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  *              Tigran Aivazian :       Restructured wdt_init() to handle failures
  30  */
  31
  32 #include <linux/config.h>
  33 #include <linux/module.h>
  34 #include <linux/version.h>
  35 #include <linux/types.h>
  36 #include <linux/errno.h>
  37 #include <linux/kernel.h>
  38 #include <linux/sched.h>
  39 #include <linux/smp_lock.h>
  40 #include <linux/miscdevice.h>
  41 #include <linux/watchdog.h>
  42 #include "wd501p.h"
  43 #include <linux/malloc.h>
  44 #include <linux/ioport.h>
  45 #include <linux/fcntl.h>
  46 #include <asm/io.h>
  47 #include <asm/uaccess.h>
  48 #include <asm/system.h>
  49 #include <linux/notifier.h>
  50 #include <linux/reboot.h>
  51 #include <linux/init.h>
  52
  53 static int wdt_is_open;
  54
  55 /*
  56  *      You must set these - there is no sane way to probe for this board.
  57  *      You can use wdt=x,y to set these now.
  58  */
  59
  60 static int io=0x240;
  61 static int irq=11;
  62
  63 #define WD_TIMO (100*60)                /* 1 minute */
  64
  65 #ifndef MODULE
  66
  67 /**
  68  *      wdt_setup:
  69  *      @str: command line string
  70  *
  71  *      Setup options. The board isn't really probe-able so we have to
  72  *      get the user to tell us the configuration. Sane people build it
  73  *      modular but the others come here.
  74  */
  75
  76 static int __init wdt_setup(char *str)
  77 {
  78         int ints[4];
  79
  80         str = get_options (str, ARRAY_SIZE(ints), ints);
  81
  82         if (ints[0] > 0)
  83         {
  84                 io = ints[1];
  85                 if(ints[0] > 1)
  86                         irq = ints[2];
  87         }
  88
  89         return 1;
  90 }
  91
  92 __setup("wdt=", wdt_setup);
  93
  94 #endif /* !MODULE */
  95
  96 MODULE_PARM(io, "i");
  97 MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
  98 MODULE_PARM(irq, "i");
  99 MODULE_PARM_DESC(irq, "WDT irq (default=11)");
 100
 101 /*
 102  *      Programming support
 103  */
 104
 105 static void wdt_ctr_mode(int ctr, int mode)
 106 {
 107         ctr<<=6;
 108         ctr|=0x30;
 109         ctr|=(mode<<1);
 110         outb_p(ctr, WDT_CR);
 111 }
 112
 113 static void wdt_ctr_load(int ctr, int val)
 114 {
 115         outb_p(val&0xFF, WDT_COUNT0+ctr);
 116         outb_p(val>>8, WDT_COUNT0+ctr);
 117 }
 118
 119 /*
 120  *      Kernel methods.
 121  */
 122
 123
 124 /**
 125  *      wdt_status:
 126  *
 127  *      Extract the status information from a WDT watchdog device. There are
 128  *      several board variants so we have to know which bits are valid. Some
 129  *      bits default to one and some to zero in order to be maximally painful.
 130  *
 131  *      we then map the bits onto the status ioctl flags.
 132  */
 133
 134 static int wdt_status(void)
 135 {
 136         /*
 137          *      Status register to bit flags
 138          */
 139
 140         int flag=0;
 141         unsigned char status=inb_p(WDT_SR);
 142         status|=FEATUREMAP1;
 143         status&=~FEATUREMAP2;
 144
 145         if(!(status&WDC_SR_TGOOD))
 146                 flag|=WDIOF_OVERHEAT;
 147         if(!(status&WDC_SR_PSUOVER))
 148                 flag|=WDIOF_POWEROVER;
 149         if(!(status&WDC_SR_PSUUNDR))
 150                 flag|=WDIOF_POWERUNDER;
 151         if(!(status&WDC_SR_FANGOOD))
 152                 flag|=WDIOF_FANFAULT;
 153         if(status&WDC_SR_ISOI0)
 154                 flag|=WDIOF_EXTERN1;
 155         if(status&WDC_SR_ISII1)
 156                 flag|=WDIOF_EXTERN2;
 157         return flag;
 158 }
 159
 160 /**
 161  *      wdt_interrupt:
 162  *      @irq:           Interrupt number
 163  *      @dev_id:        Unused as we don't allow multiple devices.
