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/smp_lock.h>
  39 #include <linux/miscdevice.h>
  40 #include <linux/watchdog.h>
  41 #include "wd501p.h"
  42 #include <linux/malloc.h>
  43 #include <linux/ioport.h>
  44 #include <linux/fcntl.h>
  45 #include <asm/io.h>
  46 #include <asm/uaccess.h>
  47 #include <asm/system.h>
  48 #include <linux/notifier.h>
  49 #include <linux/reboot.h>
  50 #include <linux/init.h>
  51
  52 static int wdt_is_open=0;
  53
  54 /*
  55  *      You must set these - there is no sane way to probe for this board.
  56  *      You can use wdt=x,y to set these now.
  57  */
  58
  59 static int io=0x240;
  60 static int irq=11;
  61
  62 #define WD_TIMO (100*60)                /* 1 minute */
  63
  64 #ifndef MODULE
  65
  66 /**
  67  *      wdt_setup:
  68  *      @str: command line string
  69  *
  70  *      Setup options. The board isn't really probe-able so we have to
  71  *      get the user to tell us the configuration. Sane people build it
  72  *      modular but the others come here.
  73  */
  74
  75 static int __init wdt_setup(char *str)
  76 {
  77         int ints[4];
  78
  79         str = get_options (str, ARRAY_SIZE(ints), ints);
  80
  81         if (ints[0] > 0)
  82         {
  83                 io = ints[1];
  84                 if(ints[0] > 1)
  85                         irq = ints[2];
  86         }
  87
  88         return 1;
  89 }
  90
  91 __setup("wdt=", wdt_setup);
  92
  93 #endif /* !MODULE */
  94
  95 MODULE_PARM(io, "i");
  96 MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
  97 MODULE_PARM(irq, "i");
  98 MODULE_PARM_DESC(irq, "WDT irq (default=11)");
  99
 100 /*
 101  *      Programming support
 102  */
 103
 104 static void wdt_ctr_mode(int ctr, int mode)
 105 {
 106         ctr<<=6;
 107         ctr|=0x30;
 108         ctr|=(mode<<1);
 109         outb_p(ctr, WDT_CR);
 110 }
 111
 112 static void wdt_ctr_load(int ctr, int val)
 113 {
 114         outb_p(val&0xFF, WDT_COUNT0+ctr);
 115         outb_p(val>>8, WDT_COUNT0+ctr);
 116 }
 117
 118 /*
 119  *      Kernel methods.
 120  */
 121
 122
 123 /**
 124  *      wdt_status:
 125  *
 126  *      Extract the status information from a WDT watchdog device. There are
 127  *      several board variants so we have to know which bits are valid. Some
 128  *      bits default to one and some to zero in order to be maximally painful.
 129  *
 130  *      we then map the bits onto the status ioctl flags.
 131  */
 132
 133 static int wdt_status(void)
 134 {
 135         /*
 136          *      Status register to bit flags
 137          */
 138
 139         int flag=0;
 140         unsigned char status=inb_p(WDT_SR);
 141         status|=FEATUREMAP1;
 142         status&=~FEATUREMAP2;
 143
 144         if(!(status&WDC_SR_TGOOD))
 145                 flag|=WDIOF_OVERHEAT;
 146         if(!(status&WDC_SR_PSUOVER))
 147                 flag|=WDIOF_POWEROVER;
 148         if(!(status&WDC_SR_PSUUNDR))
 149                 flag|=WDIOF_POWERUNDER;
 150         if(!(status&WDC_SR_FANGOOD))
 151                 flag|=WDIOF_FANFAULT;
 152         if(status&WDC_SR_ISOI0)
 153                 flag|=WDIOF_EXTERN1;
 154         if(status&WDC_SR_ISII1)
 155                 flag|=WDIOF_EXTERN2;
 156         return flag;
 157 }
 158
 159 /**
 160  *      wdt_interrupt:
 161  *      @irq:           Interrupt number
 162  *      @dev_id:        Unused as we don't allow multiple devices.
