linux-kernel - Re: [PATCH 2/3] arm64: dts: exynos: gs101: align reboot and poweroff writes with downstream

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Message-ID: <CADrjBPr9k7QnkFzrY_4Q8A-yrQjErVBaHv1x=oOYacCamn4BuA@mail.gmail.com>
Date: Mon, 10 Feb 2025 06:23:31 +0000
From: Peter Griffin <peter.griffin@...aro.org>
To: André Draszik <andre.draszik@...aro.org>
Cc: Tudor Ambarus <tudor.ambarus@...aro.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Alim Akhtar <alim.akhtar@...sung.com>, Will McVicker <willmcvicker@...gle.com>, 
	kernel-team@...roid.com, linux-arm-kernel@...ts.infradead.org, 
	linux-samsung-soc@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] arm64: dts: exynos: gs101: align reboot and poweroff
 writes with downstream

Hi André,

Thanks for your patch.

On Thu, 6 Feb 2025 at 13:08, André Draszik <andre.draszik@...aro.org> wrote:
>
> For power off, downstream only clears bit 8 and leaves all other bits
> untouched, whereas this here ends up setting bit 8 and clearing all
> others, due to how sysconf-poweroff parses the DT.

That indeed sounds like a bug.

>
> For reboot, downstream writes 0x00000002 whereas this here ends up
> setting bit 1 only and leaving all others untouched.

For SYSTEM_CONFIGURATION register Bit[0] and bit[31:2] are reserved
and say "type R" (rather than RW for bit[1] so it seems correct to be
leaving the other bits untouched?

regards,

Peter


>
> I noticed this discrepancy while debugging some reboot related
> differences between up- and downstream and it's useful to align the
> behaviour here.
>
> Signed-off-by: André Draszik <andre.draszik@...aro.org>
> ---
>  arch/arm64/boot/dts/exynos/google/gs101.dtsi | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/exynos/google/gs101.dtsi b/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> index e78dcd506a5c..4f45bfeb33c0 100644
> --- a/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> +++ b/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> @@ -1401,13 +1401,13 @@ pmu_system_controller: system-controller@...60000 {
>                         poweroff: syscon-poweroff {
>                                 compatible = "syscon-poweroff";
>                                 offset = <0x3e9c>; /* PAD_CTRL_PWR_HOLD */
> -                               mask = <0x100>; /* reset value */
> +                               mask = <0x00000100>;
> +                               value = <0x0>;
>                         };
>
>                         reboot: syscon-reboot {
>                                 compatible = "syscon-reboot";
>                                 offset = <0x3a00>; /* SYSTEM_CONFIGURATION */
> -                               mask = <0x2>; /* SWRESET_SYSTEM */
>                                 value = <0x2>; /* reset value */
>                         };
>                 };
>
> --
> 2.48.1.362.g079036d154-goog
>