RE: [PATCH V2 1/2] arm: dts: exynos: Add GPU/Mali T604 node to exynos5250

[Guillaume Gardet <Guillaume.Gardet@arm.com>]

> -----Original Message-----
> From: Krzysztof Kozlowski <krzk@kernel.org>
> Sent: 25 July 2019 14:27
> To: Guillaume Gardet <Guillaume.Gardet@arm.com>
> Cc: linux-samsung-soc@vger.kernel.org; Kukjin Kim <kgene@kernel.org>; linux-
> arm-kernel@lists.infradead.org
> Subject: Re: [PATCH V2 1/2] arm: dts: exynos: Add GPU/Mali T604 node to
> exynos5250
>
> On Thu, 25 Jul 2019 at 13:35, Guillaume Gardet <Guillaume.Gardet@arm.com>
> wrote:
> >
> >
> >
> > > -----Original Message-----
> > > From: Krzysztof Kozlowski <krzk@kernel.org>
> > > Sent: 25 July 2019 13:19
> > > To: Guillaume Gardet <Guillaume.Gardet@arm.com>
> > > Cc: linux-samsung-soc@vger.kernel.org; Kukjin Kim
> > > <kgene@kernel.org>; linux- arm-kernel@lists.infradead.org
> > > Subject: Re: [PATCH V2 1/2] arm: dts: exynos: Add GPU/Mali T604 node
> > > to
> > > exynos5250
> > >
> > > On Thu, 25 Jul 2019 at 10:34, Guillaume <guillaume.gardet@arm.com>
> wrote:
> > > >
> > > > From: Guillaume GARDET <guillaume.gardet@arm.com>
> > > >
> > > > Add nodes for GPU (Mali T604) to Exynos5250.
> > > > Tested with kmscube and glmark2-es2-drm on Chromebook snow.
> > > > Load tested on arndale board.
> > > >
> > > > Signed-off-by: Guillaume GARDET <guillaume.gardet@arm.com>
> > > >
> > > > Cc: Kukjin Kim <kgene@kernel.org>
> > > > Cc: Krzysztof Kozlowski <krzk@kernel.org>
> > > > Cc: linux-arm-kernel@lists.infradead.org
> > > > ---
> > > > V2 changes:
> > > >   * move mali node as /soc sub-node
> > > >   * move gpu_opp_table as mali sub-node
> > > >   * minor style updates
> > > >   * test on arndale board
> > > >   * enable by default
> > >
> > > I was not specific enough. It can stay disabled in the DTSI because
> > > not all resources are provided. The board DTSes (all or ones which
> > > are
> > > tested) will enable it and provide missing resources - mali-supply.
> >
> > I think all resources are provided, since no mali-supply property is needed here.
>
> No, regulator is not provided. On all Exynos boards Mali uses its own dedicated
> regulator (and sometimes additional one). It worked in your case because the
> regulator was set as always-on but this is a workaround for lack of consumers.
> Once there is a consumer, the regulator should not be always-on to save the
> energy when not used.

I do not have the required info here. Do you have it, or could I skip the mali-supply for now?

>
> > So, I can either enable it by default for all exynos5250 platforms there, or I can
> enable it only for Arndale board and Chromebook snow. What do you prefer?
>
> Then please enable it on tested platforms.

Ok.

>
> >
> > > Just like:
> > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/c
> > > ommit/?id=f
> > > 0a6208b90bdd44f48f5718c8bb0eb1e763d14c0
> > >
> > > >   * add dt bindings, in a separate patch
> > >
> > > Put the bindings before DTS change.
> >
> > Yes, makes sense.
> >
> > >
> > > >
> > > >  arch/arm/boot/dts/exynos5250.dtsi | 47
> > > > +++++++++++++++++++++++++++++++
> > > >  1 file changed, 47 insertions(+)
> > > >
> > > > diff --git a/arch/arm/boot/dts/exynos5250.dtsi
> > > > b/arch/arm/boot/dts/exynos5250.dtsi
> > > > index d5e0392b409e..f7f34d469bde 100644
> > > > --- a/arch/arm/boot/dts/exynos5250.dtsi
> > > > +++ b/arch/arm/boot/dts/exynos5250.dtsi
> > > > @@ -328,6 +328,52 @@
> > > >                         iommus = <&sysmmu_rotator>;
> > > >                 };
> > > >
> > > > +               mali: gpu@11800000 {
> > > > +                       compatible = "samsung,exynos5250-mali", "arm,mali-t604";
> > > > +                       reg = <0x11800000 0x5000>;
> > > > +                       interrupts = <GIC_SPI 118 IRQ_TYPE_LEVEL_HIGH>,
> > > > +                                    <GIC_SPI 119 IRQ_TYPE_LEVEL_HIGH>,
> > > > +                                    <GIC_SPI 117 IRQ_TYPE_LEVEL_HIGH>;
> > > > +                       interrupt-names = "job", "mmu", "gpu";
> > > > +                       clocks = <&clock CLK_G3D>;
> > > > +                       clock-names = "g3d";
> > >
> > > According to bindings this is not proper clock name. I wonder why it
> > > was working... it seems the driver expects first clock to be always the core
> clock.
> >
> > Yes, it works, because 1st clock is assumed to be the core clock.
> > Clock names are optional and could be omitted as in
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tre
> > e/arch/arm/boot/dts/rk3288.dtsi?h=v5.3-rc1#n1284
> > Not sure if it would be better to rename it to 'core', or  just skip it? Any opinion?
>
> The driver can change anytime and it might look for "core" so DTS should follow
> the bindings. Additionally, Panfrost might behave differently than Arm driver. So
> "core" please.

Ok.

Thanks,
Guillaume

>
> Best regards,
> Krzysztof
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