Re: [PATCH v6 2/9] doc: DT: venus: binding document for Qualcomm video driver

[Stanimir Varbanov]

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