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=" __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 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  *
 229  *      Handle an interrupt from the board. These are raised when the status
 230  *      map changes in what the board considers an interesting way. That means
 231  *      a failure condition occurring.
 232  */
 233
 234 static irqreturn_t wdt_interrupt(int irq, void *dev_id)
 235 {
 236         /*
 237          *      Read the status register see what is up and
 238          *      then printk it.
 239          */
 240         unsigned char status=inb_p(WDT_SR);
 241
 242         printk(KERN_CRIT "WDT status %d\n", status);
 243
 244 #ifdef CONFIG_WDT_501
 245         if (!(status & WDC_SR_TGOOD))
 246                 printk(KERN_CRIT "Overheat alarm.(%d)\n",inb_p(WDT_RT));
 247         if (!(status & WDC_SR_PSUOVER))
 248                 printk(KERN_CRIT "PSU over voltage.\n");
 249         if (!(status & WDC_SR_PSUUNDR))
 250                 printk(KERN_CRIT "PSU under voltage.\n");
 251         if (tachometer) {
 252                 if (!(status & WDC_SR_FANGOOD))
 253                         printk(KERN_CRIT "Possible fan fault.\n");
 254         }
 255 #endif /* CONFIG_WDT_501 */
 256         if (!(status & WDC_SR_WCCR))
 257 #ifdef SOFTWARE_REBOOT
 258 #ifdef ONLY_TESTING
 259                 printk(KERN_CRIT "Would Reboot.\n");
 260 #else
 261                 printk(KERN_CRIT "Initiating system reboot.\n");
 262                 emergency_restart();
 263 #endif
 264 #else
 265                 printk(KERN_CRIT "Reset in 5ms.\n");
 266 #endif
 267         return IRQ_HANDLED;
 268 }
 269
 270
 271 /**
 272  *      wdt_write:
 273  *      @file: file handle to the watchdog
 274  *      @buf: buffer to write (unused as data does not matter here
 275  *      @count: count of bytes
 276  *      @ppos: pointer to the position to write. No seeks allowed
 277  *
 278  *      A write to a watchdog device is defined as a keepalive signal. Any
 279  *      write of data will do, as we we don't define content meaning.
 280  */
 281
 282 static ssize_t wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 283 {
 284         if(count) {
 285                 if (!nowayout) {
 286                         size_t i;
 287
 288                         /* In case it was set long ago */
 289                         expect_close = 0;
 290
 291                         for (i = 0; i != count; i++) {
 292                                 char c;
 293                                 if (get_user(c, buf + i))
 294                                         return -EFAULT;
 295                                 if (c == 'V')
 296                                         expect_close = 42;
 297                         }
 298                 }
 299                 wdt_ping();
 300         }
 301         return count;
 302 }
 303
 304 /**
 305  *      wdt_ioctl:
 306  *      @inode: inode of the device
 307  *      @file: file handle to the device
 308  *      @cmd: watchdog command
 309  *      @arg: argument pointer
 310  *
 311  *      The watchdog API defines a common set of functions for all watchdogs
 312  *      according to their available features. We only actually usefully support
 313  *      querying capabilities and current status.
 314  */
 315
 316 static int wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 317         unsigned long arg)
 318 {
 319         void __user *argp = (void __user *)arg;
 320         int __user *p = argp;
 321         int new_heartbeat;
 322         int status;
 323
 324         static struct watchdog_info ident = {
 325                 .options =              WDIOF_SETTIMEOUT|
 326                                         WDIOF_MAGICCLOSE|
 327                                         WDIOF_KEEPALIVEPING,
 328                 .firmware_version =     1,
 329                 .identity =             "WDT500/501",
 330         };
 331
 332         /* Add options according to the card we have */
 333         ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);
 334 #ifdef CONFIG_WDT_501
 335         ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|WDIOF_POWEROVER);
 336         if (tachometer)
 337                 ident.options |= WDIOF_FANFAULT;
 338 #endif /* CONFIG_WDT_501 */
 339
 340         switch(cmd)
 341         {
 342                 default:
 343                         return -ENOTTY;
 344                 case WDIOC_GETSUPPORT:
 345                         return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
 346
 347                 case WDIOC_GETSTATUS:
 348                         wdt_get_status(&status);
 349                         return put_user(status, p);
 350                 case WDIOC_GETBOOTSTATUS:
 351                         return put_user(0, p);
 352                 case WDIOC_KEEPALIVE:
 353                         wdt_ping();
 354                         return 0;
 355                 case WDIOC_SETTIMEOUT:
 356                         if (get_user(new_heartbeat, p))
 357                                 return -EFAULT;
 358
 359                         if (wdt_set_heartbeat(new_heartbeat))
 360                                 return -EINVAL;
 361
 362                         wdt_ping();
 363                         /* Fall */
 364                 case WDIOC_GETTIMEOUT:
 365                         return put_user(heartbeat, p);
 366         }
 367 }
 368
 369 /**
 370  *      wdt_open:
 371  *      @inode: inode of device
 372  *      @file: file handle to device
 373  *
 374  *      The watchdog device has been opened. The watchdog device is single
 375  *      open and on opening we load the counters. Counter zero is a 100Hz
 376  *      cascade, into counter 1 which downcounts to reboot. When the counter
 377  *      triggers counter 2 downcounts the length of the reset pulse which
 378  *      set set to be as long as possible.
