LXR linux-bk/Documentation/watchdog/pcwd-watchdog.txt

   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/types.h>
  39#include <linux/watchdog.h>
  40
  41int fd;
  42
  43/*
  44 * This function simply sends an IOCTL to the driver, which in turn ticks
  45 * the PC Watchdog card to reset its internal timer so it doesn't trigger
  46 * a computer reset.
  47 */
  48void keep_alive(void)
  49{
  50    int dummy;
  51
  52    ioctl(fd, WDIOC_KEEPALIVE, &dummy);
  53}
  54
  55/*
  56 * The main program.  Run the program with "-d" to disable the card,
  57 * or "-e" to enable the card.
  58 */
  59int main(int argc, char *argv[])
  60{
  61    fd = open("/dev/watchdog", O_WRONLY);
  62
  63    if (fd == -1) {
  64        fprintf(stderr, "Watchdog device not enabled.\n");
  65        fflush(stderr);
  66        exit(-1);
  67    }
  68
  69    if (argc > 1) {
  70        if (!strncasecmp(argv[1], "-d", 2)) {
  71            ioctl(fd, WDIOC_SETOPTIONS, WDIOS_DISABLECARD);
  72            fprintf(stderr, "Watchdog card disabled.\n");
  73            fflush(stderr);
  74            exit(0);
  75        } else if (!strncasecmp(argv[1], "-e", 2)) {
  76            ioctl(fd, WDIOC_SETOPTIONS, WDIOS_ENABLECARD);
  77            fprintf(stderr, "Watchdog card enabled.\n");
  78            fflush(stderr);
  79            exit(0);
  80        } else {
  81            fprintf(stderr, "-d to disable, -e to enable.\n");
  82            fprintf(stderr, "run by itself to tick the card.\n");
  83            fflush(stderr);
  84            exit(0);
  85        }
  86    } else {
  87        fprintf(stderr, "Watchdog Ticking Away!\n");
  88        fflush(stderr);
  89    }
  90
  91    while(1) {
  92        keep_alive();
  93        sleep(1);
  94    }
  95}
  96-- End snippet --
  97
  98 Other IOCTL functions include:
  99
 100        WDIOC_GETSUPPORT
 101                This returns the support of the card itself.  This
 102                returns in structure "PCWDS" which returns:
 103                        options = WDIOS_TEMPPANIC
 104                                  (This card supports temperature)
 105                        firmware_version = xxxx
 106                                  (Firmware version of the card)
 107
 108        WDIOC_GETSTATUS
 109                This returns the status of the card, with the bits of
 110                WDIOF_* bitwise-anded into the value.  (The comments
 111                are in linux/pcwd.h)
 112
 113        WDIOC_GETBOOTSTATUS
 114                This returns the status of the card that was reported
 115                at bootup.
 116
 117        WDIOC_GETTEMP
 118                This returns the temperature of the card.  (You can also
 119                read /dev/watchdog, which gives a temperature update
 120                every second.)
 121
 122        WDIOC_SETOPTIONS
 123                This lets you set the options of the card.  You can either
 124                enable or disable the card this way.
 125
 126        WDIOC_KEEPALIVE
 127                This pings the card to tell it not to reset your computer.
 128
 129 And that's all she wrote!
 130
 131 -- Ken Hollis
 132    (kenji@bitgate.com)
 133
 134(This documentation may be out of date.  Check
 135 http://ftp.bitgate.com/pcwd/ for the absolute latest additions.)
 136