drivers/char/watchdog/w83627hf_wdt.c

   1 /*
   2  *      w83627hf WDT driver
   3  *
   4  *      (c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
   5  *
   6  *      Based on advantechwdt.c which is based on wdt.c.
   7  *      Original copyright messages:
   8  *
   9  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
  10  *
  11  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
  12  *                              http://www.redhat.com
  13  *
  14  *      This program is free software; you can redistribute it and/or
  15  *      modify it under the terms of the GNU General Public License
  16  *      as published by the Free Software Foundation; either version
  17  *      2 of the License, or (at your option) any later version.
  18  *
  19  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  20  *      warranty for any of this software. This material is provided
  21  *      "AS-IS" and at no charge.
  22  *
  23  *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/moduleparam.h>
  28 #include <linux/types.h>
  29 #include <linux/miscdevice.h>
  30 #include <linux/watchdog.h>
  31 #include <linux/fs.h>
  32 #include <linux/ioport.h>
  33 #include <linux/notifier.h>
  34 #include <linux/reboot.h>
  35 #include <linux/init.h>
  36
  37 #include <asm/io.h>
  38 #include <asm/uaccess.h>
  39 #include <asm/system.h>
  40
  41 #define WATCHDOG_NAME "w83627hf WDT"
  42 #define PFX WATCHDOG_NAME ": "
  43 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  44
  45 static unsigned long wdt_is_open;
  46 static char expect_close;
  47
  48 /* You must set this - there is no sane way to probe for this board. */
  49 static int wdt_io = 0x2E;
  50 module_param(wdt_io, int, 0);
  51 MODULE_PARM_DESC(wdt_io, "w83627hf WDT io port (default 0x2E)");
  52
  53 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  54 module_param(timeout, int, 0);
  55 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=63, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  56
  57 static int nowayout = WATCHDOG_NOWAYOUT;
  58 module_param(nowayout, int, 0);
  59 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
  60
  61 /*
  62  *      Kernel methods.
  63  */
  64
  65 #define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
  66 #define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register (same as EFER) */
  67 #define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
  68
  69 static void
  70 w83627hf_select_wd_register(void)
  71 {
  72         outb_p(0x87, WDT_EFER); /* Enter extended function mode */
  73         outb_p(0x87, WDT_EFER); /* Again according to manual */
  74
  75         outb_p(0x07, WDT_EFER); /* point to logical device number reg */
  76         outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
  77         outb_p(0x30, WDT_EFER); /* select CR30 */
  78         outb_p(0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
  79 }
  80
  81 static void
  82 w83627hf_unselect_wd_register(void)
  83 {
  84         outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
  85 }
  86
  87 /* tyan motherboards seem to set F5 to 0x4C ?
  88  * So explicitly init to appropriate value. */
  89 static void
  90 w83627hf_init(void)
  91 {
  92         unsigned char t;
  93
  94         w83627hf_select_wd_register();
  95
  96         outb_p(0xF6, WDT_EFER); /* Select CRF6 */
  97         t=inb_p(WDT_EFDR);      /* read CRF6 */
  98         if (t != 0) {
  99                 printk (KERN_INFO PFX "Watchdog already running. Resetting timeout to %d sec\n", timeout);
 100                 outb_p(timeout, WDT_EFDR);    /* Write back to CRF6 */
 101         }
 102         outb_p(0xF5, WDT_EFER); /* Select CRF5 */
 103         t=inb_p(WDT_EFDR);      /* read CRF5 */
 104         t&=~0x0C;               /* set second mode & disable keyboard turning off watchdog */
 105         outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
 106
 107         w83627hf_unselect_wd_register();
 108 }
 109
 110 static void
 111 wdt_ctrl(int timeout)
 112 {
 113         w83627hf_select_wd_register();
 114
 115         outb_p(0xF6, WDT_EFER);    /* Select CRF6 */
 116         outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF6 */
 117
 118         w83627hf_unselect_wd_register();
 119 }
 120
 121 static int
 122 wdt_ping(void)
 123 {
 124         wdt_ctrl(timeout);
 125         return 0;
 126 }
 127
 128 static int
 129 wdt_disable(void)
 130 {
 131         wdt_ctrl(0);
 132         return 0;
 133 }
 134
 135 static int
 136 wdt_set_heartbeat(int t)
 137 {
 138         if ((t < 1) || (t > 63))
 139                 return -EINVAL;
 140
 141         timeout = t;
 142         return 0;
 143 }
 144
 145 static ssize_t
 146 wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 147 {
 148         if (count) {
 149                 if (!nowayout) {
 150                         size_t i;
 151
 152                         expect_close = 0;
 153
 154                         for (i = 0; i != count; i++) {
 155                                 char c;
 156                                 if (get_user(c, buf+i))
 157                                         return -EFAULT;
 158                                 if (c == 'V')
 159                                         expect_close = 42;
 160                         }
 161                 }
 162                 wdt_ping();
 163         }
 164         return count;
 165 }
 166
 167 static int
 168 wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 169           unsigned long arg)
 170 {
 171         void __user *argp = (void __user *)arg;
