drivers/watchdog/wdt.c

   1 /*
   2  *      Industrial Computer Source WDT500/501 driver
   3  *
   4  *      (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
   5  *                                              All Rights Reserved.
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License
   9  *      as published by the Free Software Foundation; either version
  10  *      2 of the License, or (at your option) any later version.
  11  *
  12  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  13  *      warranty for any of this software. This material is provided
  14  *      "AS-IS" and at no charge.
  15  *
  16  *      (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
  17  *
  18  *      Release 0.10.
  19  *
  20  *      Fixes
  21  *              Dave Gregorich  :       Modularisation and minor bugs
  22  *              Alan Cox        :       Added the watchdog ioctl() stuff
  23  *              Alan Cox        :       Fixed the reboot problem (as noted by
  24  *                                      Matt Crocker).
  25  *              Alan Cox        :       Added wdt= boot option
  26  *              Alan Cox        :       Cleaned up copy/user stuff
  27  *              Tim Hockin      :       Added insmod parameters, comment
  28  *                                      cleanup, parameterized timeout
  29  *              Tigran Aivazian :       Restructured wdt_init() to handle
  30  *                                      failures
  31  *              Joel Becker     :       Added WDIOC_GET/SETTIMEOUT
  32  *              Matt Domsch     :       Added nowayout module option
  33  */
  34
  35 #include <linux/interrupt.h>
  36 #include <linux/module.h>
  37 #include <linux/moduleparam.h>
  38 #include <linux/types.h>
  39 #include <linux/miscdevice.h>
  40 #include <linux/watchdog.h>
  41 #include <linux/fs.h>
  42 #include <linux/ioport.h>
  43 #include <linux/notifier.h>
  44 #include <linux/reboot.h>
  45 #include <linux/init.h>
  46 #include <linux/io.h>
  47 #include <linux/uaccess.h>
  48
  49 #include <asm/system.h>
  50 #include "wd501p.h"
  51
  52 static unsigned long wdt_is_open;
  53 static char expect_close;
  54
  55 /*
  56  *      Module parameters
  57  */
  58
  59 #define WD_TIMO 60                      /* Default heartbeat = 60 seconds */
  60
  61 static int heartbeat = WD_TIMO;
  62 static int wd_heartbeat;
  63 module_param(heartbeat, int, 0);
  64 MODULE_PARM_DESC(heartbeat,
  65         "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, 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 /* You must set these - there is no sane way to probe for this board. */
  75 static int io = 0x240;
  76 static int irq = 11;
  77
  78 static DEFINE_SPINLOCK(wdt_lock);
  79
  80 module_param(io, int, 0);
  81 MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
  82 module_param(irq, int, 0);
  83 MODULE_PARM_DESC(irq, "WDT irq (default=11)");
  84
  85 #ifdef CONFIG_WDT_501
  86 /* Support for the Fan Tachometer on the WDT501-P */
  87 static int tachometer;
  88
  89 module_param(tachometer, int, 0);
  90 MODULE_PARM_DESC(tachometer,
  91                 "WDT501-P Fan Tachometer support (0=disable, default=0)");
  92 #endif /* CONFIG_WDT_501 */
  93
  94 /*
  95  *      Programming support
  96  */
  97
  98 static void wdt_ctr_mode(int ctr, int mode)
  99 {
 100         ctr <<= 6;
 101         ctr |= 0x30;
 102         ctr |= (mode << 1);
 103         outb_p(ctr, WDT_CR);
 104 }
 105
 106 static void wdt_ctr_load(int ctr, int val)
 107 {
 108         outb_p(val&0xFF, WDT_COUNT0+ctr);
 109         outb_p(val>>8, WDT_COUNT0+ctr);
 110 }
 111
 112 /**
 113  *      wdt_start:
 114  *
 115  *      Start the watchdog driver.
