[PATCH AUTOSEL 5.4 097/459] drivers: watchdog: stm32_iwdg: set WDOG_HW_RUNNING at probe
From: Sasha Levin <sashal@kernel.org>
Date: 2020-02-14 17:40:04
Also in:
linux-watchdog, lkml, stable
Subsystem:
the rest, watchdog device drivers · Maintainers:
Linus Torvalds, Wim Van Sebroeck, Guenter Roeck
From: Christophe Roullier <redacted>
[ Upstream commit 85fdc63fe256b595f923a69848cd99972ff446d8 ]
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 <redacted>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20191122132246.8473-1-christophe.roullier@st.com (local)
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/watchdog/stm32_iwdg.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/drivers/watchdog/stm32_iwdg.c b/drivers/watchdog/stm32_iwdg.c
index a3a329011a06b..25188d6bbe152 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;
--
2.20.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel