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[WATCHDOG] clean-up watchdog documentation

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Random sampling of some URLs in the Documentation tree to see how many were
stale found that one watchdog driver was now a porn site.  In fact if the
watchdogs document directory was any older it would be written in latin

Clean it up somewhat and add Last reviewed headers, something all the
Documentation could do with IMHO.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This commit is contained in:
Alan Cox 2007-05-23 14:43:52 -07:00 committed by Wim Van Sebroeck
parent ccb8f430ac
commit 4d389dcea8
4 changed files with 60 additions and 321 deletions
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8
Documentation/watchdog/pcwd-watchdog.txt
View file

@ -1,3 +1,5 @@
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>
@ -14,8 +16,8 @@
The Watchdog Driver will automatically find your watchdog card, and will
attach a running driver for use with that card. After the watchdog
drivers have initialized, you can then talk to the card using the PC
Watchdog program, available from http://ftp.bitgate.com/pcwd/.
drivers have initialized, you can then talk to the card using a PC
Watchdog program.
I suggest putting a "watchdog -d" before the beginning of an fsck, and
a "watchdog -e -t 1" immediately after the end of an fsck. (Remember
@ -62,5 +64,3 @@
-- Ken Hollis
(kenji@bitgate.com)
(This documentation may be out of date. Check
http://ftp.bitgate.com/pcwd/ for the absolute latest additions.)