 163  *      @regs:          Unused.
 164  *
 165  *      Handle an interrupt from the board. These are raised when the status
 166  *      map changes in what the board considers an interesting way. That means
 167  *      a failure condition occuring.
 168  */
 169
 170 void wdt_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 171 {
 172         /*
 173          *      Read the status register see what is up and
 174          *      then printk it.
 175          */
 176
 177         unsigned char status=inb_p(WDT_SR);
 178
 179         status|=FEATUREMAP1;
 180         status&=~FEATUREMAP2;
 181
 182         printk(KERN_CRIT "WDT status %d\n", status);
 183
 184         if(!(status&WDC_SR_TGOOD))
 185                 printk(KERN_CRIT "Overheat alarm.(%d)\n",inb_p(WDT_RT));
 186         if(!(status&WDC_SR_PSUOVER))
 187                 printk(KERN_CRIT "PSU over voltage.\n");
 188         if(!(status&WDC_SR_PSUUNDR))
 189                 printk(KERN_CRIT "PSU under voltage.\n");
 190         if(!(status&WDC_SR_FANGOOD))
 191                 printk(KERN_CRIT "Possible fan fault.\n");
 192         if(!(status&WDC_SR_WCCR))
 193 #ifdef SOFTWARE_REBOOT
 194 #ifdef ONLY_TESTING
 195                 printk(KERN_CRIT "Would Reboot.\n");
 196 #else
 197                 printk(KERN_CRIT "Initiating system reboot.\n");
 198                 machine_restart(NULL);
 199 #endif
 200 #else
 201                 printk(KERN_CRIT "Reset in 5ms.\n");
 202 #endif
 203 }
 204
 205
 206 static long long wdt_llseek(struct file *file, long long offset, int origin)
 207 {
 208         return -ESPIPE;
 209 }
 210
 211 /**
 212  *      wdt_ping:
 213  *
 214  *      Reload counter one with the watchdog timeout. We don't bother reloading
 215  *      the cascade counter.
 216  */
 217
 218 static void wdt_ping(void)
 219 {
 220         /* Write a watchdog value */
 221         inb_p(WDT_DC);
 222         wdt_ctr_mode(1,2);
 223         wdt_ctr_load(1,WD_TIMO);                /* Timeout */
 224         outb_p(0, WDT_DC);
 225 }
 226
 227 /**
 228  *      wdt_write:
 229  *      @file: file handle to the watchdog
 230  *      @buf: buffer to write (unused as data does not matter here
 231  *      @count: count of bytes
 232  *      @ppos: pointer to the position to write. No seeks allowed
 233  *
 234  *      A write to a watchdog device is defined as a keepalive signal. Any
 235  *      write of data will do, as we we don't define content meaning.
 236  */
 237
 238 static ssize_t wdt_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
 239 {
 240         /*  Can't seek (pwrite) on this device  */
 241         if (ppos != &file->f_pos)
 242                 return -ESPIPE;
 243
 244         if(count)
 245         {
 246                 wdt_ping();
 247                 return 1;
 248         }
 249         return 0;
 250 }
 251
 252 /**
 253  *      wdt_read:
 254  *      @file: file handle to the watchdog board
 255  *      @buf: buffer to write 1 byte into
 256  *      @count: length of buffer
 257  *      @ptr: offset (no seek allowed)
 258  *
 259  *      Read reports the temperature in degrees Fahrenheit. The API is in
 260  *      farenheit. It was designed by an imperial measurement luddite.
