patch-2.1.22 linux/Documentation/pcwd-watchdog.txt

• Lines: 132
• Date: Sun Jan 19 15:47:24 1997
• Orig file: v2.1.21/linux/Documentation/pcwd-watchdog.txt
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v2.1.21/linux/Documentation/pcwd-watchdog.txt linux/Documentation/pcwd-watchdog.txt
@@ -0,0 +1,131 @@
+                     Berkshire Products PC Watchdog Card
+                   Support for ISA Cards  Revision A and C
+           Documentation and Driver by Ken Hollis <khollis@nurk.org>
+
+ The PC Watchdog is a card that offers the same type of functionality that
+ the WDT card does, only it doesn't require an IRQ to run.  Furthermore,
+ the Revision C card allows you to monitor any IO Port to automatically
+ trigger the card into being reset.  This way you can make the card
+ monitor hard drive status, or anything else you need.
+
+ The Watchdog Driver has one basic role: to talk to the card and send
+ signals to it so it doesn't reset your computer ... at least during
+ normal operation.
+
+ The Watchdog Driver will automatically find your watchdog card, and will
+ attach a running driver for use with that card.  After the watchdog
+ drivers have initialized, you can then talk to the card using the PC
+ Watchdog program, available from ftp.bitgate.com:/pub/bitgate/pcwd.
+
+ I suggest putting a "watchdog -d" before the beginning of an fsck, and
+ a "watchdog -e -t 1" immediately after the end of an fsck.  (Remember
+ to run the program with an "&" to run it in the background!)
+
+ If you want to write a program to be compatible with the PC Watchdog
+ driver, simply do the following:
+
+-- Snippet of code --
+/*
+ * Watchdog Driver Test Program
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <linux/pcwd.h>
+
+int fd;
+
+/*
+ * This function simply sends an IOCTL to the driver, which in turn ticks
+ * the PC Watchdog card to reset its internal timer so it doesn't trigger
+ * a computer reset.
+ */
+void keep_alive(void)
+{
+    int dummy;
+
+    ioctl(fd, WDIOC_KEEPALIVE, &dummy);
+}
+
+/*
+ * The main program.  Run the program with "-d" to disable the card,
+ * or "-e" to enable the card.
+ */
+int main(int argc, char *argv[])
+{
+    fd = open("/dev/watchdog", O_WRONLY);
+
+    if (fd == -1) {
+	fprintf(stderr, "Watchdog device not enabled.\n");
+	fflush(stderr);
+	exit(-1);
+    }
+
+    if (argc > 1) {
+	if (!strncasecmp(argv[1], "-d", 2)) {
+	    ioctl(fd, WDIOC_SETOPTIONS, WDIOS_DISABLECARD);
+	    fprintf(stderr, "Watchdog card disabled.\n");
+	    fflush(stderr);
+	    exit(0);
+	} else if (!strncasecmp(argv[1], "-e", 2)) {
+	    ioctl(fd, WDIOC_SETOPTIONS, WDIOS_ENABLECARD);
+	    fprintf(stderr, "Watchdog card enabled.\n");
+	    fflush(stderr);
+	    exit(0);
+	} else {
+	    fprintf(stderr, "-d to disable, -e to enable.\n");
+	    fprintf(stderr, "run by itself to tick the card.\n");
+	    fflush(stderr);
+	    exit(0);
+	}
+    } else {
+	fprintf(stderr, "Watchdog Ticking Away!\n");
+	fflush(stderr);
+    }
+
+    while(1) {
+	keep_alive();
+	sleep(1);
+    }
+}
+-- End snippet --
+
+ Other IOCTL functions include:
+
+	WDIOC_GETSUPPORT
+		This returns the support of the card itself.  This
+		returns in structure "PCWDS" which returns:
+			options = WDIOS_TEMPPANIC
+				  (This card supports temperature)
+			firmware_version = xxxx
+				  (Firmware version of the card)
+
+	WDIOC_GETSTATUS
+		This returns the status of the card, with the bits of
+		WDIOF_* bitwise-anded into the value.  (The comments
+		are in linux/pcwd.h)
+
+	WDIOC_GETBOOTSTATUS
+		This returns the status of the card that was reported
+		at bootup.
+
+	WDIOC_GETTEMP
+		This returns the temperature of the card.  (You can also
+		read /dev/watchdog, which gives a temperature update
+		every second.)
+
+	WDIOC_SETOPTIONS
+		This lets you set the options of the card.  You can either
+		enable or disable the card this way.
+
+	WDIOC_KEEPALIVE
+		This pings the card to tell it not to reset your computer.
+
+ And that's all she wrote!
+
+ -- Ken Hollis
+    (khollis@nurk.org)