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