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watchdog: softdog: make pretimeout support a compile option 

It occurred to me that the panic pretimeout governor will stall the
softdog, because it is purely software which simply breaks when the
kernel panics. Testing governors with the softdog on the other hand is
really useful, so make this feature a compile time option which nees to
be enabled explicitly. This also removes the overhead if pretimeout
support is not used because it will now be compiled away (saving ~10% on
ARM32).

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
hifive-unleashed-5.1
Wolfram Sang 2017-02-07 15:03:29 +01:00 committed by Guenter Roeck
parent 8ce6796dab
commit 4cbc69023a
2 changed files with 21 additions and 8 deletions
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8
drivers/watchdog/Kconfig
View File

@ -71,6 +71,14 @@ config SOFT_WATCHDOG
To compile this driver as a module, choose M here: the
module will be called softdog.
config SOFT_WATCHDOG_PRETIMEOUT
bool "Software watchdog pretimeout governor support"
depends on SOFT_WATCHDOG && WATCHDOG_PRETIMEOUT_GOV
help
Enable this if you want to use pretimeout governors with the software
watchdog. Be aware that governors might affect the watchdog because it
is purely software, e.g. the panic governor will stall it!
config DA9052_WATCHDOG
tristate "Dialog DA9052 Watchdog"
depends on PMIC_DA9052 || COMPILE_TEST

21
drivers/watchdog/softdog.c
View File

@ -87,11 +87,13 @@ static int softdog_ping(struct watchdog_device *w)
if (!mod_timer(&softdog_ticktock, jiffies + (w->timeout * HZ)))
__module_get(THIS_MODULE);
if (w->pretimeout)
mod_timer(&softdog_preticktock, jiffies +
(w->timeout - w->pretimeout) * HZ);
else
del_timer(&softdog_preticktock);
if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT)) {
if (w->pretimeout)
mod_timer(&softdog_preticktock, jiffies +
(w->timeout - w->pretimeout) * HZ);
else
del_timer(&softdog_preticktock);
}
return 0;
}
@ -101,15 +103,15 @@ static int softdog_stop(struct watchdog_device *w)
if (del_timer(&softdog_ticktock))
module_put(THIS_MODULE);
del_timer(&softdog_preticktock);
if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT))
del_timer(&softdog_preticktock);
return 0;
}
static struct watchdog_info softdog_info = {
.identity = "Software Watchdog",
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE |
WDIOF_PRETIMEOUT,
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
};
static const struct watchdog_ops softdog_ops = {
@ -134,6 +136,9 @@ static int __init softdog_init(void)
watchdog_set_nowayout(&softdog_dev, nowayout);
watchdog_stop_on_reboot(&softdog_dev);
if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT))
softdog_info.options |= WDIOF_PRETIMEOUT;
ret = watchdog_register_device(&softdog_dev);
if (ret)
return ret;