Re: [PATCH v2] arm64: dts: monaco: extend fastrpc compute cb

[Ekansh Gupta]

On 3/30/2026 4:20 PM, Konrad Dybcio wrote:
> On 3/30/26 10:38 AM, Srinivas Kandagatla wrote:
>> On 3/27/26 1:10 PM, Konrad Dybcio wrote:
>>> On 3/26/26 4:41 PM, Srinivas Kandagatla wrote:
>>>> For some reason we ended up adding only 4 out of 11 compute cb's for
>>>> CDSP, add the missing compute cb. This will also improve the end
>>>> user-experience by enabling running multiple AI usecases in parallel.
>>>>
>>>> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxxxxxxxx>
>>>> ---
>>>>  arch/arm64/boot/dts/qcom/monaco.dtsi | 49 ++++++++++++++++++++++++++++
>>>>  1 file changed, 49 insertions(+)
>>>>
>>>> diff --git a/arch/arm64/boot/dts/qcom/monaco.dtsi b/arch/arm64/boot/dts/qcom/monaco.dtsi
>>>> index 10e799dd4a78..38fbd44c7d8f 100644
>>>> --- a/arch/arm64/boot/dts/qcom/monaco.dtsi
>>>> +++ b/arch/arm64/boot/dts/qcom/monaco.dtsi
>>>> @@ -7739,6 +7739,55 @@ compute-cb@4 {
>>>>  							 <&apps_smmu 0x1964 0x0400>;
>>>>  						dma-coherent;
>>>>  					};
>>>> +
>>>> +					compute-cb@5 {
>>>> +						compatible = "qcom,fastrpc-compute-cb";
>>>> +						reg = <5>;
>>>> +						iommus = <&apps_smmu 0x19c5 0x0400>;
>>> I see that the other CBs have 2 iommu streams, the other one
>>> having "DMA" in the name - could you shed some light on that?
>> AFAIU, These DMA streams are relevant when NPU dma engine is in the
>> picture, examples can be data pipelines which involve transferring data
>> buffers(in/out) in-cordination with different IP blocks outside DSP. May
>> be something like camera/video streams directly to NPU without CPU
>> involving...
>>
>> Personally I have not tested such usecases, but for upstream fastrpc
>> clients AFAIK only application streams matter as clients will explicitly
>> allocate the data buffers, even for sharing across ip-blocks.
> This would be nice to confirm somewhere, perhaps even denote in bindings
>
> +Ekansh could you confirm/speak more about this?
> +Dmitry for awareness

Yes, upon checking about this the details are in lines with what Srini has
mentioned. These streams are mostly used for video processing type scenarios
which is not required for this platform(as per internal discussion).

//Ekansh

>
> Konrad