linux-kernel - Re: [PATCH] ARM: dts: add 533 MHz step to p4note GPU opp table

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Date:   Mon, 31 Jan 2022 12:36:15 +0100
From:   Martin Jücker <martin.juecker@...il.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
Cc:     Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
        Martin Jücker <martin.juecker@...il.com>
Subject: Re: [PATCH] ARM: dts: add 533 MHz step to p4note GPU opp table

On Mon, Jan 31, 2022 at 09:54:00AM +0100, Krzysztof Kozlowski wrote:
> On 29/01/2022 23:14, Martin Jücker wrote:
> > The p4note devices support 533 MHz GPU speed, so let's make use of it.
> > 
> 
> If there is going to be resend, please add prefix "exynos:" in subject.
> Just like other commits (git log --oneline arch/arm/boot/dts/exynos*).
> 

Okay.

> > Signed-off-by: Martin Jücker <martin.juecker@...il.com>
> > ---
> >  arch/arm/boot/dts/exynos4412-p4note.dtsi | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/arch/arm/boot/dts/exynos4412-p4note.dtsi b/arch/arm/boot/dts/exynos4412-p4note.dtsi
> > index 4ae6eb3091c4..d277b2337ae0 100644
> > --- a/arch/arm/boot/dts/exynos4412-p4note.dtsi
> > +++ b/arch/arm/boot/dts/exynos4412-p4note.dtsi
> > @@ -355,6 +355,13 @@ &gpu {
> >  	status = "okay";
> >  };
> >  
> > +&gpu_opp_table {
> > +	opp-533000000 {
> > +		opp-hz = /bits/ 64 <533000000>;
> > +		opp-microvolt = <1075000>;
> > +	};
> > +};
> 
> This looks like Exynos4412 Prime. Please check also CPU frequencies and
> if they match, just include exynos4412-prime.dtsi (like Odroid U3).
> 

I thought so as well, but unfortunately it's not. The chip id is
0xe4412211 and according to the vendor kernel, the prime version would
need to have the last two digits being 0x20 or higher. See:

https://github.com/Viciouss/samsung_p4note_kernel_backup/blob/da306e1846bb4b9682f46be1b23b05d6fbebffba/arch/arm/mach-exynos/cpufreq-4x12.c#L619

On the other hand, this kernel has the 533 MHz step unlocked for all
versions:

https://github.com/Viciouss/samsung_p4note_kernel_backup/blob/da306e1846bb4b9682f46be1b23b05d6fbebffba/drivers/gpu/mali400/r3p2/mali/platform/pegasus-m400/exynos4_pmm.c#L88

> > +
> >  &hsotg {
> >  	vusb_a-supply = <&ldo12_reg>;
> >  	dr_mode = "peripheral";
> 
> 
> Best regards,
> Krzysztof

Kind Regards
Martin