linux/drivers/watchdog/wdt.c
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   1/*
   2 *      Industrial Computer Source WDT500/501 driver
   3 *
   4 *      (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
   5 *                                              All Rights Reserved.
   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
  28 *                                      cleanup, parameterized timeout
  29 *              Tigran Aivazian :       Restructured wdt_init() to handle
  30 *                                      failures
  31 *              Joel Becker     :       Added WDIOC_GET/SETTIMEOUT
  32 *              Matt Domsch     :       Added nowayout module option
  33 */
  34
  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#include <linux/io.h>
  47#include <linux/uaccess.h>
  48
  49#include <asm/system.h>
  50#include "wd501p.h"
  51
  52static unsigned long wdt_is_open;
  53static char expect_close;
  54
  55/*
  56 *      Module parameters
  57 */
  58
  59#define WD_TIMO 60                      /* Default heartbeat = 60 seconds */
  60
  61static int heartbeat = WD_TIMO;
  62static int wd_heartbeat;
  63module_param(heartbeat, int, 0);
  64MODULE_PARM_DESC(heartbeat,
  65        "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default="
  66                                __MODULE_STRING(WD_TIMO) ")");
  67
  68static int nowayout = WATCHDOG_NOWAYOUT;
  69module_param(nowayout, int, 0);
  70MODULE_PARM_DESC(nowayout,
  71        "Watchdog cannot be stopped once started (default="
  72                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  73
  74/* You must set these - there is no sane way to probe for this board. */
  75static int io = 0x240;
  76static int irq = 11;
  77
  78static DEFINE_SPINLOCK(wdt_lock);
  79
  80module_param(io, int, 0);
  81MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
  82module_param(irq, int, 0);
  83MODULE_PARM_DESC(irq, "WDT irq (default=11)");
  84
  85#ifdef CONFIG_WDT_501
  86/* Support for the Fan Tachometer on the WDT501-P */
  87static int tachometer;
  88
  89module_param(tachometer, int, 0);
  90MODULE_PARM_DESC(tachometer,
  91                "WDT501-P Fan Tachometer support (0=disable, default=0)");
  92#endif /* CONFIG_WDT_501 */
  93
  94/*
  95 *      Programming support
  96 */
  97
  98static void wdt_ctr_mode(int ctr, int mode)
  99{
 100        ctr <<= 6;
 101        ctr |= 0x30;
 102        ctr |= (mode << 1);
 103        outb_p(ctr, WDT_CR);
 104}
 105
 106static void wdt_ctr_load(int ctr, int val)
 107{
 108        outb_p(val&0xFF, WDT_COUNT0+ctr);
 109        outb_p(val>>8, WDT_COUNT0+ctr);
 110}
 111
 112/**
 113 *      wdt_start:
 114 *
 115 *      Start the watchdog driver.
 116 */
 117
 118static int wdt_start(void)
 119{
 120        unsigned long flags;
 121        spin_lock_irqsave(&wdt_lock, flags);
 122        inb_p(WDT_DC);                  /* Disable watchdog */
 123        wdt_ctr_mode(0, 3);             /* Program CTR0 for Mode 3:
 124                                                Square Wave Generator */
 125        wdt_ctr_mode(1, 2);             /* Program CTR1 for Mode 2:
 126                                                Rate Generator */
 127        wdt_ctr_mode(2, 0);             /* Program CTR2 for Mode 0:
 128                                                Pulse on Terminal Count */
 129        wdt_ctr_load(0, 8948);          /* Count at 100Hz */
 130        wdt_ctr_load(1, wd_heartbeat);  /* Heartbeat */
 131        wdt_ctr_load(2, 65535);         /* Length of reset pulse */
 132        outb_p(0, WDT_DC);              /* Enable watchdog */
 133        spin_unlock_irqrestore(&wdt_lock, flags);
 134        return 0;
 135}
 136
 137/**
 138 *      wdt_stop:
 139 *
 140 *      Stop the watchdog driver.
 141 */
 142
 143static int wdt_stop(void)
 144{
 145        unsigned long flags;
 146        spin_lock_irqsave(&wdt_lock, flags);
 147        /* Turn the card off */
 148        inb_p(WDT_DC);                  /* Disable watchdog */
 149        wdt_ctr_load(2, 0);             /* 0 length reset pulses now */
 150        spin_unlock_irqrestore(&wdt_lock, flags);
 151        return 0;
 152}
 153
 154/**
 155 *      wdt_ping:
 156 *
 157 *      Reload counter one with the watchdog heartbeat. We don't bother
 158 *      reloading the cascade counter.
