On Fri, Oct 25, 2019 at 5:51 PM John Stultz <john.stultz@xxxxxxxxxx> wrote:
>
> This binding specifies which CMA regions should be added to the
> dmabuf heaps interface.
Is this an ION DT binding in disguise? I thought I killed that. ;)
>
> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Laura Abbott <labbott@xxxxxxxxxx>
> Cc: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>
> Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
> Cc: Liam Mark <lmark@xxxxxxxxxxxxxx>
> Cc: Pratik Patel <pratikp@xxxxxxxxxxxxxx>
> Cc: Brian Starkey <Brian.Starkey@xxxxxxx>
> Cc: Andrew F. Davis <afd@xxxxxx>
> Cc: Chenbo Feng <fengc@xxxxxxxxxx>
> Cc: Alistair Strachan <astrachan@xxxxxxxxxx>
> Cc: Sandeep Patil <sspatil@xxxxxxxxxx>
> Cc: Hridya Valsaraju <hridya@xxxxxxxxxx>
> Cc: devicetree@xxxxxxxxxxxxxxx
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
> ---
> .../bindings/dma/dmabuf-heap-cma.txt | 31 +++++++++++++++++++
> 1 file changed, 31 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/dma/dmabuf-heap-cma.txt
>
> diff --git a/Documentation/devicetree/bindings/dma/dmabuf-heap-cma.txt b/Documentation/devicetree/bindings/dma/dmabuf-heap-cma.txt
> new file mode 100644
> index 000000000000..bde7b1f1c269
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/dmabuf-heap-cma.txt
> @@ -0,0 +1,31 @@
> +* DMA-BUF CMA Heap
> +
> +Specifies a CMA region that should be added to the dma-buf heaps
> +interface.
> +
> +Required properties:
> +- compatible: Must be "dmabuf-heap-cma"
> +- memory-region: phandle to a CMA reserved memory node
> +
> +Example:
> +This example has a camera CMA node in reserved memory, which is then
> +referenced by the dmabuf-heap-cma node.
> +
> +
> + reserved-memory {
> + #address-cells = <2>;
> + #size-cells = <2>;
> + ranges;
> + ...
> + cma_camera: cma-camera {
> + compatible = "shared-dma-pool";
> + reg = <0x0 0x24C00000 0x0 0x4000000>;
> + reusable;
> + };
> + ...
> + };
> +
> + cma_heap {
> + compatible = "dmabuf-heap-cma";
> + memory-region = <&cma_camera>;
Why the indirection here? Can't you just add a flag property to
reserved-memory nodes like we do to flag CMA nodes?
As I suspected, it's because in patch 2 you're just abusing DT to
instantiate platform devices. We already support binding drivers to
reserved-memory nodes directly.
Rob
