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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.)