 225                 /* Turn the WDT off */
 226                 advwdt_disable();
 227         }
 228         return NOTIFY_DONE;
 229 }
 230
 231 /*
 232  *      Kernel Interfaces
 233  */
 234
 235 static struct file_operations advwdt_fops = {
 236         .owner          = THIS_MODULE,
 237         .llseek         = no_llseek,
 238         .write          = advwdt_write,
 239         .ioctl          = advwdt_ioctl,
 240         .open           = advwdt_open,
 241         .release        = advwdt_close,
 242 };
 243
 244 static struct miscdevice advwdt_miscdev = {
 245         .minor = WATCHDOG_MINOR,
 246         .name = "watchdog",
 247         .fops = &advwdt_fops,
 248 };
 249
 250 /*
 251  *      The WDT needs to learn about soft shutdowns in order to
 252  *      turn the timebomb registers off.
 253  */
 254
 255 static struct notifier_block advwdt_notifier = {
 256         .notifier_call = advwdt_notify_sys,
 257 };
 258
 259 static int __init
 260 advwdt_init(void)
 261 {
 262         int ret;
 263
 264         printk(KERN_INFO "WDT driver for Advantech single board computer initialising.\n");
 265
 266         if (timeout < 1 || timeout > 63) {
 267                 timeout = WATCHDOG_TIMEOUT;
 268                 printk (KERN_INFO PFX "timeout value must be 1<=x<=63, using %d\n",
 269                         timeout);
 270         }
 271
 272         if (wdt_stop != wdt_start) {
 273                 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
 274                         printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
 275                                 wdt_stop);
 276                         ret = -EIO;
 277                         goto out;
 278                 }
 279         }
 280
 281         if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
 282                 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
 283                         wdt_start);
 284                 ret = -EIO;
 285                 goto unreg_stop;
 286         }
 287
 288         ret = register_reboot_notifier(&advwdt_notifier);
 289         if (ret != 0) {
 290                 printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 291                         ret);
 292                 goto unreg_regions;
 293         }
 294
 295         ret = misc_register(&advwdt_miscdev);
 296         if (ret != 0) {
 297                 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 298                         WATCHDOG_MINOR, ret);
 299                 goto unreg_reboot;
 300         }
 301
 302         printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 303                 timeout, nowayout);
 304
 305 out:
 306         return ret;
 307 unreg_reboot:
 308         unregister_reboot_notifier(&advwdt_notifier);
 309 unreg_regions:
 310         release_region(wdt_start, 1);
 311 unreg_stop:
 312         if (wdt_stop != wdt_start)
 313                 release_region(wdt_stop, 1);
 314         goto out;
 315 }
 316
 317 static void __exit
 318 advwdt_exit(void)
 319 {
 320         misc_deregister(&advwdt_miscdev);
 321         unregister_reboot_notifier(&advwdt_notifier);
 322         if(wdt_stop != wdt_start)
 323                 release_region(wdt_stop,1);
 324         release_region(wdt_start,1);
 325 }
 326
 327 module_init(advwdt_init);
 328 module_exit(advwdt_exit);
 329
 330 MODULE_LICENSE("GPL");
 331 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
 332 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
 333 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);