 379  */
 380
 381 static int wdt_open(struct inode *inode, struct file *file)
 382 {
 383         if(test_and_set_bit(0, &wdt_is_open))
 384                 return -EBUSY;
 385         /*
 386          *      Activate
 387          */
 388         wdt_start();
 389         return nonseekable_open(inode, file);
 390 }
 391
 392 /**
 393  *      wdt_release:
 394  *      @inode: inode to board
 395  *      @file: file handle to board
 396  *
 397  *      The watchdog has a configurable API. There is a religious dispute
 398  *      between people who want their watchdog to be able to shut down and
 399  *      those who want to be sure if the watchdog manager dies the machine
 400  *      reboots. In the former case we disable the counters, in the latter
 401  *      case you have to open it again very soon.
 402  */
 403
 404 static int wdt_release(struct inode *inode, struct file *file)
 405 {
 406         if (expect_close == 42) {
 407                 wdt_stop();
 408                 clear_bit(0, &wdt_is_open);
 409         } else {
 410                 printk(KERN_CRIT "wdt: WDT device closed unexpectedly.  WDT will not stop!\n");
 411                 wdt_ping();
 412         }
 413         expect_close = 0;
 414         return 0;
 415 }
 416
 417 #ifdef CONFIG_WDT_501
 418 /**
 419  *      wdt_temp_read:
 420  *      @file: file handle to the watchdog board
 421  *      @buf: buffer to write 1 byte into
 422  *      @count: length of buffer
 423  *      @ptr: offset (no seek allowed)
 424  *
 425  *      Temp_read reports the temperature in degrees Fahrenheit. The API is in
 426  *      farenheit. It was designed by an imperial measurement luddite.
 427  */
 428
 429 static ssize_t wdt_temp_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
 430 {
 431         int temperature;
 432
 433         if (wdt_get_temperature(&temperature))
 434                 return -EFAULT;
 435
 436         if (copy_to_user (buf, &temperature, 1))
 437                 return -EFAULT;
 438
 439         return 1;
 440 }
 441
 442 /**
 443  *      wdt_temp_open:
 444  *      @inode: inode of device
 445  *      @file: file handle to device
 446  *
 447  *      The temperature device has been opened.
 448  */
 449
 450 static int wdt_temp_open(struct inode *inode, struct file *file)
 451 {
 452         return nonseekable_open(inode, file);
 453 }
 454
 455 /**
 456  *      wdt_temp_release:
 457  *      @inode: inode to board
 458  *      @file: file handle to board
 459  *
 460  *      The temperature device has been closed.
 461  */
 462
 463 static int wdt_temp_release(struct inode *inode, struct file *file)
 464 {
 465         return 0;
 466 }
 467 #endif /* CONFIG_WDT_501 */
 468
 469 /**
 470  *      notify_sys:
 471  *      @this: our notifier block
 472  *      @code: the event being reported
 473  *      @unused: unused
 474  *
 475  *      Our notifier is called on system shutdowns. We want to turn the card
 476  *      off at reboot otherwise the machine will reboot again during memory
 477  *      test or worse yet during the following fsck. This would suck, in fact
 478  *      trust me - if it happens it does suck.
 479  */
 480
 481 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 482         void *unused)
 483 {
 484         if(code==SYS_DOWN || code==SYS_HALT) {
 485                 /* Turn the card off */
 486                 wdt_stop();
 487         }
 488         return NOTIFY_DONE;
 489 }
 490
 491 /*
 492  *      Kernel Interfaces
 493  */
 494
 495
 496 static const struct file_operations wdt_fops = {
 497         .owner          = THIS_MODULE,
 498         .llseek         = no_llseek,
 499         .write          = wdt_write,
 500         .ioctl          = wdt_ioctl,
 501         .open           = wdt_open,
 502         .release        = wdt_release,
 503 };
 504
 505 static struct miscdevice wdt_miscdev = {
 506         .minor  = WATCHDOG_MINOR,
 507         .name   = "watchdog",
 508         .fops   = &wdt_fops,
 509 };
 510
 511 #ifdef CONFIG_WDT_501
 512 static const struct file_operations wdt_temp_fops = {
 513         .owner          = THIS_MODULE,
 514         .llseek         = no_llseek,
 515         .read           = wdt_temp_read,
 516         .open           = wdt_temp_open,
 517         .release        = wdt_temp_release,
 518 };
 519
 520 static struct miscdevice temp_miscdev = {
 521         .minor  = TEMP_MINOR,
 522         .name   = "temperature",
 523         .fops   = &wdt_temp_fops,
 524 };
 525 #endif /* CONFIG_WDT_501 */
 526
 527 /*
 528  *      The WDT card needs to learn about soft shutdowns in order to
 529  *      turn the timebomb registers off.