 159 */
 160
 161static int wdt_ping(void)
 162{
 163        unsigned long flags;
 164        spin_lock_irqsave(&wdt_lock, flags);
 165        /* Write a watchdog value */
 166        inb_p(WDT_DC);                  /* Disable watchdog */
 167        wdt_ctr_mode(1, 2);             /* Re-Program CTR1 for Mode 2:
 168                                                        Rate Generator */
 169        wdt_ctr_load(1, wd_heartbeat);  /* Heartbeat */
 170        outb_p(0, WDT_DC);              /* Enable watchdog */
 171        spin_unlock_irqrestore(&wdt_lock, flags);
 172        return 0;
 173}
 174
 175/**
 176 *      wdt_set_heartbeat:
 177 *      @t:             the new heartbeat value that needs to be set.
 178 *
 179 *      Set a new heartbeat value for the watchdog device. If the heartbeat
 180 *      value is incorrect we keep the old value and return -EINVAL. If
 181 *      successful we return 0.
 182 */
 183
 184static int wdt_set_heartbeat(int t)
 185{
 186        if (t < 1 || t > 65535)
 187                return -EINVAL;
 188
 189        heartbeat = t;
 190        wd_heartbeat = t * 100;
 191        return 0;
 192}
 193
 194/**
 195 *      wdt_get_status:
 196 *      @status:                the new status.
 197 *
 198 *      Extract the status information from a WDT watchdog device. There are
 199 *      several board variants so we have to know which bits are valid. Some
 200 *      bits default to one and some to zero in order to be maximally painful.
 201 *
 202 *      we then map the bits onto the status ioctl flags.
 203 */
 204
 205static int wdt_get_status(int *status)
 206{
 207        unsigned char new_status;
 208        unsigned long flags;
 209
 210        spin_lock_irqsave(&wdt_lock, flags);
 211        new_status = inb_p(WDT_SR);
 212        spin_unlock_irqrestore(&wdt_lock, flags);
 213
 214        *status = 0;
 215        if (new_status & WDC_SR_ISOI0)
 216                *status |= WDIOF_EXTERN1;
 217        if (new_status & WDC_SR_ISII1)
 218                *status |= WDIOF_EXTERN2;
 219#ifdef CONFIG_WDT_501
 220        if (!(new_status & WDC_SR_TGOOD))
 221                *status |= WDIOF_OVERHEAT;
 222        if (!(new_status & WDC_SR_PSUOVER))
 223                *status |= WDIOF_POWEROVER;
 224        if (!(new_status & WDC_SR_PSUUNDR))
 225                *status |= WDIOF_POWERUNDER;
 226        if (tachometer) {
 227                if (!(new_status & WDC_SR_FANGOOD))
 228                        *status |= WDIOF_FANFAULT;
 229        }
 230#endif /* CONFIG_WDT_501 */
 231        return 0;
 232}
 233
 234#ifdef CONFIG_WDT_501
 235/**
 236 *      wdt_get_temperature:
 237 *
 238 *      Reports the temperature in degrees Fahrenheit. The API is in
 239 *      farenheit. It was designed by an imperial measurement luddite.
 240 */
 241
 242static int wdt_get_temperature(int *temperature)
 243{
 244        unsigned short c;
 245        unsigned long flags;
 246
 247        spin_lock_irqsave(&wdt_lock, flags);
 248        c = inb_p(WDT_RT);
 249        spin_unlock_irqrestore(&wdt_lock, flags);
 250        *temperature = (c * 11 / 15) + 7;
 251        return 0;
 252}
 253#endif /* CONFIG_WDT_501 */
 254
 255/**
 256 *      wdt_interrupt:
 257 *      @irq:           Interrupt number
 258 *      @dev_id:        Unused as we don't allow multiple devices.
 259 *
 260 *      Handle an interrupt from the board. These are raised when the status
 261 *      map changes in what the board considers an interesting way. That means
 262 *      a failure condition occurring.
 263 */
 264
 265static irqreturn_t wdt_interrupt(int irq, void *dev_id)
 266{
 267        /*
 268         *      Read the status register see what is up and
 269         *      then printk it.
