drivers/watchdog/wdt.c

   1 /*
   2  *      Industrial Computer Source WDT500/501 driver
   3  *
   4  *      (c) Copyright 1996-1997 Alan Cox <alan@redhat.com>, All Rights Reserved.
   5  *                              http://www.redhat.com
   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 cleanup
  28  *                                      Parameterized timeout
  29  *              Tigran Aivazian :       Restructured wdt_init() to handle failures
  30  *              Joel Becker     :       Added WDIOC_GET/SETTIMEOUT
  31  *              Matt Domsch     :       Added nowayout module option
  32  */
  33
  34 #include <linux/interrupt.h>
  35 #include <linux/module.h>
  36 #include <linux/moduleparam.h>
  37 #include <linux/types.h>
  38 #include <linux/miscdevice.h>
  39 #include <linux/watchdog.h>
  40 #include <linux/fs.h>
  41 #include <linux/ioport.h>
  42 #include <linux/notifier.h>
  43 #include <linux/reboot.h>
  44 #include <linux/init.h>
  45
  46 #include <asm/io.h>
  47 #include <asm/uaccess.h>
  48 #include <asm/system.h>
  49 #include "wd501p.h"
  50
  51 static unsigned long wdt_is_open;
  52 static char expect_close;
  53
  54 /*
  55  *      Module parameters
  56  */
  57
  58 #define WD_TIMO 60                      /* Default heartbeat = 60 seconds */
  59
  60 static int heartbeat = WD_TIMO;
  61 static int wd_heartbeat;
  62 module_param(heartbeat, int, 0);
  63 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (0<heartbeat<65536, default=" __MODULE_STRING(WD_TIMO) ")");
  64
  65 static int nowayout = WATCHDOG_NOWAYOUT;
  66 module_param(nowayout, int, 0);
  67 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  68
  69 /* You must set these - there is no sane way to probe for this board. */
  70 static int io=0x240;
  71 static int irq=11;
  72
  73 static DEFINE_SPINLOCK(wdt_lock);
  74
  75 module_param(io, int, 0);
  76 MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
  77 module_param(irq, int, 0);
  78 MODULE_PARM_DESC(irq, "WDT irq (default=11)");
  79
  80 #ifdef CONFIG_WDT_501
  81 /* Support for the Fan Tachometer on the WDT501-P */
  82 static int tachometer;
  83
  84 module_param(tachometer, int, 0);
  85 MODULE_PARM_DESC(tachometer, "WDT501-P Fan Tachometer support (0=disable, default=0)");
  86 #endif /* CONFIG_WDT_501 */
  87
  88 /*
  89  *      Programming support
  90  */
  91
  92 static void wdt_ctr_mode(int ctr, int mode)
  93 {
  94         ctr<<=6;
  95         ctr|=0x30;
  96         ctr|=(mode<<1);
  97         outb_p(ctr, WDT_CR);
  98 }
  99
 100 static void wdt_ctr_load(int ctr, int val)
 101 {
 102         outb_p(val&0xFF, WDT_COUNT0+ctr);
 103         outb_p(val>>8, WDT_COUNT0+ctr);
 104 }
 105
 106 /**
 107  *      wdt_start:
 108  *
 109  *      Start the watchdog driver.
 110  */
 111
 112 static int wdt_start(void)
 113 {
 114         unsigned long flags;
 115         spin_lock_irqsave(&wdt_lock, flags);
 116         inb_p(WDT_DC);                  /* Disable watchdog */
 117         wdt_ctr_mode(0,3);              /* Program CTR0 for Mode 3: Square Wave Generator */
 118         wdt_ctr_mode(1,2);              /* Program CTR1 for Mode 2: Rate Generator */
 119         wdt_ctr_mode(2,0);              /* Program CTR2 for Mode 0: Pulse on Terminal Count */
 120         wdt_ctr_load(0, 8948);          /* Count at 100Hz */
 121         wdt_ctr_load(1,wd_heartbeat);   /* Heartbeat */
 122         wdt_ctr_load(2,65535);          /* Length of reset pulse */
 123         outb_p(0, WDT_DC);              /* Enable watchdog */
 124         spin_unlock_irqrestore(&wdt_lock, flags);
 125         return 0;
 126 }
 127
 128 /**
 129  *      wdt_stop:
 130  *
 131  *      Stop the watchdog driver.
