Commit Graph

18 Commits

Author SHA1 Message Date
Hans de Goede e907df3272 watchdog: Add support for dynamically allocated watchdog_device structs
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: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2012-05-30 07:55:31 +02:00
Hans de Goede f4e9c82f64 watchdog: Add Locking support
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: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2012-05-30 07:55:23 +02:00
Alan Cox d6b469d915 watchdog: create all the proper device files
Create the watchdog class and it's associated devices.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2012-05-30 07:54:46 +02:00
Alan Cox 45f5fed30a watchdog: Add multiple device support
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: Alan Cox <alan@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2012-05-30 07:54:25 +02:00
Devendra Naga 2deca73655 Documentation/watchdog: Fix a small typo
Signed-off-by: Devendra Naga <devendra.aaru@gmail.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2012-05-23 16:27:00 +02:00
Viresh Kumar fd7b673c92 watchdog: Add support for WDIOC_GETTIMELEFT IOCTL in watchdog core
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: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2012-03-27 20:15:37 +02:00
Hans de Goede b10f7c12e0 watchdog: watchdog_dev: Let the driver update the timeout field on set_timeout success
When a set_timeout operation succeeds this does not necessarily mean that
the exact timeout requested has been achieved, because the watchdog does not
necessarily have a 1 second resolution. So rather then have the core set
the timeout member of the watchdog_device struct to the exact requested
value, instead the driver should set it to the actually achieved timeout value.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2012-03-27 20:07:43 +02:00
Masanari Iida e19865219d Documentation: Fix typo in watchdog-kernel-api.txt
Correct spelling "retruns" to "returns" in
Documentations/watchdog/watchdog-kernel-api.txt

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2012-02-21 11:40:34 +01:00
Wim Van Sebroeck ff0b3cd4a4 watchdog: add nowayout helpers to Watchdog Timer Driver Kernel API
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: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2012-01-06 15:22:04 +01:00
Wim Van Sebroeck 3f43f68e29 watchdog: WatchDog Timer Driver Core - Add minimum and max timeout
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: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
2011-07-28 08:01:18 +00:00
Wim Van Sebroeck 78d88fc012 watchdog: WatchDog Timer Driver Core - Add ioctl call
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: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
2011-07-28 08:01:16 +00:00
Wim Van Sebroeck 7e192b9c42 watchdog: WatchDog Timer Driver Core - Add nowayout feature
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: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
2011-07-28 08:01:14 +00:00
Wim Van Sebroeck 017cf08051 watchdog: WatchDog Timer Driver Core - Add Magic Close feature
Add support for the Magic Close feature to the
WatchDog Timer Driver Core framework.

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
2011-07-28 08:01:12 +00:00
Wim Van Sebroeck 014d694e5d watchdog: WatchDog Timer Driver Core - Add WDIOC_SETTIMEOUT and WDIOC_GETTIMEOUT ioctl
This part add's the WDIOC_SETTIMEOUT and WDIOC_GETTIMEOUT ioctl
functionality to the WatchDog Timer Driver Core framework.

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
2011-07-28 08:01:11 +00:00
Wim Van Sebroeck 234445b4e4 watchdog: WatchDog Timer Driver Core - Add WDIOC_SETOPTIONS ioctl
This part add's the WDIOC_SETOPTIONS ioctl functionality
to the WatchDog Timer Driver Core framework.

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
2011-07-28 08:01:09 +00:00
Wim Van Sebroeck c2dc00e494 watchdog: WatchDog Timer Driver Core - Add WDIOC_KEEPALIVE ioctl
This part add's the WDIOC_KEEPALIVE ioctl functionality to the
WatchDog Timer Driver Core framework. Please note that the
WDIOF_KEEPALIVEPING bit has to be set in the watchdog_info
options field.

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
2011-07-28 08:01:07 +00:00
Wim Van Sebroeck 2fa03560ab watchdog: WatchDog Timer Driver Core - Add basic ioctl functionality
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: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
2011-07-28 08:01:05 +00:00
Wim Van Sebroeck 43316044d4 watchdog: WatchDog Timer Driver Core - Add basic framework
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: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
2011-07-28 08:01:04 +00:00