drivers/watchdog/wdt.c

   1 /*
   2  *      Industrial Computer Source WDT501 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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  36
  37 #include <linux/interrupt.h>
  38 #include <linux/module.h>
  39 #include <linux/moduleparam.h>
  40 #include <linux/types.h>
  41 #include <linux/miscdevice.h>
  42 #include <linux/watchdog.h>
  43 #include <linux/fs.h>
  44 #include <linux/ioport.h>
  45 #include <linux/notifier.h>
  46 #include <linux/reboot.h>
  47 #include <linux/init.h>
  48 #include <linux/io.h>
  49 #include <linux/uaccess.h>
  50
  51 #include "wd501p.h"
  52
  53 static unsigned long wdt_is_open;
  54 static char expect_close;
  55
  56 /*
  57  *      Module parameters
  58  */
  59
  60 #define WD_TIMO 60                      /* Default heartbeat = 60 seconds */
  61
  62 static int heartbeat = WD_TIMO;
  63 static int wd_heartbeat;
  64 module_param(heartbeat, int, 0);
  65 MODULE_PARM_DESC(heartbeat,
  66         "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default="
  67                                 __MODULE_STRING(WD_TIMO) ")");
  68
  69 static bool nowayout = WATCHDOG_NOWAYOUT;
  70 module_param(nowayout, bool, 0);
  71 MODULE_PARM_DESC(nowayout,
  72         "Watchdog cannot be stopped once started (default="
  73                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  74
  75 /* You must set these - there is no sane way to probe for this board. */
  76 static int io = 0x240;
  77 static int irq = 11;
  78
  79 static DEFINE_SPINLOCK(wdt_lock);
  80
  81 module_param(io, int, 0);
  82 MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
  83 module_param(irq, int, 0);
  84 MODULE_PARM_DESC(irq, "WDT irq (default=11)");
  85
  86 /* Support for the Fan Tachometer on the WDT501-P */
  87 static int tachometer;
  88 module_param(tachometer, int, 0);
  89 MODULE_PARM_DESC(tachometer,
  90                 "WDT501-P Fan Tachometer support (0=disable, default=0)");
  91
  92 static int type = 500;
  93 module_param(type, int, 0);
  94 MODULE_PARM_DESC(type,
  95                 "WDT501-P Card type (500 or 501, default=500)");
  96
  97 /*
  98  *      Programming support
  99  */
 100
 101 static void wdt_ctr_mode(int ctr, int mode)
 102 {
 103         ctr <<= 6;
 104         ctr |= 0x30;
 105         ctr |= (mode << 1);
 106         outb_p(ctr, WDT_CR);
 107 }
 108
 109 static void wdt_ctr_load(int ctr, int val)
 110 {
 111         outb_p(val&0xFF, WDT_COUNT0+ctr);
 112         outb_p(val>>8, WDT_COUNT0+ctr);
 113 }
 114
 115 /**
 116  *      wdt_start:
 117  *
 118  *      Start the watchdog driver.
 119  */
 120
 121 static int wdt_start(void)
 122 {
 123         unsigned long flags;
 124         spin_lock_irqsave(&wdt_lock, flags);
 125         inb_p(WDT_DC);                  /* Disable watchdog */
 126         wdt_ctr_mode(0, 3);             /* Program CTR0 for Mode 3:
 127                                                 Square Wave Generator */
 128         wdt_ctr_mode(1, 2);             /* Program CTR1 for Mode 2:
 129                                                 Rate Generator */
 130         wdt_ctr_mode(2, 0);             /* Program CTR2 for Mode 0:
 131                                                 Pulse on Terminal Count */
 132         wdt_ctr_load(0, 8948);          /* Count at 100Hz */
 133         wdt_ctr_load(1, wd_heartbeat);  /* Heartbeat */
 134         wdt_ctr_load(2, 65535);         /* Length of reset pulse */
 135         outb_p(0, WDT_DC);              /* Enable watchdog */
 136         spin_unlock_irqrestore(&wdt_lock, flags);
 137         return 0;
 138 }
 139
 140 /**
 141  *      wdt_stop:
 142  *
 143  *      Stop the watchdog driver.