 116  */
 117
 118 static int wdt_start(void)
 119 {
 120         unsigned long flags;
 121         spin_lock_irqsave(&wdt_lock, flags);
 122         inb_p(WDT_DC);                  /* Disable watchdog */
 123         wdt_ctr_mode(0, 3);             /* Program CTR0 for Mode 3:
 124                                                 Square Wave Generator */
 125         wdt_ctr_mode(1, 2);             /* Program CTR1 for Mode 2:
 126                                                 Rate Generator */
 127         wdt_ctr_mode(2, 0);             /* Program CTR2 for Mode 0:
 128                                                 Pulse on Terminal Count */
 129         wdt_ctr_load(0, 8948);          /* Count at 100Hz */
 130         wdt_ctr_load(1, wd_heartbeat);  /* Heartbeat */
 131         wdt_ctr_load(2, 65535);         /* Length of reset pulse */
 132         outb_p(0, WDT_DC);              /* Enable watchdog */
 133         spin_unlock_irqrestore(&wdt_lock, flags);
 134         return 0;
 135 }
 136
 137 /**
 138  *      wdt_stop:
 139  *
 140  *      Stop the watchdog driver.
 141  */
 142
 143 static int wdt_stop(void)
 144 {
 145         unsigned long flags;
 146         spin_lock_irqsave(&wdt_lock, flags);
 147         /* Turn the card off */
 148         inb_p(WDT_DC);                  /* Disable watchdog */
 149         wdt_ctr_load(2, 0);             /* 0 length reset pulses now */
 150         spin_unlock_irqrestore(&wdt_lock, flags);
 151         return 0;
 152 }
 153
 154 /**
 155  *      wdt_ping:
 156  *
 157  *      Reload counter one with the watchdog heartbeat. We don't bother
 158  *      reloading the cascade counter.
 159  */
 160
 161 static int wdt_ping(void)
 162 {
 163         unsigned long flags;
 164         spin_lock_irqsave(&wdt_lock, flags);
 165         /* Write a watchdog value */
 166         inb_p(WDT_DC);                  /* Disable watchdog */
 167         wdt_ctr_mode(1, 2);             /* Re-Program CTR1 for Mode 2:
 168                                                         Rate Generator */
 169         wdt_ctr_load(1, wd_heartbeat);  /* Heartbeat */
 170         outb_p(0, WDT_DC);              /* Enable watchdog */
 171         spin_unlock_irqrestore(&wdt_lock, flags);
 172         return 0;
 173 }
 174
 175 /**
 176  *      wdt_set_heartbeat:
 177  *      @t:             the new heartbeat value that needs to be set.
 178  *
 179  *      Set a new heartbeat value for the watchdog device. If the heartbeat
 180  *      value is incorrect we keep the old value and return -EINVAL. If
 181  *      successful we return 0.
 182  */
 183
 184 static int wdt_set_heartbeat(int t)
 185 {
 186         if (t < 1 || t > 65535)
 187                 return -EINVAL;
 188
 189         heartbeat = t;
 190         wd_heartbeat = t * 100;
 191         return 0;
 192 }
 193
 194 /**
 195  *      wdt_get_status:
 196  *      @status:                the new status.
 197  *
 198  *      Extract the status information from a WDT watchdog device. There are
 199  *      several board variants so we have to know which bits are valid. Some
 200  *      bits default to one and some to zero in order to be maximally painful.
 201  *
 202  *      we then map the bits onto the status ioctl flags.
