Hi Rob, On 02/22/2017 02:09 AM, Rob Herring wrote: > On Tue, Feb 07, 2017 at 03:10:17PM +0200, Stanimir Varbanov wrote: >> Add binding document for Venus video encoder/decoder driver >> >> Cc: Rob Herring <robh+dt@xxxxxxxxxx> >> Cc: devicetree@xxxxxxxxxxxxxxx >> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx> >> --- >> Changes since previous v5: >> * dropped rproc phandle (remoteproc is not used anymore) >> * added subnodes paragraph with descrition of three subnodes: >> - video-decoder and video-encoder - describes decoder (core0) and >> encoder (core1) power-domains and clocks (applicable for msm8996 >> Venus core). >> - video-firmware - needed to get reserved memory region where the >> firmware is stored. >> >> .../devicetree/bindings/media/qcom,venus.txt | 112 +++++++++++++++++++++ >> 1 file changed, 112 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/media/qcom,venus.txt >> >> diff --git a/Documentation/devicetree/bindings/media/qcom,venus.txt b/Documentation/devicetree/bindings/media/qcom,venus.txt >> new file mode 100644 >> index 000000000000..4427af3ca5a5 >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/media/qcom,venus.txt >> @@ -0,0 +1,112 @@ > > [...] > >> +* Subnodes >> +The Venus node must contain three subnodes representing video-decoder, >> +video-encoder and video-firmware. > > [...] > >> +The video-firmware subnode should contain: >> + >> +- memory-region: >> + Usage: required >> + Value type: <phandle> >> + Definition: reference to the reserved-memory for the memory region >> + >> +* An Example >> + video-codec@1d00000 { >> + compatible = "qcom,msm8916-venus"; >> + reg = <0x01d00000 0xff000>; >> + interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_HIGH>; >> + clocks = <&gcc GCC_VENUS0_VCODEC0_CLK>, >> + <&gcc GCC_VENUS0_AHB_CLK>, >> + <&gcc GCC_VENUS0_AXI_CLK>; >> + clock-names = "core", "iface", "bus"; >> + power-domains = <&gcc VENUS_GDSC>; >> + iommus = <&apps_iommu 5>; >> + >> + video-decoder { >> + compatible = "venus-decoder"; >> + clocks = <&mmcc VIDEO_SUBCORE0_CLK>; >> + clock-names = "core"; >> + power-domains = <&mmcc VENUS_CORE0_GDSC>; >> + }; >> + >> + video-encoder { >> + compatible = "venus-encoder"; >> + clocks = <&mmcc VIDEO_SUBCORE1_CLK>; >> + clock-names = "core"; >> + power-domains = <&mmcc VENUS_CORE1_GDSC>; >> + }; >> + >> + video-firmware { >> + memory-region = <&venus_mem>; > > Why does this need to be a sub node? Because firmware reserved memory region must have separate struct device, otherwise allocating video buffers (and map them through iommu) for video-codec will fail because dma_alloc_coherent trying to allocate from per-device coherent area. -- regards, Stan