 144  */
 145
 146 static int wdt_stop(void)
 147 {
 148         unsigned long flags;
 149         spin_lock_irqsave(&wdt_lock, flags);
 150         /* Turn the card off */
 151         inb_p(WDT_DC);                  /* Disable watchdog */
 152         wdt_ctr_load(2, 0);             /* 0 length reset pulses now */
 153         spin_unlock_irqrestore(&wdt_lock, flags);
 154         return 0;
 155 }
 156
 157 /**
 158  *      wdt_ping:
 159  *
 160  *      Reload counter one with the watchdog heartbeat. We don't bother
 161  *      reloading the cascade counter.
 162  */
 163
 164 static void wdt_ping(void)
 165 {
 166         unsigned long flags;
 167         spin_lock_irqsave(&wdt_lock, flags);
 168         /* Write a watchdog value */
 169         inb_p(WDT_DC);                  /* Disable watchdog */
 170         wdt_ctr_mode(1, 2);             /* Re-Program CTR1 for Mode 2:
 171                                                         Rate Generator */
 172         wdt_ctr_load(1, wd_heartbeat);  /* Heartbeat */
 173         outb_p(0, WDT_DC);              /* Enable watchdog */
 174         spin_unlock_irqrestore(&wdt_lock, flags);
 175 }
 176
 177 /**
 178  *      wdt_set_heartbeat:
 179  *      @t:             the new heartbeat value that needs to be set.
 180  *
 181  *      Set a new heartbeat value for the watchdog device. If the heartbeat
 182  *      value is incorrect we keep the old value and return -EINVAL. If
 183  *      successful we return 0.
 184  */
 185
 186 static int wdt_set_heartbeat(int t)
 187 {
 188         if (t < 1 || t > 65535)
 189                 return -EINVAL;
 190
 191         heartbeat = t;
 192         wd_heartbeat = t * 100;
 193         return 0;
 194 }
 195
 196 /**
 197  *      wdt_get_status:
 198  *
 199  *      Extract the status information from a WDT watchdog device. There are
 200  *      several board variants so we have to know which bits are valid. Some
 201  *      bits default to one and some to zero in order to be maximally painful.
 202  *
 203  *      we then map the bits onto the status ioctl flags.
 204  */
 205
 206 static int wdt_get_status(void)
 207 {
 208         unsigned char new_status;
 209         int status = 0;
 210         unsigned long flags;
 211
 212         spin_lock_irqsave(&wdt_lock, flags);
 213         new_status = inb_p(WDT_SR);
 214         spin_unlock_irqrestore(&wdt_lock, flags);
 215
 216         if (new_status & WDC_SR_ISOI0)
 217                 status |= WDIOF_EXTERN1;
 218         if (new_status & WDC_SR_ISII1)
 219                 status |= WDIOF_EXTERN2;
 220         if (type == 501) {
 221                 if (!(new_status & WDC_SR_TGOOD))
 222                         status |= WDIOF_OVERHEAT;
 223                 if (!(new_status & WDC_SR_PSUOVER))
 224                         status |= WDIOF_POWEROVER;
 225                 if (!(new_status & WDC_SR_PSUUNDR))
 226                         status |= WDIOF_POWERUNDER;
 227                 if (tachometer) {
 228                         if (!(new_status & WDC_SR_FANGOOD))
 229                                 status |= WDIOF_FANFAULT;
 230                 }
 231         }
 232         return status;
 233 }
 234
 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(void)
 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         return (c * 11 / 15) + 7;
 251 }
 252
 253 static void wdt_decode_501(int status)
 254 {
 255         if (!(status & WDC_SR_TGOOD))
 256                 pr_crit("Overheat alarm (%d)\n", inb_p(WDT_RT));
 257         if (!(status & WDC_SR_PSUOVER))
 258                 pr_crit("PSU over voltage\n");
 259         if (!(status & WDC_SR_PSUUNDR))
 260                 pr_crit("PSU under voltage\n");
 261 }
 262
 263 /**
 264  *      wdt_interrupt:
 265  *      @irq:           Interrupt number
 266  *      @dev_id:        Unused as we don't allow multiple devices.
 267  *
 268  *      Handle an interrupt from the board. These are raised when the status
 269  *      map changes in what the board considers an interesting way. That means
 270  *      a failure condition occurring.
