136 lines
3.7 KiB
Plaintext
136 lines
3.7 KiB
Plaintext
Berkshire Products PC Watchdog Card
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Support for ISA Cards Revision A and C
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Documentation and Driver by Ken Hollis <kenji@bitgate.com>
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The PC Watchdog is a card that offers the same type of functionality that
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the WDT card does, only it doesn't require an IRQ to run. Furthermore,
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the Revision C card allows you to monitor any IO Port to automatically
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trigger the card into being reset. This way you can make the card
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monitor hard drive status, or anything else you need.
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The Watchdog Driver has one basic role: to talk to the card and send
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signals to it so it doesn't reset your computer ... at least during
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normal operation.
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The Watchdog Driver will automatically find your watchdog card, and will
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attach a running driver for use with that card. After the watchdog
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drivers have initialized, you can then talk to the card using the PC
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Watchdog program, available from http://ftp.bitgate.com/pcwd/.
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I suggest putting a "watchdog -d" before the beginning of an fsck, and
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a "watchdog -e -t 1" immediately after the end of an fsck. (Remember
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to run the program with an "&" to run it in the background!)
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If you want to write a program to be compatible with the PC Watchdog
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driver, simply do the following:
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-- Snippet of code --
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/*
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* Watchdog Driver Test Program
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#include <linux/types.h>
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#include <linux/watchdog.h>
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int fd;
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/*
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* This function simply sends an IOCTL to the driver, which in turn ticks
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* the PC Watchdog card to reset its internal timer so it doesn't trigger
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* a computer reset.
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*/
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void keep_alive(void)
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{
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int dummy;
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ioctl(fd, WDIOC_KEEPALIVE, &dummy);
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}
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/*
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* The main program. Run the program with "-d" to disable the card,
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* or "-e" to enable the card.
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*/
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int main(int argc, char *argv[])
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{
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fd = open("/dev/watchdog", O_WRONLY);
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if (fd == -1) {
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fprintf(stderr, "Watchdog device not enabled.\n");
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fflush(stderr);
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exit(-1);
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}
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if (argc > 1) {
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if (!strncasecmp(argv[1], "-d", 2)) {
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ioctl(fd, WDIOC_SETOPTIONS, WDIOS_DISABLECARD);
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fprintf(stderr, "Watchdog card disabled.\n");
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fflush(stderr);
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exit(0);
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} else if (!strncasecmp(argv[1], "-e", 2)) {
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ioctl(fd, WDIOC_SETOPTIONS, WDIOS_ENABLECARD);
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fprintf(stderr, "Watchdog card enabled.\n");
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fflush(stderr);
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exit(0);
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} else {
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fprintf(stderr, "-d to disable, -e to enable.\n");
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fprintf(stderr, "run by itself to tick the card.\n");
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fflush(stderr);
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exit(0);
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}
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} else {
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fprintf(stderr, "Watchdog Ticking Away!\n");
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fflush(stderr);
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}
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while(1) {
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keep_alive();
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sleep(1);
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}
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}
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-- End snippet --
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Other IOCTL functions include:
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WDIOC_GETSUPPORT
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This returns the support of the card itself. This
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returns in structure "PCWDS" which returns:
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options = WDIOS_TEMPPANIC
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(This card supports temperature)
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firmware_version = xxxx
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(Firmware version of the card)
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WDIOC_GETSTATUS
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This returns the status of the card, with the bits of
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WDIOF_* bitwise-anded into the value. (The comments
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are in linux/pcwd.h)
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WDIOC_GETBOOTSTATUS
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This returns the status of the card that was reported
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at bootup.
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WDIOC_GETTEMP
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This returns the temperature of the card. (You can also
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read /dev/watchdog, which gives a temperature update
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every second.)
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WDIOC_SETOPTIONS
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This lets you set the options of the card. You can either
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enable or disable the card this way.
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WDIOC_KEEPALIVE
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This pings the card to tell it not to reset your computer.
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And that's all she wrote!
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-- Ken Hollis
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(kenji@bitgate.com)
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(This documentation may be out of date. Check
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http://ftp.bitgate.com/pcwd/ for the absolute latest additions.)
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