 172         int __user *p = argp;
 173         int new_timeout;
 174         static struct watchdog_info ident = {
 175                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 176                 .firmware_version = 1,
 177                 .identity = "W83627HF WDT",
 178         };
 179
 180         switch (cmd) {
 181         case WDIOC_GETSUPPORT:
 182           if (copy_to_user(argp, &ident, sizeof(ident)))
 183             return -EFAULT;
 184           break;
 185
 186         case WDIOC_GETSTATUS:
 187         case WDIOC_GETBOOTSTATUS:
 188           return put_user(0, p);
 189
 190         case WDIOC_KEEPALIVE:
 191           wdt_ping();
 192           break;
 193
 194         case WDIOC_SETTIMEOUT:
 195           if (get_user(new_timeout, p))
 196                   return -EFAULT;
 197           if (wdt_set_heartbeat(new_timeout))
 198                   return -EINVAL;
 199           wdt_ping();
 200           /* Fall */
 201
 202         case WDIOC_GETTIMEOUT:
 203           return put_user(timeout, p);
 204
 205         case WDIOC_SETOPTIONS:
 206         {
 207           int options, retval = -EINVAL;
 208
 209           if (get_user(options, p))
 210             return -EFAULT;
 211
 212           if (options & WDIOS_DISABLECARD) {
 213             wdt_disable();
 214             retval = 0;
 215           }
 216
 217           if (options & WDIOS_ENABLECARD) {
 218             wdt_ping();
 219             retval = 0;
 220           }
 221
 222           return retval;
 223         }
 224
 225         default:
 226           return -ENOIOCTLCMD;
 227         }
 228         return 0;
 229 }
 230
 231 static int
 232 wdt_open(struct inode *inode, struct file *file)
 233 {
 234         if (test_and_set_bit(0, &wdt_is_open))
 235                 return -EBUSY;
 236         /*
 237          *      Activate
 238          */
 239
 240         wdt_ping();
 241         return nonseekable_open(inode, file);
 242 }
 243
 244 static int
 245 wdt_close(struct inode *inode, struct file *file)
 246 {
 247         if (expect_close == 42) {
 248                 wdt_disable();
 249         } else {
 250                 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
 251                 wdt_ping();
 252         }
 253         expect_close = 0;
 254         clear_bit(0, &wdt_is_open);
 255         return 0;
 256 }
 257
 258 /*
 259  *      Notifier for system down
 260  */
 261
 262 static int
 263 wdt_notify_sys(struct notifier_block *this, unsigned long code,
 264         void *unused)
 265 {
 266         if (code == SYS_DOWN || code == SYS_HALT) {
 267                 /* Turn the WDT off */
 268                 wdt_disable();
 269         }
 270         return NOTIFY_DONE;
 271 }
 272
 273 /*
 274  *      Kernel Interfaces
 275  */
 276
 277 static struct file_operations wdt_fops = {
 278         .owner          = THIS_MODULE,
 279         .llseek         = no_llseek,
 280         .write          = wdt_write,
 281         .ioctl          = wdt_ioctl,
 282         .open           = wdt_open,
 283         .release        = wdt_close,
 284 };
 285
 286 static struct miscdevice wdt_miscdev = {
 287         .minor = WATCHDOG_MINOR,
 288         .name = "watchdog",
 289         .fops = &wdt_fops,
 290 };
 291
 292 /*
 293  *      The WDT needs to learn about soft shutdowns in order to
 294  *      turn the timebomb registers off.
 295  */
 296
 297 static struct notifier_block wdt_notifier = {
 298         .notifier_call = wdt_notify_sys,
 299 };
 300
 301 static int __init
 302 wdt_init(void)
 303 {
 304         int ret;
 305
 306         printk(KERN_INFO "WDT driver for the Winbond(TM) W83627HF Super I/O chip initialising.\n");
 307
 308         if (wdt_set_heartbeat(timeout)) {
 309                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
 310                 printk (KERN_INFO PFX "timeout value must be 1<=timeout<=63, using %d\n",
 311                         WATCHDOG_TIMEOUT);
 312         }
 313
 314         if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
 315                 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
 316                         wdt_io);
 317                 ret = -EIO;
 318                 goto out;
 319         }
 320
 321         w83627hf_init();
 322
 323         ret = register_reboot_notifier(&wdt_notifier);
 324         if (ret != 0) {
 325                 printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 326                         ret);
 327                 goto unreg_regions;
 328         }
 329
 330         ret = misc_register(&wdt_miscdev);
 331         if (ret != 0) {
 332                 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 333                         WATCHDOG_MINOR, ret);
 334                 goto unreg_reboot;
 335         }
 336
 337         printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 338                 timeout, nowayout);
 339
 340 out:
 341         return ret;
 342 unreg_reboot:
 343         unregister_reboot_notifier(&wdt_notifier);
 344 unreg_regions:
 345         release_region(wdt_io, 1);
 346         goto out;
 347 }
 348
 349 static void __exit
 350 wdt_exit(void)
 351 {
 352         misc_deregister(&wdt_miscdev);
 353         unregister_reboot_notifier(&wdt_notifier);
 354         release_region(wdt_io,1);
 355 }
 356
 357 module_init(wdt_init);
 358 module_exit(wdt_exit);
 359
 360 MODULE_LICENSE("GPL");
 361 MODULE_AUTHOR("Pádraig Brady <P@draigBrady.com>");
 362 MODULE_DESCRIPTION("w83627hf WDT driver");
 363 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);