 271  */
 272
 273 static irqreturn_t wdt_interrupt(int irq, void *dev_id)
 274 {
 275         /*
 276          *      Read the status register see what is up and
 277          *      then printk it.
 278          */
 279         unsigned char status;
 280
 281         spin_lock(&wdt_lock);
 282         status = inb_p(WDT_SR);
 283
 284         pr_crit("WDT status %d\n", status);
 285
 286         if (type == 501) {
 287                 wdt_decode_501(status);
 288                 if (tachometer) {
 289                         if (!(status & WDC_SR_FANGOOD))
 290                                 pr_crit("Possible fan fault\n");
 291                 }
 292         }
 293         if (!(status & WDC_SR_WCCR)) {
 294 #ifdef SOFTWARE_REBOOT
 295 #ifdef ONLY_TESTING
 296                 pr_crit("Would Reboot\n");
 297 #else
 298                 pr_crit("Initiating system reboot\n");
 299                 emergency_restart();
 300 #endif
 301 #else
 302                 pr_crit("Reset in 5ms\n");
 303 #endif
 304         }
 305         spin_unlock(&wdt_lock);
 306         return IRQ_HANDLED;
 307 }
 308
 309
 310 /**
 311  *      wdt_write:
 312  *      @file: file handle to the watchdog
 313  *      @buf: buffer to write (unused as data does not matter here
 314  *      @count: count of bytes
 315  *      @ppos: pointer to the position to write. No seeks allowed
 316  *
 317  *      A write to a watchdog device is defined as a keepalive signal. Any
 318  *      write of data will do, as we we don't define content meaning.
 319  */
 320
 321 static ssize_t wdt_write(struct file *file, const char __user *buf,
 322                                                 size_t count, loff_t *ppos)
 323 {
 324         if (count) {
 325                 if (!nowayout) {
 326                         size_t i;
 327
 328                         /* In case it was set long ago */
 329                         expect_close = 0;
 330
 331                         for (i = 0; i != count; i++) {
 332                                 char c;
 333                                 if (get_user(c, buf + i))
 334                                         return -EFAULT;
 335                                 if (c == 'V')
 336                                         expect_close = 42;
 337                         }
 338                 }
 339                 wdt_ping();
 340         }
 341         return count;
 342 }
 343
 344 /**
 345  *      wdt_ioctl:
 346  *      @file: file handle to the device
 347  *      @cmd: watchdog command
 348  *      @arg: argument pointer
 349  *
 350  *      The watchdog API defines a common set of functions for all watchdogs
 351  *      according to their available features. We only actually usefully support
 352  *      querying capabilities and current status.
 353  */
 354
 355 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 356 {
 357         void __user *argp = (void __user *)arg;
 358         int __user *p = argp;
 359         int new_heartbeat;
 360         int status;
 361
 362         struct watchdog_info ident = {
 363                 .options =              WDIOF_SETTIMEOUT|
 364                                         WDIOF_MAGICCLOSE|
 365                                         WDIOF_KEEPALIVEPING,
 366                 .firmware_version =     1,
 367                 .identity =             "WDT500/501",
 368         };
 369
 370         /* Add options according to the card we have */
 371         ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);
 372         if (type == 501) {
 373                 ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|
 374                                                         WDIOF_POWEROVER);
 375                 if (tachometer)
 376                         ident.options |= WDIOF_FANFAULT;
 377         }
 378
 379         switch (cmd) {
 380         case WDIOC_GETSUPPORT:
 381                 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 382         case WDIOC_GETSTATUS:
 383                 status = wdt_get_status();
 384                 return put_user(status, p);
 385         case WDIOC_GETBOOTSTATUS:
 386                 return put_user(0, p);
 387         case WDIOC_KEEPALIVE:
 388                 wdt_ping();
 389                 return 0;
 390         case WDIOC_SETTIMEOUT:
 391                 if (get_user(new_heartbeat, p))
 392                         return -EFAULT;
 393                 if (wdt_set_heartbeat(new_heartbeat))
 394                         return -EINVAL;
 395                 wdt_ping();
 396                 /* Fall */
 397         case WDIOC_GETTIMEOUT:
 398                 return put_user(heartbeat, p);
 399         default:
 400                 return -ENOTTY;
 401         }
 402 }
 403
 404 /**
 405  *      wdt_open:
 406  *      @inode: inode of device
 407  *      @file: file handle to device
 408  *
 409  *      The watchdog device has been opened. The watchdog device is single
 410  *      open and on opening we load the counters. Counter zero is a 100Hz
 411  *      cascade, into counter 1 which downcounts to reboot. When the counter
 412  *      triggers counter 2 downcounts the length of the reset pulse which
 413  *      set set to be as long as possible.
