[PATCH 37/57] docs: watchdog: convert documents to ReST format

Mauro Carvalho Chehab
2019-04-16T03:01:58Z

Convert those documents and prepare them to be part of the kernel
API book, as most of the stuff there are related to the
Kernel interfaces.

Still, in the future, it would make sense to split the docs,
as some of the stuff is clearly focused on sysadmin tasks.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
---
.../convert_drivers_to_kernel_api.txt | 109 +--
Documentation/watchdog/hpwdt.txt | 23 +-
Documentation/watchdog/mlx-wdt.txt | 24 +-
Documentation/watchdog/pcwd-watchdog.txt | 13 +-
Documentation/watchdog/watchdog-api.txt | 76 +-
.../watchdog/watchdog-kernel-api.txt | 89 ++-
.../watchdog/watchdog-parameters.txt | 672 +++++++++++++-----
Documentation/watchdog/watchdog-pm.txt | 3 +
Documentation/watchdog/wdt.txt | 31 +-
9 files changed, 733 insertions(+), 307 deletions(-)

diff --git a/Documentation/watchdog/convert_drivers_to_kernel_api.txt b/Documentation/watchdog/convert_drivers_to_kernel_api.txt
index 9fffb2958d13..dd934cc08e40 100644
--- a/Documentation/watchdog/convert_drivers_to_kernel_api.txt
+++ b/Documentation/watchdog/convert_drivers_to_kernel_api.txt
@@ -1,6 +1,8 @@
+=========================================================
Converting old watchdog drivers to the watchdog framework
+=========================================================
+
by Wolfram Sang <w.sang@pengutronix.de>
-=========================================================

Before the watchdog framework came into the kernel, every driver had to
implement the API on its own. Now, as the framework factored out the common
@@ -69,16 +71,16 @@ Here is a overview of the functions and probably needed actions:
-ENOIOCTLCMD, the IOCTLs of the framework will be tried, too. Any other error
is directly given to the user.

-Example conversion:
+Example conversion::

--static const struct file_operations s3c2410wdt_fops = {
-- .owner = THIS_MODULE,
-- .llseek = no_llseek,
-- .write = s3c2410wdt_write,
-- .unlocked_ioctl = s3c2410wdt_ioctl,
-- .open = s3c2410wdt_open,
-- .release = s3c2410wdt_release,
--};
+ -static const struct file_operations s3c2410wdt_fops = {
+ - .owner = THIS_MODULE,
+ - .llseek = no_llseek,
+ - .write = s3c2410wdt_write,
+ - .unlocked_ioctl = s3c2410wdt_ioctl,
+ - .open = s3c2410wdt_open,
+ - .release = s3c2410wdt_release,
+ -};

Check the functions for device-specific stuff and keep it for later
refactoring. The rest can go.
@@ -89,24 +91,24 @@ Remove the miscdevice

Since the file_operations are gone now, you can also remove the 'struct
miscdevice'. The framework will create it on watchdog_dev_register() called by
-watchdog_register_device().
+watchdog_register_device()::

--static struct miscdevice s3c2410wdt_miscdev = {
-- .minor = WATCHDOG_MINOR,
-- .name = "watchdog",
-- .fops = &s3c2410wdt_fops,
--};
+ -static struct miscdevice s3c2410wdt_miscdev = {
+ - .minor = WATCHDOG_MINOR,
+ - .name = "watchdog",
+ - .fops = &s3c2410wdt_fops,
+ -};

Remove obsolete includes and defines
------------------------------------

Because of the simplifications, a few defines are probably unused now. Remove
-them. Includes can be removed, too. For example:
+them. Includes can be removed, too. For example::

-- #include <linux/fs.h>
-- #include <linux/miscdevice.h> (if MODULE_ALIAS_MISCDEV is not used)
-- #include <linux/uaccess.h> (if no custom IOCTLs are used)
+ - #include <linux/fs.h>
+ - #include <linux/miscdevice.h> (if MODULE_ALIAS_MISCDEV is not used)
+ - #include <linux/uaccess.h> (if no custom IOCTLs are used)

Add the watchdog operations
@@ -121,30 +123,30 @@ change the function header. Other changes are most likely not needed, because
here simply happens the direct hardware access. If you have device-specific
code left from the above steps, it should be refactored into these callbacks.

-Here is a simple example:
+Here is a simple example::

-+static struct watchdog_ops s3c2410wdt_ops = {
-+ .owner = THIS_MODULE,
-+ .start = s3c2410wdt_start,
-+ .stop = s3c2410wdt_stop,
-+ .ping = s3c2410wdt_keepalive,
-+ .set_timeout = s3c2410wdt_set_heartbeat,
-+};
+ +static struct watchdog_ops s3c2410wdt_ops = {
+ + .owner = THIS_MODULE,
+ + .start = s3c2410wdt_start,
+ + .stop = s3c2410wdt_stop,
+ + .ping = s3c2410wdt_keepalive,
+ + .set_timeout = s3c2410wdt_set_heartbeat,
+ +};

-A typical function-header change looks like:
+A typical function-header change looks like::

--static void s3c2410wdt_keepalive(void)
-+static int s3c2410wdt_keepalive(struct watchdog_device *wdd)
- {
-...
-+
-+ return 0;
- }
+ -static void s3c2410wdt_keepalive(void)
+ +static int s3c2410wdt_keepalive(struct watchdog_device *wdd)
+ {
+ ...
+ +
+ + return 0;
+ }

-...
+ ...

-- s3c2410wdt_keepalive();
-+ s3c2410wdt_keepalive(&s3c2410_wdd);
+ - s3c2410wdt_keepalive();
+ + s3c2410wdt_keepalive(&s3c2410_wdd);

Add the watchdog device
@@ -159,12 +161,12 @@ static variables. Those have to be converted to use the members in
watchdog_device. Note that the timeout values are unsigned int. Some drivers
use signed int, so this has to be converted, too.

-Here is a simple example for a watchdog device:
+Here is a simple example for a watchdog device::

-+static struct watchdog_device s3c2410_wdd = {
-+ .info = &s3c2410_wdt_ident,
-+ .ops = &s3c2410wdt_ops,
-+};
+ +static struct watchdog_device s3c2410_wdd = {
+ + .info = &s3c2410_wdt_ident,
+ + .ops = &s3c2410wdt_ops,
+ +};

Handle the 'nowayout' feature
@@ -173,12 +175,12 @@ Handle the 'nowayout' feature
A few drivers use nowayout statically, i.e. there is no module parameter for it
and only CONFIG_WATCHDOG_NOWAYOUT determines if the feature is going to be
used. This needs to be converted by initializing the status variable of the
-watchdog_device like this:
+watchdog_device like this::

.status = WATCHDOG_NOWAYOUT_INIT_STATUS,

Most drivers, however, also allow runtime configuration of nowayout, usually
-by adding a module parameter. The conversion for this would be something like:
+by adding a module parameter. The conversion for this would be something like::

watchdog_set_nowayout(&s3c2410_wdd, nowayout);

@@ -191,15 +193,15 @@ Register the watchdog device

Replace misc_register(&miscdev) with watchdog_register_device(&watchdog_dev).
Make sure the return value gets checked and the error message, if present,
-still fits. Also convert the unregister case.
+still fits. Also convert the unregister case::

-- ret = misc_register(&s3c2410wdt_miscdev);
-+ ret = watchdog_register_device(&s3c2410_wdd);
+ - ret = misc_register(&s3c2410wdt_miscdev);
+ + ret = watchdog_register_device(&s3c2410_wdd);

-...
+ ...

