CHROMIUMOS: daisydog: convert test/demo code to a daemon
Chromium.org copyright was missing.
Setup main loop so we would determine HW watchdog reset interval and pet
more often than that. :)
BUG=chrome-os-partner:9403
TEST=manual
Change-Id: I399e010b6ebefdd164572952a056a28b6a726371
Signed-off-by: Grant Grundler <grundler@chromium.org>
diff --git a/daisydog.c b/daisydog.c
index 071a7db..d1c1a23 100644
--- a/daisydog.c
+++ b/daisydog.c
@@ -1,6 +1,8 @@
/*
- * Linux watchdog demo for LPC313x
+ * Simple Linux HW watchdog daemon
+ *
* Copyright (c) 2010 Daniel Widyanko. All rights reserved.
+ * Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@@ -29,6 +31,8 @@
#include <linux/watchdog.h>
#define WATCHDOGDEV "/dev/watchdog"
+#define MIN_WD_TIMEOUT 5 /* WD must be at least 5 seconds */
+
static const char *const short_options = "hd:i:";
static const struct option long_options[] = {
{"help", 0, NULL, 'h'},
@@ -42,32 +46,31 @@
fprintf(stream, "Usage: %s [options]\n", app_name);
fprintf(stream,
" -h --help Display this usage information.\n"
-" -d --dev <device_file> Use <device_file> as watchdog device file.\n"
-" The default device file is '/dev/watchdog'\n"
-" -i --interval <interval> Change the watchdog interval time\n");
+" -d --dev <device_file> Use <device_file> as HW watchdog device file.\n"
+" The default is '/dev/watchdog'\n"
+" -i --interval <interval> Change the HW watchdog interval time\n"
+" Must be at least %d seconds\n", MIN_WD_TIMEOUT
+ );
exit(exit_code);
}
int main(int argc, char **argv)
{
- int fd; /* File handler for watchdog */
- int interval; /* Watchdog timeout interval (in secs) */
+ int fd; /* File handler for HW watchdog */
int bootstatus; /* Wathdog last boot status */
- char *dev; /* Watchdog default device file */
+ char *dev = WATCHDOGDEV;/* Watchdog default device file */
int next_option; /* getopt iteration var */
- char kick_watchdog; /* kick_watchdog options */
-
- /* Init variables */
- dev = WATCHDOGDEV;
- interval = 0;
- kick_watchdog = 0;
+ int wd_timeout; /* when HW watchdog goes balistic */
+ int interval = 0; /* user parameter for wd_timeout */
+ int pet_interval; /* how often we should pet the HW watchdog */
+ int slept_well; /* return of sleep call */
/* Parse options if any */
do {
next_option = getopt_long(argc, argv, short_options,
- long_options, NULL);
+ long_options, NULL);
switch (next_option) {
case 'h':
print_usage(stdout, argv[0], EXIT_SUCCESS);
@@ -76,9 +79,11 @@
break;
case 'i':
interval = atoi(optarg);
+ if (interval < MIN_WD_TIMEOUT)
+ print_usage(stderr, argv[0], -EINVAL);
break;
case '?': /* Invalid options */
- print_usage(stderr, argv[0], EXIT_FAILURE);
+ print_usage(stderr, argv[0], -EINVAL);
case -1: /* Done with options */
break;
default: /* Unexpected stuffs */
@@ -95,26 +100,39 @@
exit(EXIT_FAILURE);
}
- /* If user wants to change the watchdog interval */
- if (interval != 0) {
- fprintf(stdout, "Set watchdog interval to %d\n", interval);
+ /* If user wants to change the HW watchdog timeout */
+ if (interval) {
if (ioctl(fd, WDIOC_SETTIMEOUT, &interval) != 0) {
- fprintf(stderr,
- "Error: Set watchdog interval failed\n");
+ fprintf(stderr, "Error: Could not set HW watchdog"
+ "interval to %d\n", interval);
exit(EXIT_FAILURE);
}
+
}
- /* Display current watchdog interval */
- if (ioctl(fd, WDIOC_GETTIMEOUT, &interval) == 0) {
- fprintf(stdout, "Current watchdog interval is %d\n",
- interval);
+ /* Get/Display current HW watchdog interval.
+ * Let user know if it's not exactly what they specified.
+ */
+ if (ioctl(fd, WDIOC_GETTIMEOUT, &wd_timeout) == 0) {
+ fprintf(stdout, "HW watchdog interval is %d seconds",
+ wd_timeout);
+
+ if (interval && interval != wd_timeout)
+ fprintf(stdout, " (user asked for %d seconds)\n",
+ interval);
+
+ fprintf(stdout, "\n");
} else {
- fprintf(stderr, "Error: Cannot read watchdog interval\n");
+ fprintf(stderr, "Error: Cannot read HW watchdog interval\n");
exit(EXIT_FAILURE);
}
- /* Check if last boot is caused by watchdog */
+ /* Adjust petting interval to give some "margin of error" vs
+ * when the HW watchdog will fire.
+ */
+ pet_interval = wd_timeout / 2;
+
+ /* Check if last boot is caused by HW watchdog */
if (ioctl(fd, WDIOC_GETBOOTSTATUS, &bootstatus) == 0) {
fprintf(stdout, "Last boot is caused by : %s\n",
(bootstatus != 0) ? "Watchdog" : "Power-On-Reset");
@@ -123,41 +141,35 @@
exit(EXIT_FAILURE);
}
- /* There are two ways to kick the watchdog:
- - by writing any dummy value into watchdog device file, or
- - by using IOCTL WDIOC_KEEPALIVE
+ /* There are two ways to pet the watchdog:
+ * 1) by writing any dummy value into watchdog device file, or
+ * 2) by using IOCTL WDIOC_KEEPALIVE
+ *
+ * Use the first method since it's easier. :)
*/
- fprintf(stdout,
- "Use:\n"
- " <w> to kick through writing over device file\n"
- " <i> to kick through IOCTL\n"
- " <x> to exit the program\n");
do {
- kick_watchdog = getchar();
- switch (kick_watchdog) {
- case 'w':
- write(fd, "w", 1);
- fprintf(stdout,
- "Kick watchdog through writing over device file\n");
- break;
- case 'i':
- ioctl(fd, WDIOC_KEEPALIVE, NULL);
- fprintf(stdout, "Kick watchdog through IOCTL\n");
- break;
- case 'x':
- fprintf(stdout, "Goodbye !\n");
- break;
- default:
- fprintf(stdout, "Unknown command\n");
- break;
- }
- } while (kick_watchdog != 'x');
+ write(fd, "w", 1);
- /* The 'V' value needs to be written into watchdog device file to indicate
- that we intend to close/stop the watchdog. Otherwise, debug message
- 'Watchdog timer closed unexpectedly' will be printed
+ /* force immediate exit of loop if write fails. */
+ if (errno)
+ slept_well = -errno;
+ else
+ slept_well = sleep(pet_interval);
+
+ } while (slept_well == 0);
+
+ fprintf(stdout, "Exiting (%d)\n", slept_well);
+
+ /* Writing 'V' into watchdog device indicates the close/stop
+ * of the watchdog was intentional. Otherwise, debug message
+ * 'Watchdog timer closed unexpectedly' will be printed to
+ * dmesg and the system will reboot in wd_timeout seconds since
+ * the last time the watchdog was pet.
*/
write(fd, "V", 1);
+
/* Closing the watchdog device will deactivate the watchdog. */
close(fd);
+
+ exit(slept_well);
}