 164  *      @regs:          Unused.
 165  *
 166  *      Handle an interrupt from the board. These are raised when the status
 167  *      map changes in what the board considers an interesting way. That means
 168  *      a failure condition occuring.
 169  */
 170
 171 void wdt_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 172 {
 173         /*
 174          *      Read the status register see what is up and
 175          *      then printk it.
 176          */
 177
 178         unsigned char status=inb_p(WDT_SR);
 179
 180         status|=FEATUREMAP1;
 181         status&=~FEATUREMAP2;
 182
 183         printk(KERN_CRIT "WDT status %d\n", status);
 184
 185         if(!(status&WDC_SR_TGOOD))
 186                 printk(KERN_CRIT "Overheat alarm.(%d)\n",inb_p(WDT_RT));
 187         if(!(status&WDC_SR_PSUOVER))
 188                 printk(KERN_CRIT "PSU over voltage.\n");
 189         if(!(status&WDC_SR_PSUUNDR))
 190                 printk(KERN_CRIT "PSU under voltage.\n");
 191         if(!(status&WDC_SR_FANGOOD))
 192                 printk(KERN_CRIT "Possible fan fault.\n");
 193         if(!(status&WDC_SR_WCCR))
 194 #ifdef SOFTWARE_REBOOT
 195 #ifdef ONLY_TESTING
 196                 printk(KERN_CRIT "Would Reboot.\n");
 197 #else
 198                 printk(KERN_CRIT "Initiating system reboot.\n");
 199                 machine_restart(NULL);
 200 #endif
 201 #else
 202                 printk(KERN_CRIT "Reset in 5ms.\n");
 203 #endif
 204 }
 205
 206
 207 static long long wdt_llseek(struct file *file, long long offset, int origin)
 208 {
 209         return -ESPIPE;
 210 }
 211
 212 /**
 213  *      wdt_ping:
 214  *
 215  *      Reload counter one with the watchdog timeout. We don't bother reloading
 216  *      the cascade counter.
 217  */
 218
 219 static void wdt_ping(void)
 220 {
 221         /* Write a watchdog value */
 222         inb_p(WDT_DC);
 223         wdt_ctr_mode(1,2);
 224         wdt_ctr_load(1,WD_TIMO);                /* Timeout */
 225         outb_p(0, WDT_DC);
 226 }
 227
 228 /**
 229  *      wdt_write:
 230  *      @file: file handle to the watchdog
 231  *      @buf: buffer to write (unused as data does not matter here
 232  *      @count: count of bytes
 233  *      @ppos: pointer to the position to write. No seeks allowed
 234  *
 235  *      A write to a watchdog device is defined as a keepalive signal. Any
 236  *      write of data will do, as we we don't define content meaning.
 237  */
 238
 239 static ssize_t wdt_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
 240 {
 241         /*  Can't seek (pwrite) on this device  */
 242         if (ppos != &file->f_pos)
 243                 return -ESPIPE;
 244
 245         if(count)
 246         {
 247                 wdt_ping();
 248                 return 1;
 249         }
 250         return 0;
 251 }
 252
 253 /**
 254  *      wdt_read:
 255  *      @file: file handle to the watchdog board
 256  *      @buf: buffer to write 1 byte into
 257  *      @count: length of buffer
 258  *      @ptr: offset (no seek allowed)
 259  *
 260  *      Read reports the temperature in degrees Fahrenheit. The API is in
 261  *      farenheit. It was designed by an imperial measurement luddite.
 262  */
 263
 264 static ssize_t wdt_read(struct file *file, char *buf, size_t count, loff_t *ptr)
 265 {
 266         unsigned short c=inb_p(WDT_RT);
 267         unsigned char cp;
 268
 269         /*  Can't seek (pread) on this device  */
 270         if (ptr != &file->f_pos)
 271                 return -ESPIPE;
 272
 273         switch(MINOR(file->f_dentry->d_inode->i_rdev))
 274         {
 275                 case TEMP_MINOR:
 276                         c*=11;
 277                         c/=15;
 278                         cp=c+7;
 279                         if(copy_to_user(buf,&cp,1))
 280                                 return -EFAULT;
 281                         return 1;
 282                 default:
 283                         return -EINVAL;
 284         }
 285 }
 286
 287 /**
 288  *      wdt_ioctl:
 289  *      @inode: inode of the device
 290  *      @file: file handle to the device
 291  *      @cmd: watchdog command
 292  *      @arg: argument pointer
 293  *
 294  *      The watchdog API defines a common set of functions for all watchdogs
 295  *      according to their available features. We only actually usefully support
 296  *      querying capabilities and current status.