-- misc_deregister(&s3c2410wdt_miscdev);
-+ watchdog_unregister_device(&s3c2410_wdd);
+ - misc_deregister(&s3c2410wdt_miscdev);
+ + watchdog_unregister_device(&s3c2410_wdd);

Update the Kconfig-entry
@@ -207,7 +209,7 @@ Update the Kconfig-entry

The entry for the driver now needs to select WATCHDOG_CORE:

-+ select WATCHDOG_CORE
+ + select WATCHDOG_CORE

Create a patch and send it to upstream
@@ -215,4 +217,3 @@ Create a patch and send it to upstream

Make sure you understood Documentation/process/submitting-patches.rst and send your patch to
linux-watchdog@vger.kernel.org. We are looking forward to it :)
-
diff --git a/Documentation/watchdog/hpwdt.txt b/Documentation/watchdog/hpwdt.txt
index 55df692c5595..a8c6751321de 100644
--- a/Documentation/watchdog/hpwdt.txt
+++ b/Documentation/watchdog/hpwdt.txt
@@ -1,7 +1,12 @@
+===========================
+HPE iLO NMI Watchdog Driver
+===========================
+
+for iLO based ProLiant Servers
+==============================
+
Last reviewed: 08/20/2018

- HPE iLO NMI Watchdog Driver
- for iLO based ProLiant Servers

The HPE iLO NMI Watchdog driver is a kernel module that provides basic
watchdog functionality and handler for the iLO "Generate NMI to System"
@@ -20,21 +25,24 @@ Last reviewed: 08/20/2018

The hpwdt driver also has the following module parameters:

- soft_margin - allows the user to set the watchdog timer value.
+ ============ ================================================================
+ soft_margin allows the user to set the watchdog timer value.
Default value is 30 seconds.
- timeout - an alias of soft_margin.
- pretimeout - allows the user to set the watchdog pretimeout value.
+ timeout an alias of soft_margin.
+ pretimeout allows the user to set the watchdog pretimeout value.
This is the number of seconds before timeout when an
NMI is delivered to the system. Setting the value to
zero disables the pretimeout NMI.
Default value is 9 seconds.
- nowayout - basic watchdog parameter that does not allow the timer to
+ nowayout basic watchdog parameter that does not allow the timer to
be restarted or an impending ASR to be escaped.
Default value is set when compiling the kernel. If it is set
to "Y", then there is no way of disabling the watchdog once
it has been started.
+ ============ ================================================================

- NOTE: More information about watchdog drivers in general, including the ioctl
+ NOTE:
+ More information about watchdog drivers in general, including the ioctl
interface to /dev/watchdog can be found in
Documentation/watchdog/watchdog-api.txt and Documentation/IPMI.txt.

@@ -63,4 +71,3 @@ Last reviewed: 08/20/2018

The HPE iLO NMI Watchdog Driver and documentation were originally developed
by Tom Mingarelli.
-
diff --git a/Documentation/watchdog/mlx-wdt.txt b/Documentation/watchdog/mlx-wdt.txt
index 66eeb78505c3..bf5bafac47f0 100644
--- a/Documentation/watchdog/mlx-wdt.txt
+++ b/Documentation/watchdog/mlx-wdt.txt
@@ -1,5 +1,9 @@
- Mellanox watchdog drivers
- for x86 based system switches
+=========================
+Mellanox watchdog drivers
+=========================
+
+for x86 based system switches
+=============================

This driver provides watchdog functionality for various Mellanox
Ethernet and Infiniband switch systems.
@@ -9,16 +13,16 @@ Mellanox watchdog device is implemented in a programmable logic device.
There are 2 types of HW watchdog implementations.

Type 1:
-Actual HW timeout can be defined as a power of 2 msec.
-e.g. timeout 20 sec will be rounded up to 32768 msec.
-The maximum timeout period is 32 sec (32768 msec.),
-Get time-left isn't supported
+ Actual HW timeout can be defined as a power of 2 msec.
+ e.g. timeout 20 sec will be rounded up to 32768 msec.
+ The maximum timeout period is 32 sec (32768 msec.),
+ Get time-left isn't supported

Type 2:
-Actual HW timeout is defined in sec. and it's the same as
-a user-defined timeout.
-Maximum timeout is 255 sec.
-Get time-left is supported.
+ Actual HW timeout is defined in sec. and it's the same as
+ a user-defined timeout.
+ Maximum timeout is 255 sec.
+ Get time-left is supported.

Type 1 HW watchdog implementation exist in old systems and
all new systems have type 2 HW watchdog.
diff --git a/Documentation/watchdog/pcwd-watchdog.txt b/Documentation/watchdog/pcwd-watchdog.txt
index b8e60a441a43..405e2a370082 100644
--- a/Documentation/watchdog/pcwd-watchdog.txt
+++ b/Documentation/watchdog/pcwd-watchdog.txt
@@ -1,8 +1,13 @@
+===================================
+Berkshire Products PC Watchdog Card
+===================================
+
Last reviewed: 10/05/2007

- Berkshire Products PC Watchdog Card
- Support for ISA Cards Revision A and C
- Documentation and Driver by Ken Hollis <kenji@bitgate.com>
+Support for ISA Cards Revision A and C
+=======================================
+
+Documentation and Driver by Ken Hollis <kenji@bitgate.com>

The PC Watchdog is a card that offers the same type of functionality that
the WDT card does, only it doesn't require an IRQ to run. Furthermore,
@@ -33,6 +38,7 @@ Last reviewed: 10/05/2007
WDIOC_GETSUPPORT
This returns the support of the card itself. This
returns in structure "PCWDS" which returns:
+
options = WDIOS_TEMPPANIC
(This card supports temperature)
firmware_version = xxxx
@@ -63,4 +69,3 @@ Last reviewed: 10/05/2007

-- Ken Hollis
(kenji@bitgate.com)
-
diff --git a/Documentation/watchdog/watchdog-api.txt b/Documentation/watchdog/watchdog-api.txt
index 0e62ba33b7fb..c6c1e9fa9f73 100644
--- a/Documentation/watchdog/watchdog-api.txt
+++ b/Documentation/watchdog/watchdog-api.txt
@@ -1,7 +1,10 @@
+=============================
+The Linux Watchdog driver API
+=============================
+
Last reviewed: 10/05/2007

-The Linux Watchdog driver API.

Copyright 2002 Christer Weingel <wingel@nano-system.com>

@@ -10,7 +13,8 @@ driver which is (c) Copyright 2000 Jakob Oestergaard <jakob@ostenfeld.dk>

This document describes the state of the Linux 2.4.18 kernel.

