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Commit 33b71126 authored by Pratyush Anand's avatar Pratyush Anand Committed by Wim Van Sebroeck
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watchdog: Read device status through sysfs attributes 



This patch adds following attributes to watchdog device's sysfs interface
to read its different status.

* state - reads whether device is active or not
* identity - reads Watchdog device's identity string.
* timeout - reads current timeout.
* timeleft - reads timeleft before watchdog generates a reset
* bootstatus - reads status of the watchdog device at boot
* status - reads watchdog device's  internal status bits
* nowayout - reads whether nowayout feature was set or not

Testing with iTCO_wdt:
 # cd /sys/class/watchdog/watchdog1/
 # ls
bootstatus  dev  device  identity  nowayout  power  state
subsystem  timeleft  timeout  uevent
 # cat identity
iTCO_wdt
 # cat timeout
30
 # cat state
inactive
 # echo > /dev/watchdog1
 # cat timeleft
26
 # cat state
active
 # cat bootstatus
0
 # cat nowayout
0

Signed-off-by: default avatarPratyush Anand <panand@redhat.com>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
parent 906d7a5c

Documentation/ABI/testing/sysfs-class-watchdog

0 → 100644
+51 −0
Original line number Diff line number Diff line 
What:		/sys/class/watchdog/watchdogn/bootstatus

Date:		August 2015

Contact:	Wim Van Sebroeck <wim@iguana.be>

Description:

		It is a read only file. It contains status of the watchdog

		device at boot. It is equivalent to WDIOC_GETBOOTSTATUS of

		ioctl interface.



What:		/sys/class/watchdog/watchdogn/identity

Date:		August 2015

Contact:	Wim Van Sebroeck <wim@iguana.be>

Description:

		It is a read only file. It contains identity string of

		watchdog device.



What:		/sys/class/watchdog/watchdogn/nowayout

Date:		August 2015

Contact:	Wim Van Sebroeck <wim@iguana.be>

Description:

		It is a read only file. While reading, it gives '1' if that

		device supports nowayout feature else, it gives '0'.



What:		/sys/class/watchdog/watchdogn/state

Date:		August 2015

Contact:	Wim Van Sebroeck <wim@iguana.be>

Description:

		It is a read only file. It gives active/inactive status of

		watchdog device.



What:		/sys/class/watchdog/watchdogn/status

Date:		August 2015

Contact:	Wim Van Sebroeck <wim@iguana.be>

Description:

		It is a read only file. It contains watchdog device's

		internal status bits. It is equivalent to WDIOC_GETSTATUS

		of ioctl interface.



What:		/sys/class/watchdog/watchdogn/timeleft

Date:		August 2015

Contact:	Wim Van Sebroeck <wim@iguana.be>

Description:

		It is a read only file. It contains value of time left for

		reset generation. It is equivalent to WDIOC_GETTIMELEFT of

		ioctl interface.



What:		/sys/class/watchdog/watchdogn/timeout

Date:		August 2015

Contact:	Wim Van Sebroeck <wim@iguana.be>

Description:

		It is a read only file. It is read to know about current

		value of timeout programmed.

drivers/watchdog/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -46,6 +46,13 @@ config WATCHDOG_NOWAYOUT 
	  get killed. If you say Y here, the watchdog cannot be stopped once

	  it has been started.



config WATCHDOG_SYSFS

	bool "Read different watchdog information through sysfs"

	default n

	help

	  Say Y here if you want to enable watchdog device status read through

	  sysfs attributes.



