Commit cc2a2d19 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Jonathan Corbet

docs: watchdog: convert docs to ReST and rename to *.rst

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.

The conversion is actually:
  - add blank lines and identation in order to identify paragraphs;
  - fix tables markups;
  - add some lists markups;
  - mark literal blocks;
  - adjust title markups.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 458f69ef
...@@ -5160,7 +5160,7 @@ ...@@ -5160,7 +5160,7 @@
Default: 3 = cyan. Default: 3 = cyan.
watchdog timers [HW,WDT] For information on watchdog timers, watchdog timers [HW,WDT] For information on watchdog timers,
see Documentation/watchdog/watchdog-parameters.txt see Documentation/watchdog/watchdog-parameters.rst
or other driver-specific files in the or other driver-specific files in the
Documentation/watchdog/ directory. Documentation/watchdog/ directory.
......
...@@ -348,7 +348,7 @@ To reduce its OS jitter, do at least one of the following: ...@@ -348,7 +348,7 @@ To reduce its OS jitter, do at least one of the following:
2. Boot with "nosoftlockup=0", which will also prevent these kthreads 2. Boot with "nosoftlockup=0", which will also prevent these kthreads
from being created. Other related watchdog and softlockup boot from being created. Other related watchdog and softlockup boot
parameters may be found in Documentation/admin-guide/kernel-parameters.rst parameters may be found in Documentation/admin-guide/kernel-parameters.rst
and Documentation/watchdog/watchdog-parameters.txt. and Documentation/watchdog/watchdog-parameters.rst.
3. Echo a zero to /proc/sys/kernel/watchdog to disable the 3. Echo a zero to /proc/sys/kernel/watchdog to disable the
watchdog timer. watchdog timer.
4. Echo a large number of /proc/sys/kernel/watchdog_thresh in 4. Echo a large number of /proc/sys/kernel/watchdog_thresh in
......
=========================================================
Converting old watchdog drivers to the watchdog framework Converting old watchdog drivers to the watchdog framework
by Wolfram Sang <w.sang@pengutronix.de>
========================================================= =========================================================
by Wolfram Sang <w.sang@pengutronix.de>
Before the watchdog framework came into the kernel, every driver had to 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 implement the API on its own. Now, as the framework factored out the common
components, those drivers can be lightened making it a user of the framework. components, those drivers can be lightened making it a user of the framework.
...@@ -69,16 +71,16 @@ Here is a overview of the functions and probably needed actions: ...@@ -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 -ENOIOCTLCMD, the IOCTLs of the framework will be tried, too. Any other error
is directly given to the user. is directly given to the user.
Example conversion: Example conversion::
-static const struct file_operations s3c2410wdt_fops = { -static const struct file_operations s3c2410wdt_fops = {
- .owner = THIS_MODULE, - .owner = THIS_MODULE,
- .llseek = no_llseek, - .llseek = no_llseek,
- .write = s3c2410wdt_write, - .write = s3c2410wdt_write,
- .unlocked_ioctl = s3c2410wdt_ioctl, - .unlocked_ioctl = s3c2410wdt_ioctl,
- .open = s3c2410wdt_open, - .open = s3c2410wdt_open,
- .release = s3c2410wdt_release, - .release = s3c2410wdt_release,
-}; -};
Check the functions for device-specific stuff and keep it for later Check the functions for device-specific stuff and keep it for later
refactoring. The rest can go. refactoring. The rest can go.
