startup: inhibit watchdogs on non-interactive autoboot abort ...

nv.autoboot=abort has been added as development aid to have barebox stop
at the shell prompt automatically. It makes sense to inhibit all watchdogs
in this mode, so the user can later use the shell in peace.

This also applies to fastboot aborting the shell prompt. If this
happens, watchdog will be automatically inhibited as well.
Behavior on user aborting the shell prompt via keypad or uart input
remains unchanged for backwards-compatibility.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: permit `wd 0` for non-stoppable, but inactive, watchdogs ...

A watchdog that can't be stopped returns -ENOSYS on set_timeout(0).
If the watchdog supports communicating whether it's running, we could
still allow `wd 0`, if it hasn't been started yet.

Setting device parameter .priority=0 disables a watchdog. One would
expect this to always succeed for a not-running watchdog, but currently
it doesn't, if the driver's set_timeout(0) returns -ENOSYS. With this
fix, this is supported making the user API less surprising.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

poller: Give pollers a name ...

It helps debugging when pollers have a name, so give them one.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: Fix error path ...

In case of an error (e.g. dev_add_param_tristate_ro() returns -ENOSYS),
device registration must be reverted.

Signed-off-by: Christian Eggers <ceggers@arri.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: core: use new dev_add_param_tristate helper for .running param ...

Previous commit added a dev_add_param_tristate_ro that can be readily
used instead of the enum parameter here. Use it.
This also fixes the issue that running_names had external linkage.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: implement generic support for .running device parameter ...

Linux watchdog have an optional WDOG_HW_RUNNING bit that is used in
conjunction with CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED to automatically
ping running watchdogs until userspace takes over.

So far, when we ported Linux drivers, we dropped this detection, but it
would be useful to have this information in barebox as well:

The American Megatrends BIOS I am using allows configuring the hardware
watchdog from the BIOS. barebox enables the WDT as well, so in normal
operation we would never notice if after a BIOS update, the watchdog is
no longer enabled. If we maintain a running parameter on watchdog
devices, board code can be written to check whether the watchdog device
is indeed running.

To achieve this, add the necessary bits to the watchdog API. How we go
about it differs from Linux a little:

- We use an enum instead of a single bit, so we can differentiate between
  watchdogs that are not running and watchdogs whose running status is
  unknown.
- Because we can check whether watchdog_hw_running is supported, it now
  can fail and return a negative value in that case
- We do the maintenance of the running parameter after barebox
  feeds/disables the watchdog in the core, so it doesn't need to
  be replicated across drivers. Drivers hould only initialize the
  running parameter once at probe time.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: always populate watchdog priority from device tree if possible ...

So far, only the da9063 and da9053 have made use of the optional barebox
watchdog-priority binding. Move it into the core, so other device
drivers automatically have their watchdog-priority property parsed as
well. This patch doesn't introduce any functional changes for upstream
boards.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: add timeout_cur parameter only when poller is enabled ...

timeout_curr is the timeout programmed into the watchdog hardware every
500 milliseconds. If watchdog poller support is disabled, it still
shows up as a configurable device parameter, but has no effect.

Improve user experience by having it show up only if watchdog poller
support was compiled in. This is already the case for the autoping
parameter. The timeout_max parameter is a generic parameter and will
remain unchanged.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: rename timeout_curr to poller_timeout_curr internally ...

timeout_curr is the timeout programmed into the watchdog hardware every
500 milliseconds. If watchdog poller support is disabled, it serves
no purpose, prefix it with poller_ to better communicate this fact.

No functional change.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: export API to configure watchdogs by name ...

So far watchdog users could only configure the watchdog with the highest
priority. In preparation for having the wd command configure a watchdog
by name, extend watchdog_set_timeout with a struct watchdog *parameter
and export functions to query default watchdog and to find watchdog by
name.
No functional change.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: export priority as device parameter ...

8f4cf30903 ("watchdog: Allow multiple watchdogs") introduced the ability
to set a per-watchdog priority from within drivers, which is usually
populated with of_get_watchdog_priority.

For debugging, it can be useful to query and override this priority on
the fly.  Provide a device parameter to do so.
As watchdog_get_default only considers priorities > 0, it makes sense
to have a newly set priority of 0 disable the watchdog.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

drivers: Introduce dev_set_name() ...

Introduce dev_set_name() in order to hide implementation details of
setting device's name so it'd be easier to change it.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: core: check hwdev before use it ...

Avoid null pointer access, if hwdev was not
set before call watchdog_register.

Signed-off-by: Andreas Schmidt <mail@schmidt-andreas.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: add watchdog poller ...

In some cases it is practical to supervise as much as possible of
the barebox execution with a watchdog (or multiple watchdogs). This
patch provides an async poller for watchdog core framework which can
be enabled by the user and stores this configuration to nv.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: provide timeout_cur value ...

timeout_cur will be used for watchdog poller.
Provided values should be good enough for most users
and still can be changed for separate projects and
fit to needed requirements.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: set some reasonable timeout_max value if no other is available ...

Some drivers do not provide timeout_max value.
Using some value is probably better then setting timeout_max to 0.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: move max timeout test in to wd_core ...

this also will be needed for watchdog poller as well

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: register watchdog virtual device with short name wdog ...

the watchdog hwdev is usually named with devicetree schema
which is not practical for CLI.

On device registration "wdog" will be extended with some index number
extracted from devicetree (if awailable) or automatically assigned
first available number. End result will be "wdog0" .. etc.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: rename dev to hwdev ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: Give watchdogs a name ...

This adds a dev and name member to struct watchdog which helps distinguishing
between different watchdogs. Also add some debugging aids.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: Allow multiple watchdogs ...

Put watchdogs on a list to allow multiple watchdogs. Add a priority
field to be able to pick the highest priority watchdog.
This patch also provides a of_get_watchdog_priority() function to
allow configuring the watchdog priority from the device tree.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Add a simple watchdog framework ...

This patch adds a simple wd command which can setup, trigger and stop a watchdog
on the platform.

Signed-off-by: Juergen Beisert <jbe@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>