 203  */
 204
 205 static int wdt_get_status(int *status)
 206 {
 207         unsigned char new_status;
 208         unsigned long flags;
 209
 210         spin_lock_irqsave(&wdt_lock, flags);
 211         new_status = inb_p(WDT_SR);
 212         spin_unlock_irqrestore(&wdt_lock, flags);
 213
 214         *status = 0;
 215         if (new_status & WDC_SR_ISOI0)
 216                 *status |= WDIOF_EXTERN1;
 217         if (new_status & WDC_SR_ISII1)
 218                 *status |= WDIOF_EXTERN2;
 219 #ifdef CONFIG_WDT_501
 220         if (!(new_status & WDC_SR_TGOOD))
 221                 *status |= WDIOF_OVERHEAT;
 222         if (!(new_status & WDC_SR_PSUOVER))
 223                 *status |= WDIOF_POWEROVER;
 224         if (!(new_status & WDC_SR_PSUUNDR))
 225                 *status |= WDIOF_POWERUNDER;
 226         if (tachometer) {
 227                 if (!(new_status & WDC_SR_FANGOOD))
 228                         *status |= WDIOF_FANFAULT;
 229         }
 230 #endif /* CONFIG_WDT_501 */
 231         return 0;
 232 }
 233
 234 #ifdef CONFIG_WDT_501
 235 /**
 236  *      wdt_get_temperature:
 237  *
 238  *      Reports the temperature in degrees Fahrenheit. The API is in
 239  *      farenheit. It was designed by an imperial measurement luddite.
 240  */
 241
 242 static int wdt_get_temperature(int *temperature)
 243 {
 244         unsigned short c;
 245         unsigned long flags;
 246
 247         spin_lock_irqsave(&wdt_lock, flags);
 248         c = inb_p(WDT_RT);
 249         spin_unlock_irqrestore(&wdt_lock, flags);
 250         *temperature = (c * 11 / 15) + 7;
 251         return 0;
 252 }
 253 #endif /* CONFIG_WDT_501 */
 254
 255 /**
 256  *      wdt_interrupt:
 257  *      @irq:           Interrupt number
 258  *      @dev_id:        Unused as we don't allow multiple devices.
 259  *
 260  *      Handle an interrupt from the board. These are raised when the status
 261  *      map changes in what the board considers an interesting way. That means
 262  *      a failure condition occurring.
 263  */
 264
 265 static irqreturn_t wdt_interrupt(int irq, void *dev_id)
 266 {
 267         /*
 268          *      Read the status register see what is up and
 269          *      then printk it.
 270          */
 271         unsigned char status;
 272
 273         spin_lock(&wdt_lock);
 274         status = inb_p(WDT_SR);
 275
 276         printk(KERN_CRIT "WDT status %d\n", status);
 277
 278 #ifdef CONFIG_WDT_501
 279         if (!(status & WDC_SR_TGOOD))
 280                 printk(KERN_CRIT "Overheat alarm.(%d)\n", inb_p(WDT_RT));
 281         if (!(status & WDC_SR_PSUOVER))
 282                 printk(KERN_CRIT "PSU over voltage.\n");
 283         if (!(status & WDC_SR_PSUUNDR))
 284                 printk(KERN_CRIT "PSU under voltage.\n");
 285         if (tachometer) {
 286                 if (!(status & WDC_SR_FANGOOD))
 287                         printk(KERN_CRIT "Possible fan fault.\n");
 288         }
 289 #endif /* CONFIG_WDT_501 */
 290         if (!(status & WDC_SR_WCCR)) {
 291 #ifdef SOFTWARE_REBOOT
 292 #ifdef ONLY_TESTING
 293                 printk(KERN_CRIT "Would Reboot.\n");
 294 #else
 295                 printk(KERN_CRIT "Initiating system reboot.\n");
 296                 emergency_restart();
 297 #endif
 298 #else
 299                 printk(KERN_CRIT "Reset in 5ms.\n");
 300 #endif
 301         }
 302         spin_unlock(&wdt_lock);
 303         return IRQ_HANDLED;
 304 }
 305
 306
 307 /**
 308  *      wdt_write:
 309  *      @file: file handle to the watchdog
 310  *      @buf: buffer to write (unused as data does not matter here
 311  *      @count: count of bytes
 312  *      @ppos: pointer to the position to write. No seeks allowed
 313  *
 314  *      A write to a watchdog device is defined as a keepalive signal. Any
 315  *      write of data will do, as we we don't define content meaning.
