From 85fdc63fe256b595f923a69848cd99972ff446d8 Mon Sep 17 00:00:00 2001 From: Christophe Roullier Date: Fri, 22 Nov 2019 14:22:46 +0100 Subject: drivers: watchdog: stm32_iwdg: set WDOG_HW_RUNNING at probe If the watchdog hardware is already enabled during the boot process, when the Linux watchdog driver loads, it should start/reset the watchdog and tell the watchdog framework. As a result, ping can be generated from the watchdog framework (if CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is set), until the userspace watchdog daemon takes over control Fixes:4332d113c66a ("watchdog: Add STM32 IWDG driver") Signed-off-by: Christophe Roullier Reviewed-by: Guenter Roeck Link: https://lore.kernel.org/r/20191122132246.8473-1-christophe.roullier@st.com Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- drivers/watchdog/stm32_iwdg.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'drivers/watchdog') diff --git a/drivers/watchdog/stm32_iwdg.c b/drivers/watchdog/stm32_iwdg.c index a3a329011a06..25188d6bbe15 100644 --- a/drivers/watchdog/stm32_iwdg.c +++ b/drivers/watchdog/stm32_iwdg.c @@ -262,6 +262,24 @@ static int stm32_iwdg_probe(struct platform_device *pdev) watchdog_set_nowayout(wdd, WATCHDOG_NOWAYOUT); watchdog_init_timeout(wdd, 0, dev); + /* + * In case of CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is set + * (Means U-Boot/bootloaders leaves the watchdog running) + * When we get here we should make a decision to prevent + * any side effects before user space daemon will take care of it. + * The best option, taking into consideration that there is no + * way to read values back from hardware, is to enforce watchdog + * being run with deterministic values. + */ + if (IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) { + ret = stm32_iwdg_start(wdd); + if (ret) + return ret; + + /* Make sure the watchdog is serviced */ + set_bit(WDOG_HW_RUNNING, &wdd->status); + } + ret = devm_watchdog_register_device(dev, wdd); if (ret) return ret; -- cgit v1.2.3-59-g8ed1b