...@@ -89,24 +91,24 @@ Remove the miscdevice ...@@ -89,24 +91,24 @@ Remove the miscdevice
Since the file_operations are gone now, you can also remove the 'struct 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 miscdevice'. The framework will create it on watchdog_dev_register() called by
watchdog_register_device(). watchdog_register_device()::
-static struct miscdevice s3c2410wdt_miscdev = { -static struct miscdevice s3c2410wdt_miscdev = {
- .minor = WATCHDOG_MINOR, - .minor = WATCHDOG_MINOR,
- .name = "watchdog", - .name = "watchdog",
- .fops = &s3c2410wdt_fops, - .fops = &s3c2410wdt_fops,
-}; -};
Remove obsolete includes and defines Remove obsolete includes and defines
------------------------------------ ------------------------------------
Because of the simplifications, a few defines are probably unused now. Remove 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/fs.h>
- #include <linux/miscdevice.h> (if MODULE_ALIAS_MISCDEV is not used) - #include <linux/miscdevice.h> (if MODULE_ALIAS_MISCDEV is not used)
- #include <linux/uaccess.h> (if no custom IOCTLs are used) - #include <linux/uaccess.h> (if no custom IOCTLs are used)
Add the watchdog operations Add the watchdog operations
...@@ -121,30 +123,30 @@ change the function header. Other changes are most likely not needed, because ...@@ -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 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. 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 = { +static struct watchdog_ops s3c2410wdt_ops = {
+ .owner = THIS_MODULE, + .owner = THIS_MODULE,
+ .start = s3c2410wdt_start, + .start = s3c2410wdt_start,
+ .stop = s3c2410wdt_stop, + .stop = s3c2410wdt_stop,
+ .ping = s3c2410wdt_keepalive, + .ping = s3c2410wdt_keepalive,
+ .set_timeout = s3c2410wdt_set_heartbeat, + .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 void s3c2410wdt_keepalive(void)
+static int s3c2410wdt_keepalive(struct watchdog_device *wdd) +static int s3c2410wdt_keepalive(struct watchdog_device *wdd)
{ {
... ...
+ +
+ return 0; + return 0;
} }
... ...
- s3c2410wdt_keepalive(); - s3c2410wdt_keepalive();
+ s3c2410wdt_keepalive(&s3c2410_wdd); + s3c2410wdt_keepalive(&s3c2410_wdd);
Add the watchdog device Add the watchdog device
...@@ -159,12 +161,12 @@ static variables. Those have to be converted to use the members in ...@@ -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 watchdog_device. Note that the timeout values are unsigned int. Some drivers
use signed int, so this has to be converted, too. 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 = { +static struct watchdog_device s3c2410_wdd = {
+ .info = &s3c2410_wdt_ident, + .info = &s3c2410_wdt_ident,
+ .ops = &s3c2410wdt_ops, + .ops = &s3c2410wdt_ops,
+}; +};
Handle the 'nowayout' feature Handle the 'nowayout' feature
...@@ -173,12 +175,12 @@ 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 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 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 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, .status = WATCHDOG_NOWAYOUT_INIT_STATUS,
Most drivers, however, also allow runtime configuration of nowayout, usually 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); watchdog_set_nowayout(&s3c2410_wdd, nowayout);
...@@ -191,15 +193,15 @@ Register the watchdog device ...@@ -191,15 +193,15 @@ Register the watchdog device
Replace misc_register(&miscdev) with watchdog_register_device(&watchdog_dev). Replace misc_register(&miscdev) with watchdog_register_device(&watchdog_dev).
Make sure the return value gets checked and the error message, if present, 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 = misc_register(&s3c2410wdt_miscdev);
+ ret = watchdog_register_device(&s3c2410_wdd); + ret = watchdog_register_device(&s3c2410_wdd);
... ...
- misc_deregister(&s3c2410wdt_miscdev); - misc_deregister(&s3c2410wdt_miscdev);
+ watchdog_unregister_device(&s3c2410_wdd); + watchdog_unregister_device(&s3c2410_wdd);
Update the Kconfig-entry Update the Kconfig-entry
...@@ -207,7 +209,7 @@ Update the Kconfig-entry ...@@ -207,7 +209,7 @@ Update the Kconfig-entry
The entry for the driver now needs to select WATCHDOG_CORE: 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 Create a patch and send it to upstream
...@@ -215,4 +217,3 @@ 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 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 :) linux-watchdog@vger.kernel.org. We are looking forward to it :)
===========================
HPE iLO NMI Watchdog Driver
===========================
for iLO based ProLiant Servers
==============================
Last reviewed: 08/20/2018 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 The HPE iLO NMI Watchdog driver is a kernel module that provides basic
watchdog functionality and handler for the iLO "Generate NMI to System" watchdog functionality and handler for the iLO "Generate NMI to System"
...@@ -20,23 +25,26 @@ Last reviewed: 08/20/2018 ...@@ -20,23 +25,26 @@ Last reviewed: 08/20/2018
The hpwdt driver also has the following module parameters: 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. Default value is 30 seconds.
