drivers/char/wdt.c

   1 /*
   2  *      Industrial Computer Source WDT500/501 driver for Linux 2.1.x
   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 0.08.
  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  */
  30
  31 #include <linux/config.h>
  32 #include <linux/module.h>
  33 #include <linux/version.h>
  34 #include <linux/types.h>
  35 #include <linux/errno.h>
  36 #include <linux/kernel.h>
  37 #include <linux/sched.h>
  38 #include <linux/miscdevice.h>
  39 #include <linux/watchdog.h>
  40 #include "wd501p.h"
  41 #include <linux/malloc.h>
  42 #include <linux/ioport.h>
  43 #include <linux/fcntl.h>
  44 #include <asm/io.h>
  45 #include <asm/uaccess.h>
  46 #include <asm/system.h>
  47 #include <linux/notifier.h>
  48 #include <linux/reboot.h>
  49 #include <linux/init.h>
  50
  51 static int wdt_is_open=0;
  52
  53 /*
  54  *      You must set these - there is no sane way to probe for this board.
  55  *      You can use wdt=x,y to set these now.
  56  */
  57
  58 static int io=0x240;
  59 static int irq=11;
  60
  61 #define WD_TIMO (100*60)                /* 1 minute */
  62
  63 #ifndef MODULE
  64
  65 /**
  66  *      wdt_setup:
  67  *      @str: command line string
  68  *
  69  *      Setup options. The board isn't really probe-able so we have to
  70  *      get the user to tell us the configuration. Sane people build it
  71  *      modular but the others come here.
  72  */
  73
  74 static int __init wdt_setup(char *str)
  75 {
  76         int ints[4];
  77
  78         str = get_options (str, ARRAY_SIZE(ints), ints);
  79
  80         if (ints[0] > 0)
  81         {
  82                 io = ints[1];
  83                 if(ints[0] > 1)
  84                         irq = ints[2];
  85         }
  86
  87         return 1;
  88 }
  89
  90 __setup("wdt=", wdt_setup);
  91
  92 #endif /* !MODULE */
  93
  94 /*
  95  *      Programming support
  96  */
  97
  98 static 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
 106 static 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  *      Kernel methods.
 114  */
 115
 116
 117 /**
 118  *      wdt_status:
 119  *
 120  *      Extract the status information from a WDT watchdog device. There are
 121  *      several board variants so we have to know which bits are valid. Some
 122  *      bits default to one and some to zero in order to be maximally painful.
 123  *
 124  *      we then map the bits onto the status ioctl flags.
 125  */
 126
 127 static int wdt_status(void)
 128 {
 129         /*
 130          *      Status register to bit flags
 131          */
 132
 133         int flag=0;
 134         unsigned char status=inb_p(WDT_SR);
 135         status|=FEATUREMAP1;
 136         status&=~FEATUREMAP2;
 137
 138         if(!(status&WDC_SR_TGOOD))
 139                 flag|=WDIOF_OVERHEAT;
 140         if(!(status&WDC_SR_PSUOVER))
 141                 flag|=WDIOF_POWEROVER;
 142         if(!(status&WDC_SR_PSUUNDR))
 143                 flag|=WDIOF_POWERUNDER;
 144         if(!(status&WDC_SR_FANGOOD))
 145                 flag|=WDIOF_FANFAULT;
 146         if(status&WDC_SR_ISOI0)
 147                 flag|=WDIOF_EXTERN1;
 148         if(status&WDC_SR_ISII1)
 149                 flag|=WDIOF_EXTERN2;
 150         return flag;
 151 }
 152
 153 /**
 154  *      wdt_interrupt:
 155  *      @irq:           Interrupt number
 156  *      @dev_id:        Unused as we don't allow multiple devices.
 157  *      @regs:          Unused.
 158  *
 159  *      Handle an interrupt from the board. These are raised when the status
 160  *      map changes in what the board considers an interesting way. That means
 161  *      a failure condition occuring.