 316  */
 317
 318 static ssize_t wdt_write(struct file *file, const char __user *buf,
 319                                                 size_t count, loff_t *ppos)
 320 {
 321         if (count) {
 322                 if (!nowayout) {
 323                         size_t i;
 324
 325                         /* In case it was set long ago */
 326                         expect_close = 0;
 327
 328                         for (i = 0; i != count; i++) {
 329                                 char c;
 330                                 if (get_user(c, buf + i))
 331                                         return -EFAULT;
 332                                 if (c == 'V')
 333                                         expect_close = 42;
 334                         }
 335                 }
 336                 wdt_ping();
 337         }
 338         return count;
 339 }
 340
 341 /**
 342  *      wdt_ioctl:
 343  *      @file: file handle to the device
 344  *      @cmd: watchdog command
 345  *      @arg: argument pointer
 346  *
 347  *      The watchdog API defines a common set of functions for all watchdogs
 348  *      according to their available features. We only actually usefully support
 349  *      querying capabilities and current status.
 350  */
 351
 352 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 353 {
 354         void __user *argp = (void __user *)arg;
 355         int __user *p = argp;
 356         int new_heartbeat;
 357         int status;
 358
 359         static struct watchdog_info ident = {
 360                 .options =              WDIOF_SETTIMEOUT|
 361                                         WDIOF_MAGICCLOSE|
 362                                         WDIOF_KEEPALIVEPING,
 363                 .firmware_version =     1,
 364                 .identity =             "WDT500/501",
 365         };
 366
 367         /* Add options according to the card we have */
 368         ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);
 369 #ifdef CONFIG_WDT_501
 370         ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|WDIOF_POWEROVER);
 371         if (tachometer)
 372                 ident.options |= WDIOF_FANFAULT;
 373 #endif /* CONFIG_WDT_501 */
 374
 375         switch (cmd) {
 376         case WDIOC_GETSUPPORT:
 377                 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 378         case WDIOC_GETSTATUS:
 379                 wdt_get_status(&status);
 380                 return put_user(status, p);
 381         case WDIOC_GETBOOTSTATUS:
 382                 return put_user(0, p);
 383         case WDIOC_KEEPALIVE:
 384                 wdt_ping();
 385                 return 0;
 386         case WDIOC_SETTIMEOUT:
 387                 if (get_user(new_heartbeat, p))
 388                         return -EFAULT;
 389                 if (wdt_set_heartbeat(new_heartbeat))
 390                         return -EINVAL;
 391                 wdt_ping();
 392                 /* Fall */
 393         case WDIOC_GETTIMEOUT:
 394                 return put_user(heartbeat, p);
 395         default:
 396                 return -ENOTTY;
 397         }
 398 }
 399
 400 /**
 401  *      wdt_open:
 402  *      @inode: inode of device
 403  *      @file: file handle to device
 404  *
 405  *      The watchdog device has been opened. The watchdog device is single
 406  *      open and on opening we load the counters. Counter zero is a 100Hz
 407  *      cascade, into counter 1 which downcounts to reboot. When the counter
 408  *      triggers counter 2 downcounts the length of the reset pulse which
 409  *      set set to be as long as possible.
 410  */
 411
 412 static int wdt_open(struct inode *inode, struct file *file)
 413 {
 414         if (test_and_set_bit(0, &wdt_is_open))
 415                 return -EBUSY;
 416         /*
 417          *      Activate
 418          */
 419         wdt_start();
 420         return nonseekable_open(inode, file);
 421 }
 422
 423 /**
 424  *      wdt_release:
 425  *      @inode: inode to board
 426  *      @file: file handle to board
 427  *
 428  *      The watchdog has a configurable API. There is a religious dispute
 429  *      between people who want their watchdog to be able to shut down and
 430  *      those who want to be sure if the watchdog manager dies the machine
 431  *      reboots. In the former case we disable the counters, in the latter
 432  *      case you have to open it again very soon.
