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