-Introduction:
+Introduction
+============

A Watchdog Timer (WDT) is a hardware circuit that can reset the
computer system in case of a software fault. You probably knew that
@@ -30,7 +34,8 @@ drivers implement different, and sometimes incompatible, parts of it.
This file is an attempt to document the existing usage and allow
future driver writers to use it as a reference.

-The simplest API:
+The simplest API
+================

All drivers support the basic mode of operation, where the watchdog
activates as soon as /dev/watchdog is opened and will reboot unless
@@ -54,7 +59,8 @@ after the timeout has passed. Watchdog devices also usually support
the nowayout module parameter so that this option can be controlled at
runtime.

-Magic Close feature:
+Magic Close feature
+===================

If a driver supports "Magic Close", the driver will not disable the
watchdog unless a specific magic character 'V' has been sent to
@@ -64,7 +70,8 @@ will assume that the daemon (and userspace in general) died, and will
stop pinging the watchdog without disabling it first. This will then
cause a reboot if the watchdog is not re-opened in sufficient time.

-The ioctl API:
+The ioctl API
+=============

All conforming drivers also support an ioctl API.

@@ -73,7 +80,7 @@ Pinging the watchdog using an ioctl:
All drivers that have an ioctl interface support at least one ioctl,
KEEPALIVE. This ioctl does exactly the same thing as a write to the
watchdog device, so the main loop in the above program could be
-replaced with:
+replaced with::

while (1) {
ioctl(fd, WDIOC_KEEPALIVE, 0);
@@ -82,14 +89,15 @@ replaced with:

the argument to the ioctl is ignored.

-Setting and getting the timeout:
+Setting and getting the timeout
+===============================

For some drivers it is possible to modify the watchdog timeout on the
fly with the SETTIMEOUT ioctl, those drivers have the WDIOF_SETTIMEOUT
flag set in their option field. The argument is an integer
representing the timeout in seconds. The driver returns the real
timeout used in the same variable, and this timeout might differ from
-the requested one due to limitation of the hardware.
+the requested one due to limitation of the hardware::

int timeout = 45;
ioctl(fd, WDIOC_SETTIMEOUT, &timeout);
@@ -99,18 +107,19 @@ This example might actually print "The timeout was set to 60 seconds"
if the device has a granularity of minutes for its timeout.

Starting with the Linux 2.4.18 kernel, it is possible to query the
-current timeout using the GETTIMEOUT ioctl.
+current timeout using the GETTIMEOUT ioctl::

ioctl(fd, WDIOC_GETTIMEOUT, &timeout);
printf("The timeout was is %d seconds\n", timeout);

-Pretimeouts:
+Pretimeouts
+===========

Some watchdog timers can be set to have a trigger go off before the
actual time they will reset the system. This can be done with an NMI,
interrupt, or other mechanism. This allows Linux to record useful
information (like panic information and kernel coredumps) before it
-resets.
+resets::

pretimeout = 10;
ioctl(fd, WDIOC_SETPRETIMEOUT, &pretimeout);
@@ -121,89 +130,113 @@ the pretimeout. So, for instance, if you set the timeout to 60 seconds
and the pretimeout to 10 seconds, the pretimeout will go off in 50
seconds. Setting a pretimeout to zero disables it.

-There is also a get function for getting the pretimeout:
+There is also a get function for getting the pretimeout::

ioctl(fd, WDIOC_GETPRETIMEOUT, &timeout);
printf("The pretimeout was is %d seconds\n", timeout);

Not all watchdog drivers will support a pretimeout.

-Get the number of seconds before reboot:
+Get the number of seconds before reboot
+=======================================

Some watchdog drivers have the ability to report the remaining time
before the system will reboot. The WDIOC_GETTIMELEFT is the ioctl
-that returns the number of seconds before reboot.
+that returns the number of seconds before reboot::

ioctl(fd, WDIOC_GETTIMELEFT, &timeleft);
printf("The timeout was is %d seconds\n", timeleft);

-Environmental monitoring:
+Environmental monitoring
+========================

All watchdog drivers are required return more information about the system,
some do temperature, fan and power level monitoring, some can tell you
the reason for the last reboot of the system. The GETSUPPORT ioctl is
-available to ask what the device can do:
+available to ask what the device can do::

struct watchdog_info ident;
ioctl(fd, WDIOC_GETSUPPORT, &ident);

the fields returned in the ident struct are:

+ ================ =============================================
identity a string identifying the watchdog driver
firmware_version the firmware version of the card if available
options a flags describing what the device supports
+ ================ =============================================

the options field can have the following bits set, and describes what
kind of information that the GET_STATUS and GET_BOOT_STATUS ioctls can
return. [FIXME -- Is this correct?]

+ ================ =========================
WDIOF_OVERHEAT Reset due to CPU overheat
+ ================ =========================

The machine was last rebooted by the watchdog because the thermal limit was
-exceeded
+exceeded:

+ ============== ==========
WDIOF_FANFAULT Fan failed
+ ============== ==========

A system fan monitored by the watchdog card has failed

+ ============= ================
WDIOF_EXTERN1 External relay 1
+ ============= ================

External monitoring relay/source 1 was triggered. Controllers intended for
real world applications include external monitoring pins that will trigger
a reset.

+ ============= ================
WDIOF_EXTERN2 External relay 2
+ ============= ================

External monitoring relay/source 2 was triggered

+ ================ =====================
WDIOF_POWERUNDER Power bad/power fault
+ ================ =====================

The machine is showing an undervoltage status

+ =============== =============================
WDIOF_CARDRESET Card previously reset the CPU
+ =============== =============================

The last reboot was caused by the watchdog card

+ ================ =====================
WDIOF_POWEROVER Power over voltage
+ ================ =====================

The machine is showing an overvoltage status. Note that if one level is
under and one over both bits will be set - this may seem odd but makes
sense.

+ =================== =====================
WDIOF_KEEPALIVEPING Keep alive ping reply
+ =================== =====================

The watchdog saw a keepalive ping since it was last queried.

+ ================ =======================
WDIOF_SETTIMEOUT Can set/get the timeout
+ ================ =======================

The watchdog can do pretimeouts.

+ ================ ================================
WDIOF_PRETIMEOUT Pretimeout (in seconds), get/set
+ ================ ================================

For those drivers that return any bits set in the option field, the
GETSTATUS and GETBOOTSTATUS ioctls can be used to ask for the current
-status, and the status at the last reboot, respectively.
+status, and the status at the last reboot, respectively::

int flags;
ioctl(fd, WDIOC_GETSTATUS, &flags);
@@ -216,22 +249,23 @@ Note that not all devices support these two calls, and some only
support the GETBOOTSTATUS call.