timeout - an alias of soft_margin. timeout an alias of soft_margin.
pretimeout - allows the user to set the watchdog pretimeout value. pretimeout allows the user to set the watchdog pretimeout value.
This is the number of seconds before timeout when an This is the number of seconds before timeout when an
NMI is delivered to the system. Setting the value to NMI is delivered to the system. Setting the value to
zero disables the pretimeout NMI. zero disables the pretimeout NMI.
Default value is 9 seconds. 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. be restarted or an impending ASR to be escaped.
Default value is set when compiling the kernel. If it is set Default value is set when compiling the kernel. If it is set
to "Y", then there is no way of disabling the watchdog once to "Y", then there is no way of disabling the watchdog once
it has been started. 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 interface to /dev/watchdog can be found in
Documentation/watchdog/watchdog-api.txt and Documentation/IPMI.txt. Documentation/watchdog/watchdog-api.rst and Documentation/IPMI.txt.
Due to limitations in the iLO hardware, the NMI pretimeout if enabled, Due to limitations in the iLO hardware, the NMI pretimeout if enabled,
can only be set to 9 seconds. Attempts to set pretimeout to other can only be set to 9 seconds. Attempts to set pretimeout to other
...@@ -63,4 +71,3 @@ Last reviewed: 08/20/2018 ...@@ -63,4 +71,3 @@ Last reviewed: 08/20/2018
The HPE iLO NMI Watchdog Driver and documentation were originally developed The HPE iLO NMI Watchdog Driver and documentation were originally developed
by Tom Mingarelli. by Tom Mingarelli.
:orphan:
======================
Linux Watchdog Support
======================
.. toctree::
:maxdepth: 1
hpwdt
mlx-wdt
pcwd-watchdog
watchdog-api
watchdog-kernel-api
watchdog-parameters
watchdog-pm
wdt
convert_drivers_to_kernel_api
.. only:: subproject and html
Indices
=======
* :ref:`genindex`
Mellanox watchdog drivers =========================
for x86 based system switches Mellanox watchdog drivers
=========================
for x86 based system switches
=============================
This driver provides watchdog functionality for various Mellanox This driver provides watchdog functionality for various Mellanox
Ethernet and Infiniband switch systems. Ethernet and Infiniband switch systems.
...@@ -9,16 +13,16 @@ Mellanox watchdog device is implemented in a programmable logic device. ...@@ -9,16 +13,16 @@ Mellanox watchdog device is implemented in a programmable logic device.
There are 2 types of HW watchdog implementations. There are 2 types of HW watchdog implementations.
Type 1: Type 1:
Actual HW timeout can be defined as a power of 2 msec. Actual HW timeout can be defined as a power of 2 msec.
e.g. timeout 20 sec will be rounded up to 32768 msec. e.g. timeout 20 sec will be rounded up to 32768 msec.
The maximum timeout period is 32 sec (32768 msec.), The maximum timeout period is 32 sec (32768 msec.),
Get time-left isn't supported Get time-left isn't supported
Type 2: Type 2:
Actual HW timeout is defined in sec. and it's the same as Actual HW timeout is defined in sec. and it's the same as
a user-defined timeout. a user-defined timeout.
Maximum timeout is 255 sec. Maximum timeout is 255 sec.
Get time-left is supported. Get time-left is supported.
Type 1 HW watchdog implementation exist in old systems and Type 1 HW watchdog implementation exist in old systems and
all new systems have type 2 HW watchdog. all new systems have type 2 HW watchdog.
......
