drivers/char/watchdog/wdt977.c

   1 /*
   2  *      Wdt977  0.03:   A Watchdog Device for Netwinder W83977AF chip
   3  *
   4  *      (c) Copyright 1998 Rebel.com (Woody Suwalski <woody@netwinder.org>)
   5  *
   6  *                      -----------------------
   7  *
   8  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  *
  13  *                      -----------------------
  14  *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  15  *           Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  16  *      19-Dec-2001 Woody Suwalski: Netwinder fixes, ioctl interface
  17  *      06-Jan-2002 Woody Suwalski: For compatibility, convert all timeouts
  18  *                                  from minutes to seconds.
  19  *      07-Jul-2003 Daniele Bellucci: Audit return code of misc_register in
  20  *                                    nwwatchdog_init.
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/moduleparam.h>
  25 #include <linux/config.h>
  26 #include <linux/types.h>
  27 #include <linux/kernel.h>
  28 #include <linux/fs.h>
  29 #include <linux/miscdevice.h>
  30 #include <linux/init.h>
  31 #include <linux/watchdog.h>
  32 #include <linux/notifier.h>
  33 #include <linux/reboot.h>
  34
  35 #include <asm/io.h>
  36 #include <asm/system.h>
  37 #include <asm/mach-types.h>
  38 #include <asm/uaccess.h>
  39
  40 #define PFX "Wdt977: "
  41 #define WATCHDOG_MINOR  130
  42
  43 #define DEFAULT_TIMEOUT 60                      /* default timeout in seconds */
  44
  45 static  int timeout = DEFAULT_TIMEOUT;
  46 static  int timeoutM;                           /* timeout in minutes */
  47 static  unsigned long timer_alive;
  48 static  int testmode;
  49 static  char expect_close;
  50
  51 module_param(timeout, int, 0);
  52 MODULE_PARM_DESC(timeout,"Watchdog timeout in seconds (60..15300), default=" __MODULE_STRING(DEFAULT_TIMEOUT) ")");
  53 module_param(testmode, int, 0);
  54 MODULE_PARM_DESC(testmode,"Watchdog testmode (1 = no reboot), default=0");
  55
  56 #ifdef CONFIG_WATCHDOG_NOWAYOUT
  57 static int nowayout = 1;
  58 #else
  59 static int nowayout = 0;
  60 #endif
  61
  62 module_param(nowayout, int, 0);
  63 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
  64
  65 /*
  66  * Start the watchdog
  67  */
  68
  69 static int wdt977_start(void)
  70 {
  71         /* unlock the SuperIO chip */
  72         outb(0x87,0x370);
  73         outb(0x87,0x370);
  74
  75         /* select device Aux2 (device=8) and set watchdog regs F2, F3 and F4
  76          * F2 has the timeout in minutes
  77          * F3 could be set to the POWER LED blink (with GP17 set to PowerLed)
  78          *   at timeout, and to reset timer on kbd/mouse activity (not impl.)
  79          * F4 is used to just clear the TIMEOUT'ed state (bit 0)
  80          */
  81         outb(0x07,0x370);
  82         outb(0x08,0x371);
  83         outb(0xF2,0x370);
  84         outb(timeoutM,0x371);
  85         outb(0xF3,0x370);
  86         outb(0x00,0x371);       /* another setting is 0E for kbd/mouse/LED */
  87         outb(0xF4,0x370);
  88         outb(0x00,0x371);
  89
  90         /* at last select device Aux1 (dev=7) and set GP16 as a watchdog output */
  91         /* in test mode watch the bit 1 on F4 to indicate "triggered" */
  92         if (!testmode)
  93         {
  94                 outb(0x07,0x370);
  95                 outb(0x07,0x371);
  96                 outb(0xE6,0x370);
  97                 outb(0x08,0x371);
  98         }
  99
 100         /* lock the SuperIO chip */
 101         outb(0xAA,0x370);
 102
 103         printk(KERN_INFO PFX "activated.\n");
 104
 105         return 0;
 106 }
 107
 108 /*
 109  * Stop the watchdog
 110  */
 111
 112 static int wdt977_stop(void)
 113 {
 114         /* unlock the SuperIO chip */
 115         outb(0x87,0x370);
 116         outb(0x87,0x370);
 117
 118         /* select device Aux2 (device=8) and set watchdog regs F2,F3 and F4
 119         * F3 is reset to its default state
 120         * F4 can clear the TIMEOUT'ed state (bit 0) - back to default
 121         * We can not use GP17 as a PowerLed, as we use its usage as a RedLed
 122         */
 123         outb(0x07,0x370);
 124         outb(0x08,0x371);
 125         outb(0xF2,0x370);
 126         outb(0xFF,0x371);
 127         outb(0xF3,0x370);
 128         outb(0x00,0x371);
 129         outb(0xF4,0x370);
 130         outb(0x00,0x371);
 131         outb(0xF2,0x370);
 132         outb(0x00,0x371);
 133
 134         /* at last select device Aux1 (dev=7) and set GP16 as a watchdog output */
 135         outb(0x07,0x370);
 136         outb(0x07,0x371);
 137         outb(0xE6,0x370);
 138         outb(0x08,0x371);
 139
 140         /* lock the SuperIO chip */
 141         outb(0xAA,0x370);
 142
 143         printk(KERN_INFO PFX "shutdown.\n");
 144
 145         return 0;
 146 }