 414  */
 415
 416 static int wdt_open(struct inode *inode, struct file *file)
 417 {
 418         if (test_and_set_bit(0, &wdt_is_open))
 419                 return -EBUSY;
 420         /*
 421          *      Activate
 422          */
 423         wdt_start();
 424         return nonseekable_open(inode, file);
 425 }
 426
 427 /**
 428  *      wdt_release:
 429  *      @inode: inode to board
 430  *      @file: file handle to board
 431  *
 432  *      The watchdog has a configurable API. There is a religious dispute
 433  *      between people who want their watchdog to be able to shut down and
 434  *      those who want to be sure if the watchdog manager dies the machine
 435  *      reboots. In the former case we disable the counters, in the latter
 436  *      case you have to open it again very soon.
 437  */
 438
 439 static int wdt_release(struct inode *inode, struct file *file)
 440 {
 441         if (expect_close == 42) {
 442                 wdt_stop();
 443                 clear_bit(0, &wdt_is_open);
 444         } else {
 445                 pr_crit("WDT device closed unexpectedly.  WDT will not stop!\n");
 446                 wdt_ping();
 447         }
 448         expect_close = 0;
 449         return 0;
 450 }
 451
 452 /**
 453  *      wdt_temp_read:
 454  *      @file: file handle to the watchdog board
 455  *      @buf: buffer to write 1 byte into
 456  *      @count: length of buffer
 457  *      @ptr: offset (no seek allowed)
 458  *
 459  *      Temp_read reports the temperature in degrees Fahrenheit. The API is in
 460  *      farenheit. It was designed by an imperial measurement luddite.
 461  */
 462
 463 static ssize_t wdt_temp_read(struct file *file, char __user *buf,
 464                                                 size_t count, loff_t *ptr)
 465 {
 466         int temperature = wdt_get_temperature();
 467
 468         if (copy_to_user(buf, &temperature, 1))
 469                 return -EFAULT;
 470
 471         return 1;
 472 }
 473
 474 /**
 475  *      wdt_temp_open:
 476  *      @inode: inode of device
 477  *      @file: file handle to device
 478  *
 479  *      The temperature device has been opened.
 480  */
 481
 482 static int wdt_temp_open(struct inode *inode, struct file *file)
 483 {
 484         return nonseekable_open(inode, file);
 485 }
 486
 487 /**
 488  *      wdt_temp_release:
 489  *      @inode: inode to board
 490  *      @file: file handle to board
 491  *
 492  *      The temperature device has been closed.
 493  */
 494
 495 static int wdt_temp_release(struct inode *inode, struct file *file)
 496 {
 497         return 0;
 498 }
 499
 500 /**
 501  *      notify_sys:
 502  *      @this: our notifier block
 503  *      @code: the event being reported
 504  *      @unused: unused
 505  *
 506  *      Our notifier is called on system shutdowns. We want to turn the card
 507  *      off at reboot otherwise the machine will reboot again during memory
 508  *      test or worse yet during the following fsck. This would suck, in fact
 509  *      trust me - if it happens it does suck.
 510  */
 511
 512 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 513         void *unused)
 514 {
 515         if (code == SYS_DOWN || code == SYS_HALT)
 516                 wdt_stop();
 517         return NOTIFY_DONE;
 518 }
 519
 520 /*
 521  *      Kernel Interfaces
 522  */
 523
 524
 525 static const struct file_operations wdt_fops = {
 526         .owner          = THIS_MODULE,
 527         .llseek         = no_llseek,
 528         .write          = wdt_write,
 529         .unlocked_ioctl = wdt_ioctl,
 530         .open           = wdt_open,
 531         .release        = wdt_release,
 532 };
 533
 534 static struct miscdevice wdt_miscdev = {
 535         .minor  = WATCHDOG_MINOR,
 536         .name   = "watchdog",
 537         .fops   = &wdt_fops,
 538 };
 539
 540 static const struct file_operations wdt_temp_fops = {
 541         .owner          = THIS_MODULE,
 542         .llseek         = no_llseek,
 543         .read           = wdt_temp_read,
 544         .open           = wdt_temp_open,
 545         .release        = wdt_temp_release,
 546 };
 547
 548 static struct miscdevice temp_miscdev = {
 549         .minor  = TEMP_MINOR,
 550         .name   = "temperature",
 551         .fops   = &wdt_temp_fops,
 552 };
 553
 554 /*
 555  *      The WDT card needs to learn about soft shutdowns in order to
 556  *      turn the timebomb registers off.