 530  */
 531
 532 static struct notifier_block wdt_notifier = {
 533         .notifier_call = wdt_notify_sys,
 534 };
 535
 536 /**
 537  *      cleanup_module:
 538  *
 539  *      Unload the watchdog. You cannot do this with any file handles open.
 540  *      If your watchdog is set to continue ticking on close and you unload
 541  *      it, well it keeps ticking. We won't get the interrupt but the board
 542  *      will not touch PC memory so all is fine. You just have to load a new
 543  *      module in 60 seconds or reboot.
 544  */
 545
 546 static void __exit wdt_exit(void)
 547 {
 548         misc_deregister(&wdt_miscdev);
 549 #ifdef CONFIG_WDT_501
 550         misc_deregister(&temp_miscdev);
 551 #endif /* CONFIG_WDT_501 */
 552         unregister_reboot_notifier(&wdt_notifier);
 553         free_irq(irq, NULL);
 554         release_region(io,8);
 555 }
 556
 557 /**
 558  *      wdt_init:
 559  *
 560  *      Set up the WDT watchdog board. All we have to do is grab the
 561  *      resources we require and bitch if anyone beat us to them.
 562  *      The open() function will actually kick the board off.
 563  */
 564
 565 static int __init wdt_init(void)
 566 {
 567         int ret;
 568
 569         /* Check that the heartbeat value is within it's range ; if not reset to the default */
 570         if (wdt_set_heartbeat(heartbeat)) {
 571                 wdt_set_heartbeat(WD_TIMO);
 572                 printk(KERN_INFO "wdt: heartbeat value must be 0<heartbeat<65536, using %d\n",
 573                         WD_TIMO);
 574         }
 575
 576         if (!request_region(io, 8, "wdt501p")) {
 577                 printk(KERN_ERR "wdt: I/O address 0x%04x already in use\n", io);
 578                 ret = -EBUSY;
 579                 goto out;
 580         }
 581
 582         ret = request_irq(irq, wdt_interrupt, IRQF_DISABLED, "wdt501p", NULL);
 583         if(ret) {
 584                 printk(KERN_ERR "wdt: IRQ %d is not free.\n", irq);
 585                 goto outreg;
 586         }
 587
 588         ret = register_reboot_notifier(&wdt_notifier);
 589         if(ret) {
 590                 printk(KERN_ERR "wdt: cannot register reboot notifier (err=%d)\n", ret);
 591                 goto outirq;
 592         }
 593
 594 #ifdef CONFIG_WDT_501
 595         ret = misc_register(&temp_miscdev);
 596         if (ret) {
 597                 printk(KERN_ERR "wdt: cannot register miscdev on minor=%d (err=%d)\n",
 598                         TEMP_MINOR, ret);
 599                 goto outrbt;
 600         }
 601 #endif /* CONFIG_WDT_501 */
 602
 603         ret = misc_register(&wdt_miscdev);
 604         if (ret) {
 605                 printk(KERN_ERR "wdt: cannot register miscdev on minor=%d (err=%d)\n",
 606                         WATCHDOG_MINOR, ret);
 607                 goto outmisc;
 608         }
 609
 610         ret = 0;
 611         printk(KERN_INFO "WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
 612                 io, irq, heartbeat, nowayout);
 613 #ifdef CONFIG_WDT_501
 614         printk(KERN_INFO "wdt: Fan Tachometer is %s\n", (tachometer ? "Enabled" : "Disabled"));
 615 #endif /* CONFIG_WDT_501 */
 616
 617 out:
 618         return ret;
 619
 620 outmisc:
 621 #ifdef CONFIG_WDT_501
 622         misc_deregister(&temp_miscdev);
 623 outrbt:
 624 #endif /* CONFIG_WDT_501 */
 625         unregister_reboot_notifier(&wdt_notifier);
 626 outirq:
 627         free_irq(irq, NULL);
 628 outreg:
 629         release_region(io,8);
 630         goto out;
 631 }
 632
 633 module_init(wdt_init);
 634 module_exit(wdt_exit);
 635
 636 MODULE_AUTHOR("Alan Cox");
 637 MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");
 638 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 639 MODULE_ALIAS_MISCDEV(TEMP_MINOR);
 640 MODULE_LICENSE("GPL");