 270         */
 271        unsigned char status;
 272
 273        spin_lock(&wdt_lock);
 274        status = inb_p(WDT_SR);
 275
 276        printk(KERN_CRIT "WDT status %d\n", status);
 277
 278#ifdef CONFIG_WDT_501
 279        if (!(status & WDC_SR_TGOOD))
 280                printk(KERN_CRIT "Overheat alarm.(%d)\n", inb_p(WDT_RT));
 281        if (!(status & WDC_SR_PSUOVER))
 282                printk(KERN_CRIT "PSU over voltage.\n");
 283        if (!(status & WDC_SR_PSUUNDR))
 284                printk(KERN_CRIT "PSU under voltage.\n");
 285        if (tachometer) {
 286                if (!(status & WDC_SR_FANGOOD))
 287                        printk(KERN_CRIT "Possible fan fault.\n");
 288        }
 289#endif /* CONFIG_WDT_501 */
 290        if (!(status & WDC_SR_WCCR)) {
 291#ifdef SOFTWARE_REBOOT
 292#ifdef ONLY_TESTING
 293                printk(KERN_CRIT "Would Reboot.\n");
 294#else
 295                printk(KERN_CRIT "Initiating system reboot.\n");
 296                emergency_restart();
 297#endif
 298#else
 299                printk(KERN_CRIT "Reset in 5ms.\n");
 300#endif
 301        }
 302        spin_unlock(&wdt_lock);
 303        return IRQ_HANDLED;
 304}
 305
 306
 307/**
 308 *      wdt_write:
 309 *      @file: file handle to the watchdog
 310 *      @buf: buffer to write (unused as data does not matter here
 311 *      @count: count of bytes
 312 *      @ppos: pointer to the position to write. No seeks allowed
 313 *
 314 *      A write to a watchdog device is defined as a keepalive signal. Any
 315 *      write of data will do, as we we don't define content meaning.
 316 */
 317
 318static ssize_t wdt_write(struct file *file, const char __user *buf,
 319                                                size_t count, loff_t *ppos)
 320{
 321        if (count) {
 322                if (!nowayout) {
 323                        size_t i;
 324
 325                        /* In case it was set long ago */
 326                        expect_close = 0;
 327
 328                        for (i = 0; i != count; i++) {
 329                                char c;
 330                                if (get_user(c, buf + i))
 331                                        return -EFAULT;
 332                                if (c == 'V')
 333                                        expect_close = 42;
 334                        }
 335                }
 336                wdt_ping();
 337        }
 338        return count;
 339}
 340
 341/**
 342 *      wdt_ioctl:
 343 *      @file: file handle to the device
 344 *      @cmd: watchdog command
 345 *      @arg: argument pointer
 346 *
 347 *      The watchdog API defines a common set of functions for all watchdogs
 348 *      according to their available features. We only actually usefully support
 349 *      querying capabilities and current status.
 350 */
 351
 352static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 353{
 354        void __user *argp = (void __user *)arg;
 355        int __user *p = argp;
 356        int new_heartbeat;
 357        int status;
 358
 359        static struct watchdog_info ident = {
 360                .options =              WDIOF_SETTIMEOUT|
 361                                        WDIOF_MAGICCLOSE|
 362                                        WDIOF_KEEPALIVEPING,
 363                .firmware_version =     1,
 364                .identity =             "WDT500/501",
 365        };
 366
 367        /* Add options according to the card we have */
 368        ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);
 369#ifdef CONFIG_WDT_501
 370        ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|WDIOF_POWEROVER);
 371        if (tachometer)
 372                ident.options |= WDIOF_FANFAULT;
 373#endif /* CONFIG_WDT_501 */
 374
 375        switch (cmd) {
 376        case WDIOC_GETSUPPORT:
 377                return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 378        case WDIOC_GETSTATUS:
 379                wdt_get_status(&status);
 380                return put_user(status, p);
 381        case WDIOC_GETBOOTSTATUS:
 382                return put_user(0, p);
 383        case WDIOC_KEEPALIVE:
 384                wdt_ping();
 385                return 0;
 386        case WDIOC_SETTIMEOUT:
 387                if (get_user(new_heartbeat, p))
 388                        return -EFAULT;
 389                if (wdt_set_heartbeat(new_heartbeat))
 390                        return -EINVAL;
 391                wdt_ping();
 392                /* Fall */
 393        case WDIOC_GETTIMEOUT:
 394                return put_user(heartbeat, p);
 395        default:
 396                return -ENOTTY;
 397        }
 398}
 399
 400/**
 401 *      wdt_open:
 402 *      @inode: inode of device
 403 *      @file: file handle to device
 404 *
 405 *      The watchdog device has been opened. The watchdog device is single
 406 *      open and on opening we load the counters. Counter zero is a 100Hz
 407 *      cascade, into counter 1 which downcounts to reboot. When the counter
 408 *      triggers counter 2 downcounts the length of the reset pulse which
 409 *      set set to be as long as possible.
