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> |
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drivers/watchdog/wd_core.c |
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include/watchdog.h |
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