watchdog: pretimeout: add noop pretimeout governor

The change adds noop watchdog pretimeout governor, only an
informational message is printed to the kernel log buffer when a
watchdog triggers a pretimeout event.

While introducing the first pretimeout governor the selected design
assumes that the default pretimeout governor is selected by its name
and it is always built-in, thus the default pretimeout governor can
not be unregistered and the correspondent check can be removed from
the watchdog_unregister_governor() function.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 47 insertions, 0 deletions

diff --git a/drivers/watchdog/pretimeout_noop.c b/drivers/watchdog/pretimeout_noop.c
new file mode 100644
index 000000000000..85f5299d197c
--- /dev/null
+++ b/drivers/watchdog/pretimeout_noop.c
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2015-2016 Mentor Graphics
+ *
+ * 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
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/watchdog.h>
+
+#include "watchdog_pretimeout.h"
+
+/**
+ * pretimeout_noop - No operation on watchdog pretimeout event
+ * @wdd - watchdog_device
+ *
+ * This function prints a message about pretimeout to kernel log.
+ */
+static void pretimeout_noop(struct watchdog_device *wdd)
+{
+	pr_alert("watchdog%d: pretimeout event\n", wdd->id);
+}
+
+static struct watchdog_governor watchdog_gov_noop = {
+	.name		= "noop",
+	.pretimeout	= pretimeout_noop,
+};
+
+static int __init watchdog_gov_noop_register(void)
+{
+	return watchdog_register_governor(&watchdog_gov_noop);
+}
+
+static void __exit watchdog_gov_noop_unregister(void)
+{
+	watchdog_unregister_governor(&watchdog_gov_noop);
+}
+module_init(watchdog_gov_noop_register);
+module_exit(watchdog_gov_noop_unregister);
+
+MODULE_AUTHOR("Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>");
+MODULE_DESCRIPTION("Panic watchdog pretimeout governor");
+MODULE_LICENSE("GPL");