 147
 148 /*
 149  * Send a keepalive ping to the watchdog
 150  * This is done by simply re-writing the timeout to reg. 0xF2
 151  */
 152
 153 static int wdt977_keepalive(void)
 154 {
 155         /* unlock the SuperIO chip */
 156         outb(0x87,0x370);
 157         outb(0x87,0x370);
 158
 159         /* select device Aux2 (device=8) and kicks watchdog reg F2 */
 160         /* F2 has the timeout in minutes */
 161         outb(0x07,0x370);
 162         outb(0x08,0x371);
 163         outb(0xF2,0x370);
 164         outb(timeoutM,0x371);
 165
 166         /* lock the SuperIO chip */
 167         outb(0xAA,0x370);
 168
 169         return 0;
 170 }
 171
 172 /*
 173  * Set the watchdog timeout value
 174  */
 175
 176 static int wdt977_set_timeout(int t)
 177 {
 178         int tmrval;
 179
 180         /* convert seconds to minutes, rounding up */
 181         tmrval = (t + 59) / 60;
 182
 183         if (machine_is_netwinder()) {
 184                 /* we have a hw bug somewhere, so each 977 minute is actually only 30sec
 185                  *  this limits the max timeout to half of device max of 255 minutes...
 186                  */
 187                 tmrval += tmrval;
 188         }
 189
 190         if ((tmrval < 1) || (tmrval > 255))
 191                 return -EINVAL;
 192
 193         /* timeout is the timeout in seconds, timeoutM is the timeout in minutes) */
 194         timeout = t;
 195         timeoutM = tmrval;
 196         return 0;
 197 }
 198
 199 /*
 200  * Get the watchdog status
 201  */
 202
 203 static int wdt977_get_status(int *status)
 204 {
 205         int new_status;
 206
 207         *status=0;
 208
 209         /* unlock the SuperIO chip */
 210         outb(0x87,0x370);
 211         outb(0x87,0x370);
 212
 213         /* select device Aux2 (device=8) and read watchdog reg F4 */
 214         outb(0x07,0x370);
 215         outb(0x08,0x371);
 216         outb(0xF4,0x370);
 217         new_status = inb(0x371);
 218
 219         /* lock the SuperIO chip */
 220         outb(0xAA,0x370);
 221
 222         if (new_status & 1)
 223                 *status |= WDIOF_CARDRESET;
 224
 225         return 0;
 226 }
 227
 228
 229 /*
 230  *      /dev/watchdog handling
 231  */
 232
 233 static int wdt977_open(struct inode *inode, struct file *file)
 234 {
 235         /* If the watchdog is alive we don't need to start it again */
 236         if( test_and_set_bit(0,&timer_alive) )
 237                 return -EBUSY;
 238
 239         if (nowayout)
 240                 __module_get(THIS_MODULE);
 241
 242         wdt977_start();
 243         return nonseekable_open(inode, file);
 244 }
 245
 246 static int wdt977_release(struct inode *inode, struct file *file)
 247 {
 248         /*
 249          *      Shut off the timer.
 250          *      Lock it in if it's a module and we set nowayout
 251          */
 252         if (expect_close == 42)
 253         {
 254                 wdt977_stop();
 255                 clear_bit(0,&timer_alive);
 256         } else {
 257                 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
 258                 wdt977_keepalive();
 259         }
 260         expect_close = 0;
 261         return 0;
 262 }
 263
 264
 265 /*
 266  *      wdt977_write:
 267  *      @file: file handle to the watchdog
 268  *      @buf: buffer to write (unused as data does not matter here
 269  *      @count: count of bytes
 270  *      @ppos: pointer to the position to write. No seeks allowed
 271  *
 272  *      A write to a watchdog device is defined as a keepalive signal. Any
 273  *      write of data will do, as we we don't define content meaning.
 274  */
 275
 276 static ssize_t wdt977_write(struct file *file, const char __user *buf,
 277                             size_t count, loff_t *ppos)
 278 {
 279         if (count) {
 280                 if (!nowayout) {
 281                         size_t i;
 282
 283                         /* In case it was set long ago */
 284                         expect_close = 0;
 285
 286                         for (i = 0; i != count; i++) {
 287                                 char c;
 288                                 if (get_user(c, buf + i))
 289                                         return -EFAULT;
 290                                 if (c == 'V')
 291                                         expect_close = 42;
 292                         }
 293                 }
 294
 295                 wdt977_keepalive();
 296         }
 297         return count;
 298 }
 299
 300 /*
 301  *      wdt977_ioctl:
 302  *      @inode: inode of the device
 303  *      @file: file handle to the device
 304  *      @cmd: watchdog command
 305  *      @arg: argument pointer
 306  *
 307  *      The watchdog API defines a common set of functions for all watchdogs
 308  *      according to their available features.