 132  */
 133
 134 static int wdt_stop (void)
 135 {
 136         unsigned long flags;
 137         spin_lock_irqsave(&wdt_lock, flags);
 138         /* Turn the card off */
 139         inb_p(WDT_DC);                  /* Disable watchdog */
 140         wdt_ctr_load(2,0);              /* 0 length reset pulses now */
 141         spin_unlock_irqrestore(&wdt_lock, flags);
 142         return 0;
 143 }
 144
 145 /**
 146  *      wdt_ping:
 147  *
 148  *      Reload counter one with the watchdog heartbeat. We don't bother reloading
 149  *      the cascade counter.
 150  */
 151
 152 static int wdt_ping(void)
 153 {
 154         unsigned long flags;
 155         spin_lock_irqsave(&wdt_lock, flags);
 156         /* Write a watchdog value */
 157         inb_p(WDT_DC);                  /* Disable watchdog */
 158         wdt_ctr_mode(1,2);              /* Re-Program CTR1 for Mode 2: Rate Generator */
 159         wdt_ctr_load(1,wd_heartbeat);   /* Heartbeat */
 160         outb_p(0, WDT_DC);              /* Enable watchdog */
 161         spin_unlock_irqrestore(&wdt_lock, flags);
 162         return 0;
 163 }
 164
 165 /**
 166  *      wdt_set_heartbeat:
 167  *      @t:             the new heartbeat value that needs to be set.
 168  *
 169  *      Set a new heartbeat value for the watchdog device. If the heartbeat value is
 170  *      incorrect we keep the old value and return -EINVAL. If successfull we
 171  *      return 0.
 172  */
 173 static int wdt_set_heartbeat(int t)
 174 {
 175         if ((t < 1) || (t > 65535))
 176                 return -EINVAL;
 177
 178         heartbeat = t;
 179         wd_heartbeat = t * 100;
 180         return 0;
 181 }
 182
 183 /**
 184  *      wdt_get_status:
 185  *      @status:                the new status.
 186  *
 187  *      Extract the status information from a WDT watchdog device. There are
 188  *      several board variants so we have to know which bits are valid. Some
 189  *      bits default to one and some to zero in order to be maximally painful.
 190  *
 191  *      we then map the bits onto the status ioctl flags.
 192  */
 193
 194 static int wdt_get_status(int *status)
 195 {
 196         unsigned char new_status;
 197         unsigned long flags;
 198
 199         spin_lock_irqsave(&wdt_lock, flags);
 200         new_status = inb_p(WDT_SR);
 201         spin_unlock_irqrestore(&wdt_lock, flags);
 202
 203         *status=0;
 204         if (new_status & WDC_SR_ISOI0)
 205                 *status |= WDIOF_EXTERN1;
 206         if (new_status & WDC_SR_ISII1)
 207                 *status |= WDIOF_EXTERN2;
 208 #ifdef CONFIG_WDT_501
 209         if (!(new_status & WDC_SR_TGOOD))
 210                 *status |= WDIOF_OVERHEAT;
 211         if (!(new_status & WDC_SR_PSUOVER))
 212                 *status |= WDIOF_POWEROVER;
 213         if (!(new_status & WDC_SR_PSUUNDR))
 214                 *status |= WDIOF_POWERUNDER;
 215         if (tachometer) {
 216                 if (!(new_status & WDC_SR_FANGOOD))
 217                         *status |= WDIOF_FANFAULT;
 218         }
 219 #endif /* CONFIG_WDT_501 */
 220         return 0;
 221 }
 222
 223 #ifdef CONFIG_WDT_501
 224 /**
 225  *      wdt_get_temperature:
 226  *
 227  *      Reports the temperature in degrees Fahrenheit. The API is in
 228  *      farenheit. It was designed by an imperial measurement luddite.
