Merge git://www.linux-watchdog.org/linux-watchdog

Pull watchdog updates from Wim Van Sebroeck:

 - new drivers for: NI 903x/913x watchdog driver, WinSystems EBC-C384
   watchdog timer and ARM SBSA watchdog driver

 - Support for NCT6102D devices

 - Improvements of the generic watchdog framework (improve restart
   handler, make set_timeout optional, introduce infrastructure
   triggered keepalives, ...

 - improvements on the pnx4008 watchdog driver

 - several smaller fixes and improvements

* git://www.linux-watchdog.org/linux-watchdog: (28 commits)
  watchdog: Ensure that wdd is not dereferenced if NULL
  watchdog: imx2: Convert to use infrastructure triggered keepalives
  watchdog: dw_wdt: Convert to use watchdog infrastructure
  watchdog: Add support for minimum time between heartbeats
  watchdog: Make stop function optional
  watchdog: Introduce WDOG_HW_RUNNING flag
  watchdog: Introduce hardware maximum heartbeat in watchdog core
  watchdog: Make set_timeout function optional
  arm: lpc32xx: remove restart handler
  arm: lpc32xx: phy3250 remove restart hook
  watchdog: pnx4008: restart: support "cmd" from userspace
  watchdog: pnx4008: add support for soft reset
  watchdog: pnx4008: add restart handler
  watchdog: pnx4008: update logging during power-on
  watchdog: tangox_wdt: test clock rate to avoid division by 0
  watchdog: atlas7_wdt: test clock rate to avoid division by 0
  watchdog: s3c2410_wdt: Add max and min timeout values
  Watchdog: introduce ARM SBSA watchdog driver
  Documentation: add sbsa-gwdt driver documentation
  watchdog: Add watchdog timer support for the WinSystems EBC-C384
  ...

2 files changed, 59 insertions, 12 deletions

diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
index 55120a055a14..917eeeabfa5e 100644
--- a/Documentation/watchdog/watchdog-kernel-api.txt
+++ b/Documentation/watchdog/watchdog-kernel-api.txt
@@ -52,6 +52,8 @@ struct watchdog_device {
 	unsigned int timeout;
 	unsigned int min_timeout;
 	unsigned int max_timeout;
+	unsigned int min_hw_heartbeat_ms;
+	unsigned int max_hw_heartbeat_ms;
 	struct notifier_block reboot_nb;
 	struct notifier_block restart_nb;
 	void *driver_data;
@@ -73,8 +75,21 @@ It contains following fields:
   additional information about the watchdog timer itself. (Like it's unique name)
 * ops: a pointer to the list of watchdog operations that the watchdog supports.
 * timeout: the watchdog timer's timeout value (in seconds).
+  This is the time after which the system will reboot if user space does
+  not send a heartbeat request if WDOG_ACTIVE is set.
 * min_timeout: the watchdog timer's minimum timeout value (in seconds).
-* max_timeout: the watchdog timer's maximum timeout value (in seconds).
+  If set, the minimum configurable value for 'timeout'.
+* max_timeout: the watchdog timer's maximum timeout value (in seconds),
+  as seen from userspace. If set, the maximum configurable value for
+  'timeout'. Not used if max_hw_heartbeat_ms is non-zero.
+* min_hw_heartbeat_ms: Minimum time between heartbeats sent to the chip,
+  in milli-seconds.
+* max_hw_heartbeat_ms: Maximum hardware heartbeat, in milli-seconds.
+  If set, the infrastructure will send heartbeats to the watchdog driver
+  if 'timeout' is larger than max_hw_heartbeat_ms, unless WDOG_ACTIVE
+  is set and userspace failed to send a heartbeat for at least 'timeout'
+  seconds. max_hw_heartbeat_ms must be set if a driver does not implement
+  the stop function.
 * reboot_nb: notifier block that is registered for reboot notifications, for
   internal use only. If the driver calls watchdog_stop_on_reboot, watchdog core
   will stop the watchdog on such notifications.
@@ -123,17 +138,20 @@ are:
   device.
   The routine needs a pointer to the watchdog timer device structure as a
   parameter. It returns zero on success or a negative errno code for failure.
-* stop: with this routine the watchdog timer device is being stopped.
-  The routine needs a pointer to the watchdog timer device structure as a
-  parameter. It returns zero on success or a negative errno code for failure.
-  Some watchdog timer hardware can only be started and not be stopped. The
-  driver supporting this hardware needs to make sure that a start and stop
-  routine is being provided. This can be done by using a timer in the driver
-  that regularly sends a keepalive ping to the watchdog timer hardware.
 
