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