 229  */
 230
 231 static int wdt_get_temperature(int *temperature)
 232 {
 233         unsigned short c;
 234         unsigned long flags;
 235
 236         spin_lock_irqsave(&wdt_lock, flags);
 237         c = inb_p(WDT_RT);
 238         spin_unlock_irqrestore(&wdt_lock, flags);
 239         *temperature = (c * 11 / 15) + 7;
 240         return 0;
 241 }
 242 #endif /* CONFIG_WDT_501 */
 243
 244 /**
 245  *      wdt_interrupt:
 246  *      @irq:           Interrupt number
 247  *      @dev_id:        Unused as we don't allow multiple devices.
 248  *
 249  *      Handle an interrupt from the board. These are raised when the status
 250  *      map changes in what the board considers an interesting way. That means
 251  *      a failure condition occurring.
 252  */
 253
 254 static irqreturn_t wdt_interrupt(int irq, void *dev_id)
 255 {
 256         /*
 257          *      Read the status register see what is up and
 258          *      then printk it.
 259          */
 260         unsigned char status;
 261
 262         spin_lock(&wdt_lock);
 263         status = inb_p(WDT_SR);
 264
 265         printk(KERN_CRIT "WDT status %d\n", status);
 266
 267 #ifdef CONFIG_WDT_501
 268         if (!(status & WDC_SR_TGOOD))
 269                 printk(KERN_CRIT "Overheat alarm.(%d)\n",inb_p(WDT_RT));
 270         if (!(status & WDC_SR_PSUOVER))
 271                 printk(KERN_CRIT "PSU over voltage.\n");
 272         if (!(status & WDC_SR_PSUUNDR))
 273                 printk(KERN_CRIT "PSU under voltage.\n");
 274         if (tachometer) {
 275                 if (!(status & WDC_SR_FANGOOD))
 276                         printk(KERN_CRIT "Possible fan fault.\n");
 277         }
 278 #endif /* CONFIG_WDT_501 */
 279         if (!(status & WDC_SR_WCCR)) {
 280 #ifdef SOFTWARE_REBOOT
 281 #ifdef ONLY_TESTING
 282                 printk(KERN_CRIT "Would Reboot.\n");
 283 #else
 284                 printk(KERN_CRIT "Initiating system reboot.\n");
 285                 emergency_restart();
 286 #endif
 287 #else
 288                 printk(KERN_CRIT "Reset in 5ms.\n");
 289 #endif
 290         }
 291         spin_unlock(&wdt_lock);
 292         return IRQ_HANDLED;
 293 }
 294
 295
 296 /**
 297  *      wdt_write:
 298  *      @file: file handle to the watchdog
 299  *      @buf: buffer to write (unused as data does not matter here
 300  *      @count: count of bytes
 301  *      @ppos: pointer to the position to write. No seeks allowed
 302  *
 303  *      A write to a watchdog device is defined as a keepalive signal. Any
 304  *      write of data will do, as we we don't define content meaning.
 305  */
 306
 307 static ssize_t wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 308 {
 309         if(count) {
 310                 if (!nowayout) {
 311                         size_t i;
 312
 313                         /* In case it was set long ago */
 314                         expect_close = 0;
 315
 316                         for (i = 0; i != count; i++) {
 317                                 char c;
 318                                 if (get_user(c, buf + i))
 319                                         return -EFAULT;
 320                                 if (c == 'V')
 321                                         expect_close = 42;
 322                         }
 323                 }
 324                 wdt_ping();
 325         }
 326         return count;
 327 }
 328
 329 /**
 330  *      wdt_ioctl:
 331  *      @inode: inode of the device
 332  *      @file: file handle to the device
 333  *      @cmd: watchdog command
 334  *      @arg: argument pointer
 335  *
 336  *      The watchdog API defines a common set of functions for all watchdogs
 337  *      according to their available features. We only actually usefully support
 338  *      querying capabilities and current status.
