From: Christophe Roullier christophe.roullier@st.com
commit 85fdc63fe256b595f923a69848cd99972ff446d8 upstream.
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 christophe.roullier@st.com Reviewed-by: Guenter Roeck linux@roeck-us.net Link: https://lore.kernel.org/r/20191122132246.8473-1-christophe.roullier@st.com Signed-off-by: Guenter Roeck linux@roeck-us.net Signed-off-by: Wim Van Sebroeck wim@linux-watchdog.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/watchdog/stm32_iwdg.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)
--- a/drivers/watchdog/stm32_iwdg.c +++ b/drivers/watchdog/stm32_iwdg.c @@ -262,6 +262,24 @@ static int stm32_iwdg_probe(struct platf 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;