Re: [RFC 3/3] arm64: dts: renesas: r8a774a1: Add GPU Node

[Adam Ford <aford173@gmail.com>]

On Wed, Jun 7, 2023 at 8:21 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Adam,
>
> 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.

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

adam
>
> 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