From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Christophe Roullier <christophe.roullier@st.com>,
Guenter Roeck <linux@roeck-us.net>,
Wim Van Sebroeck <wim@linux-watchdog.org>,
Sasha Levin <sashal@kernel.org>,
linux-watchdog@vger.kernel.org,
linux-stm32@st-md-mailman.stormreply.com,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 5.5 113/542] drivers: watchdog: stm32_iwdg: set WDOG_HW_RUNNING at probe
Date: Fri, 14 Feb 2020 10:41:45 -0500 [thread overview]
Message-ID: <20200214154854.6746-113-sashal@kernel.org> (raw)
In-Reply-To: <20200214154854.6746-1-sashal@kernel.org>
From: Christophe Roullier <christophe.roullier@st.com>
[ 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 <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: 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
next parent reply other threads:[~2020-02-14 18:17 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200214154854.6746-1-sashal@kernel.org>
2020-02-14 15:41 ` Sasha Levin [this message]
2020-02-14 15:41 ` [PATCH AUTOSEL 5.5 114/542] watchdog: qcom: Use platform_get_irq_optional() for bark irq Sasha Levin
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