Merge master.kernel.org:/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog (fffcb480) · Commits · e / devices / android_kernel_xiaomi_markw

Documentation/watchdog/pcwd-watchdog.txt

+3 −72

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		@@ -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:

Documentation/watchdog/src/watchdog-simple.c

0 → 100644

+15 −0

Original line number	Diff line number	Diff line
		#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);
		}
		}

Documentation/watchdog/src/watchdog-test.c

0 → 100644

+68 −0

Original line number	Diff line number	Diff line
		/*
		* 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);
		}
		}

Documentation/watchdog/watchdog-api.txt

+39 −17

Original line number	Diff line number	Diff line
		@@ -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

Documentation/watchdog/watchdog.txt

+1 −22

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		@@ -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


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