===================================
Berkshire Products PC Watchdog Card
===================================
Last reviewed: 10/05/2007 Last reviewed: 10/05/2007
Berkshire Products PC Watchdog Card Support for ISA Cards Revision A and C
Support for ISA Cards Revision A and C =======================================
Documentation and Driver by Ken Hollis <kenji@bitgate.com>
Documentation and Driver by Ken Hollis <kenji@bitgate.com>
The PC Watchdog is a card that offers the same type of functionality that 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, the WDT card does, only it doesn't require an IRQ to run. Furthermore,
...@@ -33,6 +38,7 @@ Last reviewed: 10/05/2007 ...@@ -33,6 +38,7 @@ Last reviewed: 10/05/2007
WDIOC_GETSUPPORT WDIOC_GETSUPPORT
This returns the support of the card itself. This This returns the support of the card itself. This
returns in structure "PCWDS" which returns: returns in structure "PCWDS" which returns:
options = WDIOS_TEMPPANIC options = WDIOS_TEMPPANIC
(This card supports temperature) (This card supports temperature)
firmware_version = xxxx firmware_version = xxxx
...@@ -63,4 +69,3 @@ Last reviewed: 10/05/2007 ...@@ -63,4 +69,3 @@ Last reviewed: 10/05/2007
-- Ken Hollis -- Ken Hollis
(kenji@bitgate.com) (kenji@bitgate.com)
=============================
The Linux Watchdog driver API
=============================
Last reviewed: 10/05/2007 Last reviewed: 10/05/2007
The Linux Watchdog driver API.
Copyright 2002 Christer Weingel <wingel@nano-system.com> Copyright 2002 Christer Weingel <wingel@nano-system.com>
...@@ -10,7 +13,8 @@ driver which is (c) Copyright 2000 Jakob Oestergaard <jakob@ostenfeld.dk> ...@@ -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. 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 A Watchdog Timer (WDT) is a hardware circuit that can reset the
computer system in case of a software fault. You probably knew that 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. ...@@ -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 This file is an attempt to document the existing usage and allow
future driver writers to use it as a reference. 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 All drivers support the basic mode of operation, where the watchdog
activates as soon as /dev/watchdog is opened and will reboot unless 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 ...@@ -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 the nowayout module parameter so that this option can be controlled at
runtime. runtime.
Magic Close feature: Magic Close feature
===================
If a driver supports "Magic Close", the driver will not disable the If a driver supports "Magic Close", the driver will not disable the
watchdog unless a specific magic character 'V' has been sent to 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 ...@@ -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 stop pinging the watchdog without disabling it first. This will then
cause a reboot if the watchdog is not re-opened in sufficient time. 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. All conforming drivers also support an ioctl API.
...@@ -73,7 +80,7 @@ Pinging the watchdog using an ioctl: ...@@ -73,7 +80,7 @@ Pinging the watchdog using an ioctl:
All drivers that have an ioctl interface support at least one 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 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 watchdog device, so the main loop in the above program could be
replaced with: replaced with::
while (1) { while (1) {
ioctl(fd, WDIOC_KEEPALIVE, 0); ioctl(fd, WDIOC_KEEPALIVE, 0);
...@@ -82,14 +89,15 @@ replaced with: ...@@ -82,14 +89,15 @@ replaced with:
the argument to the ioctl is ignored. 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 For some drivers it is possible to modify the watchdog timeout on the
fly with the SETTIMEOUT ioctl, those drivers have the WDIOF_SETTIMEOUT fly with the SETTIMEOUT ioctl, those drivers have the WDIOF_SETTIMEOUT
flag set in their option field. The argument is an integer flag set in their option field. The argument is an integer
representing the timeout in seconds. The driver returns the real representing the timeout in seconds. The driver returns the real
timeout used in the same variable, and this timeout might differ from 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; int timeout = 45;
ioctl(fd, WDIOC_SETTIMEOUT, &timeout); ioctl(fd, WDIOC_SETTIMEOUT, &timeout);
...@@ -99,18 +107,19 @@ This example might actually print "The timeout was set to 60 seconds" ...@@ -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. 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 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); ioctl(fd, WDIOC_GETTIMEOUT, &timeout);
