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watchdog: Read device status through sysfs attributes

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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: Pratyush Anand <panand@redhat.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This commit is contained in:
Pratyush Anand 2015-12-17 17:53:59 +05:30 committed by Wim Van Sebroeck
parent 906d7a5cfe
commit 33b711269a
4 changed files with 173 additions and 1 deletions
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51
Documentation/ABI/testing/sysfs-class-watchdog Normal file
View File

@ -0,0 +1,51 @@
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.

7
drivers/watchdog/Kconfig
View File

@ -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
#

2
drivers/watchdog/watchdog_core.c
View File

@ -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);

114
drivers/watchdog/watchdog_dev.c
View File

@ -247,6 +247,119 @@ out_timeleft:
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,
};
/*