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