236
Documentation/watchdog/watchdog-api.txt
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@ -1,3 +1,6 @@
Last reviewed: 10/05/2007
The Linux Watchdog driver API.
Copyright 2002 Christer Weingel <wingel@nano-system.com>
@ -22,7 +25,7 @@ the system. If userspace fails (RAM error, kernel bug, whatever), the
notifications cease to occur, and the hardware watchdog will reset the
system (causing a reboot) after the timeout occurs.
The Linux watchdog API is a rather AD hoc construction and different
The Linux watchdog API is a rather ad-hoc construction and different
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.
@ -46,14 +49,16 @@ some of the drivers support the configuration option "Disable watchdog
shutdown on close", CONFIG_WATCHDOG_NOWAYOUT. If it is set to Y when
compiling the kernel, there is no way of disabling the watchdog once
it has been started. So, if the watchdog daemon crashes, the system
will reboot after the timeout has passed.
will reboot after the timeout has passed. Watchdog devices also usually
support the nowayout module parameter so that this option can be controlled
at runtime.
Some other drivers will not disable the watchdog, unless a specific
magic character 'V' has been sent /dev/watchdog just before closing
the file. If the userspace daemon closes the file without sending
this special character, the driver 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.
Drivers will not disable the watchdog, unless a specific magic character 'V'
has been sent /dev/watchdog just before closing the file. If the userspace
daemon closes the file without sending this special character, the driver
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:
@ -227,218 +232,3 @@ The following options are available:
[FIXME -- better explanations]
Implementations in the current drivers in the kernel tree:
Here I have tried to summarize what the different drivers support and
where they do strange things compared to the other drivers.
acquirewdt.c -- Acquire Single Board Computer
This driver has a hardcoded timeout of 1 minute
Supports CONFIG_WATCHDOG_NOWAYOUT
GETSUPPORT returns KEEPALIVEPING. GETSTATUS will return 1 if
the device is open, 0 if not. [FIXME -- isn't this rather
silly? To be able to use the ioctl, the device must be open
and so GETSTATUS will always return 1].
advantechwdt.c -- Advantech Single Board Computer
Timeout that defaults to 60 seconds, supports SETTIMEOUT.
Supports CONFIG_WATCHDOG_NOWAYOUT
GETSUPPORT returns WDIOF_KEEPALIVEPING and WDIOF_SETTIMEOUT.
The GETSTATUS call returns if the device is open or not.
[FIXME -- silliness again?]
booke_wdt.c -- PowerPC BookE Watchdog Timer
Timeout default varies according to frequency, supports
SETTIMEOUT
Watchdog cannot be turned off, CONFIG_WATCHDOG_NOWAYOUT
does not make sense
GETSUPPORT returns the watchdog_info struct, and
GETSTATUS returns the supported options. GETBOOTSTATUS
returns a 1 if the last reset was caused by the
watchdog and a 0 otherwise. This watchdog cannot be
disabled once it has been started. The wdt_period kernel
parameter selects which bit of the time base changing
from 0->1 will trigger the watchdog exception. Changing
the timeout from the ioctl calls will change the
wdt_period as defined above. Finally if you would like to
replace the default Watchdog Handler you can implement the
WatchdogHandler() function in your own code.
eurotechwdt.c -- Eurotech CPU-1220/1410
The timeout can be set using the SETTIMEOUT ioctl and defaults
to 60 seconds.
Also has a module parameter "ev", event type which controls
what should happen on a timeout, the string "int" or anything
else that causes a reboot. [FIXME -- better description]
Supports CONFIG_WATCHDOG_NOWAYOUT
GETSUPPORT returns CARDRESET and WDIOF_SETTIMEOUT but
GETSTATUS is not supported and GETBOOTSTATUS just returns 0.
i810-tco.c -- Intel 810 chipset
Also has support for a lot of other i8x0 stuff, but the
watchdog is one of the things.
The timeout is set using the module parameter "i810_margin",
which is in steps of 0.6 seconds where 2<i810_margin<64. The
driver supports the SETTIMEOUT ioctl.
Supports CONFIG_WATCHDOG_NOWAYOUT.
GETSUPPORT returns WDIOF_SETTIMEOUT. The GETSTATUS call
returns some kind of timer value which ist not compatible with
the other drivers. GETBOOT status returns some kind of
hardware specific boot status. [FIXME -- describe this]
ib700wdt.c -- IB700 Single Board Computer
Default timeout of 30 seconds and the timeout is settable
using the SETTIMEOUT ioctl. Note that only a few timeout
values are supported.
Supports CONFIG_WATCHDOG_NOWAYOUT
GETSUPPORT returns WDIOF_KEEPALIVEPING and WDIOF_SETTIMEOUT.
The GETSTATUS call returns if the device is open or not.
[FIXME -- silliness again?]
machzwd.c -- MachZ ZF-Logic
Hardcoded timeout of 10 seconds
Has a module parameter "action" that controls what happens
when the timeout runs out which can be 0 = RESET (default),
1 = SMI, 2 = NMI, 3 = SCI.
Supports CONFIG_WATCHDOG_NOWAYOUT and the magic character
'V' close handling.
GETSUPPORT returns WDIOF_KEEPALIVEPING, and the GETSTATUS call
returns if the device is open or not. [FIXME -- silliness
again?]
mixcomwd.c -- MixCom Watchdog
[FIXME -- I'm unable to tell what the timeout is]
Supports CONFIG_WATCHDOG_NOWAYOUT
GETSUPPORT returns WDIOF_KEEPALIVEPING, GETSTATUS returns if
the device is opened or not [FIXME -- I'm not really sure how
this works, there seems to be some magic connected to
CONFIG_WATCHDOG_NOWAYOUT]
pcwd.c -- Berkshire PC Watchdog
Hardcoded timeout of 1.5 seconds
Supports CONFIG_WATCHDOG_NOWAYOUT
GETSUPPORT returns WDIOF_OVERHEAT|WDIOF_CARDRESET and both
GETSTATUS and GETBOOTSTATUS return something useful.
The SETOPTIONS call can be used to enable and disable the card
and to ask the driver to call panic if the system overheats.
sbc60xxwdt.c -- 60xx Single Board Computer
Hardcoded timeout of 10 seconds
Does not support CONFIG_WATCHDOG_NOWAYOUT, but has the magic
character 'V' close handling.
No bits set in GETSUPPORT
scx200.c -- National SCx200 CPUs
Not in the kernel yet.
The timeout is set using a module parameter "margin" which
defaults to 60 seconds. The timeout can also be set using
SETTIMEOUT and read using GETTIMEOUT.
Supports a module parameter "nowayout" that is initialized
with the value of CONFIG_WATCHDOG_NOWAYOUT. Also supports the
magic character 'V' handling.
shwdt.c -- SuperH 3/4 processors
[FIXME -- I'm unable to tell what the timeout is]
Supports CONFIG_WATCHDOG_NOWAYOUT
GETSUPPORT returns WDIOF_KEEPALIVEPING, and the GETSTATUS call
returns if the device is open or not. [FIXME -- silliness
again?]
softdog.c -- Software watchdog
The timeout is set with the module parameter "soft_margin"
which defaults to 60 seconds, the timeout is also settable
using the SETTIMEOUT ioctl.
Supports CONFIG_WATCHDOG_NOWAYOUT
WDIOF_SETTIMEOUT bit set in GETSUPPORT
w83877f_wdt.c -- W83877F Computer
Hardcoded timeout of 30 seconds
Does not support CONFIG_WATCHDOG_NOWAYOUT, but has the magic
character 'V' close handling.
No bits set in GETSUPPORT
w83627hf_wdt.c -- w83627hf watchdog
Timeout that defaults to 60 seconds, supports SETTIMEOUT.
Supports CONFIG_WATCHDOG_NOWAYOUT
GETSUPPORT returns WDIOF_KEEPALIVEPING and WDIOF_SETTIMEOUT.
The GETSTATUS call returns if the device is open or not.
wdt.c -- ICS WDT500/501 ISA and
wdt_pci.c -- ICS WDT500/501 PCI
Default timeout of 60 seconds. The timeout is also settable
using the SETTIMEOUT ioctl.
Supports CONFIG_WATCHDOG_NOWAYOUT
GETSUPPORT returns with bits set depending on the actual
card. The WDT501 supports a lot of external monitoring, the
WDT500 much less.
wdt285.c -- Footbridge watchdog
The timeout is set with the module parameter "soft_margin"
which defaults to 60 seconds. The timeout is also settable
using the SETTIMEOUT ioctl.
Does not support CONFIG_WATCHDOG_NOWAYOUT
WDIOF_SETTIMEOUT bit set in GETSUPPORT
wdt977.c -- Netwinder W83977AF chip
Hardcoded timeout of 3 minutes
Supports CONFIG_WATCHDOG_NOWAYOUT
Does not support any ioctls at all.