printf("The timeout was is %d seconds\n", 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 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, actual time they will reset the system. This can be done with an NMI,
interrupt, or other mechanism. This allows Linux to record useful interrupt, or other mechanism. This allows Linux to record useful
information (like panic information and kernel coredumps) before it information (like panic information and kernel coredumps) before it
resets. resets::
pretimeout = 10; pretimeout = 10;
ioctl(fd, WDIOC_SETPRETIMEOUT, &pretimeout); ioctl(fd, WDIOC_SETPRETIMEOUT, &pretimeout);
...@@ -121,89 +130,113 @@ the pretimeout. So, for instance, if you set the timeout to 60 seconds ...@@ -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 and the pretimeout to 10 seconds, the pretimeout will go off in 50
seconds. Setting a pretimeout to zero disables it. 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); ioctl(fd, WDIOC_GETPRETIMEOUT, &timeout);
printf("The pretimeout was is %d seconds\n", timeout); printf("The pretimeout was is %d seconds\n", timeout);
Not all watchdog drivers will support a pretimeout. 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 Some watchdog drivers have the ability to report the remaining time
before the system will reboot. The WDIOC_GETTIMELEFT is the ioctl 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); ioctl(fd, WDIOC_GETTIMELEFT, &timeleft);
printf("The timeout was is %d seconds\n", 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, All watchdog drivers are required return more information about the system,
some do temperature, fan and power level monitoring, some can tell you 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 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; struct watchdog_info ident;
ioctl(fd, WDIOC_GETSUPPORT, &ident); ioctl(fd, WDIOC_GETSUPPORT, &ident);
the fields returned in the ident struct are: the fields returned in the ident struct are:
================ =============================================
identity a string identifying the watchdog driver identity a string identifying the watchdog driver
firmware_version the firmware version of the card if available firmware_version the firmware version of the card if available
options a flags describing what the device supports options a flags describing what the device supports
================ =============================================
the options field can have the following bits set, and describes what 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 kind of information that the GET_STATUS and GET_BOOT_STATUS ioctls can
return. [FIXME -- Is this correct?] return. [FIXME -- Is this correct?]
================ =========================
WDIOF_OVERHEAT Reset due to CPU overheat WDIOF_OVERHEAT Reset due to CPU overheat
================ =========================
The machine was last rebooted by the watchdog because the thermal limit was The machine was last rebooted by the watchdog because the thermal limit was
exceeded exceeded:
============== ==========
WDIOF_FANFAULT Fan failed WDIOF_FANFAULT Fan failed
============== ==========
A system fan monitored by the watchdog card has failed A system fan monitored by the watchdog card has failed
============= ================
WDIOF_EXTERN1 External relay 1 WDIOF_EXTERN1 External relay 1
============= ================
External monitoring relay/source 1 was triggered. Controllers intended for External monitoring relay/source 1 was triggered. Controllers intended for
real world applications include external monitoring pins that will trigger real world applications include external monitoring pins that will trigger
a reset. a reset.
============= ================
WDIOF_EXTERN2 External relay 2 WDIOF_EXTERN2 External relay 2
============= ================
External monitoring relay/source 2 was triggered External monitoring relay/source 2 was triggered
================ =====================
WDIOF_POWERUNDER Power bad/power fault WDIOF_POWERUNDER Power bad/power fault
================ =====================
The machine is showing an undervoltage status The machine is showing an undervoltage status
=============== =============================
WDIOF_CARDRESET Card previously reset the CPU WDIOF_CARDRESET Card previously reset the CPU
=============== =============================
The last reboot was caused by the watchdog card The last reboot was caused by the watchdog card
================ =====================
WDIOF_POWEROVER Power over voltage WDIOF_POWEROVER Power over voltage
================ =====================
The machine is showing an overvoltage status. Note that if one level is 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 under and one over both bits will be set - this may seem odd but makes
sense. sense.