 410 */
 411
 412static int wdt_open(struct inode *inode, struct file *file)
 413{
 414        if (test_and_set_bit(0, &wdt_is_open))
 415                return -EBUSY;
 416        /*
 417         *      Activate
 418         */
 419        wdt_start();
 420        return nonseekable_open(inode, file);
 421}
 422
 423/**
 424 *      wdt_release:
 425 *      @inode: inode to board
 426 *      @file: file handle to board
 427 *
 428 *      The watchdog has a configurable API. There is a religious dispute
 429 *      between people who want their watchdog to be able to shut down and
 430 *      those who want to be sure if the watchdog manager dies the machine
 431 *      reboots. In the former case we disable the counters, in the latter
 432 *      case you have to open it again very soon.
 433 */
 434
 435static int wdt_release(struct inode *inode, struct file *file)
 436{
 437        if (expect_close == 42) {
 438                wdt_stop();
 439                clear_bit(0, &wdt_is_open);
 440        } else {
 441                printk(KERN_CRIT
 442                 "wdt: WDT device closed unexpectedly.  WDT will not stop!\n");
 443                wdt_ping();
 444        }
 445        expect_close = 0;
 446        return 0;
 447}
 448
 449#ifdef CONFIG_WDT_501
 450/**
 451 *      wdt_temp_read:
 452 *      @file: file handle to the watchdog board
 453 *      @buf: buffer to write 1 byte into
 454 *      @count: length of buffer
 455 *      @ptr: offset (no seek allowed)
 456 *
 457 *      Temp_read reports the temperature in degrees Fahrenheit. The API is in
 458 *      farenheit. It was designed by an imperial measurement luddite.
 459 */
 460
 461static ssize_t wdt_temp_read(struct file *file, char __user *buf,
 462                                                size_t count, loff_t *ptr)
 463{
 464        int temperature;
 465
 466        if (wdt_get_temperature(&temperature))
 467                return -EFAULT;
 468
 469        if (copy_to_user(buf, &temperature, 1))
 470                return -EFAULT;
 471
 472        return 1;
 473}
 474
 475/**
 476 *      wdt_temp_open:
 477 *      @inode: inode of device
 478 *      @file: file handle to device
 479 *
 480 *      The temperature device has been opened.
 481 */
 482
 483static int wdt_temp_open(struct inode *inode, struct file *file)
 484{
 485        return nonseekable_open(inode, file);
 486}
 487
 488/**
 489 *      wdt_temp_release:
 490 *      @inode: inode to board
 491 *      @file: file handle to board
 492 *
 493 *      The temperature device has been closed.
 494 */
 495
 496static int wdt_temp_release(struct inode *inode, struct file *file)
 497{
 498        return 0;
 499}
 500#endif /* CONFIG_WDT_501 */
 501
 502/**
 503 *      notify_sys:
 504 *      @this: our notifier block
 505 *      @code: the event being reported
 506 *      @unused: unused
 507 *
 508 *      Our notifier is called on system shutdowns. We want to turn the card
 509 *      off at reboot otherwise the machine will reboot again during memory
 510 *      test or worse yet during the following fsck. This would suck, in fact
 511 *      trust me - if it happens it does suck.
 512 */
 513
 514static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 515        void *unused)
 516{
 517        if (code == SYS_DOWN || code == SYS_HALT)
 518                wdt_stop();
 519        return NOTIFY_DONE;
 520}
 521
 522/*
 523 *      Kernel Interfaces
 524 */
 525
 526
 527static const struct file_operations wdt_fops = {
 528        .owner          = THIS_MODULE,
 529        .llseek         = no_llseek,
 530        .write          = wdt_write,
 531        .unlocked_ioctl = wdt_ioctl,
 532        .open           = wdt_open,
 533        .release        = wdt_release,
 534};
 535
 536static struct miscdevice wdt_miscdev = {
 537        .minor  = WATCHDOG_MINOR,
 538        .name   = "watchdog",
 539        .fops   = &wdt_fops,
 540};
 541
 542#ifdef CONFIG_WDT_501
 543static const struct file_operations wdt_temp_fops = {
 544        .owner          = THIS_MODULE,
 545        .llseek         = no_llseek,
 546        .read           = wdt_temp_read,
 547        .open           = wdt_temp_open,
 548        .release        = wdt_temp_release,
 549};
 550
 551static struct miscdevice temp_miscdev = {
 552        .minor  = TEMP_MINOR,
 553        .name   = "temperature",
 554        .fops   = &wdt_temp_fops,
 555};
 556#endif /* CONFIG_WDT_501 */
 557
 558/*
 559 *      The WDT card needs to learn about soft shutdowns in order to
 560 *      turn the timebomb registers off.