 339  */
 340
 341 static int wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 342         unsigned long arg)
 343 {
 344         void __user *argp = (void __user *)arg;
 345         int __user *p = argp;
 346         int new_heartbeat;
 347         int status;
 348
 349         static struct watchdog_info ident = {
 350                 .options =              WDIOF_SETTIMEOUT|
 351                                         WDIOF_MAGICCLOSE|
 352                                         WDIOF_KEEPALIVEPING,
 353                 .firmware_version =     1,
 354                 .identity =             "WDT500/501",
 355         };
 356
 357         /* Add options according to the card we have */
 358         ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);
 359 #ifdef CONFIG_WDT_501
 360         ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|WDIOF_POWEROVER);
 361         if (tachometer)
 362                 ident.options |= WDIOF_FANFAULT;
 363 #endif /* CONFIG_WDT_501 */
 364
 365         switch(cmd)
 366         {
 367                 default:
 368                         return -ENOTTY;
 369                 case WDIOC_GETSUPPORT:
 370                         return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
 371
 372                 case WDIOC_GETSTATUS:
 373                         wdt_get_status(&status);
 374                         return put_user(status, p);
 375                 case WDIOC_GETBOOTSTATUS:
 376                         return put_user(0, p);
 377                 case WDIOC_KEEPALIVE:
 378                         wdt_ping();
 379                         return 0;
 380                 case WDIOC_SETTIMEOUT:
 381                         if (get_user(new_heartbeat, p))
 382                                 return -EFAULT;
 383
 384                         if (wdt_set_heartbeat(new_heartbeat))
 385                                 return -EINVAL;
 386
 387                         wdt_ping();
 388                         /* Fall */
 389                 case WDIOC_GETTIMEOUT:
 390                         return put_user(heartbeat, p);
 391         }
 392 }
 393
 394 /**
 395  *      wdt_open:
 396  *      @inode: inode of device
 397  *      @file: file handle to device
 398  *
 399  *      The watchdog device has been opened. The watchdog device is single
 400  *      open and on opening we load the counters. Counter zero is a 100Hz
 401  *      cascade, into counter 1 which downcounts to reboot. When the counter
 402  *      triggers counter 2 downcounts the length of the reset pulse which
 403  *      set set to be as long as possible.
 404  */
 405
 406 static int wdt_open(struct inode *inode, struct file *file)
 407 {
 408         if(test_and_set_bit(0, &wdt_is_open))
 409                 return -EBUSY;
 410         /*
 411          *      Activate
 412          */
 413         wdt_start();
 414         return nonseekable_open(inode, file);
 415 }
 416
 417 /**
 418  *      wdt_release:
 419  *      @inode: inode to board
 420  *      @file: file handle to board
 421  *
 422  *      The watchdog has a configurable API. There is a religious dispute
 423  *      between people who want their watchdog to be able to shut down and
 424  *      those who want to be sure if the watchdog manager dies the machine
 425  *      reboots. In the former case we disable the counters, in the latter
 426  *      case you have to open it again very soon.
 427  */
 428
 429 static int wdt_release(struct inode *inode, struct file *file)
 430 {
 431         if (expect_close == 42) {
 432                 wdt_stop();
 433                 clear_bit(0, &wdt_is_open);
 434         } else {
 435                 printk(KERN_CRIT "wdt: WDT device closed unexpectedly.  WDT will not stop!\n");
 436                 wdt_ping();
 437         }
 438         expect_close = 0;
 439         return 0;
 440 }
 441
 442 #ifdef CONFIG_WDT_501
 443 /**
 444  *      wdt_temp_read:
 445  *      @file: file handle to the watchdog board
 446  *      @buf: buffer to write 1 byte into
 447  *      @count: length of buffer
 448  *      @ptr: offset (no seek allowed)
 449  *
 450  *      Temp_read reports the temperature in degrees Fahrenheit. The API is in
 451  *      farenheit. It was designed by an imperial measurement luddite.