 309  */
 310
 311 static struct watchdog_info ident = {
 312         .options =              WDIOF_SETTIMEOUT |
 313                                 WDIOF_MAGICCLOSE |
 314                                 WDIOF_KEEPALIVEPING,
 315         .firmware_version =     1,
 316         .identity =             "Winbond 83977",
 317 };
 318
 319 static int wdt977_ioctl(struct inode *inode, struct file *file,
 320         unsigned int cmd, unsigned long arg)
 321 {
 322         int status;
 323         int new_options, retval = -EINVAL;
 324         int new_timeout;
 325         union {
 326                 struct watchdog_info __user *ident;
 327                 int __user *i;
 328         } uarg;
 329
 330         uarg.i = (int __user *)arg;
 331
 332         switch(cmd)
 333         {
 334         default:
 335                 return -ENOIOCTLCMD;
 336
 337         case WDIOC_GETSUPPORT:
 338                 return copy_to_user(uarg.ident, &ident,
 339                         sizeof(ident)) ? -EFAULT : 0;
 340
 341         case WDIOC_GETSTATUS:
 342                 wdt977_get_status(&status);
 343                 return put_user(status, uarg.i);
 344
 345         case WDIOC_GETBOOTSTATUS:
 346                 return put_user(0, uarg.i);
 347
 348         case WDIOC_KEEPALIVE:
 349                 wdt977_keepalive();
 350                 return 0;
 351
 352         case WDIOC_SETOPTIONS:
 353                 if (get_user (new_options, uarg.i))
 354                         return -EFAULT;
 355
 356                 if (new_options & WDIOS_DISABLECARD) {
 357                         wdt977_stop();
 358                         retval = 0;
 359                 }
 360
 361                 if (new_options & WDIOS_ENABLECARD) {
 362                         wdt977_start();
 363                         retval = 0;
 364                 }
 365
 366                 return retval;
 367
 368         case WDIOC_SETTIMEOUT:
 369                 if (get_user(new_timeout, uarg.i))
 370                         return -EFAULT;
 371
 372                 if (wdt977_set_timeout(new_timeout))
 373                     return -EINVAL;
 374
 375                 wdt977_keepalive();
 376                 /* Fall */
 377
 378         case WDIOC_GETTIMEOUT:
 379                 return put_user(timeout, uarg.i);
 380
 381         }
 382 }
 383
 384 static int wdt977_notify_sys(struct notifier_block *this, unsigned long code,
 385         void *unused)
 386 {
 387         if(code==SYS_DOWN || code==SYS_HALT)
 388                 wdt977_stop();
 389         return NOTIFY_DONE;
 390 }
 391
 392 static struct file_operations wdt977_fops=
 393 {
 394         .owner          = THIS_MODULE,
 395         .llseek         = no_llseek,
 396         .write          = wdt977_write,
 397         .ioctl          = wdt977_ioctl,
 398         .open           = wdt977_open,
 399         .release        = wdt977_release,
 400 };
 401
 402 static struct miscdevice wdt977_miscdev=
 403 {
 404         .minor          = WATCHDOG_MINOR,
 405         .name           = "watchdog",
 406         .fops           = &wdt977_fops,
 407 };
 408
 409 static struct notifier_block wdt977_notifier = {
 410         .notifier_call = wdt977_notify_sys,
 411 };
 412
 413 static int __init nwwatchdog_init(void)
 414 {
 415         int retval;
 416         if (!machine_is_netwinder())
 417                 return -ENODEV;
 418
 419         /* Check that the timeout value is within it's range ; if not reset to the default */
 420         if (wdt977_set_timeout(timeout)) {
 421                 wdt977_set_timeout(DEFAULT_TIMEOUT);
 422                 printk(KERN_INFO PFX "timeout value must be 60<timeout<15300, using %d\n",
 423                         DEFAULT_TIMEOUT);
 424         }
 425
 426         retval = register_reboot_notifier(&wdt977_notifier);
 427         if (retval) {
 428                 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 429                         retval);
 430                 return retval;
 431         }
 432
 433         retval = misc_register(&wdt977_miscdev);
 434         if (retval) {
 435                 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 436                         WATCHDOG_MINOR, retval);
 437                 unregister_reboot_notifier(&wdt977_notifier);
 438                 return retval;
 439         }
 440
 441         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d, testmode = %i)\n",
 442                 timeout, nowayout, testmode);
 443
 444         return 0;
 445 }
 446
 447 static void __exit nwwatchdog_exit(void)
 448 {
 449         misc_deregister(&wdt977_miscdev);
 450         unregister_reboot_notifier(&wdt977_notifier);
 451 }
 452
 453 module_init(nwwatchdog_init);
 454 module_exit(nwwatchdog_exit);
 455
 456 MODULE_AUTHOR("Woody Suwalski <woody@netwinder.org>");
 457 MODULE_DESCRIPTION("W83977AF Watchdog driver");
 458 MODULE_LICENSE("GPL");
 459 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);