Re: [PATCH v7 6/9] interconnect: qcom: rpm: Handle interface clocks

Bryan O'Donoghue
2023-03-11T14:29:56Z

On 11/03/2023 14:01, Dmitry Baryshkov wrote:
>>
>> Limit the number of bus_clocks to 2 (which is the maximum that SMD
>> RPM interconnect supports anyway) and handle non-scaling clocks
>> separately. Update MSM8996 and SDM660 drivers to make sure they do
>> not regress with this change.
>>
>> This unfortunately has to be done in one patch to prevent either
>> compile errors or broken bisect.
>
> Can we determine somehow if the intf clocks are required for the whole
> NoC or just for a single node? I don't think that clocks like a0noc_ufs
> are requiered to be up for the whole aggre_noc. Instead they probably
> have to be enabled only when UFS makes use of the NoC (in other words
> when is has voted for the bandwidth).

Its probably worthwhile experimenting to see if the *ufs*_clk can/should
be added to the UFS device list of clocks.

I hadn't realised we were talking about enabling the intf clocks always
but, actually that is what we are talking about isn't it ?

It seems pretty unlikely that other devices would depend on clocks named
*ufs*

OTOH "clk-aggre2-noc-clk-no-rate" may be used across different nodes,
seems like a pretty generic name, though still suspicious it is bundled
with UFS, likely it is only required for UFS ?!?

Konrad can you try:

1. Moving the intf_clks/QoS clocks be contained to UFS alone ?
2. If that doesn't work just the *ufs* clocks be put there with
2a. "clk-aggre2-noc-clk-no-rate" alone added to the intf_clk list

It seems wrong to be enabling ufs related NoC clocks unless we are
actually switching on UFS.

---
bod