#

# General Watchdog drivers

#

drivers/watchdog/watchdog_core.c

+1 −1
Original line number Diff line number Diff line
@@ -249,7 +249,7 @@ static int __watchdog_register_device(struct watchdog_device *wdd) 


	devno = wdd->cdev.dev;

	wdd->dev = device_create(watchdog_class, wdd->parent, devno,

					NULL, "watchdog%d", wdd->id);

					wdd, "watchdog%d", wdd->id);

	if (IS_ERR(wdd->dev)) {

		watchdog_dev_unregister(wdd);

		ida_simple_remove(&watchdog_ida, id);

drivers/watchdog/watchdog_dev.c

+114 −0
Original line number Diff line number Diff line
@@ -247,6 +247,119 @@ static int watchdog_get_timeleft(struct watchdog_device *wdd, 
	return err;

}



#ifdef CONFIG_WATCHDOG_SYSFS

static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr,

				char *buf)

{

	struct watchdog_device *wdd = dev_get_drvdata(dev);



	return sprintf(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, &wdd->status));

}

static DEVICE_ATTR_RO(nowayout);



static ssize_t status_show(struct device *dev, struct device_attribute *attr,

				char *buf)

{

	struct watchdog_device *wdd = dev_get_drvdata(dev);

	ssize_t status;

	unsigned int val;



	status = watchdog_get_status(wdd, &val);

	if (!status)

		status = sprintf(buf, "%u\n", val);



	return status;

}

static DEVICE_ATTR_RO(status);



static ssize_t bootstatus_show(struct device *dev,

				struct device_attribute *attr, char *buf)

{

	struct watchdog_device *wdd = dev_get_drvdata(dev);



	return sprintf(buf, "%u\n", wdd->bootstatus);

}

static DEVICE_ATTR_RO(bootstatus);



static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr,

				char *buf)

{

	struct watchdog_device *wdd = dev_get_drvdata(dev);

	ssize_t status;

	unsigned int val;



	status = watchdog_get_timeleft(wdd, &val);

	if (!status)

		status = sprintf(buf, "%u\n", val);



	return status;

}

static DEVICE_ATTR_RO(timeleft);



static ssize_t timeout_show(struct device *dev, struct device_attribute *attr,

				char *buf)

{

	struct watchdog_device *wdd = dev_get_drvdata(dev);



	return sprintf(buf, "%u\n", wdd->timeout);

}

static DEVICE_ATTR_RO(timeout);



static ssize_t identity_show(struct device *dev, struct device_attribute *attr,

				char *buf)

{

	struct watchdog_device *wdd = dev_get_drvdata(dev);



	return sprintf(buf, "%s\n", wdd->info->identity);

}

static DEVICE_ATTR_RO(identity);



static ssize_t state_show(struct device *dev, struct device_attribute *attr,

				char *buf)

{

	struct watchdog_device *wdd = dev_get_drvdata(dev);



	if (watchdog_active(wdd))

		return sprintf(buf, "active\n");



	return sprintf(buf, "inactive\n");

}

static DEVICE_ATTR_RO(state);



static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr,

				int n)

{

	struct device *dev = container_of(kobj, struct device, kobj);

	struct watchdog_device *wdd = dev_get_drvdata(dev);

	umode_t mode = attr->mode;



	if (attr == &dev_attr_status.attr && !wdd->ops->status)

		mode = 0;

	else if (attr == &dev_attr_timeleft.attr && !wdd->ops->get_timeleft)

		mode = 0;



	return mode;

}

static struct attribute *wdt_attrs[] = {

	&dev_attr_state.attr,

	&dev_attr_identity.attr,

	&dev_attr_timeout.attr,

	&dev_attr_timeleft.attr,

	&dev_attr_bootstatus.attr,

	&dev_attr_status.attr,

	&dev_attr_nowayout.attr,

	NULL,

};



static const struct attribute_group wdt_group = {

	.attrs = wdt_attrs,

	.is_visible = wdt_is_visible,

};

__ATTRIBUTE_GROUPS(wdt);

#else

#define wdt_groups	NULL

#endif



/*

 *	watchdog_ioctl_op: call the watchdog drivers ioctl op if defined

 *	@wdd: the watchdog device to do the ioctl on
@@ -584,6 +697,7 @@ int watchdog_dev_unregister(struct watchdog_device *wdd) 
static struct class watchdog_class = {

	.name =		"watchdog",

	.owner =	THIS_MODULE,

	.dev_groups =	wdt_groups,

};



/*