[PATCH 1/2] dt-bindings: gpu: Add Mali Utgard bindings

[robh+dt@kernel.org (Rob Herring)]

On Fri, Jan 20, 2017 at 3:16 AM, Maxime Ripard
<maxime.ripard@free-electrons.com> wrote:
> Hi John,
>
> On Thu, Jan 19, 2017 at 11:24:38AM -0800, John Stultz wrote:
>> On Mon, Jan 16, 2017 at 5:24 AM, Maxime Ripard
>> <maxime.ripard@free-electrons.com> wrote:
>> > The ARM Mali Utgard GPU family is embedded into a number of SoCs from
>> > Allwinner, Amlogic, Mediatek or Rockchip.
>> >
>> > Add a binding for the GPU of that family.
>> >
>> > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
>> > ---
>> >  .../devicetree/bindings/gpu/arm,mali-utgard.txt    | 76 ++++++++++++++++++++++
>> >  1 file changed, 76 insertions(+)
>> >  create mode 100644 Documentation/devicetree/bindings/gpu/arm,mali-utgard.txt
>> >
>> > diff --git a/Documentation/devicetree/bindings/gpu/arm,mali-utgard.txt b/Documentation/devicetree/bindings/gpu/arm,mali-utgard.txt
>> > new file mode 100644
>> > index 000000000000..df05ba0ec357
>> > --- /dev/null
>> > +++ b/Documentation/devicetree/bindings/gpu/arm,mali-utgard.txt
>> > @@ -0,0 +1,76 @@
>> > +ARM Mali Utgard GPU
>> > +===================
>> > +
>> > +Required properties:
>> > +  - compatible:
>> > +    * "arm,mali-utgard" and one of the following:
>> > +      + "arm,mali-300"
>> > +      + "arm,mali-400"
>> > +      + "arm,mali-450"
>> > +
>> > +  - reg: Physical base address and length of the GPU registers
>> > +
>> > +  - interrupts: an entry for each entry in interrupt-names.
>> > +    See ../interrupt-controller/interrupts.txt for details.
>> > +
>> > +  - interrupt-names:
>> > +    * ppX: Pixel Processor X interrupt (X from 0 to 7)
>> > +    * ppmmuX: Pixel Processor X MMU interrupt (X from 0 to 7)
>> > +    * pp: Pixel Processor broadcast interrupt (mali-450 only)
>> > +    * gp: Geometry Processor interrupt
>> > +    * gpmmu: Geometry Processor MMU interrupt
>> > +
>> > +
>> > +Optional properties:
>> > +  - interrupt-names:
>> > +    * pmu: Power Management Unit interrupt, if implemented in hardware
>> > +
>> > +Vendor-specific bindings
>> > +------------------------
>> > +
>> > +The Mali GPU is integrated very differently from one SoC to
>> > +another. In order to accommodate those differences, you have the option
>> > +to specify one more vendor-specific compatible, among:
>> > +
>> > +  - allwinner,sun4i-a10-mali
>> > +    Required properties:
>> > +      * clocks: an entry for each entry in clock-names
>> > +      * clock-names:
>> > +        + bus: bus clock for the GPU
>> > +        + core: clock driving the GPU itself
>> > +      * resets: phandle to the reset line for the GPU
>> > +
>> > +  - allwinner,sun7i-a20-mali
>> > +    Required properties:
>> > +      * clocks: an entry for each entry in clock-names
>> > +      * clock-names:
>> > +        + bus: bus clock for the GPU
>> > +        + core: clock driving the GPU itself
>> > +      * resets: phandle to the reset line for the GPU
>> > +
>> > +Example:
>> > +
>> > +mali: gpu at 01c40000 {
>> > +       compatible = "allwinner,sun7i-a20-mali", "arm,mali-400",
>> > +                    "arm,mali-utgard";
>> > +       reg = <0x01c40000 0x10000>;
>> > +       interrupts = <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>,
>> > +                    <GIC_SPI 98 IRQ_TYPE_LEVEL_HIGH>,
>> > +                    <GIC_SPI 99 IRQ_TYPE_LEVEL_HIGH>,
>> > +                    <GIC_SPI 100 IRQ_TYPE_LEVEL_HIGH>,
>> > +                    <GIC_SPI 102 IRQ_TYPE_LEVEL_HIGH>,
>> > +                    <GIC_SPI 103 IRQ_TYPE_LEVEL_HIGH>,
>> > +                    <GIC_SPI 101 IRQ_TYPE_LEVEL_HIGH>;
>> > +       interrupt-names = "gp",
>> > +                         "gpmmu",
>> > +                         "pp0",
>> > +                         "ppmmu0",
>> > +                         "pp1",
>> > +                         "ppmmu1",
>> > +                         "pmu";
>> > +       clocks = <&ccu CLK_BUS_GPU>, <&ccu CLK_GPU>;
>> > +       clock-names = "bus", "core";
>> > +       resets = <&ccu RST_BUS_GPU>;
>> > +};
>>
>> Having a mali utgard binding upstream would be great. However I'm a
>> little worried that the mali driver I've used sort of only half way
>> uses DT, and still requires a custom built in platform driver to setup
>> numerous other things.  Curious if you have a pointer to the kernel
>> driver you've been using with the vendor specific bindings above?  I'd
>> like to try to adapt what we have to your method to validate the above
>> as generic.
>
> I've created a custom platform driver, so just like you it seems,
> because I've not managed to make ARM's DT support work.
>
> https://github.com/mripard/sunxi-mali/blob/master/driver/src/devicedrv/mali/platform/sunxi/sunxi.c
>
> I haven't updated it yet with the bindings suggested above, but only
> the interrupt and clock names have changed. The rest very much
> applies.
>
> The only thing that might be vendor specific would be the (optional)
> declaration of the mali_gpu_device_data structure. As far as I know,
> there's two things of importance there:
>   - the list of the valid OPPs in order to do DVFS, but that could be
>     made generic too using the operating-points binding
>
>   - And the valid area for the buffers for the fbdev blobs (fb_start,
>     fb_size and shared_mem_size). I'm not entirely happy with this one
>     so far (which is also why I've not pushed it). We'd need to come
>     up with a way to get the base address and size of the CMA region
>     backing the framebuffer allocation, but I haven't find any trivial
>     way to do so, so for now I just hardcoded it. Worst case scenario,
>     we can hardcode values based on the compatible.

memory-region property?

>
>> And, just for context, here's the node we've been using with hikey:
>>
>>                 mali:mali at f4080000 {
>>                         compatible = "arm,mali-450", "arm,mali-utgard";
>>                         reg = <0x0 0x3f100000 0x0 0x00708000>;
>
> This is because the hikey is using a 64 bits CPU, right?

Having 2 cells for address and size is generally entirely pointless.
The peripheral regions generally don't need 64-bits of address space
or size. ranges should be used.

Rob