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>

Attached patch removes #ifdef CONFIG_WATCHDOG_NOWAYOUT mess duplicated in
almost every watchdog driver and replaces it with common define in
linux/watchdog.h.
Signed-off-by: NAndrey Panin <pazke@donpac.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!