Some watchdogs require a minimum time between heartbeats.
Examples are the watchdogs in DA9062 and AT91SAM9x.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

The WDOG_HW_RUNNING flag is expected to be set by watchdog drivers if
the hardware watchdog is running. If the flag is set, the watchdog
subsystem will ping the watchdog even if the watchdog device is closed.

The watchdog driver stop function is now optional and may be omitted
if the watchdog can not be stopped. If stopping the watchdog is not
possible but the driver implements a stop function, it is responsible
to set the WDOG_HW_RUNNING flag in its stop function.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

Introduce an optional hardware maximum heartbeat in the watchdog core.
The hardware maximum heartbeat can be lower than the maximum timeout.

Drivers can set the maximum hardware heartbeat value in the watchdog data
structure. If the configured timeout exceeds the maximum hardware heartbeat,
the watchdog core enables a timer function to assist sending keepalive
requests to the watchdog driver.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

The 'action' (or restart mode) and data parameters may be used by restart
handlers, so they should be passed to the restart callback functions.

Cc: Sylvain Lemieux <slemieux@tycoint.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

The lifetime of the watchdog device pointer is different from the lifetime
of its character device. Remove it entirely to avoid race conditions.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

The Zodiac watchdog driver attaches additional sysfs attributes to the
watchdog device. This has a number of problems: The watchdog device
lifetime differs from the driver lifetime, and the device structure
should therefore not be accessed from drivers. Also, creating sysfs
attributes after driver registration results in a potential race condition
if user space expects the attributes to exist but they don't exist yet.

Add support for creating driver specific sysfs attributes to the watchdog
core to solve the problems.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

ref/unref ops are not called at all so even marked them as deprecated
is misleading, we need to just drop the API.
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

All variables required by the watchdog core to manage a watchdog are
currently stored in struct watchdog_device. The lifetime of those
variables is determined by the watchdog driver. However, the lifetime
of variables used by the watchdog core differs from the lifetime of
struct watchdog_device. To remedy this situation, watchdog drivers
can implement ref and unref callbacks, to be used by the watchdog
core to lock struct watchdog_device in memory.

While this solves the immediate problem, it depends on watchdog drivers
to actually implement the ref/unref callbacks. This is error prone,
often not implemented in the first place, or not implemented correctly.

To solve the problem without requiring driver support, split the variables
in struct watchdog_device into two data structures - one for variables
associated with the watchdog driver, one for variables associated with
the watchdog core. With this approach, the watchdog core can keep track
of its variable lifetime and no longer depends on ref/unref callbacks
in the driver. As a side effect, some of the variables originally in
struct watchdog_driver are now private to the watchdog core and no longer
visible in watchdog drivers.

As a side effect of the changes made, an ioctl will now always fail
with -ENODEV after a watchdog device was unregistered with the character
device still open. Previously, it would only fail with -ENODEV in some
situations. Also, ioctl operations are now atomic from driver perspective.
With this change, it is now guaranteed that the driver will not unregister
a watchdog between a timeout change and the subsequent ping.

The 'ref' and 'unref' callbacks in struct watchdog_driver are no longer
used and marked as deprecated.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

Many watchdog drivers register a reboot notifier in order to stop the
watchdog on system reboot. Thus we can factorize this code in the
watchdog core.

For that purpose, a new notifier block is added in watchdog_device for
internal use only, as well as a new watchdog_stop_on_reboot helper
function.

If this helper is called, watchdog core registers the related notifier
block and will stop the watchdog when SYS_HALT or SYS_DOWN is received.

Since this operation can be critical on some platforms, abort the device
registration if the reboot notifier registration fails.
Suggested-by: NVivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: NDamien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: NVivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

Many watchdog drivers implement the same code to register a restart
handler. This patch provides a generic way to set such a function.

The patch adds a new restart watchdog operation. If a restart priority
greater than 0 is needed, the driver can call
watchdog_set_restart_priority to set it.
Suggested-by: NVivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: NDamien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Reviewed-by: NVivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

Up to now, a new timeout value is only evaluated against min_timeout
if max_timeout is provided. This does not really make sense; a driver
can have a minimum timeout even if it does not have a maximum timeout.
Ensure that it is not smaller than min_timeout, even if max_timeout
is not set.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

The kernel's NMI watchdog has nothing to do with the watchdog subsystem.
Its header declarations should be in linux/nmi.h, not linux/watchdog.h.

The code provided two sets of dummy functions if HARDLOCKUP_DETECTOR is
not configured, one in the include file and one in kernel/watchdog.c.
Remove the dummy functions from kernel/watchdog.c and use those from the
include file.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Cc: Stephane Eranian <eranian@google.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Don Zickus <dzickus@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, watchdog subsystem require the misc subsystem to
register a watchdog. This may not be the case in case of an
early registration of a watchdog, which can be required when
the watchdog cannot be disabled.

This patch introduces a deferral mechanism to remove this requirement.
Signed-off-by: NJean-Baptiste Theou <jtheou@adeneo-embedded.us>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

This patch adds two new functions to enable/disable
the watchdog across all CPUs.