Some drivers can measure the temperature using the GETTEMP ioctl. The
-returned value is the temperature in degrees fahrenheit.
+returned value is the temperature in degrees fahrenheit::

int temperature;
ioctl(fd, WDIOC_GETTEMP, &temperature);

Finally the SETOPTIONS ioctl can be used to control some aspects of
-the cards operation.
+the cards operation::

int options = 0;
ioctl(fd, WDIOC_SETOPTIONS, &options);

The following options are available:

+ ================= ================================
WDIOS_DISABLECARD Turn off the watchdog timer
WDIOS_ENABLECARD Turn on the watchdog timer
WDIOS_TEMPPANIC Kernel panic on temperature trip
+ ================= ================================

[FIXME -- better explanations]
-
diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
index 3a91ef5af044..452002be568c 100644
--- a/Documentation/watchdog/watchdog-kernel-api.txt
+++ b/Documentation/watchdog/watchdog-kernel-api.txt
@@ -1,5 +1,7 @@
-The Linux WatchDog Timer Driver Core kernel API.
===============================================
+The Linux WatchDog Timer Driver Core kernel API
+===============================================
+
Last reviewed: 12-Feb-2013

Wim Van Sebroeck <wim@iguana.be>
@@ -23,10 +25,10 @@ The API
Each watchdog timer driver that wants to use the WatchDog Timer Driver Core
must #include <linux/watchdog.h> (you would have to do this anyway when
writing a watchdog device driver). This include file contains following
-register/unregister routines:
+register/unregister routines::

-extern int watchdog_register_device(struct watchdog_device *);
-extern void watchdog_unregister_device(struct watchdog_device *);
+ extern int watchdog_register_device(struct watchdog_device *);
+ extern void watchdog_unregister_device(struct watchdog_device *);

The watchdog_register_device routine registers a watchdog timer device.
The parameter of this routine is a pointer to a watchdog_device structure.
@@ -40,9 +42,9 @@ The watchdog subsystem includes an registration deferral mechanism,
which allows you to register an watchdog as early as you wish during
the boot process.

-The watchdog device structure looks like this:
+The watchdog device structure looks like this::

-struct watchdog_device {
+ struct watchdog_device {
int id;
struct device *parent;
const struct attribute_group **groups;
@@ -62,9 +64,10 @@ struct watchdog_device {
struct watchdog_core_data *wd_data;
unsigned long status;
struct list_head deferred;
-};
+ };

It contains following fields:
+
* id: set by watchdog_register_device, id 0 is special. It has both a
/dev/watchdog0 cdev (dynamic major, minor 0) as well as the old
/dev/watchdog miscdev. The id is set automatically when calling
@@ -114,9 +117,9 @@ It contains following fields:
* deferred: entry in wtd_deferred_reg_list which is used to
register early initialized watchdogs.

-The list of watchdog operations is defined as:
+The list of watchdog operations is defined as::

-struct watchdog_ops {
+ struct watchdog_ops {
struct module *owner;
/* mandatory operations */
int (*start)(struct watchdog_device *);
@@ -129,7 +132,7 @@ struct watchdog_ops {
unsigned int (*get_timeleft)(struct watchdog_device *);
int (*restart)(struct watchdog_device *);
long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long);
-};
+ };

It is important that you first define the module owner of the watchdog timer
driver's operations. This module owner will be used to lock the module when
@@ -138,6 +141,7 @@ module and /dev/watchdog is still open).

Some operations are mandatory and some are optional. The mandatory operations
are:
+
* start: this is a pointer to the routine that starts the watchdog timer
device.
The routine needs a pointer to the watchdog timer device structure as a
@@ -146,51 +150,64 @@ are:
Not all watchdog timer hardware supports the same functionality. That's why
all other routines/operations are optional. They only need to be provided if
they are supported. These optional routines/operations are:
+
* stop: with this routine the watchdog timer device is being stopped.
+
The routine needs a pointer to the watchdog timer device structure as a
parameter. It returns zero on success or a negative errno code for failure.
Some watchdog timer hardware can only be started and not be stopped. A
driver supporting such hardware does not have to implement the stop routine.
+
If a driver has no stop function, the watchdog core will set WDOG_HW_RUNNING
and start calling the driver's keepalive pings function after the watchdog
device is closed.
+
If a watchdog driver does not implement the stop function, it must set
max_hw_heartbeat_ms.
* ping: this is the routine that sends a keepalive ping to the watchdog timer
hardware.
+
The routine needs a pointer to the watchdog timer device structure as a
parameter. It returns zero on success or a negative errno code for failure.
+
Most hardware that does not support this as a separate function uses the
start function to restart the watchdog timer hardware. And that's also what
the watchdog timer driver core does: to send a keepalive ping to the watchdog
timer hardware it will either use the ping operation (when available) or the
start operation (when the ping operation is not available).
+
(Note: the WDIOC_KEEPALIVE ioctl call will only be active when the
WDIOF_KEEPALIVEPING bit has been set in the option field on the watchdog's
info structure).
* status: this routine checks the status of the watchdog timer device. The
status of the device is reported with watchdog WDIOF_* status flags/bits.
+
WDIOF_MAGICCLOSE and WDIOF_KEEPALIVEPING are reported by the watchdog core;
it is not necessary to report those bits from the driver. Also, if no status
function is provided by the driver, the watchdog core reports the status bits
provided in the bootstatus variable of struct watchdog_device.
+
* set_timeout: this routine checks and changes the timeout of the watchdog
timer device. It returns 0 on success, -EINVAL for "parameter out of range"
and -EIO for "could not write value to the watchdog". On success this
routine should set the timeout value of the watchdog_device to the
achieved timeout value (which may be different from the requested one
because the watchdog does not necessarily have a 1 second resolution).
+
Drivers implementing max_hw_heartbeat_ms set the hardware watchdog heartbeat
to the minimum of timeout and max_hw_heartbeat_ms. Those drivers set the
timeout value of the watchdog_device either to the requested timeout value
(if it is larger than max_hw_heartbeat_ms), or to the achieved timeout value.
(Note: the WDIOF_SETTIMEOUT needs to be set in the options field of the
watchdog's info structure).
+
If the watchdog driver does not have to perform any action but setting the
watchdog_device.timeout, this callback can be omitted.
+
If set_timeout is not provided but, WDIOF_SETTIMEOUT is set, the watchdog
infrastructure updates the timeout value of the watchdog_device internally
to the requested value.
+
If the pretimeout feature is used (WDIOF_PRETIMEOUT), then set_timeout must
also take care of checking if pretimeout is still valid and set up the timer
accordingly. This can't be done in the core without races, so it is the
@@ -201,13 +218,16 @@ they are supported. These optional routines/operations are:
seconds before the actual timeout would happen. It returns 0 on success,
-EINVAL for "parameter out of range" and -EIO for "could not write value to
the watchdog". A value of 0 disables pretimeout notification.
+
(Note: the WDIOF_PRETIMEOUT needs to be set in the options field of the
watchdog's info structure).
+
If the watchdog driver does not have to perform any action but setting the
watchdog_device.pretimeout, this callback can be omitted. That means if
set_pretimeout is not provided but WDIOF_PRETIMEOUT is set, the watchdog
infrastructure updates the pretimeout value of the watchdog_device internally
to the requested value.
+
* get_timeleft: this routines returns the time that's left before a reset.
* restart: this routine restarts the machine. It returns 0 on success or a
negative errno code for failure.
@@ -218,6 +238,7 @@ they are supported. These optional routines/operations are:

The status bits should (preferably) be set with the set_bit and clear_bit alike
bit-operations. The status bits that are defined are:
+
* WDOG_ACTIVE: this status bit indicates whether or not a watchdog timer device
is active or not from user perspective. User space is expected to send
heartbeat requests to the driver while this flag is set.
@@ -235,22 +256,30 @@ bit-operations. The status bits that are defined are:

To set the WDOG_NO_WAY_OUT status bit (before registering your watchdog
timer device) you can either:
+
* set it statically in your watchdog_device struct with
+
.status = WATCHDOG_NOWAYOUT_INIT_STATUS,
+
(this will set the value the same as CONFIG_WATCHDOG_NOWAYOUT) or
- * use the following helper function:
- static inline void watchdog_set_nowayout(struct watchdog_device *wdd, int nowayout)
+ * use the following helper function::
+
+ static inline void watchdog_set_nowayout(struct watchdog_device *wdd,
+ int nowayout)
+
+Note:
+ The WatchDog Timer Driver Core supports the magic close feature and
+ the nowayout feature. To use the magic close feature you must set the
+ WDIOF_MAGICCLOSE bit in the options field of the watchdog's info structure.

-Note: The WatchDog Timer Driver Core supports the magic close feature and
-the nowayout feature. To use the magic close feature you must set the
-WDIOF_MAGICCLOSE bit in the options field of the watchdog's info structure.
The nowayout feature will overrule the magic close feature.

To get or set driver specific data the following two helper functions should be
-used:
+used::

-static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
-static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
+ static inline void watchdog_set_drvdata(struct watchdog_device *wdd,
+ void *data)
+ static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)

The watchdog_set_drvdata function allows you to add driver specific data. The
arguments of this function are the watchdog device where you want to add the
@@ -260,10 +289,11 @@ The watchdog_get_drvdata function allows you to retrieve driver specific data.
The argument of this function is the watchdog device where you want to retrieve
data from. The function returns the pointer to the driver specific data.

-To initialize the timeout field, the following function can be used:
+To initialize the timeout field, the following function can be used::

-extern int watchdog_init_timeout(struct watchdog_device *wdd,
- unsigned int timeout_parm, struct device *dev);
+ extern int watchdog_init_timeout(struct watchdog_device *wdd,
+ unsigned int timeout_parm,
+ struct device *dev);

The watchdog_init_timeout function allows you to initialize the timeout field
using the module timeout parameter or by retrieving the timeout-sec property from
@@ -272,30 +302,33 @@ to set the default timeout value as timeout value in the watchdog_device and
then use this function to set the user "preferred" timeout value.
This routine returns zero on success and a negative errno code for failure.

-To disable the watchdog on reboot, the user must call the following helper:
+To disable the watchdog on reboot, the user must call the following helper::

-static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd);
+ static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd);

To disable the watchdog when unregistering the watchdog, the user must call
the following helper. Note that this will only stop the watchdog if the
nowayout flag is not set.

-static inline void watchdog_stop_on_unregister(struct watchdog_device *wdd);
+::
+
+ static inline void watchdog_stop_on_unregister(struct watchdog_device *wdd);

To change the priority of the restart handler the following helper should be
-used:
+used::

-void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
+ void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);

User should follow the following guidelines for setting the priority:
+
* 0: should be called in last resort, has limited restart capabilities
* 128: default restart handler, use if no other handler is expected to be
available, and/or if restart is sufficient to restart the entire system
* 255: highest priority, will preempt all other restart handlers

-To raise a pretimeout notification, the following function should be used:
+To raise a pretimeout notification, the following function should be used::

-void watchdog_notify_pretimeout(struct watchdog_device *wdd)
+ void watchdog_notify_pretimeout(struct watchdog_device *wdd)

The function can be called in the interrupt context. If watchdog pretimeout
governor framework (kbuild CONFIG_WATCHDOG_PRETIMEOUT_GOV symbol) is enabled,
diff --git a/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt
index 0b88e333f9e1..b121caae7798 100644
--- a/Documentation/watchdog/watchdog-parameters.txt
+++ b/Documentation/watchdog/watchdog-parameters.txt
@@ -1,410 +1,736 @@
+==========================
+WatchDog Module Parameters
+==========================
+
This file provides information on the module parameters of many of
the Linux watchdog drivers. Watchdog driver parameter specs should
be listed here unless the driver has its own driver-specific information
file.

-
See Documentation/admin-guide/kernel-parameters.rst for information on
providing kernel parameters for builtin drivers versus loadable
modules.