=================== =====================
WDIOF_KEEPALIVEPING Keep alive ping reply WDIOF_KEEPALIVEPING Keep alive ping reply
=================== =====================
The watchdog saw a keepalive ping since it was last queried. The watchdog saw a keepalive ping since it was last queried.
================ =======================
WDIOF_SETTIMEOUT Can set/get the timeout WDIOF_SETTIMEOUT Can set/get the timeout
================ =======================
The watchdog can do pretimeouts. The watchdog can do pretimeouts.
================ ================================
WDIOF_PRETIMEOUT Pretimeout (in seconds), get/set WDIOF_PRETIMEOUT Pretimeout (in seconds), get/set
================ ================================
For those drivers that return any bits set in the option field, the 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 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; int flags;
ioctl(fd, WDIOC_GETSTATUS, &flags); ioctl(fd, WDIOC_GETSTATUS, &flags);
...@@ -216,22 +249,23 @@ Note that not all devices support these two calls, and some only ...@@ -216,22 +249,23 @@ Note that not all devices support these two calls, and some only
support the GETBOOTSTATUS call. support the GETBOOTSTATUS call.
Some drivers can measure the temperature using the GETTEMP ioctl. The 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; int temperature;
ioctl(fd, WDIOC_GETTEMP, &temperature); ioctl(fd, WDIOC_GETTEMP, &temperature);
Finally the SETOPTIONS ioctl can be used to control some aspects of Finally the SETOPTIONS ioctl can be used to control some aspects of
the cards operation. the cards operation::
int options = 0; int options = 0;
ioctl(fd, WDIOC_SETOPTIONS, &options); ioctl(fd, WDIOC_SETOPTIONS, &options);
The following options are available: The following options are available:
================= ================================
WDIOS_DISABLECARD Turn off the watchdog timer WDIOS_DISABLECARD Turn off the watchdog timer
WDIOS_ENABLECARD Turn on the watchdog timer WDIOS_ENABLECARD Turn on the watchdog timer
WDIOS_TEMPPANIC Kernel panic on temperature trip WDIOS_TEMPPANIC Kernel panic on temperature trip
================= ================================
[FIXME -- better explanations] [FIXME -- better explanations]
===============================================
The Linux WatchDog Timer Power Management Guide The Linux WatchDog Timer Power Management Guide
=============================================== ===============================================
Last reviewed: 17-Dec-2018 Last reviewed: 17-Dec-2018
Wolfram Sang <wsa+renesas@sang-engineering.com> 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 ...@@ -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] userspace enough time to resume. [1] [2]
[1] https://patchwork.kernel.org/patch/10252209/ [1] https://patchwork.kernel.org/patch/10252209/
[2] https://patchwork.kernel.org/patch/10711625/ [2] https://patchwork.kernel.org/patch/10711625/
============================================================
WDT Watchdog Timer Interfaces For The Linux Operating System
============================================================
Last Reviewed: 10/05/2007 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
ICS WDT501-P (no fan tachometer) - ICS WDT501-P (no fan tachometer)
ICS WDT500-P - ICS WDT500-P
All the interfaces provide /dev/watchdog, which when open must be written 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 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. ...@@ -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 third interface logs kernel messages on additional alert events.
The ICS ISA-bus wdt card cannot be safely probed for. Instead you need to 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 wdt.io=0x240 wdt.irq=11
Other "wdt" driver parameters are: Other "wdt" driver parameters are:
=========== ======================================================
heartbeat Watchdog heartbeat in seconds (default 60) heartbeat Watchdog heartbeat in seconds (default 60)
nowayout Watchdog cannot be stopped once started (kernel nowayout Watchdog cannot be stopped once started (kernel
build parameter) build parameter)
tachometer WDT501-P Fan Tachometer support (0=disable, default=0) tachometer WDT501-P Fan Tachometer support (0=disable, default=0)
type WDT501-P Card type (500 or 501, default=500) type WDT501-P Card type (500 or 501, default=500)
=========== ======================================================
Features Features
-------- --------
WDT501P WDT500P
================ ======= =======
WDT501P WDT500P
================ ======= =======
Reboot Timer X X Reboot Timer X X
External Reboot X X External Reboot X X
I/O Port Monitor o o I/O Port Monitor o o
...@@ -42,9 +52,12 @@ Fan Speed X o ...@@ -42,9 +52,12 @@ Fan Speed X o
Power Under X o Power Under X o
Power Over X o Power Over X o
Overheat X o Overheat X o
================ ======= =======
The external event interfaces on the WDT boards are not currently supported. The external event interfaces on the WDT boards are not currently supported.
