linux-kernel - Re: [PATCH 1/4] arm64: dts: rockchip: list all CPU supplies on ArmSoM Sige5

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Message-ID: <CABjd4YxBHn4f4QRVxk1uLGgt7-n=VQqF0_ZSJsKSxZuVtrLiaw@mail.gmail.com>
Date: Wed, 4 Jun 2025 23:54:14 +0400
From: Alexey Charkov <alchark@...il.com>
To: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
	Conor Dooley <conor+dt@...nel.org>, Heiko Stuebner <heiko@...ech.de>, devicetree@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-rockchip@...ts.infradead.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/4] arm64: dts: rockchip: list all CPU supplies on ArmSoM Sige5

On Wed, Jun 4, 2025 at 11:23 PM Nicolas Frattaroli
<nicolas.frattaroli@...labora.com> wrote:
>
> On Wednesday, 4 June 2025 21:12:35 Central European Summer Time Alexey Charkov wrote:
> > On Wed, Jun 4, 2025 at 10:38 PM Nicolas Frattaroli
> > <nicolas.frattaroli@...labora.com> wrote:
> > >
> > > On Tuesday, 3 June 2025 19:01:13 Central European Summer Time Alexey Charkov wrote:
> > > > List both CPU supply regulators which drive the little and big CPU
> > > > clusters, respectively, so that cpufreq can pick them up.
> > > >
> > > > Signed-off-by: Alexey Charkov <alchark@...il.com>
> > > > ---
> > > >  .../boot/dts/rockchip/rk3576-armsom-sige5.dts      | 28 ++++++++++++++++++++++
> > > >  1 file changed, 28 insertions(+)
> > > >
> > > > diff --git a/arch/arm64/boot/dts/rockchip/rk3576-armsom-sige5.dts b/arch/arm64/boot/dts/rockchip/rk3576-armsom-sige5.dts
> > > > index b09e789c75c47fec7cf7e9810ab0dcca32d9404a..d9c129be55a0d997e04e6d677cdc98fb50353418 100644
> > > > --- a/arch/arm64/boot/dts/rockchip/rk3576-armsom-sige5.dts
> > > > +++ b/arch/arm64/boot/dts/rockchip/rk3576-armsom-sige5.dts
> > > > @@ -207,6 +207,22 @@ vcc_3v3_ufs_s0: regulator-vcc-ufs-s0 {
> > > >       };
> > > >  };
> > > >
> > > > +&cpu_b0 {
> > > > +     cpu-supply = <&vdd_cpu_big_s0>;
> > > > +};
> > > > +
> > > > +&cpu_b1 {
> > > > +     cpu-supply = <&vdd_cpu_big_s0>;
> > > > +};
> > > > +
> > > > +&cpu_b2 {
> > > > +     cpu-supply = <&vdd_cpu_big_s0>;
> > > > +};
> > > > +
> > > > +&cpu_b3 {
> > > > +     cpu-supply = <&vdd_cpu_big_s0>;
> > > > +};
> > > > +
> > > >  &combphy0_ps {
> > > >       status = "okay";
> > > >  };
> > > > @@ -215,6 +231,18 @@ &cpu_l0 {
> > > >       cpu-supply = <&vdd_cpu_lit_s0>;
> > > >  };
> > > >
> > > > +&cpu_l1 {
> > > > +     cpu-supply = <&vdd_cpu_lit_s0>;
> > > > +};
> > > > +
> > > > +&cpu_l2 {
> > > > +     cpu-supply = <&vdd_cpu_lit_s0>;
> > > > +};
> > > > +
> > > > +&cpu_l3 {
> > > > +     cpu-supply = <&vdd_cpu_lit_s0>;
> > > > +};
> > > > +
> > > >  &gmac0 {
> > > >       phy-mode = "rgmii-id";
> > > >       clock_in_out = "output";
> > > >
> > > >
> > >
> > > Reviewed-by: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
> > > Tested-by: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
> > >
> > > > so that cpufreq can pick them up.
> > >
> > > Fwiw, even without this patch they're picked up by cpufreq-dt for me:
> > >
> > >     user@...xie:~$ sudo cpupower frequency-info
> > >       analyzing CPU 5:
> > >       driver: cpufreq-dt
> > >       CPUs which run at the same hardware frequency: 4 5 6 7
> > >       CPUs which need to have their frequency coordinated by software: 4 5 6 7
> > >       maximum transition latency: 40.0 us
> > >       hardware limits: 408 MHz - 2.30 GHz
> > >       available frequency steps:  408 MHz, 600 MHz, 816 MHz, 1.01 GHz, 1.20 GHz, 1.42 GHz, 1.61 GHz, 1.80 GHz, 2.02 GHz, 2.21 GHz, 2.30 GHz
> > >       available cpufreq governors: ondemand userspace performance schedutil
> > >       current policy: frequency should be within 408 MHz and 2.30 GHz.
> > >                       The governor "schedutil" may decide which speed to use
> > >                       within this range.
> > >       current CPU frequency: 1.61 GHz (asserted by call to hardware)
> > >     user@...xie:~$ uname -a
> > >     Linux trixie 6.15.0-11173-g546b1c9e93c2 #2 SMP PREEMPT Wed Jun  4 20:32:52 CEST 2025 aarch64 GNU/Linux
> >
> > Frequencies are fine, but I don't think the more power hungry big CPU
> > cluster gets any voltage scaling without it. Once I try to load the
> > system enough that the governor decides to bump the big cluster
> > frequency up, the regulator stays at 850000 microvolts, causing random
> > reboots when the whole cluster starts starving. With the patch,
> > voltage oscillates between 700000-737000 microvolts in idle and jumps
> > up to 950000 under load, and the system seems stable.
>
> Okay, that sounds pretty serious and in this case you should add the
> following tag at the end of the commit message, usually as the first
> thing after the line break:
>
>   Fixes: 40f742b07ab2 ("arm64: dts: rockchip: Add rk3576-armsom-sige5 board")
>
> That way, our stable kernel robot overlords will pick it up and
> backport it to the kernels that already contain the mentioned commit.

Will do, thanks!

Best regards,
Alexey