-
-------------------------------------------------
+
acquirewdt:
-wdt_stop: Acquire WDT 'stop' io port (default 0x43)
-wdt_start: Acquire WDT 'start' io port (default 0x443)
-nowayout: Watchdog cannot be stopped once started
+ wdt_stop:
+ Acquire WDT 'stop' io port (default 0x43)
+ wdt_start:
+ Acquire WDT 'start' io port (default 0x443)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
advantechwdt:
-wdt_stop: Advantech WDT 'stop' io port (default 0x443)
-wdt_start: Advantech WDT 'start' io port (default 0x443)
-timeout: Watchdog timeout in seconds. 1<= timeout <=63, default=60.
-nowayout: Watchdog cannot be stopped once started
+ wdt_stop:
+ Advantech WDT 'stop' io port (default 0x443)
+ wdt_start:
+ Advantech WDT 'start' io port (default 0x443)
+ timeout:
+ Watchdog timeout in seconds. 1<= timeout <=63, default=60.
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
alim1535_wdt:
-timeout: Watchdog timeout in seconds. (0 < timeout < 18000, default=60
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in seconds. (0 < timeout < 18000, default=60
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
alim7101_wdt:
-timeout: Watchdog timeout in seconds. (1<=timeout<=3600, default=30
-use_gpio: Use the gpio watchdog (required by old cobalt boards).
+ timeout:
+ Watchdog timeout in seconds. (1<=timeout<=3600, default=30
+ use_gpio:
+ Use the gpio watchdog (required by old cobalt boards).
default=0/off/no
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
ar7_wdt:
-margin: Watchdog margin in seconds (default=60)
-nowayout: Disable watchdog shutdown on close
+ margin:
+ Watchdog margin in seconds (default=60)
+ nowayout:
+ Disable watchdog shutdown on close
(default=kernel config parameter)
+
-------------------------------------------------
+
armada_37xx_wdt:
-timeout: Watchdog timeout in seconds. (default=120)
-nowayout: Disable watchdog shutdown on close
+ timeout:
+ Watchdog timeout in seconds. (default=120)
+ nowayout:
+ Disable watchdog shutdown on close
(default=kernel config parameter)
+
-------------------------------------------------
+
at91rm9200_wdt:
-wdt_time: Watchdog time in seconds. (default=5)
-nowayout: Watchdog cannot be stopped once started
+ wdt_time:
+ Watchdog time in seconds. (default=5)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
at91sam9_wdt:
-heartbeat: Watchdog heartbeats in seconds. (default = 15)
-nowayout: Watchdog cannot be stopped once started
+ heartbeat:
+ Watchdog heartbeats in seconds. (default = 15)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
bcm47xx_wdt:
-wdt_time: Watchdog time in seconds. (default=30)
-nowayout: Watchdog cannot be stopped once started
+ wdt_time:
+ Watchdog time in seconds. (default=30)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
coh901327_wdt:
-margin: Watchdog margin in seconds (default 60s)
+ margin:
+ Watchdog margin in seconds (default 60s)
+
-------------------------------------------------
+
cpu5wdt:
-port: base address of watchdog card, default is 0x91
-verbose: be verbose, default is 0 (no)
-ticks: count down ticks, default is 10000
+ port:
+ base address of watchdog card, default is 0x91
+ verbose:
+ be verbose, default is 0 (no)
+ ticks:
+ count down ticks, default is 10000
+
-------------------------------------------------
+
cpwd:
-wd0_timeout: Default watchdog0 timeout in 1/10secs
-wd1_timeout: Default watchdog1 timeout in 1/10secs
-wd2_timeout: Default watchdog2 timeout in 1/10secs
+ wd0_timeout:
+ Default watchdog0 timeout in 1/10secs
+ wd1_timeout:
+ Default watchdog1 timeout in 1/10secs
+ wd2_timeout:
+ Default watchdog2 timeout in 1/10secs
+
-------------------------------------------------
+
da9052wdt:
-timeout: Watchdog timeout in seconds. 2<= timeout <=131, default=2.048s
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in seconds. 2<= timeout <=131, default=2.048s
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
davinci_wdt:
-heartbeat: Watchdog heartbeat period in seconds from 1 to 600, default 60
+ heartbeat:
+ Watchdog heartbeat period in seconds from 1 to 600, default 60
+
-------------------------------------------------
+
ebc-c384_wdt:
-timeout: Watchdog timeout in seconds. (1<=timeout<=15300, default=60)
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in seconds. (1<=timeout<=15300, default=60)
+ nowayout:
+ Watchdog cannot be stopped once started
+
-------------------------------------------------
+
ep93xx_wdt:
-nowayout: Watchdog cannot be stopped once started
-timeout: Watchdog timeout in seconds. (1<=timeout<=3600, default=TBD)
+ nowayout:
+ Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in seconds. (1<=timeout<=3600, default=TBD)
+
-------------------------------------------------
+
eurotechwdt:
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
-io: Eurotech WDT io port (default=0x3f0)
-irq: Eurotech WDT irq (default=10)
-ev: Eurotech WDT event type (default is `int')
+ io:
+ Eurotech WDT io port (default=0x3f0)
+ irq:
+ Eurotech WDT irq (default=10)
+ ev:
+ Eurotech WDT event type (default is `int`)
+
-------------------------------------------------
+
gef_wdt:
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
geodewdt:
-timeout: Watchdog timeout in seconds. 1<= timeout <=131, default=60.
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in seconds. 1<= timeout <=131, default=60.
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
i6300esb:
-heartbeat: Watchdog heartbeat in seconds. (1<heartbeat<2046, default=30)
-nowayout: Watchdog cannot be stopped once started
+ heartbeat:
+ Watchdog heartbeat in seconds. (1<heartbeat<2046, default=30)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
iTCO_wdt:
-heartbeat: Watchdog heartbeat in seconds.
+ heartbeat:
+ Watchdog heartbeat in seconds.
(2<heartbeat<39 (TCO v1) or 613 (TCO v2), default=30)
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
iTCO_vendor_support:
-vendorsupport: iTCO vendor specific support mode, default=0 (none),
+ vendorsupport:
+ iTCO vendor specific support mode, default=0 (none),
1=SuperMicro Pent3, 2=SuperMicro Pent4+, 911=Broken SMI BIOS
+
-------------------------------------------------
+
ib700wdt:
-timeout: Watchdog timeout in seconds. 0<= timeout <=30, default=30.
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in seconds. 0<= timeout <=30, default=30.
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
ibmasr:
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
imx2_wdt:
-timeout: Watchdog timeout in seconds (default 60 s)
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in seconds (default 60 s)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
indydog:
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
iop_wdt:
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
it8712f_wdt:
-margin: Watchdog margin in seconds (default 60)
-nowayout: Disable watchdog shutdown on close
+ margin:
+ Watchdog margin in seconds (default 60)
+ nowayout:
+ Disable watchdog shutdown on close
(default=kernel config parameter)
+
-------------------------------------------------
+
it87_wdt:
-nogameport: Forbid the activation of game port, default=0
-nocir: Forbid the use of CIR (workaround for some buggy setups); set to 1 if
+ nogameport:
+ Forbid the activation of game port, default=0
+ nocir:
+ Forbid the use of CIR (workaround for some buggy setups); set to 1 if
system resets despite watchdog daemon running, default=0
-exclusive: Watchdog exclusive device open, default=1
-timeout: Watchdog timeout in seconds, default=60
-testmode: Watchdog test mode (1 = no reboot), default=0
-nowayout: Watchdog cannot be stopped once started
+ exclusive:
+ Watchdog exclusive device open, default=1
+ timeout:
+ Watchdog timeout in seconds, default=60
+ testmode:
+ Watchdog test mode (1 = no reboot), default=0
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
ixp4xx_wdt:
-heartbeat: Watchdog heartbeat in seconds (default 60s)
-nowayout: Watchdog cannot be stopped once started
+ heartbeat:
+ Watchdog heartbeat in seconds (default 60s)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
ks8695_wdt:
-wdt_time: Watchdog time in seconds. (default=5)
-nowayout: Watchdog cannot be stopped once started
+ wdt_time:
+ Watchdog time in seconds. (default=5)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
machzwd:
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
-action: after watchdog resets, generate:
+ action:
+ after watchdog resets, generate:
0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI
+
-------------------------------------------------
+
max63xx_wdt:
-heartbeat: Watchdog heartbeat period in seconds from 1 to 60, default 60
-nowayout: Watchdog cannot be stopped once started
+ heartbeat:
+ Watchdog heartbeat period in seconds from 1 to 60, default 60
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
-nodelay: Force selection of a timeout setting without initial delay
+ nodelay:
+ Force selection of a timeout setting without initial delay
(max6373/74 only, default=0)
+
-------------------------------------------------
+
mixcomwd:
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
mpc8xxx_wdt:
-timeout: Watchdog timeout in ticks. (0<timeout<65536, default=65535)
-reset: Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in ticks. (0<timeout<65536, default=65535)
+ reset:
+ Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
mv64x60_wdt:
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
ni903x_wdt:
-timeout: Initial watchdog timeout in seconds (0<timeout<516, default=60)
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Initial watchdog timeout in seconds (0<timeout<516, default=60)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
nic7018_wdt:
-timeout: Initial watchdog timeout in seconds (0<timeout<464, default=80)
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Initial watchdog timeout in seconds (0<timeout<464, default=80)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
nuc900_wdt:
-heartbeat: Watchdog heartbeats in seconds.
+ heartbeat:
+ Watchdog heartbeats in seconds.
(default = 15)
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
omap_wdt:
-timer_margin: initial watchdog timeout (in seconds)
-early_enable: Watchdog is started on module insertion (default=0
-nowayout: Watchdog cannot be stopped once started
+ timer_margin:
+ initial watchdog timeout (in seconds)
+ early_enable:
+ Watchdog is started on module insertion (default=0
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
orion_wdt:
-heartbeat: Initial watchdog heartbeat in seconds
-nowayout: Watchdog cannot be stopped once started
+ heartbeat:
+ Initial watchdog heartbeat in seconds
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
pc87413_wdt:
-io: pc87413 WDT I/O port (default: io).
-timeout: Watchdog timeout in minutes (default=timeout).