 297  */
 298
 299 static int wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 300         unsigned long arg)
 301 {
 302         static struct watchdog_info ident=
 303         {
 304                 WDIOF_OVERHEAT|WDIOF_POWERUNDER|WDIOF_POWEROVER
 305                         |WDIOF_EXTERN1|WDIOF_EXTERN2|WDIOF_FANFAULT,
 306                 1,
 307                 "WDT500/501"
 308         };
 309
 310         ident.options&=WDT_OPTION_MASK; /* Mask down to the card we have */
 311         switch(cmd)
 312         {
 313                 default:
 314                         return -ENOIOCTLCMD;
 315                 case WDIOC_GETSUPPORT:
 316                         return copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident))?-EFAULT:0;
 317
 318                 case WDIOC_GETSTATUS:
 319                         return put_user(wdt_status(),(int *)arg);
 320                 case WDIOC_GETBOOTSTATUS:
 321                         return put_user(0, (int *)arg);
 322                 case WDIOC_KEEPALIVE:
 323                         wdt_ping();
 324                         return 0;
 325         }
 326 }
 327
 328 /**
 329  *      wdt_open:
 330  *      @inode: inode of device
 331  *      @file: file handle to device
 332  *
 333  *      One of our two misc devices has been opened. The watchdog device is
 334  *      single open and on opening we load the counters. Counter zero is a
 335  *      100Hz cascade, into counter 1 which downcounts to reboot. When the
 336  *      counter triggers counter 2 downcounts the length of the reset pulse
 337  *      which set set to be as long as possible.
 338  */
 339
 340 static int wdt_open(struct inode *inode, struct file *file)
 341 {
 342         switch(MINOR(inode->i_rdev))
 343         {
 344                 case WATCHDOG_MINOR:
 345                         if(wdt_is_open)
 346                                 return -EBUSY;
 347                         /*
 348                          *      Activate
 349                          */
 350
 351                         wdt_is_open=1;
 352                         inb_p(WDT_DC);          /* Disable */
 353                         wdt_ctr_mode(0,3);
 354                         wdt_ctr_mode(1,2);
 355                         wdt_ctr_mode(2,0);
 356                         wdt_ctr_load(0, 8948);          /* count at 100Hz */
 357                         wdt_ctr_load(1,WD_TIMO);        /* Timeout 120 seconds */
 358                         wdt_ctr_load(2,65535);
 359                         outb_p(0, WDT_DC);      /* Enable */
 360                         return 0;
 361                 case TEMP_MINOR:
 362                         return 0;
 363                 default:
 364                         return -ENODEV;
 365         }
 366 }
 367
 368 /**
 369  *      wdt_close:
 370  *      @inode: inode to board
 371  *      @file: file handle to board
 372  *
 373  *      The watchdog has a configurable API. There is a religious dispute
 374  *      between people who want their watchdog to be able to shut down and
 375  *      those who want to be sure if the watchdog manager dies the machine
 376  *      reboots. In the former case we disable the counters, in the latter
 377  *      case you have to open it again very soon.
 378  */
 379
 380 static int wdt_release(struct inode *inode, struct file *file)
 381 {
 382         lock_kernel();
 383         if(MINOR(inode->i_rdev)==WATCHDOG_MINOR)
 384         {
 385 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 386                 inb_p(WDT_DC);          /* Disable counters */
 387                 wdt_ctr_load(2,0);      /* 0 length reset pulses now */
 388 #endif
 389                 wdt_is_open=0;
 390         }
 391         unlock_kernel();
 392         return 0;
 393 }
 394
 395 /**
 396  *      notify_sys:
 397  *      @this: our notifier block
 398  *      @code: the event being reported
 399  *      @unused: unused
 400  *
 401  *      Our notifier is called on system shutdowns. We want to turn the card
 402  *      off at reboot otherwise the machine will reboot again during memory
 403  *      test or worse yet during the following fsck. This would suck, in fact
 404  *      trust me - if it happens it does suck.
