The optional SMCWD_GET_TIMELEFT command can be used to detect if
the watchdog has already been started.
See the implementation in OP-TEE secure OS [1].
At probe time, check if the watchdog is already started and then
set WDOG_HW_RUNNING in the watchdog status. This will cause the
watchdog framework to ping the watchdog until a userspace watchdog
daemon takes over the control.
Link: https://github.com/OP-TEE/optee_os/commit/a7f2d4bd8632 [1]
Signed-off-by: Antonio Borneo <antonio.borneo@foss.st.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20250520085952.210723-1-antonio.borneo@foss.st.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
This patch adds a watchdog driver that can be used on ARM systems
with the appropriate watchdog implemented in Secure Monitor firmware.
The driver communicates with firmware via a Secure Monitor Call.
This may be useful for platforms using TrustZone that want
the Secure Monitor firmware to have the final control over the watchdog.
This is implemented on mt8173 chromebook devices oak, elm and hana in
arm trusted firmware file plat/mediatek/mt8173/drivers/wdt/wdt.c.
Signed-off-by: Julius Werner <jwerner@chromium.org>
Signed-off-by: Evan Benn <evanbenn@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: Xingyu Chen<xingyu.chen@amlogic.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200505131242.v6.2.Ia92bb4d4ce84bcefeba1d00aaa1c1e919b6164ef@changeid
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