 452  */
 453
 454 static ssize_t wdt_temp_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
 455 {
 456         int temperature;
 457
 458         if (wdt_get_temperature(&temperature))
 459                 return -EFAULT;
 460
 461         if (copy_to_user (buf, &temperature, 1))
 462                 return -EFAULT;
 463
 464         return 1;
 465 }
 466
 467 /**
 468  *      wdt_temp_open:
 469  *      @inode: inode of device
 470  *      @file: file handle to device
 471  *
 472  *      The temperature device has been opened.
 473  */
 474
 475 static int wdt_temp_open(struct inode *inode, struct file *file)
 476 {
 477         return nonseekable_open(inode, file);
 478 }
 479
 480 /**
 481  *      wdt_temp_release:
 482  *      @inode: inode to board
 483  *      @file: file handle to board
 484  *
 485  *      The temperature device has been closed.
 486  */
 487
 488 static int wdt_temp_release(struct inode *inode, struct file *file)
 489 {
 490         return 0;
 491 }
 492 #endif /* CONFIG_WDT_501 */
 493
 494 /**
 495  *      notify_sys:
 496  *      @this: our notifier block
 497  *      @code: the event being reported
 498  *      @unused: unused
 499  *
 500  *      Our notifier is called on system shutdowns. We want to turn the card
 501  *      off at reboot otherwise the machine will reboot again during memory
 502  *      test or worse yet during the following fsck. This would suck, in fact
 503  *      trust me - if it happens it does suck.
 504  */
 505
 506 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 507         void *unused)
 508 {
 509         if(code==SYS_DOWN || code==SYS_HALT) {
 510                 /* Turn the card off */
 511                 wdt_stop();
 512         }
 513         return NOTIFY_DONE;
 514 }
 515
 516 /*
 517  *      Kernel Interfaces
 518  */
 519
 520
 521 static const struct file_operations wdt_fops = {
 522         .owner          = THIS_MODULE,
 523         .llseek         = no_llseek,
 524         .write          = wdt_write,
 525         .ioctl          = wdt_ioctl,
 526         .open           = wdt_open,
 527         .release        = wdt_release,
 528 };
 529
 530 static struct miscdevice wdt_miscdev = {
 531         .minor  = WATCHDOG_MINOR,
 532         .name   = "watchdog",
 533         .fops   = &wdt_fops,
 534 };
 535
 536 #ifdef CONFIG_WDT_501
 537 static const struct file_operations wdt_temp_fops = {
 538         .owner          = THIS_MODULE,
 539         .llseek         = no_llseek,
 540         .read           = wdt_temp_read,
 541         .open           = wdt_temp_open,
 542         .release        = wdt_temp_release,
 543 };
 544
 545 static struct miscdevice temp_miscdev = {
 546         .minor  = TEMP_MINOR,
 547         .name   = "temperature",
 548         .fops   = &wdt_temp_fops,
 549 };
 550 #endif /* CONFIG_WDT_501 */
 551
 552 /*
 553  *      The WDT card needs to learn about soft shutdowns in order to
 554  *      turn the timebomb registers off.
 555  */
 556
 557 static struct notifier_block wdt_notifier = {
 558         .notifier_call = wdt_notify_sys,
 559 };
 560
 561 /**
 562  *      cleanup_module:
 563  *
 564  *      Unload the watchdog. You cannot do this with any file handles open.