 162  */
 163
 164 void wdt_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 165 {
 166         /*
 167          *      Read the status register see what is up and
 168          *      then printk it.
 169          */
 170
 171         unsigned char status=inb_p(WDT_SR);
 172
 173         status|=FEATUREMAP1;
 174         status&=~FEATUREMAP2;
 175
 176         printk(KERN_CRIT "WDT status %d\n", status);
 177
 178         if(!(status&WDC_SR_TGOOD))
 179                 printk(KERN_CRIT "Overheat alarm.(%d)\n",inb_p(WDT_RT));
 180         if(!(status&WDC_SR_PSUOVER))
 181                 printk(KERN_CRIT "PSU over voltage.\n");
 182         if(!(status&WDC_SR_PSUUNDR))
 183                 printk(KERN_CRIT "PSU under voltage.\n");
 184         if(!(status&WDC_SR_FANGOOD))
 185                 printk(KERN_CRIT "Possible fan fault.\n");
 186         if(!(status&WDC_SR_WCCR))
 187 #ifdef SOFTWARE_REBOOT
 188 #ifdef ONLY_TESTING
 189                 printk(KERN_CRIT "Would Reboot.\n");
 190 #else
 191                 printk(KERN_CRIT "Initiating system reboot.\n");
 192                 machine_restart(NULL);
 193 #endif
 194 #else
 195                 printk(KERN_CRIT "Reset in 5ms.\n");
 196 #endif
 197 }
 198
 199
 200 static long long wdt_llseek(struct file *file, long long offset, int origin)
 201 {
 202         return -ESPIPE;
 203 }
 204
 205 /**
 206  *      wdt_ping:
 207  *
 208  *      Reload counter one with the watchdog timeout. We don't bother reloading
 209  *      the cascade counter.
 210  */
 211
 212 static void wdt_ping(void)
 213 {
 214         /* Write a watchdog value */
 215         inb_p(WDT_DC);
 216         wdt_ctr_mode(1,2);
 217         wdt_ctr_load(1,WD_TIMO);                /* Timeout */
 218         outb_p(0, WDT_DC);
 219 }
 220
 221 /**
 222  *      wdt_write:
 223  *      @file: file handle to the watchdog
 224  *      @buf: buffer to write (unused as data does not matter here
 225  *      @count: count of bytes
 226  *      @ppos: pointer to the position to write. No seeks allowed
 227  *
 228  *      A write to a watchdog device is defined as a keepalive signal. Any
 229  *      write of data will do, as we we don't define content meaning.
 230  */
 231
 232 static ssize_t wdt_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
 233 {
 234         /*  Can't seek (pwrite) on this device  */
 235         if (ppos != &file->f_pos)
 236                 return -ESPIPE;
 237
 238         if(count)
 239         {
 240                 wdt_ping();
 241                 return 1;
 242         }
 243         return 0;
 244 }
 245
 246 /**
 247  *      wdt_read:
 248  *      @file: file handle to the watchdog board
 249  *      @buf: buffer to write 1 byte into
 250  *      @count: length of buffer
 251  *      @ptr: offset (no seek allowed)
 252  *
 253  *      Read reports the temperature in degrees Fahrenheit. The API is in
 254  *      farenheit. It was designed by an imperial measurement luddite.
 255  */
 256
 257 static ssize_t wdt_read(struct file *file, char *buf, size_t count, loff_t *ptr)
 258 {
 259         unsigned short c=inb_p(WDT_RT);
 260         unsigned char cp;
 261
 262         /*  Can't seek (pread) on this device  */
 263         if (ptr != &file->f_pos)
 264                 return -ESPIPE;
 265
 266         switch(MINOR(file->f_dentry->d_inode->i_rdev))
 267         {
 268                 case TEMP_MINOR:
 269                         c*=11;
 270                         c/=15;
 271                         cp=c+7;
 272                         if(copy_to_user(buf,&cp,1))
 273                                 return -EFAULT;
 274                         return 1;
 275                 default:
 276                         return -EINVAL;
 277         }
 278 }
 279
 280 /**
 281  *      wdt_ioctl:
 282  *      @inode: inode of the device
 283  *      @file: file handle to the device
 284  *      @cmd: watchdog command
 285  *      @arg: argument pointer
 286  *
 287  *      The watchdog API defines a common set of functions for all watchdogs
 288  *      according to their available features. We only actually usefully support
 289  *      querying capabilities and current status.