 561 */
 562
 563static struct notifier_block wdt_notifier = {
 564        .notifier_call = wdt_notify_sys,
 565};
 566
 567/**
 568 *      cleanup_module:
 569 *
 570 *      Unload the watchdog. You cannot do this with any file handles open.
 571 *      If your watchdog is set to continue ticking on close and you unload
 572 *      it, well it keeps ticking. We won't get the interrupt but the board
 573 *      will not touch PC memory so all is fine. You just have to load a new
 574 *      module in 60 seconds or reboot.
 575 */
 576
 577static void __exit wdt_exit(void)
 578{
 579        misc_deregister(&wdt_miscdev);
 580#ifdef CONFIG_WDT_501
 581        misc_deregister(&temp_miscdev);
 582#endif /* CONFIG_WDT_501 */
 583        unregister_reboot_notifier(&wdt_notifier);
 584        free_irq(irq, NULL);
 585        release_region(io, 8);
 586}
 587
 588/**
 589 *      wdt_init:
 590 *
 591 *      Set up the WDT watchdog board. All we have to do is grab the
 592 *      resources we require and bitch if anyone beat us to them.
 593 *      The open() function will actually kick the board off.
 594 */
 595
 596static int __init wdt_init(void)
 597{
 598        int ret;
 599
 600        /* Check that the heartbeat value is within it's range;
 601           if not reset to the default */
 602        if (wdt_set_heartbeat(heartbeat)) {
 603                wdt_set_heartbeat(WD_TIMO);
 604                printk(KERN_INFO "wdt: heartbeat value must be 0 < heartbeat < 65536, using %d\n",
 605                        WD_TIMO);
 606        }
 607
 608        if (!request_region(io, 8, "wdt501p")) {
 609                printk(KERN_ERR
 610                        "wdt: I/O address 0x%04x already in use\n", io);
 611                ret = -EBUSY;
 612                goto out;
 613        }
 614
 615        ret = request_irq(irq, wdt_interrupt, IRQF_DISABLED, "wdt501p", NULL);
 616        if (ret) {
 617                printk(KERN_ERR "wdt: IRQ %d is not free.\n", irq);
 618                goto outreg;
 619        }
 620
 621        ret = register_reboot_notifier(&wdt_notifier);
 622        if (ret) {
 623                printk(KERN_ERR
 624                      "wdt: cannot register reboot notifier (err=%d)\n", ret);
 625                goto outirq;
 626        }
 627
 628#ifdef CONFIG_WDT_501
 629        ret = misc_register(&temp_miscdev);
 630        if (ret) {
 631                printk(KERN_ERR
 632                        "wdt: cannot register miscdev on minor=%d (err=%d)\n",
 633                                                        TEMP_MINOR, ret);
 634                goto outrbt;
 635        }
 636#endif /* CONFIG_WDT_501 */
 637
 638        ret = misc_register(&wdt_miscdev);
 639        if (ret) {
 640                printk(KERN_ERR
 641                        "wdt: cannot register miscdev on minor=%d (err=%d)\n",
 642                                                        WATCHDOG_MINOR, ret);
 643                goto outmisc;
 644        }
 645
 646        ret = 0;
 647        printk(KERN_INFO "WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
 648                io, irq, heartbeat, nowayout);
 649#ifdef CONFIG_WDT_501
 650        printk(KERN_INFO "wdt: Fan Tachometer is %s\n",
 651                                (tachometer ? "Enabled" : "Disabled"));
 652#endif /* CONFIG_WDT_501 */
 653
 654out:
 655        return ret;
 656
 657outmisc:
 658#ifdef CONFIG_WDT_501
 659        misc_deregister(&temp_miscdev);
 660outrbt:
 661#endif /* CONFIG_WDT_501 */
 662        unregister_reboot_notifier(&wdt_notifier);
 663outirq:
 664        free_irq(irq, NULL);
 665outreg:
 666        release_region(io, 8);
 667        goto out;
 668}
 669
 670module_init(wdt_init);
 671module_exit(wdt_exit);
 672
 673MODULE_AUTHOR("Alan Cox");
 674MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");
 675MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 676MODULE_ALIAS_MISCDEV(TEMP_MINOR);
 677MODULE_LICENSE("GPL");
 678