 433  */
 434
 435 static int wdt_release(struct inode *inode, struct file *file)
 436 {
 437         if (expect_close == 42) {
 438                 wdt_stop();
 439                 clear_bit(0, &wdt_is_open);
 440         } else {
 441                 printk(KERN_CRIT
 442                  "wdt: WDT device closed unexpectedly.  WDT will not stop!\n");
 443                 wdt_ping();
 444         }
 445         expect_close = 0;
 446         return 0;
 447 }
 448
 449 #ifdef CONFIG_WDT_501
 450 /**
 451  *      wdt_temp_read:
 452  *      @file: file handle to the watchdog board
 453  *      @buf: buffer to write 1 byte into
 454  *      @count: length of buffer
 455  *      @ptr: offset (no seek allowed)
 456  *
 457  *      Temp_read reports the temperature in degrees Fahrenheit. The API is in
 458  *      farenheit. It was designed by an imperial measurement luddite.
 459  */
 460
 461 static ssize_t wdt_temp_read(struct file *file, char __user *buf,
 462                                                 size_t count, loff_t *ptr)
 463 {
 464         int temperature;
 465
 466         if (wdt_get_temperature(&temperature))
 467                 return -EFAULT;
 468
 469         if (copy_to_user(buf, &temperature, 1))
 470                 return -EFAULT;
 471
 472         return 1;
 473 }
 474
 475 /**
 476  *      wdt_temp_open:
 477  *      @inode: inode of device
 478  *      @file: file handle to device
 479  *
 480  *      The temperature device has been opened.
 481  */
 482
 483 static int wdt_temp_open(struct inode *inode, struct file *file)
 484 {
 485         return nonseekable_open(inode, file);
 486 }
 487
 488 /**
 489  *      wdt_temp_release:
 490  *      @inode: inode to board
 491  *      @file: file handle to board
 492  *
 493  *      The temperature device has been closed.
 494  */
 495
 496 static int wdt_temp_release(struct inode *inode, struct file *file)
 497 {
 498         return 0;
 499 }
 500 #endif /* CONFIG_WDT_501 */
 501
 502 /**
 503  *      notify_sys:
 504  *      @this: our notifier block
 505  *      @code: the event being reported
 506  *      @unused: unused
 507  *
 508  *      Our notifier is called on system shutdowns. We want to turn the card
 509  *      off at reboot otherwise the machine will reboot again during memory
 510  *      test or worse yet during the following fsck. This would suck, in fact
 511  *      trust me - if it happens it does suck.
 512  */
 513
 514 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 515         void *unused)
 516 {
 517         if (code == SYS_DOWN || code == SYS_HALT)
 518                 wdt_stop();
 519         return NOTIFY_DONE;
 520 }
 521
 522 /*
 523  *      Kernel Interfaces
 524  */
 525
 526
 527 static const struct file_operations wdt_fops = {
 528         .owner          = THIS_MODULE,
 529         .llseek         = no_llseek,
 530         .write          = wdt_write,
 531         .unlocked_ioctl = wdt_ioctl,
 532         .open           = wdt_open,
 533         .release        = wdt_release,
 534 };
 535
 536 static struct miscdevice wdt_miscdev = {
 537         .minor  = WATCHDOG_MINOR,
 538         .name   = "watchdog",
 539         .fops   = &wdt_fops,
 540 };
 541
 542 #ifdef CONFIG_WDT_501
 543 static const struct file_operations wdt_temp_fops = {
 544         .owner          = THIS_MODULE,
 545         .llseek         = no_llseek,
 546         .read           = wdt_temp_read,
 547         .open           = wdt_temp_open,
 548         .release        = wdt_temp_release,
 549 };
 550
 551 static struct miscdevice temp_miscdev = {
 552         .minor  = TEMP_MINOR,
 553         .name   = "temperature",
 554         .fops   = &wdt_temp_fops,
 555 };
 556 #endif /* CONFIG_WDT_501 */
 557
 558 /*
 559  *      The WDT card needs to learn about soft shutdowns in order to
 560  *      turn the timebomb registers off.
 561  */
 562
 563 static struct notifier_block wdt_notifier = {
 564         .notifier_call = wdt_notify_sys,
 565 };
 566
 567 /**
 568  *      cleanup_module:
 569  *
 570  *      Unload the watchdog. You cannot do this with any file handles open.