 565  *      If your watchdog is set to continue ticking on close and you unload
 566  *      it, well it keeps ticking. We won't get the interrupt but the board
 567  *      will not touch PC memory so all is fine. You just have to load a new
 568  *      module in 60 seconds or reboot.
 569  */
 570
 571 static void __exit wdt_exit(void)
 572 {
 573         misc_deregister(&wdt_miscdev);
 574 #ifdef CONFIG_WDT_501
 575         misc_deregister(&temp_miscdev);
 576 #endif /* CONFIG_WDT_501 */
 577         unregister_reboot_notifier(&wdt_notifier);
 578         free_irq(irq, NULL);
 579         release_region(io,8);
 580 }
 581
 582 /**
 583  *      wdt_init:
 584  *
 585  *      Set up the WDT watchdog board. All we have to do is grab the
 586  *      resources we require and bitch if anyone beat us to them.
 587  *      The open() function will actually kick the board off.
 588  */
 589
 590 static int __init wdt_init(void)
 591 {
 592         int ret;
 593
 594         /* Check that the heartbeat value is within it's range ; if not reset to the default */
 595         if (wdt_set_heartbeat(heartbeat)) {
 596                 wdt_set_heartbeat(WD_TIMO);
 597                 printk(KERN_INFO "wdt: heartbeat value must be 0<heartbeat<65536, using %d\n",
 598                         WD_TIMO);
 599         }
 600
 601         if (!request_region(io, 8, "wdt501p")) {
 602                 printk(KERN_ERR "wdt: I/O address 0x%04x already in use\n", io);
 603                 ret = -EBUSY;
 604                 goto out;
 605         }
 606
 607         ret = request_irq(irq, wdt_interrupt, IRQF_DISABLED, "wdt501p", NULL);
 608         if(ret) {
 609                 printk(KERN_ERR "wdt: IRQ %d is not free.\n", irq);
 610                 goto outreg;
 611         }
 612
 613         ret = register_reboot_notifier(&wdt_notifier);
 614         if(ret) {
 615                 printk(KERN_ERR "wdt: cannot register reboot notifier (err=%d)\n", ret);
 616                 goto outirq;
 617         }
 618
 619 #ifdef CONFIG_WDT_501
 620         ret = misc_register(&temp_miscdev);
 621         if (ret) {
 622                 printk(KERN_ERR "wdt: cannot register miscdev on minor=%d (err=%d)\n",
 623                         TEMP_MINOR, ret);
 624                 goto outrbt;
 625         }
 626 #endif /* CONFIG_WDT_501 */
 627
 628         ret = misc_register(&wdt_miscdev);
 629         if (ret) {
 630                 printk(KERN_ERR "wdt: cannot register miscdev on minor=%d (err=%d)\n",
 631                         WATCHDOG_MINOR, ret);
 632                 goto outmisc;
 633         }
 634
 635         ret = 0;
 636         printk(KERN_INFO "WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
 637                 io, irq, heartbeat, nowayout);
 638 #ifdef CONFIG_WDT_501
 639         printk(KERN_INFO "wdt: Fan Tachometer is %s\n", (tachometer ? "Enabled" : "Disabled"));
 640 #endif /* CONFIG_WDT_501 */
 641
 642 out:
 643         return ret;
 644
 645 outmisc:
 646 #ifdef CONFIG_WDT_501
 647         misc_deregister(&temp_miscdev);
 648 outrbt:
 649 #endif /* CONFIG_WDT_501 */
 650         unregister_reboot_notifier(&wdt_notifier);
 651 outirq:
 652         free_irq(irq, NULL);
 653 outreg:
 654         release_region(io,8);
 655         goto out;
 656 }
 657
 658 module_init(wdt_init);
 659 module_exit(wdt_exit);
 660
 661 MODULE_AUTHOR("Alan Cox");
 662 MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");
 663 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 664 MODULE_ALIAS_MISCDEV(TEMP_MINOR);
 665 MODULE_LICENSE("GPL");