94
Documentation/watchdog/watchdog.txt
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@ -1,94 +0,0 @@
Watchdog Timer Interfaces For The Linux Operating System
Alan Cox <alan@lxorguk.ukuu.org.uk>
Custom Linux Driver And Program Development
The following watchdog drivers are currently implemented:
ICS WDT501-P
ICS WDT501-P (no fan tachometer)
ICS WDT500-P
Software Only
SA1100 Internal Watchdog
Berkshire Products PC Watchdog Revision A & C (by Ken Hollis)
All six interfaces provide /dev/watchdog, which when open must be written
to within a timeout or the machine will reboot. Each write delays the reboot
time another timeout. In the case of the software watchdog the ability to
reboot will depend on the state of the machines and interrupts. The hardware
boards physically pull the machine down off their own onboard timers and
will reboot from almost anything.
A second temperature monitoring interface is available on the WDT501P cards
and some Berkshire cards. This provides /dev/temperature. This is the machine
internal temperature in degrees Fahrenheit. Each read returns a single byte
giving the temperature.
The third interface logs kernel messages on additional alert events.
Both software and hardware watchdog drivers are available in the standard
kernel. If you are using the software watchdog, you probably also want
to use "panic=60" as a boot argument as well.
The wdt card cannot be safely probed for. Instead you need to pass
wdt=ioaddr,irq as a boot parameter - eg "wdt=0x240,11".
The SA1100 watchdog module can be configured with the "sa1100_margin"
commandline argument which specifies timeout value in seconds.
The i810 TCO watchdog modules can be configured with the "i810_margin"
commandline argument which specifies the counter initial value. The counter
is decremented every 0.6 seconds and default to 50 (30 seconds). Values can
range between 3 and 63.
The i810 TCO watchdog driver also implements the WDIOC_GETSTATUS and
WDIOC_GETBOOTSTATUS ioctl()s. WDIOC_GETSTATUS returns the actual counter value
and WDIOC_GETBOOTSTATUS returns the value of TCO2 Status Register (see Intel's
documentation for the 82801AA and 82801AB datasheet).
Features
--------
WDT501P WDT500P Software Berkshire i810 TCO SA1100WD
Reboot Timer X X X X X X
External Reboot X X o o o X
I/O Port Monitor o o o X o o
Temperature X o o X o o
Fan Speed X o o o o o
Power Under X o o o o o
Power Over X o o o o o
Overheat X o o o o o
The external event interfaces on the WDT boards are not currently supported.
Minor numbers are however allocated for it.
Example Watchdog Driver: see Documentation/watchdog/src/watchdog-simple.c
Contact Information
People keep asking about the WDT watchdog timer hardware: The phone contacts
for Industrial Computer Source are:
Industrial Computer Source
http://www.indcompsrc.com
ICS Advent, San Diego
6260 Sequence Dr.
San Diego, CA 92121-4371
Phone (858) 677-0877
FAX: (858) 677-0895
>
ICS Advent Europe, UK
Oving Road
Chichester,
West Sussex,
PO19 4ET, UK
Phone: 00.44.1243.533900
and please mention Linux when enquiring.
For full information about the PCWD cards see the pcwd-watchdog.txt document.

43
Documentation/watchdog/wdt.txt Normal file
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@ -0,0 +1,43 @@
Last Reviewed: 10/05/2007
WDT Watchdog Timer Interfaces For The Linux Operating System
Alan Cox <alan@lxorguk.ukuu.org.uk>
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
time another timeout. In the case of the software watchdog the ability to
reboot will depend on the state of the machines and interrupts. The hardware
boards physically pull the machine down off their own onboard timers and
will reboot from almost anything.
A second temperature monitoring interface is available on the WDT501P cards
This provides /dev/temperature. This is the machine internal temperature in
degrees Fahrenheit. Each read returns a single byte giving the temperature.
The third interface logs kernel messages on additional alert events.
The wdt card cannot be safely probed for. Instead you need to pass
wdt=ioaddr,irq as a boot parameter - eg "wdt=0x240,11".
Features
--------
WDT501P WDT500P
Reboot Timer X X
External Reboot X X
I/O Port Monitor o o
Temperature X o
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 Documentation/watchdog/src/watchdog-simple.c