 261  */
 262
 263 static ssize_t wdt_read(struct file *file, char *buf, size_t count, loff_t *ptr)
 264 {
 265         unsigned short c=inb_p(WDT_RT);
 266         unsigned char cp;
 267
 268         /*  Can't seek (pread) on this device  */
 269         if (ptr != &file->f_pos)
 270                 return -ESPIPE;
 271
 272         switch(MINOR(file->f_dentry->d_inode->i_rdev))
 273         {
 274                 case TEMP_MINOR:
 275                         c*=11;
 276                         c/=15;
 277                         cp=c+7;
 278                         if(copy_to_user(buf,&cp,1))
 279                                 return -EFAULT;
 280                         return 1;
 281                 default:
 282                         return -EINVAL;
 283         }
 284 }
 285
 286 /**
 287  *      wdt_ioctl:
 288  *      @inode: inode of the device
 289  *      @file: file handle to the device
 290  *      @cmd: watchdog command
 291  *      @arg: argument pointer
 292  *
 293  *      The watchdog API defines a common set of functions for all watchdogs
 294  *      according to their available features. We only actually usefully support
 295  *      querying capabilities and current status.
 296  */
 297
 298 static int wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 299         unsigned long arg)
 300 {
 301         static struct watchdog_info ident=
 302         {
 303                 WDIOF_OVERHEAT|WDIOF_POWERUNDER|WDIOF_POWEROVER
 304                         |WDIOF_EXTERN1|WDIOF_EXTERN2|WDIOF_FANFAULT,
 305                 1,
 306                 "WDT500/501"
 307         };
 308
 309         ident.options&=WDT_OPTION_MASK; /* Mask down to the card we have */
 310         switch(cmd)
 311         {
 312                 default:
 313                         return -ENOIOCTLCMD;
 314                 case WDIOC_GETSUPPORT:
 315                         return copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident))?-EFAULT:0;
 316
 317                 case WDIOC_GETSTATUS:
 318                         return put_user(wdt_status(),(int *)arg);
 319                 case WDIOC_GETBOOTSTATUS:
 320                         return put_user(0, (int *)arg);
 321                 case WDIOC_KEEPALIVE:
 322                         wdt_ping();
 323                         return 0;
 324         }
 325 }
 326
 327 /**
 328  *      wdt_open:
 329  *      @inode: inode of device
 330  *      @file: file handle to device
 331  *
 332  *      One of our two misc devices has been opened. The watchdog device is
 333  *      single open and on opening we load the counters. Counter zero is a
 334  *      100Hz cascade, into counter 1 which downcounts to reboot. When the
 335  *      counter triggers counter 2 downcounts the length of the reset pulse
 336  *      which set set to be as long as possible.
 337  */
 338
 339 static int wdt_open(struct inode *inode, struct file *file)
 340 {
 341         switch(MINOR(inode->i_rdev))
 342         {
 343                 case WATCHDOG_MINOR:
 344                         if(wdt_is_open)
 345                                 return -EBUSY;
 346                         /*
 347                          *      Activate
 348                          */
 349
 350                         wdt_is_open=1;
 351                         inb_p(WDT_DC);          /* Disable */
 352                         wdt_ctr_mode(0,3);
 353                         wdt_ctr_mode(1,2);
 354                         wdt_ctr_mode(2,0);
 355                         wdt_ctr_load(0, 8948);          /* count at 100Hz */
 356                         wdt_ctr_load(1,WD_TIMO);        /* Timeout 120 seconds */
 357                         wdt_ctr_load(2,65535);
 358                         outb_p(0, WDT_DC);      /* Enable */
 359                         return 0;
 360                 case TEMP_MINOR:
 361                         return 0;
 362                 default:
 363                         return -ENODEV;
 364         }
 365 }
 366
 367 /**
 368  *      wdt_close:
 369  *      @inode: inode to board
 370  *      @file: file handle to board
 371  *
 372  *      The watchdog has a configurable API. There is a religious dispute
 373  *      between people who want their watchdog to be able to shut down and
 374  *      those who want to be sure if the watchdog manager dies the machine
 375  *      reboots. In the former case we disable the counters, in the latter
 376  *      case you have to open it again very soon.