 290  */
 291
 292 static int wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 293         unsigned long arg)
 294 {
 295         static struct watchdog_info ident=
 296         {
 297                 WDIOF_OVERHEAT|WDIOF_POWERUNDER|WDIOF_POWEROVER
 298                         |WDIOF_EXTERN1|WDIOF_EXTERN2|WDIOF_FANFAULT,
 299                 1,
 300                 "WDT500/501"
 301         };
 302
 303         ident.options&=WDT_OPTION_MASK; /* Mask down to the card we have */
 304         switch(cmd)
 305         {
 306                 default:
 307                         return -ENOIOCTLCMD;
 308                 case WDIOC_GETSUPPORT:
 309                         return copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident))?-EFAULT:0;
 310
 311                 case WDIOC_GETSTATUS:
 312                         return put_user(wdt_status(),(int *)arg);
 313                 case WDIOC_GETBOOTSTATUS:
 314                         return put_user(0, (int *)arg);
 315                 case WDIOC_KEEPALIVE:
 316                         wdt_ping();
 317                         return 0;
 318         }
 319 }
 320
 321 /**
 322  *      wdt_open:
 323  *      @inode: inode of device
 324  *      @file: file handle to device
 325  *
 326  *      One of our two misc devices has been opened. The watchdog device is
 327  *      single open and on opening we load the counters. Counter zero is a
 328  *      100Hz cascade, into counter 1 which downcounts to reboot. When the
 329  *      counter triggers counter 2 downcounts the length of the reset pulse
 330  *      which set set to be as long as possible.
 331  */
 332
 333 static int wdt_open(struct inode *inode, struct file *file)
 334 {
 335         switch(MINOR(inode->i_rdev))
 336         {
 337                 case WATCHDOG_MINOR:
 338                         if(wdt_is_open)
 339                                 return -EBUSY;
 340                         /*
 341                          *      Activate
 342                          */
 343
 344                         wdt_is_open=1;
 345                         inb_p(WDT_DC);          /* Disable */
 346                         wdt_ctr_mode(0,3);
 347                         wdt_ctr_mode(1,2);
 348                         wdt_ctr_mode(2,0);
 349                         wdt_ctr_load(0, 8948);          /* count at 100Hz */
 350                         wdt_ctr_load(1,WD_TIMO);        /* Timeout 120 seconds */
 351                         wdt_ctr_load(2,65535);
 352                         outb_p(0, WDT_DC);      /* Enable */
 353                         return 0;
 354                 case TEMP_MINOR:
 355                         return 0;
 356                 default:
 357                         return -ENODEV;
 358         }
 359 }
 360
 361 /**
 362  *      wdt_close:
 363  *      @inode: inode to board
 364  *      @file: file handle to board
 365  *
 366  *      The watchdog has a configurable API. There is a religious dispute
 367  *      between people who want their watchdog to be able to shut down and
 368  *      those who want to be sure if the watchdog manager dies the machine
 369  *      reboots. In the former case we disable the counters, in the latter
 370  *      case you have to open it again very soon.