Minor numbers are however allocated for it. 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
...@@ -7009,7 +7009,7 @@ F: drivers/media/usb/hdpvr/ ...@@ -7009,7 +7009,7 @@ F: drivers/media/usb/hdpvr/
HEWLETT PACKARD ENTERPRISE ILO NMI WATCHDOG DRIVER HEWLETT PACKARD ENTERPRISE ILO NMI WATCHDOG DRIVER
M: Jerry Hoemann <jerry.hoemann@hpe.com> M: Jerry Hoemann <jerry.hoemann@hpe.com>
S: Supported S: Supported
F: Documentation/watchdog/hpwdt.txt F: Documentation/watchdog/hpwdt.rst
F: drivers/watchdog/hpwdt.c F: drivers/watchdog/hpwdt.c
HEWLETT-PACKARD SMART ARRAY RAID DRIVER (hpsa) HEWLETT-PACKARD SMART ARRAY RAID DRIVER (hpsa)
......
...@@ -18,7 +18,7 @@ menuconfig WATCHDOG ...@@ -18,7 +18,7 @@ menuconfig WATCHDOG
reboot the machine) and a driver for hardware watchdog boards, which reboot the machine) and a driver for hardware watchdog boards, which
are more robust and can also keep track of the temperature inside are more robust and can also keep track of the temperature inside
your computer. For details, read your computer. For details, read
<file:Documentation/watchdog/watchdog-api.txt> in the kernel source. <file:Documentation/watchdog/watchdog-api.rst> in the kernel source.
The watchdog is usually used together with the watchdog daemon The watchdog is usually used together with the watchdog daemon
which is available from which is available from
...@@ -1870,7 +1870,7 @@ config BOOKE_WDT ...@@ -1870,7 +1870,7 @@ config BOOKE_WDT
Watchdog driver for PowerPC Book-E chips, such as the Freescale Watchdog driver for PowerPC Book-E chips, such as the Freescale
MPC85xx SOCs and the IBM PowerPC 440. MPC85xx SOCs and the IBM PowerPC 440.
Please see Documentation/watchdog/watchdog-api.txt for Please see Documentation/watchdog/watchdog-api.rst for
more information. more information.
config BOOKE_WDT_DEFAULT_TIMEOUT config BOOKE_WDT_DEFAULT_TIMEOUT
...@@ -2019,7 +2019,7 @@ config PCWATCHDOG ...@@ -2019,7 +2019,7 @@ config PCWATCHDOG
This card simply watches your kernel to make sure it doesn't freeze, This card simply watches your kernel to make sure it doesn't freeze,
and if it does, it reboots your computer after a certain amount of and if it does, it reboots your computer after a certain amount of
time. This driver is like the WDT501 driver but for different time. This driver is like the WDT501 driver but for different
hardware. Please read <file:Documentation/watchdog/pcwd-watchdog.txt>. The PC hardware. Please read <file:Documentation/watchdog/pcwd-watchdog.rst>. The PC
watchdog cards can be ordered from <http://www.berkprod.com/>. watchdog cards can be ordered from <http://www.berkprod.com/>.
To compile this driver as a module, choose M here: the To compile this driver as a module, choose M here: the
......
...@@ -36,7 +36,7 @@ ...@@ -36,7 +36,7 @@
* mknod /dev/watchdog c 10 130 * mknod /dev/watchdog c 10 130
* *
* For an example userspace keep-alive daemon, see: * For an example userspace keep-alive daemon, see:
* Documentation/watchdog/wdt.txt * Documentation/watchdog/wdt.rst
*/ */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
......
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