This will be used by the HT PMU bug workaround code to
disable/enable the NMI watchdog across quirk enablement.
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: bp@alien8.de
Cc: jolsa@redhat.com
Cc: kan.liang@intel.com
Cc: maria.n.dimakopoulou@gmail.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1416251225-17721-12-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NUwe Kleine-K=C3=B6nig <u.kleine-koenig@pengutronix.de>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

Add support for watchdog drivers to initialize/set the timeout field
of the watchdog_device structure. The timeout field is initialised
either with the module timeout parameter value (if valid) or with the
timeout-sec dt property (if valid). If both are invalid the initial
value is unchanged.
Signed-off-by: NFabio Porcedda <fabio.porcedda@gmail.com>
Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

Signed-off-by: NFabio Porcedda <fabio.porcedda@gmail.com>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

"Whether" is misspelled in various comments across the tree; this
fixes them. No code changes.
Signed-off-by: NAdam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: NDave Jones <davej@redhat.com>

If a driver's watchdog_device struct is part of a dynamically allocated
struct (which it often will be), merely locking the module is not enough,
even with a drivers module locked, the driver can be unbound from the device,
examples:
1) The root user can unbind it through sysfd
2) The i2c bus master driver being unloaded for an i2c watchdog

I will gladly admit that these are corner cases, but we still need to handle
them correctly.

The fix for this consists of 2 parts:
1) Add ref / unref operations, so that the driver can refcount the struct
   holding the watchdog_device struct and delay freeing it until any
   open filehandles referring to it are closed
2) Most driver operations will do IO on the device and the driver should not
   do any IO on the device after it has been unbound. Rather then letting each
   driver deal with this internally, it is better to ensure at the watchdog
   core level that no operations (other then unref) will get called after
   the driver has called watchdog_unregister_device(). This actually is the
   bulk of this patch.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

This patch fixes some potential multithreading issues, despite only
allowing one process to open the /dev/watchdog device, we can still get
called multiple times at the same time, since a program could be using thread,
or could share the fd after a fork.

This causes 2 potential problems:
1) watchdog_start / open do an unlocked test_n_set / test_n_clear,
   if these 2 race, the watchdog could be stopped while the active
   bit indicates it is running or visa versa.

2) Most watchdog_dev drivers probably assume that only one
   watchdog-op will get called at a time, this is not necessary
   true atm.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

Create the watchdog class and it's associated devices.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

Some watchdogs merely trigger external alarms and controls. In a managed
environment this is very useful but we want drivers to be able to figure
out which is which now multiple dogs can be loaded. Thus add an ALARMONLY
feature flag.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

We keep the old /dev/watchdog interface file for the first watchdog via
miscdev. This is basically a cut and paste of the relevant interface code
from the rtc driver layer tweaked for watchdog.

Revised to fix problems noted by Hans de Goede
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

Some watchdog may need to check if watchdog is ACTIVE or not, for example in
their suspend/resume hooks.

This patch adds this routine and changes the core drivers to use it.
Signed-off-by: NViresh Kumar <viresh.kumar@st.com>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

This patch adds support for WDIOC_GETTIMELEFT IOCTL in watchdog core. So, there
is another function pointer added to struct watchdog_ops, which can be passed by
drivers to support this IOCTL.

Related documentation is updated too.
Signed-off-by: NViresh Kumar <viresh.kumar@st.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

nowayout is actually a boolean value.
So make it bool for all watchdog device drivers.
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

Add two nowayout helpers for the Watchdog Timer Driver Kernel API.
And apply this to the already converted drivers.
Note: s3c2410_wdt lost the nowayout feature during the conversion.
Reviewed-by: NWolfram Sang <w.sang@pengutronix.de>
Acked-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

Add min_timeout (minimum timeout) and max_timeout
values so that the framework can check if the new
timeout value is between the minimum and maximum
timeout values. If both values are 0, then the
framework will leave the check for the watchdog
device driver itself.
Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>

Add support for extra ioctl calls by adding a
ioctl watchdog operation. This operation will be
called before we do our own handling of ioctl
commands. This way we can override the internal
ioctl command handling and we can also add
extra ioctl commands. The ioctl watchdog operation
should return the appropriate error codes or
-ENOIOCTLCMD if the ioctl command should be handled
through the internal ioctl handling of the framework.
Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>

Add support for the nowayout feature to the
WatchDog Timer Driver Core framework.
This feature prevents the watchdog timer from being
stopped.
Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>

Add support for the Magic Close feature to the
WatchDog Timer Driver Core framework.
Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>

This part add's the WDIOC_SETTIMEOUT and WDIOC_GETTIMEOUT ioctl
functionality to the WatchDog Timer Driver Core framework.
Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>

This part add's the WDIOC_SETOPTIONS ioctl functionality
to the WatchDog Timer Driver Core framework.
Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>

This part add's the basic ioctl functionality to the
WatchDog Timer Driver Core framework. The supported
ioctl call's are:
	WDIOC_GETSUPPORT
	WDIOC_GETSTATUS
	WDIOC_GETBOOTSTATUS
Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>

The WatchDog Timer Driver Core is a framework
that contains the common code for all watchdog-driver's.
It also introduces a watchdog device structure and the
operations that go with it.

This is the introduction of this framework. This part
supports the minimal watchdog userspace API (or with
other words: the functionality to use /dev/watchdog's
open, release and write functionality as defined in
the simplest watchdog API). Extra functionality will
follow in the next set of patches.
Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>

Some watchdog drivers have the ability to report the remaining time
before the system will reboot. With the WDIOC_GETTIMELEFT ioctl
you can now read the time left before the watchdog would reboot
your system.

The following drivers support this new IOCTL:
i8xx_tco.c, pcwd_pci.c and pcwd_usb.c .
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>
Signed-off-by: NAndrew Morton <akpm@osdl.org>

Some watchdog timers support the concept of a "pretimeout" which
occurs some time before the real timeout.  The pretimeout can
be delivered via an interrupt or NMI and can be used to panic
the system when it occurs (so you get useful information instead
of a blind reboot).
Signed-off-by: NCorey Minyard <minyard@acm.org>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>
Signed-off-by: NAndrew Morton <akpm@osdl.org>