-nowayout: Watchdog cannot be stopped once started
+ io:
+ pc87413 WDT I/O port (default: io).
+ timeout:
+ Watchdog timeout in minutes (default=timeout).
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
pika_wdt:
-heartbeat: Watchdog heartbeats in seconds. (default = 15)
-nowayout: Watchdog cannot be stopped once started
+ heartbeat:
+ Watchdog heartbeats in seconds. (default = 15)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
pnx4008_wdt:
-heartbeat: Watchdog heartbeat period in seconds from 1 to 60, default 19
-nowayout: Set to 1 to keep watchdog running after device release
+ heartbeat:
+ Watchdog heartbeat period in seconds from 1 to 60, default 19
+ nowayout:
+ Set to 1 to keep watchdog running after device release
+
-------------------------------------------------
+
pnx833x_wdt:
-timeout: Watchdog timeout in Mhz. (68Mhz clock), default=2040000000 (30 seconds)
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in Mhz. (68Mhz clock), default=2040000000 (30 seconds)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
-start_enabled: Watchdog is started on module insertion (default=1)
+ start_enabled:
+ Watchdog is started on module insertion (default=1)
+
-------------------------------------------------
+
rc32434_wdt:
-timeout: Watchdog timeout value, in seconds (default=20)
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout value, in seconds (default=20)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
riowd:
-riowd_timeout: Watchdog timeout in minutes (default=1)
+ riowd_timeout:
+ Watchdog timeout in minutes (default=1)
+
-------------------------------------------------
+
s3c2410_wdt:
-tmr_margin: Watchdog tmr_margin in seconds. (default=15)
-tmr_atboot: Watchdog is started at boot time if set to 1, default=0
-nowayout: Watchdog cannot be stopped once started
+ tmr_margin:
+ Watchdog tmr_margin in seconds. (default=15)
+ tmr_atboot:
+ Watchdog is started at boot time if set to 1, default=0
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
-soft_noboot: Watchdog action, set to 1 to ignore reboots, 0 to reboot
-debug: Watchdog debug, set to >1 for debug, (default 0)
+ soft_noboot:
+ Watchdog action, set to 1 to ignore reboots, 0 to reboot
+ debug:
+ Watchdog debug, set to >1 for debug, (default 0)
+
-------------------------------------------------
+
sa1100_wdt:
-margin: Watchdog margin in seconds (default 60s)
+ margin:
+ Watchdog margin in seconds (default 60s)
+
-------------------------------------------------
+
sb_wdog:
-timeout: Watchdog timeout in microseconds (max/default 8388607 or 8.3ish secs)
+ timeout:
+ Watchdog timeout in microseconds (max/default 8388607 or 8.3ish secs)
+
-------------------------------------------------
+
sbc60xxwdt:
-wdt_stop: SBC60xx WDT 'stop' io port (default 0x45)
-wdt_start: SBC60xx WDT 'start' io port (default 0x443)
-timeout: Watchdog timeout in seconds. (1<=timeout<=3600, default=30)
-nowayout: Watchdog cannot be stopped once started
+ wdt_stop:
+ SBC60xx WDT 'stop' io port (default 0x45)
+ wdt_start:
+ SBC60xx WDT 'start' io port (default 0x443)
+ timeout:
+ Watchdog timeout in seconds. (1<=timeout<=3600, default=30)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
sbc7240_wdt:
-timeout: Watchdog timeout in seconds. (1<=timeout<=255, default=30)
-nowayout: Disable watchdog when closing device file
+ timeout:
+ Watchdog timeout in seconds. (1<=timeout<=255, default=30)
+ nowayout:
+ Disable watchdog when closing device file
+
-------------------------------------------------
+
sbc8360:
-timeout: Index into timeout table (0-63) (default=27 (60s))
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Index into timeout table (0-63) (default=27 (60s))
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
sbc_epx_c3:
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
sbc_fitpc2_wdt:
-margin: Watchdog margin in seconds (default 60s)
-nowayout: Watchdog cannot be stopped once started
+ margin:
+ Watchdog margin in seconds (default 60s)
+ nowayout:
+ Watchdog cannot be stopped once started
+
-------------------------------------------------
+
sbsa_gwdt:
-timeout: Watchdog timeout in seconds. (default 10s)
-action: Watchdog action at the first stage timeout,
+ timeout:
+ Watchdog timeout in seconds. (default 10s)
+ action:
+ Watchdog action at the first stage timeout,
set to 0 to ignore, 1 to panic. (default=0)
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
sc1200wdt:
-isapnp: When set to 0 driver ISA PnP support will be disabled (default=1)
-io: io port
-timeout: range is 0-255 minutes, default is 1
-nowayout: Watchdog cannot be stopped once started
+ isapnp:
+ When set to 0 driver ISA PnP support will be disabled (default=1)
+ io:
+ io port
+ timeout:
+ range is 0-255 minutes, default is 1
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
sc520_wdt:
-timeout: Watchdog timeout in seconds. (1 <= timeout <= 3600, default=30)
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in seconds. (1 <= timeout <= 3600, default=30)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
sch311x_wdt:
-force_id: Override the detected device ID
-therm_trip: Should a ThermTrip trigger the reset generator
-timeout: Watchdog timeout in seconds. 1<= timeout <=15300, default=60
-nowayout: Watchdog cannot be stopped once started
+ force_id:
+ Override the detected device ID
+ therm_trip:
+ Should a ThermTrip trigger the reset generator
+ timeout:
+ Watchdog timeout in seconds. 1<= timeout <=15300, default=60
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
scx200_wdt:
-margin: Watchdog margin in seconds
-nowayout: Disable watchdog shutdown on close
+ margin:
+ Watchdog margin in seconds
+ nowayout:
+ Disable watchdog shutdown on close
+
-------------------------------------------------
+
shwdt:
-clock_division_ratio: Clock division ratio. Valid ranges are from 0x5 (1.31ms)
+ clock_division_ratio:
+ Clock division ratio. Valid ranges are from 0x5 (1.31ms)
to 0x7 (5.25ms). (default=7)
-heartbeat: Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default=30
-nowayout: Watchdog cannot be stopped once started
+ heartbeat:
+ Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default=30
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
smsc37b787_wdt:
-timeout: range is 1-255 units, default is 60
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ range is 1-255 units, default is 60
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
softdog:
-soft_margin: Watchdog soft_margin in seconds.
+ soft_margin:
+ Watchdog soft_margin in seconds.
(0 < soft_margin < 65536, default=60)
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
-soft_noboot: Softdog action, set to 1 to ignore reboots, 0 to reboot
+ soft_noboot:
+ Softdog action, set to 1 to ignore reboots, 0 to reboot
(default=0)
+
-------------------------------------------------
+
stmp3xxx_wdt:
-heartbeat: Watchdog heartbeat period in seconds from 1 to 4194304, default 19
+ heartbeat:
+ Watchdog heartbeat period in seconds from 1 to 4194304, default 19
+
-------------------------------------------------
+
tegra_wdt:
-heartbeat: Watchdog heartbeats in seconds. (default = 120)
-nowayout: Watchdog cannot be stopped once started
+ heartbeat:
+ Watchdog heartbeats in seconds. (default = 120)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
ts72xx_wdt:
-timeout: Watchdog timeout in seconds. (1 <= timeout <= 8, default=8)
-nowayout: Disable watchdog shutdown on close
+ timeout:
+ Watchdog timeout in seconds. (1 <= timeout <= 8, default=8)
+ nowayout:
+ Disable watchdog shutdown on close
+
-------------------------------------------------
+
twl4030_wdt:
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
txx9wdt:
-timeout: Watchdog timeout in seconds. (0<timeout<N, default=60)
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in seconds. (0<timeout<N, default=60)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
uniphier_wdt:
-timeout: Watchdog timeout in power of two seconds.
+ timeout:
+ Watchdog timeout in power of two seconds.
(1 <= timeout <= 128, default=64)
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
w83627hf_wdt:
-wdt_io: w83627hf/thf WDT io port (default 0x2E)
-timeout: Watchdog timeout in seconds. 1 <= timeout <= 255, default=60.
-nowayout: Watchdog cannot be stopped once started
+ wdt_io:
+ w83627hf/thf WDT io port (default 0x2E)
+ timeout:
+ Watchdog timeout in seconds. 1 <= timeout <= 255, default=60.
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
w83877f_wdt:
-timeout: Watchdog timeout in seconds. (1<=timeout<=3600, default=30)
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in seconds. (1<=timeout<=3600, default=30)
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
w83977f_wdt:
-timeout: Watchdog timeout in seconds (15..7635), default=45)
-testmode: Watchdog testmode (1 = no reboot), default=0
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in seconds (15..7635), default=45)
+ testmode:
+ Watchdog testmode (1 = no reboot), default=0
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
wafer5823wdt:
-timeout: Watchdog timeout in seconds. 1 <= timeout <= 255, default=60.
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in seconds. 1 <= timeout <= 255, default=60.
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
wdt285:
-soft_margin: Watchdog timeout in seconds (default=60)
+ soft_margin:
+ Watchdog timeout in seconds (default=60)
+
-------------------------------------------------
+
wdt977:
-timeout: Watchdog timeout in seconds (60..15300, default=60)
-testmode: Watchdog testmode (1 = no reboot), default=0
-nowayout: Watchdog cannot be stopped once started
+ timeout:
+ Watchdog timeout in seconds (60..15300, default=60)
+ testmode:
+ Watchdog testmode (1 = no reboot), default=0
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
wm831x_wdt:
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
wm8350_wdt:
-nowayout: Watchdog cannot be stopped once started
+ nowayout:
+ Watchdog cannot be stopped once started
(default=kernel config parameter)
+
-------------------------------------------------
+
sun4v_wdt:
-timeout_ms: Watchdog timeout in milliseconds 1..180000, default=60000)
-nowayout: Watchdog cannot be stopped once started
--------------------------------------------------
+ timeout_ms:
+ Watchdog timeout in milliseconds 1..180000, default=60000)
+ nowayout:
+ Watchdog cannot be stopped once started
diff --git a/Documentation/watchdog/watchdog-pm.txt b/Documentation/watchdog/watchdog-pm.txt
index 7a4dd46e0d24..646e1f28f31f 100644
--- a/Documentation/watchdog/watchdog-pm.txt
+++ b/Documentation/watchdog/watchdog-pm.txt
@@ -1,5 +1,7 @@
+===============================================
The Linux WatchDog Timer Power Management Guide
===============================================
+
Last reviewed: 17-Dec-2018

