diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/watchdog/pcwd-watchdog.txt | 75 | ||||
| -rw-r--r-- | Documentation/watchdog/src/watchdog-simple.c | 15 | ||||
| -rw-r--r-- | Documentation/watchdog/src/watchdog-test.c | 68 | ||||
| -rw-r--r-- | Documentation/watchdog/watchdog-api.txt | 56 | ||||
| -rw-r--r-- | Documentation/watchdog/watchdog.txt | 23 |
5 files changed, 126 insertions, 111 deletions
diff --git a/Documentation/watchdog/pcwd-watchdog.txt b/Documentation/watchdog/pcwd-watchdog.txt index 12187a33e310..d9ee6336c1d4 100644 --- a/Documentation/watchdog/pcwd-watchdog.txt +++ b/Documentation/watchdog/pcwd-watchdog.txt @@ -22,78 +22,9 @@ 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/types.h> -#include <linux/watchdog.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 -- + driver, simply use of modify the watchdog test program: + Documentation/watchdog/src/watchdog-test.c + Other IOCTL functions include: diff --git a/Documentation/watchdog/src/watchdog-simple.c b/Documentation/watchdog/src/watchdog-simple.c new file mode 100644 index 000000000000..85cf17c48669 --- /dev/null +++ b/Documentation/watchdog/src/watchdog-simple.c @@ -0,0 +1,15 @@ +#include <stdlib.h> +#include <fcntl.h> + +int main(int argc, const char *argv[]) { + int fd = open("/dev/watchdog", O_WRONLY); + if (fd == -1) { + perror("watchdog"); + exit(1); + } + while (1) { + write(fd, "\0", 1); + fsync(fd); + sleep(10); + } +} diff --git a/Documentation/watchdog/src/watchdog-test.c b/Documentation/watchdog/src/watchdog-test.c new file mode 100644 index 000000000000..65f6c19cb865 --- /dev/null +++ b/Documentation/watchdog/src/watchdog-test.c @@ -0,0 +1,68 @@ +/* + * 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/types.h> +#include <linux/watchdog.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); + } +} diff --git a/Documentation/watchdog/watchdog-api.txt b/Documentation/watchdog/watchdog-api.txt index 21ed51173662..958ff3d48be3 100644 --- a/Documentation/watchdog/watchdog-api.txt +++ b/Documentation/watchdog/watchdog-api.txt @@ -34,22 +34,7 @@ activates as soon as /dev/watchdog is opened and will reboot unless the watchdog is pinged within a certain time, this time is called the timeout or margin. The simplest way to ping the watchdog is to write some data to the device. So a very simple watchdog daemon would look -like this: - -#include <stdlib.h> -#include <fcntl.h> - -int main(int argc, const char *argv[]) { - int fd=open("/dev/watchdog",O_WRONLY); - if (fd==-1) { - perror("watchdog"); - exit(1); - } - while(1) { - write(fd, "\0", 1); - sleep(10); - } -} +like this source file: see Documentation/watchdog/src/watchdog-simple.c A more advanced driver could for example check that a HTTP server is still responding before doing the write call to ping the watchdog. @@ -110,7 +95,40 @@ current timeout using the GETTIMEOUT ioctl. ioctl(fd, WDIOC_GETTIMEOUT, &timeout); printf("The timeout was is %d seconds\n", timeout); -Envinronmental monitoring: +Pretimeouts: + +Some watchdog timers can be set to have a trigger go off before the +actual time they will reset the system. This can be done with an NMI, +interrupt, or other mechanism. This allows Linux to record useful +information (like panic information and kernel coredumps) before it +resets. + + pretimeout = 10; + ioctl(fd, WDIOC_SETPRETIMEOUT, &pretimeout); + +Note that the pretimeout is the number of seconds before the time +when the timeout will go off. It is not the number of seconds until +the pretimeout. So, for instance, if you set the timeout to 60 seconds +and the pretimeout to 10 seconds, the pretimout will go of in 50 +seconds. Setting a pretimeout to zero disables it. + +There is also a get function for getting the pretimeout: + + ioctl(fd, WDIOC_GETPRETIMEOUT, &timeout); + printf("The pretimeout was is %d seconds\n", timeout); + +Not all watchdog drivers will support a pretimeout. + +Get the number of seconds before reboot: + +Some watchdog drivers have the ability to report the remaining time +before the system will reboot. The WDIOC_GETTIMELEFT is the ioctl +that returns the number of seconds before reboot. + + ioctl(fd, WDIOC_GETTIMELEFT, &timeleft); + printf("The timeout was is %d seconds\n", timeleft); + +Environmental monitoring: All watchdog drivers are required return more information about the system, some do temperature, fan and power level monitoring, some can tell you @@ -169,6 +187,10 @@ The watchdog saw a keepalive ping since it was last queried. WDIOF_SETTIMEOUT Can set/get the timeout +The watchdog can do pretimeouts. + + WDIOF_PRETIMEOUT Pretimeout (in seconds), get/set + For those drivers that return any bits set in the option field, the GETSTATUS and GETBOOTSTATUS ioctls can be used to ask for the current diff --git a/Documentation/watchdog/watchdog.txt b/Documentation/watchdog/watchdog.txt index dffda29c8799..4b1ff69cc19a 100644 --- a/Documentation/watchdog/watchdog.txt +++ b/Documentation/watchdog/watchdog.txt @@ -65,28 +65,7 @@ The external event interfaces on the WDT boards are not currently supported. Minor numbers are however allocated for it. -Example Watchdog Driver ------------------------ - -#include <stdio.h> -#include <unistd.h> -#include <fcntl.h> - -int main(int argc, const char *argv[]) -{ - int fd=open("/dev/watchdog",O_WRONLY); - if(fd==-1) - { - perror("watchdog"); - exit(1); - } - while(1) - { - write(fd,"\0",1); - fsync(fd); - sleep(10); - } -} +Example Watchdog Driver: see Documentation/watchdog/src/watchdog-simple.c Contact Information |