watchdog: sunxi_wdt: preserve boot-enabled watchdog

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sunxi_wdt_probe() unconditionally stops the watchdog even when firmware
left it running. This opens an unprotected interval during boot and
prevents CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED from taking over the active
watchdog.

Detect an enabled watchdog and decode its programmed interval. Preserve
representable timeouts, and round the 0.5-second interval up to the
minimum representable one-second timeout. Use the configured timeout for
reserved interval encodings. Set the Linux reset mode and ping the
watchdog without clearing its enable bit, then mark it hardware-running
before registration so the watchdog core services it until userspace
takes control. Leave disabled watchdogs untouched.

Fixes: d00680ed00 ("watchdog: sunxi: New watchdog driver for Allwinner A10/A13")
Cc: stable@vger.kernel.org
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Link: https://patch.msgid.link/20260827-submit-sunxi-wdt-boot-enabled-v1-v2-1-610d37dccc97@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

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James Hilliard 2026-08-27 22:42:31 -06:00 • committed by Guenter Roeck

parent cee9395acd

commit aab55360fa

1 changed files with 44 additions and 1 deletions

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drivers/watchdog/sunxi_wdt.c

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