 377  */
 378
 379 static int wdt_release(struct inode *inode, struct file *file)
 380 {
 381         lock_kernel();
 382         if(MINOR(inode->i_rdev)==WATCHDOG_MINOR)
 383         {
 384 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 385                 inb_p(WDT_DC);          /* Disable counters */
 386                 wdt_ctr_load(2,0);      /* 0 length reset pulses now */
 387 #endif
 388                 wdt_is_open=0;
 389         }
 390         unlock_kernel();
 391         return 0;
 392 }
 393
 394 /**
 395  *      notify_sys:
 396  *      @this: our notifier block
 397  *      @code: the event being reported
 398  *      @unused: unused
 399  *
 400  *      Our notifier is called on system shutdowns. We want to turn the card
 401  *      off at reboot otherwise the machine will reboot again during memory
 402  *      test or worse yet during the following fsck. This would suck, in fact
 403  *      trust me - if it happens it does suck.
 404  */
 405
 406 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 407         void *unused)
 408 {
 409         if(code==SYS_DOWN || code==SYS_HALT)
 410         {
 411                 /* Turn the card off */
 412                 inb_p(WDT_DC);
 413                 wdt_ctr_load(2,0);
 414         }
 415         return NOTIFY_DONE;
 416 }
 417
 418 /*
 419  *      Kernel Interfaces
 420  */
 421
 422
 423 static struct file_operations wdt_fops = {
 424         owner:          THIS_MODULE,
 425         llseek:         wdt_llseek,
 426         read:           wdt_read,
 427         write:          wdt_write,
 428         ioctl:          wdt_ioctl,
 429         open:           wdt_open,
 430         release:        wdt_release,
 431 };
 432
 433 static struct miscdevice wdt_miscdev=
 434 {
 435         WATCHDOG_MINOR,
 436         "watchdog",
 437         &wdt_fops
 438 };
 439
 440 #ifdef CONFIG_WDT_501
 441 static struct miscdevice temp_miscdev=
 442 {
 443         TEMP_MINOR,
 444         "temperature",
 445         &wdt_fops
 446 };
 447 #endif
 448
 449 /*
 450  *      The WDT card needs to learn about soft shutdowns in order to
 451  *      turn the timebomb registers off.
 452  */
 453
 454 static struct notifier_block wdt_notifier=
 455 {
 456         wdt_notify_sys,
 457         NULL,
 458         0
 459 };
 460
 461 #ifdef MODULE
 462
 463 #define wdt_init init_module
 464
 465 /**
 466  *      cleanup_module:
 467  *
 468  *      Unload the watchdog. You cannot do this with any file handles open.
 469  *      If your watchdog is set to continue ticking on close and you unload
 470  *      it, well it keeps ticking. We won't get the interrupt but the board
 471  *      will not touch PC memory so all is fine. You just have to load a new
 472  *      module in 60 seconds or reboot.
 473  */
 474
 475 void cleanup_module(void)
 476 {
 477         misc_deregister(&wdt_miscdev);
 478 #ifdef CONFIG_WDT_501
 479         misc_deregister(&temp_miscdev);
 480 #endif
 481         unregister_reboot_notifier(&wdt_notifier);
 482         release_region(io,8);
 483         free_irq(irq, NULL);
 484 }
 485
 486 #endif
 487
 488 /**
 489  *      wdt_init:
 490  *
 491  *      Set up the WDT watchdog board. All we have to do is grab the
 492  *      resources we require and bitch if anyone beat us to them.
 493  *      The open() function will actually kick the board off.
 494  */
 495
 496 int __init wdt_init(void)
 497 {
 498         printk(KERN_INFO "WDT500/501-P driver 0.07 at %X (Interrupt %d)\n", io,irq);
 499         if(request_irq(irq, wdt_interrupt, SA_INTERRUPT, "wdt501p", &wdt_miscdev))
 500         {
 501                 printk(KERN_ERR "IRQ %d is not free.\n", irq);
 502                 return -EIO;
 503         }
 504         misc_register(&wdt_miscdev);
 505 #ifdef CONFIG_WDT_501
 506         misc_register(&temp_miscdev);
 507 #endif
 508         request_region(io, 8, "wdt501p");
 509         register_reboot_notifier(&wdt_notifier);
 510         return 0;
 511 }
 512