 405  */
 406
 407 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 408         void *unused)
 409 {
 410         if(code==SYS_DOWN || code==SYS_HALT)
 411         {
 412                 /* Turn the card off */
 413                 inb_p(WDT_DC);
 414                 wdt_ctr_load(2,0);
 415         }
 416         return NOTIFY_DONE;
 417 }
 418
 419 /*
 420  *      Kernel Interfaces
 421  */
 422
 423
 424 static struct file_operations wdt_fops = {
 425         owner:          THIS_MODULE,
 426         llseek:         wdt_llseek,
 427         read:           wdt_read,
 428         write:          wdt_write,
 429         ioctl:          wdt_ioctl,
 430         open:           wdt_open,
 431         release:        wdt_release,
 432 };
 433
 434 static struct miscdevice wdt_miscdev=
 435 {
 436         WATCHDOG_MINOR,
 437         "watchdog",
 438         &wdt_fops
 439 };
 440
 441 #ifdef CONFIG_WDT_501
 442 static struct miscdevice temp_miscdev=
 443 {
 444         TEMP_MINOR,
 445         "temperature",
 446         &wdt_fops
 447 };
 448 #endif
 449
 450 /*
 451  *      The WDT card needs to learn about soft shutdowns in order to
 452  *      turn the timebomb registers off.
 453  */
 454
 455 static struct notifier_block wdt_notifier=
 456 {
 457         wdt_notify_sys,
 458         NULL,
 459         0
 460 };
 461
 462 #ifdef MODULE
 463
 464 #define wdt_init init_module
 465
 466 /**
 467  *      cleanup_module:
 468  *
 469  *      Unload the watchdog. You cannot do this with any file handles open.
 470  *      If your watchdog is set to continue ticking on close and you unload
 471  *      it, well it keeps ticking. We won't get the interrupt but the board
 472  *      will not touch PC memory so all is fine. You just have to load a new
 473  *      module in 60 seconds or reboot.
 474  */
 475
 476 void cleanup_module(void)
 477 {
 478         misc_deregister(&wdt_miscdev);
 479 #ifdef CONFIG_WDT_501
 480         misc_deregister(&temp_miscdev);
 481 #endif
 482         unregister_reboot_notifier(&wdt_notifier);
 483         release_region(io,8);
 484         free_irq(irq, NULL);
 485 }
 486
 487 #endif
 488
 489 /**
 490  *      wdt_init:
 491  *
 492  *      Set up the WDT watchdog board. All we have to do is grab the
 493  *      resources we require and bitch if anyone beat us to them.
 494  *      The open() function will actually kick the board off.
 495  */
 496
 497 int __init wdt_init(void)
 498 {
 499         int ret;
 500
 501         ret = misc_register(&wdt_miscdev);
 502         if (ret) {
 503                 printk(KERN_ERR "wdt: can't misc_register on minor=%d\n", WATCHDOG_MINOR);
 504                 goto out;
 505         }
 506         ret = request_irq(irq, wdt_interrupt, SA_INTERRUPT, "wdt501p", NULL);
 507         if(ret) {
 508                 printk(KERN_ERR "wdt: IRQ %d is not free.\n", irq);
 509                 goto outmisc;
 510         }
 511         if (!request_region(io, 8, "wdt501p")) {
 512                 printk(KERN_ERR "wdt: IO %X is not free.\n", io);
 513                 ret = -EBUSY;
 514                 goto outirq;
 515         }
 516         ret = register_reboot_notifier(&wdt_notifier);
 517         if(ret) {
 518                 printk(KERN_ERR "wdt: can't register reboot notifier (err=%d)\n", ret);
 519                 goto outreg;
 520         }
 521
 522 #ifdef CONFIG_WDT_501
 523         ret = misc_register(&temp_miscdev);
 524         if (ret) {
 525                 printk(KERN_ERR "wdt: can't misc_register (temp) on minor=%d\n", TEMP_MINOR);
 526                 goto outrbt;
 527         }
 528 #endif
 529
 530         ret = 0;
 531         printk(KERN_INFO "WDT500/501-P driver 0.07 at %X (Interrupt %d)\n", io, irq);
 532 out:
 533         return ret;
 534
 535 #ifdef CONFIG_WDT_501
 536 outrbt:
 537         unregister_reboot_notifier(&wdt_notifier);
 538 #endif
 539
 540 outreg:
 541         release_region(io,8);
 542 outirq:
 543         free_irq(irq, NULL);
 544 outmisc:
 545         misc_deregister(&wdt_miscdev);
 546         goto out;
 547 }
 548