 371  */
 372
 373 static int wdt_release(struct inode *inode, struct file *file)
 374 {
 375         if(MINOR(inode->i_rdev)==WATCHDOG_MINOR)
 376         {
 377 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 378                 inb_p(WDT_DC);          /* Disable counters */
 379                 wdt_ctr_load(2,0);      /* 0 length reset pulses now */
 380 #endif
 381                 wdt_is_open=0;
 382         }
 383         return 0;
 384 }
 385
 386 /**
 387  *      notify_sys:
 388  *      @this: our notifier block
 389  *      @code: the event being reported
 390  *      @unused: unused
 391  *
 392  *      Our notifier is called on system shutdowns. We want to turn the card
 393  *      off at reboot otherwise the machine will reboot again during memory
 394  *      test or worse yet during the following fsck. This would suck, in fact
 395  *      trust me - if it happens it does suck.
 396  */
 397
 398 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 399         void *unused)
 400 {
 401         if(code==SYS_DOWN || code==SYS_HALT)
 402         {
 403                 /* Turn the card off */
 404                 inb_p(WDT_DC);
 405                 wdt_ctr_load(2,0);
 406         }
 407         return NOTIFY_DONE;
 408 }
 409
 410 /*
 411  *      Kernel Interfaces
 412  */
 413
 414
 415 static struct file_operations wdt_fops = {
 416         owner:          THIS_MODULE,
 417         llseek:         wdt_llseek,
 418         read:           wdt_read,
 419         write:          wdt_write,
 420         ioctl:          wdt_ioctl,
 421         open:           wdt_open,
 422         release:        wdt_release,
 423 };
 424
 425 static struct miscdevice wdt_miscdev=
 426 {
 427         WATCHDOG_MINOR,
 428         "watchdog",
 429         &wdt_fops
 430 };
 431
 432 #ifdef CONFIG_WDT_501
 433 static struct miscdevice temp_miscdev=
 434 {
 435         TEMP_MINOR,
 436         "temperature",
 437         &wdt_fops
 438 };
 439 #endif
 440
 441 /*
 442  *      The WDT card needs to learn about soft shutdowns in order to
 443  *      turn the timebomb registers off.
 444  */
 445
 446 static struct notifier_block wdt_notifier=
 447 {
 448         wdt_notify_sys,
 449         NULL,
 450         0
 451 };
 452
 453 #ifdef MODULE
 454
 455 #define wdt_init init_module
 456
 457 /**
 458  *      cleanup_module:
 459  *
 460  *      Unload the watchdog. You cannot do this with any file handles open.
 461  *      If your watchdog is set to continue ticking on close and you unload
 462  *      it, well it keeps ticking. We won't get the interrupt but the board
 463  *      will not touch PC memory so all is fine. You just have to load a new
 464  *      module in 60 seconds or reboot.
 465  */
 466
 467 void cleanup_module(void)
 468 {
 469         misc_deregister(&wdt_miscdev);
 470 #ifdef CONFIG_WDT_501
 471         misc_deregister(&temp_miscdev);
 472 #endif
 473         unregister_reboot_notifier(&wdt_notifier);
 474         release_region(io,8);
 475         free_irq(irq, NULL);
 476 }
 477
 478 #endif
 479
 480 /**
 481  *      wdt_init:
 482  *
 483  *      Set up the WDT watchdog board. All we have to do is grab the
 484  *      resources we require and bitch if anyone beat us to them.
 485  *      The open() function will actually kick the board off.
 486  */
 487
 488 int __init wdt_init(void)
 489 {
 490         printk(KERN_INFO "WDT500/501-P driver 0.07 at %X (Interrupt %d)\n", io,irq);
 491         if(request_irq(irq, wdt_interrupt, SA_INTERRUPT, "wdt501p", &wdt_miscdev))
 492         {
 493                 printk(KERN_ERR "IRQ %d is not free.\n", irq);
 494                 return -EIO;
 495         }
 496         misc_register(&wdt_miscdev);
 497 #ifdef CONFIG_WDT_501
 498         misc_register(&temp_miscdev);
 499 #endif
 500         request_region(io, 8, "wdt501p");
 501         register_reboot_notifier(&wdt_notifier);
 502         return 0;
 503 }
 504