linux-kernel - Re: [PATCH] ARM: dts: exynos: ordering wrong order tmu_cpu on Odroid-XU3/4 thermal-zones definition

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Message-ID: <CAJKOXPdDFm=7wNLt5Nzf-y8TS4u6gmo51Y70bFv_pKdFK42VDQ@mail.gmail.com>
Date:   Fri, 21 Sep 2018 13:46:09 +0200
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     willy.mh.wolff.ml@...il.com
Cc:     robh+dt@...nel.org, mark.rutland@....com, kgene@...nel.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        "linux-samsung-soc@...r.kernel.org" 
        <linux-samsung-soc@...r.kernel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ARM: dts: exynos: ordering wrong order tmu_cpu on
 Odroid-XU3/4 thermal-zones definition

On Fri, 21 Sep 2018 at 13:33, Willy Wolff <willy.mh.wolff.ml@...il.com> wrote:
>
> This patch is to open a discussion about wrong order of tmu_cpu.
>
> It seems that tmu_cpu1 correspond to cpu3, and tmu_cpu3 match cpu1.
> Note, cpu{0|3} in dtsi correspond to cpu{3|7} in linux and are the big
> cores.

Hi,

I do not understand this sentence. In DTSI, the CPU0-3 are the A7,
little cores. Defined by exynos5422-cpus.dtsi. What did you mean here?

> By dependencis from exynos5422-odroidxu3-common.dtsi to
> exynos5800.dtsi -> exynos5420.dtsi, I guess definitions of tmu_cpuX are
> incorrect. However, changing the address, reg interrupts or clocks
> would breack other boards depending on it. As I can't test other boards,
> I've just overload the reference in the thermal-zones node.

There are 8 CPUs (4 little and 4 big) but only 4 thermal zones for
CPUs. The mapping of names of CPU nodes and TMU nodes in DTS is not
direct. These are just indices ... although more important is to map
the cooling devices to proper TMU. This should be mentioned in DTS as
this the real problem here.

>
> To reproduce the problem, I provide two scripts:
> == script_stress:
>
> for i in 0 10 20 40 80; do
>     echo $i
>     taskset $i stress -t 10 -c 1
> done;
>
> == script_read_temp:
>
> while true; do
>     for i in 0 1 2 3 4; do
>         echo $i
>         cat /sys/devices/virtual/thermal/thermal_zone$i/temp
>     done;
>     sleep 1
>     clear
> done;
>
> Signed-off-by: Willy Wolff <willy.mh.wolff@...il.com>
> ---
>  arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
> index 96e281c0a118..4512ffad2785 100644
> --- a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
> +++ b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
> @@ -135,7 +135,8 @@
>                         };
>                 };
>                 cpu1_thermal: cpu1-thermal {
> -                       thermal-sensors = <&tmu_cpu1 0>;
> +                       // thermal-sensors = <&tmu_cpu1 0>;

Do not leave commented lines, there are not needed.

Also your email does not match signed-off-by. You must have something
wrong with either git setup or mailer (git commit --si will use the
same address for From and SoB so I guess the mailer...).

Best regards,
Krzysztof