 557  */
 558
 559 static struct notifier_block wdt_notifier = {
 560         .notifier_call = wdt_notify_sys,
 561 };
 562
 563 /**
 564  *      cleanup_module:
 565  *
 566  *      Unload the watchdog. You cannot do this with any file handles open.
 567  *      If your watchdog is set to continue ticking on close and you unload
 568  *      it, well it keeps ticking. We won't get the interrupt but the board
 569  *      will not touch PC memory so all is fine. You just have to load a new
 570  *      module in 60 seconds or reboot.
 571  */
 572
 573 static void __exit wdt_exit(void)
 574 {
 575         misc_deregister(&wdt_miscdev);
 576         if (type == 501)
 577                 misc_deregister(&temp_miscdev);
 578         unregister_reboot_notifier(&wdt_notifier);
 579         free_irq(irq, NULL);
 580         release_region(io, 8);
 581 }
 582
 583 /**
 584  *      wdt_init:
 585  *
 586  *      Set up the WDT watchdog board. All we have to do is grab the
 587  *      resources we require and bitch if anyone beat us to them.
 588  *      The open() function will actually kick the board off.
 589  */
 590
 591 static int __init wdt_init(void)
 592 {
 593         int ret;
 594
 595         if (type != 500 && type != 501) {
 596                 pr_err("unknown card type '%d'\n", type);
 597                 return -ENODEV;
 598         }
 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                 pr_info("heartbeat value must be 0 < heartbeat < 65536, using %d\n",
 605                         WD_TIMO);
 606         }
 607
 608         if (!request_region(io, 8, "wdt501p")) {
 609                 pr_err("I/O address 0x%04x already in use\n", io);
 610                 ret = -EBUSY;
 611                 goto out;
 612         }
 613
 614         ret = request_irq(irq, wdt_interrupt, 0, "wdt501p", NULL);
 615         if (ret) {
 616                 pr_err("IRQ %d is not free\n", irq);
 617                 goto outreg;
 618         }
 619
 620         ret = register_reboot_notifier(&wdt_notifier);
 621         if (ret) {
 622                 pr_err("cannot register reboot notifier (err=%d)\n", ret);
 623                 goto outirq;
 624         }
 625
 626         if (type == 501) {
 627                 ret = misc_register(&temp_miscdev);
 628                 if (ret) {
 629                         pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 630                                TEMP_MINOR, ret);
 631                         goto outrbt;
 632                 }
 633         }
 634
 635         ret = misc_register(&wdt_miscdev);
 636         if (ret) {
 637                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 638                        WATCHDOG_MINOR, ret);
 639                 goto outmisc;
 640         }
 641
 642         pr_info("WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
 643                 io, irq, heartbeat, nowayout);
 644         if (type == 501)
 645                 pr_info("Fan Tachometer is %s\n",
 646                         tachometer ? "Enabled" : "Disabled");
 647         return 0;
 648
 649 outmisc:
 650         if (type == 501)
 651                 misc_deregister(&temp_miscdev);
 652 outrbt:
 653         unregister_reboot_notifier(&wdt_notifier);
 654 outirq:
 655         free_irq(irq, NULL);
 656 outreg:
 657         release_region(io, 8);
 658 out:
 659         return ret;
 660 }
 661
 662 module_init(wdt_init);
 663 module_exit(wdt_exit);
 664
 665 MODULE_AUTHOR("Alan Cox");
 666 MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");
 667 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 668 MODULE_ALIAS_MISCDEV(TEMP_MINOR);
 669 MODULE_LICENSE("GPL");