linux-old/Documentation/pcwd-watchdog.txt
<<
>>
Prefs
   1                     Berkshire Products PC Watchdog Card
   2                   Support for ISA Cards  Revision A and C
   3           Documentation and Driver by Ken Hollis <kenji@bitgate.com>
   4
   5 The PC Watchdog is a card that offers the same type of functionality that
   6 the WDT card does, only it doesn't require an IRQ to run.  Furthermore,
   7 the Revision C card allows you to monitor any IO Port to automatically
   8 trigger the card into being reset.  This way you can make the card
   9 monitor hard drive status, or anything else you need.
  10
  11 The Watchdog Driver has one basic role: to talk to the card and send
  12 signals to it so it doesn't reset your computer ... at least during
  13 normal operation.
  14
  15 The Watchdog Driver will automatically find your watchdog card, and will
  16 attach a running driver for use with that card.  After the watchdog
  17 drivers have initialized, you can then talk to the card using the PC
  18 Watchdog program, available from http://ftp.bitgate.com/pcwd/.
  19
  20 I suggest putting a "watchdog -d" before the beginning of an fsck, and
  21 a "watchdog -e -t 1" immediately after the end of an fsck.  (Remember
  22 to run the program with an "&" to run it in the background!)
  23
  24 If you want to write a program to be compatible with the PC Watchdog
  25 driver, simply do the following:
  26
  27-- Snippet of code --
  28/*
  29 * Watchdog Driver Test Program
  30 */
  31
  32#include <stdio.h>
  33#include <stdlib.h>
  34#include <string.h>
  35#include <unistd.h>
  36#include <fcntl.h>
  37#include <sys/ioctl.h>
  38#include <linux/pcwd.h>
  39
  40int fd;
  41
  42/*
  43 * This function simply sends an IOCTL to the driver, which in turn ticks
  44 * the PC Watchdog card to reset its internal timer so it doesn't trigger
  45 * a computer reset.
  46 */
  47void keep_alive(void)
  48{
  49    int dummy;
  50
  51    ioctl(fd, WDIOC_KEEPALIVE, &dummy);
  52}
  53
  54/*
  55 * The main program.  Run the program with "-d" to disable the card,
  56 * or "-e" to enable the card.
  57 */
  58int main(int argc, char *argv[])
  59{
  60    fd = open("/dev/watchdog", O_WRONLY);
  61
  62    if (fd == -1) {
  63        fprintf(stderr, "Watchdog device not enabled.\n");
  64        fflush(stderr);
  65        exit(-1);
  66    }
  67
  68    if (argc > 1) {
  69        if (!strncasecmp(argv[1], "-d", 2)) {
  70            ioctl(fd, WDIOC_SETOPTIONS, WDIOS_DISABLECARD);
  71            fprintf(stderr, "Watchdog card disabled.\n");
  72            fflush(stderr);
  73            exit(0);
  74        } else if (!strncasecmp(argv[1], "-e", 2)) {
  75            ioctl(fd, WDIOC_SETOPTIONS, WDIOS_ENABLECARD);
  76            fprintf(stderr, "Watchdog card enabled.\n");
  77            fflush(stderr);
  78            exit(0);
  79        } else {
  80            fprintf(stderr, "-d to disable, -e to enable.\n");
  81            fprintf(stderr, "run by itself to tick the card.\n");
  82            fflush(stderr);
  83            exit(0);
  84        }
  85    } else {
  86        fprintf(stderr, "Watchdog Ticking Away!\n");
  87        fflush(stderr);
  88    }
  89
  90    while(1) {
  91        keep_alive();
  92        sleep(1);
  93    }
  94}
  95-- End snippet --
  96
  97 Other IOCTL functions include:
  98
  99        WDIOC_GETSUPPORT
 100                This returns the support of the card itself.  This
 101                returns in structure "PCWDS" which returns:
 102                        options = WDIOS_TEMPPANIC
 103                                  (This card supports temperature)
 104                        firmware_version = xxxx
 105                                  (Firmware version of the card)
 106
 107        WDIOC_GETSTATUS
 108                This returns the status of the card, with the bits of
 109                WDIOF_* bitwise-anded into the value.  (The comments
 110                are in linux/pcwd.h)
 111
 112        WDIOC_GETBOOTSTATUS
 113                This returns the status of the card that was reported
 114                at bootup.
 115
 116        WDIOC_GETTEMP
 117                This returns the temperature of the card.  (You can also
 118                read /dev/watchdog, which gives a temperature update
 119                every second.)
 120
 121        WDIOC_SETOPTIONS
 122                This lets you set the options of the card.  You can either
 123                enable or disable the card this way.
 124
 125        WDIOC_KEEPALIVE
 126                This pings the card to tell it not to reset your computer.
 127
 128 And that's all she wrote!
 129
 130 -- Ken Hollis
 131    (kenji@bitgate.com)
 132
 133(This documentation may be out of date.  Check
 134 http://ftp.bitgate.com/pcwd/ for the absolute latest additions.)
 135
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.