 Not all watchdog timer hardware supports the same functionality. That's why
 all other routines/operations are optional. They only need to be provided if
 they are supported. These optional routines/operations are:
+* stop: with this routine the watchdog timer device is being stopped.
+  The routine needs a pointer to the watchdog timer device structure as a
+  parameter. It returns zero on success or a negative errno code for failure.
+  Some watchdog timer hardware can only be started and not be stopped. A
+  driver supporting such hardware does not have to implement the stop routine.
+  If a driver has no stop function, the watchdog core will set WDOG_HW_RUNNING
+  and start calling the driver's keepalive pings function after the watchdog
+  device is closed.
+  If a watchdog driver does not implement the stop function, it must set
+  max_hw_heartbeat_ms.
 * ping: this is the routine that sends a keepalive ping to the watchdog timer
   hardware.
   The routine needs a pointer to the watchdog timer device structure as a
@@ -153,9 +171,18 @@ they are supported. These optional routines/operations are:
   and -EIO for "could not write value to the watchdog". On success this
   routine should set the timeout value of the watchdog_device to the
   achieved timeout value (which may be different from the requested one
-  because the watchdog does not necessarily has a 1 second resolution).
+  because the watchdog does not necessarily have a 1 second resolution).
+  Drivers implementing max_hw_heartbeat_ms set the hardware watchdog heartbeat
+  to the minimum of timeout and max_hw_heartbeat_ms. Those drivers set the
+  timeout value of the watchdog_device either to the requested timeout value
+  (if it is larger than max_hw_heartbeat_ms), or to the achieved timeout value.
   (Note: the WDIOF_SETTIMEOUT needs to be set in the options field of the
   watchdog's info structure).
+  If the watchdog driver does not have to perform any action but setting the
+  watchdog_device.timeout, this callback can be omitted.
+  If set_timeout is not provided but, WDIOF_SETTIMEOUT is set, the watchdog
+  infrastructure updates the timeout value of the watchdog_device internally
+  to the requested value.
 * get_timeleft: this routines returns the time that's left before a reset.
 * restart: this routine restarts the machine. It returns 0 on success or a
   negative errno code for failure.
@@ -169,11 +196,19 @@ The 'ref' and 'unref' operations are no longer used and deprecated.
 The status bits should (preferably) be set with the set_bit and clear_bit alike
 bit-operations. The status bits that are defined are:
 * WDOG_ACTIVE: this status bit indicates whether or not a watchdog timer device
-  is active or not. When the watchdog is active after booting, then you should
-  set this status bit (Note: when you register the watchdog timer device with
-  this bit set, then opening /dev/watchdog will skip the start operation)
+  is active or not from user perspective. User space is expected to send
+  heartbeat requests to the driver while this flag is set.
 * WDOG_NO_WAY_OUT: this bit stores the nowayout setting for the watchdog.
   If this bit is set then the watchdog timer will not be able to stop.
+* WDOG_HW_RUNNING: Set by the watchdog driver if the hardware watchdog is
+  running. The bit must be set if the watchdog timer hardware can not be
+  stopped. The bit may also be set if the watchdog timer is running after
+  booting, before the watchdog device is opened. If set, the watchdog
+  infrastructure will send keepalives to the watchdog hardware while
+  WDOG_ACTIVE is not set.
+  Note: when you register the watchdog timer device with this bit set,
+  then opening /dev/watchdog will skip the start operation but send a keepalive
+  request instead.
 
   To set the WDOG_NO_WAY_OUT status bit (before registering your watchdog
   timer device) you can either:
diff --git a/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt
index 4e4b6f10d841..c161399a6b5c 100644
--- a/Documentation/watchdog/watchdog-parameters.txt
+++ b/Documentation/watchdog/watchdog-parameters.txt
@@ -200,6 +200,11 @@ mv64x60_wdt:
 nowayout: Watchdog cannot be stopped once started
 	(default=kernel config parameter)
 -------------------------------------------------
+ni903x_wdt:
+timeout: Initial watchdog timeout in seconds (0<timeout<516, default=60)
+nowayout: Watchdog cannot be stopped once started
+	(default=kernel config parameter)
+-------------------------------------------------
 nuc900_wdt:
 heartbeat: Watchdog heartbeats in seconds.
 	(default = 15)
@@ -284,6 +289,13 @@ sbc_fitpc2_wdt:
 margin: Watchdog margin in seconds (default 60s)
 nowayout: Watchdog cannot be stopped once started
 -------------------------------------------------
+sbsa_gwdt:
+timeout: Watchdog timeout in seconds. (default 10s)
+action: Watchdog action at the first stage timeout,
+	set to 0 to ignore, 1 to panic. (default=0)
+nowayout: Watchdog cannot be stopped once started
+	(default=kernel config parameter)
+-------------------------------------------------
 sc1200wdt:
 isapnp: When set to 0 driver ISA PnP support will be disabled (default=1)
 io: io port