[PATCH 0/3] arm64: dts: qcom: sa8775p: Add interconnect to SMMU

[Konrad Dybcio]

On 9.06.2023 16:45, Robin Murphy wrote:
> On 2023-06-09 13:56, Parikshit Pareek wrote:
>> On Fri, Jun 09, 2023 at 10:52:26AM +0200, Konrad Dybcio wrote:
>>>
>>>
>>> On 9.06.2023 07:41, Parikshit Pareek wrote:
>>>> Some qcom SoCs have SMMUs, which need the interconnect bandwidth to be
>>>> This series introduce the due support for associated interconnect, and
>>>> setting of the due interconnect-bandwidth. Setting due interconnect
>>>> bandwidth is needed to avoid the issues like [1], caused by not having
>>>> due clock votes(indirectly dependent upon interconnect bandwidth).
>>>
>>> [1] ???
>>
>> My bad. Intended to mention following:
>> https://lore.kernel.org/linux-arm-msm/20230418165224.vmok75fwcjqdxspe@echanude/
> 
> This sounds super-dodgy - do you really have to rely on configuration of the interconnect path from the SMMU's pagetable walker to RAM to keep a completely different interconnect path clocked for the CPU to access SMMU registers? You can't just request the programming interface clock directly like on other SoCs?
On Qualcomm platforms, particularly so with the more recent ones, some
clocks are managed by various remote cores. Half of what the interconnect
infra does on these SoCs is telling one such core to change the internally
managed clock's rate based on the requested bw.

Konrad
> 
> Thanks,
> Robin.