Commit f77710c4 authored by Vladimir Zapolskiy's avatar Vladimir Zapolskiy Committed by Wim Van Sebroeck
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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: default avatarVladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Reviewed-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
parent ff84136c

drivers/watchdog/Kconfig

+28 −0
Original line number Diff line number Diff line
@@ -1838,4 +1838,32 @@ config WATCHDOG_PRETIMEOUT_GOV 
	help

	  The option allows to select watchdog pretimeout governors.



if WATCHDOG_PRETIMEOUT_GOV



choice

	prompt "Default Watchdog Pretimeout Governor"

	default WATCHDOG_PRETIMEOUT_DEFAULT_GOV_PANIC

	help

	  This option selects a default watchdog pretimeout governor.

	  The governor takes its action, if a watchdog is capable

	  to report a pretimeout event.



config WATCHDOG_PRETIMEOUT_DEFAULT_GOV_NOOP

	bool "noop"

	select WATCHDOG_PRETIMEOUT_GOV_NOOP

	help

	  Use noop watchdog pretimeout governor by default. If noop

	  governor is selected by a user, write a short message to

	  the kernel log buffer and don't do any system changes.



endchoice



config WATCHDOG_PRETIMEOUT_GOV_NOOP

	tristate "Noop watchdog pretimeout governor"

	help

	  Noop watchdog pretimeout governor, only an informational

	  message is added to kernel log buffer.



endif # WATCHDOG_PRETIMEOUT_GOV



endif # WATCHDOG

drivers/watchdog/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -9,6 +9,8 @@ watchdog-objs += watchdog_core.o watchdog_dev.o 


watchdog-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV)	+= watchdog_pretimeout.o



obj-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV_NOOP)	+= pretimeout_noop.o



# Only one watchdog can succeed. We probe the ISA/PCI/USB based

# watchdog-cards first, then the architecture specific watchdog

# drivers and then the architecture independent "softdog" driver.

drivers/watchdog/pretimeout_noop.c

0 → 100644
+47 −0
Original line number Diff line number Diff line 
/*

 * 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");

drivers/watchdog/watchdog_pretimeout.h

+4 −0
Original line number Diff line number Diff line
@@ -20,6 +20,10 @@ int watchdog_register_pretimeout(struct watchdog_device *wdd); 
void watchdog_unregister_pretimeout(struct watchdog_device *wdd);

int watchdog_pretimeout_governor_get(struct watchdog_device *wdd, char *buf);



#if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_DEFAULT_GOV_NOOP)

#define WATCHDOG_PRETIMEOUT_DEFAULT_GOV		"noop"

#endif



#else

static inline int watchdog_register_pretimeout(struct watchdog_device *wdd)

{

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