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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Wed, 7 Jun 2023 15:44:58 +0200
Message-ID: <CAMuHMdX9vrnwZ5cA1_u9MtRetME-wt+BaaU=JX=Yc4jeJb9H9g@mail.gmail.com>
Subject: Re: [RFC 3/3] arm64: dts: renesas: r8a774a1: Add GPU Node
To:     Adam Ford <aford173@gmail.com>
Cc:     linux-renesas-soc@vger.kernel.org, biju.das.jz@bp.renesas.com,
        marek.vasut+renesas@gmail.com, cstevens@beaconembedded.com,
        aford@beaconembedded.com, Magnus Damm <magnus.damm@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org
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Hi Adam,

On Wed, Jun 7, 2023 at 3:31 PM Adam Ford <aford173@gmail.com> wrote:
> On Wed, Jun 7, 2023 at 8:21 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > On Tue, May 30, 2023 at 1:21 PM Adam Ford <aford173@gmail.com> wrote:
> > > With the 3dge and ZG clocks now available, the generic GPU node can
> > > be added.  Until proper firmware is made, it is not usable.
> > >
> > > Signed-off-by: Adam Ford <aford173@gmail.com>
> > > ---
> > > This is based on the assumption that the Rogue 6250 could use
> > > generic driver [1] and firmware [2] being implemebted by the Mesa group
> > > and others.  In practice, the firmware isn't really compatible since
> > > the 6250 in the RZ/G2M appears to be a different variant.
> > >
> > > [1] - https://gitlab.freedesktop.org/frankbinns/powervr/-/tree/powervr-next
> > > [2] - https://gitlab.freedesktop.org/frankbinns/linux-firmware/-/tree/powervr/powervr
> >
> > Thanks for your patch!
> >
> > > --- a/arch/arm64/boot/dts/renesas/r8a774a1.dtsi
> > > +++ b/arch/arm64/boot/dts/renesas/r8a774a1.dtsi
> > > @@ -226,6 +226,27 @@ extalr_clk: extalr {
> > >                 clock-frequency = <0>;
> > >         };
> > >
> > > +       gpu_opp_table: opp-table {
> > > +               compatible = "operating-points-v2";
> > > +
> > > +               opp-200000000 {
> > > +                       opp-hz = /bits/ 64 <200000000>;
> > > +                       opp-microvolt = <830000>;
> > > +               };
> > > +               opp-300000000 {
> > > +                       opp-hz = /bits/ 64 <300000000>;
> > > +                       opp-microvolt = <830000>;
> > > +               };
> > > +               opp-400000000 {
> > > +                       opp-hz = /bits/ 64 <400000000>;
> > > +                       opp-microvolt = <830000>;
> > > +               };
> > > +               opp-600000000 {
> > > +                       opp-hz = /bits/ 64 <600000000>;
> > > +                       opp-microvolt = <830000>;
> > > +               };
> > > +       };
> > > +
> > >         /* External PCIe clock - can be overridden by the board */
> > >         pcie_bus_clk: pcie_bus {
> > >                 compatible = "fixed-clock";
> > > @@ -2347,6 +2368,18 @@ gic: interrupt-controller@f1010000 {
> > >                         resets = <&cpg 408>;
> > >                 };
> > >
> > > +               gpu@fd000000 {
> > > +                       compatible = "img,powervr-series6xt";
> > > +                       reg = <0 0xfd000000 0 0x40000>;
> > > +                       interrupts = <GIC_SPI 119 IRQ_TYPE_LEVEL_HIGH>;
> > > +                       clocks = <&cpg CPG_MOD 112>, <&cpg CPG_MOD 112>,<&cpg CPG_MOD 112>;
> > > +                       clock-names = "core", "mem", "sys";
> > > +                       interrupt-names = "gpu";
> > > +                       operating-points-v2 = <&gpu_opp_table>;
> > > +                       power-domains = <&sysc R8A774A1_PD_3DG_B>;
> > > +                       resets = <&cpg 112>;
> > > +               };
> > > +
> > >                 pciec0: pcie@fe000000 {
> > >                         compatible = "renesas,pcie-r8a774a1",
> > >                                      "renesas,pcie-rcar-gen3";
> >
> > LGTM.  But obviously I cannot take this as-is, as there are no DT bindings
> > for this device, and it didn't work for you...
>
> It was mostly to follow up to the previous ones with links for the
> mainline Rogue video driver in the hopes that someone from Renesas
> might have some input on whether or not Renesas might be able to
> support this and have a discussion.  I knew when I submitted it that
> it wouldn't be accepted which is why I posted it as an RFC.
> If I address concerns you have in the previous patches, would you be
> OK with me submitting then as a formal patch to at least get the rest
> of the system ready in the event the GPU driver/firmware becomes
> available?  It seems harmless, but I also see the argument that it's
> dead code without the GPU node.

The clock patches are almost there, and I'm happy to accept them
when the last rough edges have been removed.

> If not, I'll shelve this for now, and hope to get some responses from Renesas.

Good luck! ;-)

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds