Re: [PATCH 4.19.y-cip 2/6] arm64: dts: renesas: r8a774c0-cat874: Add RWDT support


Biju Das <biju.das@...>
 

Hi Pavel,

Thanks for the feedback.

Subject: Re: [cip-dev] [PATCH 4.19.y-cip 2/6] arm64: dts: renesas: r8a774c0-
cat874: Add RWDT support

On Mon 2019-07-15 15:28:46, Biju Das wrote:
From: Fabrizio Castro <fabrizio.castro@...>

commit 79223ca1f57776d2770da9561c26cc2f2dd42205 upstream.

Enable RWDT and use 60 seconds as default timeout.
So this will reboot machine if userspace does not ping it within 60 seconds by
default?
Yes, if you enable watchdog in user space and there is no ping activity for 60 sec.
We can verify this by using the below command

cat > /dev/watchdog0 & for i in $(seq 100); do echo $i; sleep 1; done

Will that break user configurations that worked up till now, but do not
contain watchdog support?

Do we care?
As per [1]
- timeout-sec : Contains the watchdog timeout in seconds
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/watchdog/renesas-wdt.txt?h=v5.2

If time-out is not specified, then it uses the default timeout mentioned by the driver.

Regards,
Biju

@@ -137,6 +137,11 @@
};
};

+&rwdt {
+ timeout-sec = <60>;
+ status = "okay";
+};
+
&scif2 {
pinctrl-0 = <&scif2_pins>;
pinctrl-names = "default";
--
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