 571  *      If your watchdog is set to continue ticking on close and you unload
 572  *      it, well it keeps ticking. We won't get the interrupt but the board
 573  *      will not touch PC memory so all is fine. You just have to load a new
 574  *      module in 60 seconds or reboot.
 575  */
 576
 577 static void __exit wdt_exit(void)
 578 {
 579         misc_deregister(&wdt_miscdev);
 580 #ifdef CONFIG_WDT_501
 581         misc_deregister(&temp_miscdev);
 582 #endif /* CONFIG_WDT_501 */
 583         unregister_reboot_notifier(&wdt_notifier);
 584         free_irq(irq, NULL);
 585         release_region(io, 8);
 586 }
 587
 588 /**
 589  *      wdt_init:
 590  *
 591  *      Set up the WDT watchdog board. All we have to do is grab the
 592  *      resources we require and bitch if anyone beat us to them.
 593  *      The open() function will actually kick the board off.
 594  */
 595
 596 static int __init wdt_init(void)
 597 {
 598         int ret;
 599
 600         /* Check that the heartbeat value is within it's range;
 601            if not reset to the default */
 602         if (wdt_set_heartbeat(heartbeat)) {
 603                 wdt_set_heartbeat(WD_TIMO);
 604                 printk(KERN_INFO "wdt: heartbeat value must be 0 < heartbeat < 65536, using %d\n",
 605                         WD_TIMO);
 606         }
 607
 608         if (!request_region(io, 8, "wdt501p")) {
 609                 printk(KERN_ERR
 610                         "wdt: I/O address 0x%04x already in use\n", io);
 611                 ret = -EBUSY;
 612                 goto out;
 613         }
 614
 615         ret = request_irq(irq, wdt_interrupt, IRQF_DISABLED, "wdt501p", NULL);
 616         if (ret) {
 617                 printk(KERN_ERR "wdt: IRQ %d is not free.\n", irq);
 618                 goto outreg;
 619         }
 620
 621         ret = register_reboot_notifier(&wdt_notifier);
 622         if (ret) {
 623                 printk(KERN_ERR
 624                       "wdt: cannot register reboot notifier (err=%d)\n", ret);
 625                 goto outirq;
 626         }
 627
 628 #ifdef CONFIG_WDT_501
 629         ret = misc_register(&temp_miscdev);
 630         if (ret) {
 631                 printk(KERN_ERR
 632                         "wdt: cannot register miscdev on minor=%d (err=%d)\n",
 633                                                         TEMP_MINOR, ret);
 634                 goto outrbt;
 635         }
 636 #endif /* CONFIG_WDT_501 */
 637
 638         ret = misc_register(&wdt_miscdev);
 639         if (ret) {
 640                 printk(KERN_ERR
 641                         "wdt: cannot register miscdev on minor=%d (err=%d)\n",
 642                                                         WATCHDOG_MINOR, ret);
 643                 goto outmisc;
 644         }
 645
 646         ret = 0;
 647         printk(KERN_INFO "WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
 648                 io, irq, heartbeat, nowayout);
 649 #ifdef CONFIG_WDT_501
 650         printk(KERN_INFO "wdt: Fan Tachometer is %s\n",
 651                                 (tachometer ? "Enabled" : "Disabled"));
 652 #endif /* CONFIG_WDT_501 */
 653
 654 out:
 655         return ret;
 656
 657 outmisc:
 658 #ifdef CONFIG_WDT_501
 659         misc_deregister(&temp_miscdev);
 660 outrbt:
 661 #endif /* CONFIG_WDT_501 */
 662         unregister_reboot_notifier(&wdt_notifier);
 663 outirq:
 664         free_irq(irq, NULL);
 665 outreg:
 666         release_region(io, 8);
 667         goto out;
 668 }
 669
 670 module_init(wdt_init);
 671 module_exit(wdt_exit);
 672
 673 MODULE_AUTHOR("Alan Cox");
 674 MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");
 675 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 676 MODULE_ALIAS_MISCDEV(TEMP_MINOR);
 677 MODULE_LICENSE("GPL");