Wolfram Sang <wsa+renesas@sang-engineering.com>
@@ -16,4 +18,5 @@ On resume, a watchdog timer shall be reset to its selected value to give
userspace enough time to resume. [1] [2]

[1] https://patchwork.kernel.org/patch/10252209/
+
[2] https://patchwork.kernel.org/patch/10711625/
diff --git a/Documentation/watchdog/wdt.txt b/Documentation/watchdog/wdt.txt
index ed2f0b860869..d97b0361535b 100644
--- a/Documentation/watchdog/wdt.txt
+++ b/Documentation/watchdog/wdt.txt
@@ -1,11 +1,14 @@
+============================================================
+WDT Watchdog Timer Interfaces For The Linux Operating System
+============================================================
+
Last Reviewed: 10/05/2007

- WDT Watchdog Timer Interfaces For The Linux Operating System
- Alan Cox <alan@lxorguk.ukuu.org.uk>
+Alan Cox <alan@lxorguk.ukuu.org.uk>

- ICS WDT501-P
- ICS WDT501-P (no fan tachometer)
- ICS WDT500-P
+ - ICS WDT501-P
+ - ICS WDT501-P (no fan tachometer)
+ - ICS WDT500-P

All the interfaces provide /dev/watchdog, which when open must be written
to within a timeout or the machine will reboot. Each write delays the reboot
@@ -21,19 +24,26 @@ degrees Fahrenheit. Each read returns a single byte giving the temperature.
The third interface logs kernel messages on additional alert events.

The ICS ISA-bus wdt card cannot be safely probed for. Instead you need to
-pass IO address and IRQ boot parameters. E.g.:
+pass IO address and IRQ boot parameters. E.g.::
+
wdt.io=0x240 wdt.irq=11

Other "wdt" driver parameters are:
+
+ =========== ======================================================
heartbeat Watchdog heartbeat in seconds (default 60)
nowayout Watchdog cannot be stopped once started (kernel
- build parameter)
+ build parameter)
tachometer WDT501-P Fan Tachometer support (0=disable, default=0)
type WDT501-P Card type (500 or 501, default=500)
+ =========== ======================================================

Features
--------
- WDT501P WDT500P
+
+================ ======= =======
+ WDT501P WDT500P
+================ ======= =======
Reboot Timer X X
External Reboot X X
I/O Port Monitor o o
@@ -42,9 +52,12 @@ Fan Speed X o
Power Under X o
Power Over X o
Overheat X o
+================ ======= =======

The external event interfaces on the WDT boards are not currently supported.
Minor numbers are however allocated for it.

-Example Watchdog Driver: see samples/watchdog/watchdog-simple.c
+Example Watchdog Driver:
+
+ see samples/watchdog/watchdog-simple.c
--
2.20.1