Re: [PATCH] arm64: dts: qcom: sm8750: add cpu OPP table with DDR and LLCC bandwidths

[Aaron Kling]

On Wed, Jun 17, 2026 at 5:41 AM Konrad Dybcio
<konrad.dybcio@xxxxxxxxxxxxxxxx> wrote:
>
> On 6/6/26 12:36 AM, Aaron Kling via B4 Relay wrote:
> > From: Aaron Kling <webgeek1234@xxxxxxxxx>
> >
> > Add the OPP tables for each CPU cluster (cpu0-1-2-3-4-5 & cpu6-7) to
> > permit scaling the Last Level Cache Controller (LLCC) and DDR frequency
> > by aggregating bandwidth requests of all CPU core with reference to the
> > current OPP they are configured in by the hardware.
> >
> > The effect is proper caches & DDR frequency scaling when CPU cores
> > change frequency.
> >
> > The OPP tables were built using the downstream memlat ddr & llcc tables
> > for each cluster types with the actual cpufreq LUT tables from running a
> > CQ8725S device.
> >
> > Also add the interconnect entry for each cpu, with 2 different paths:
> > - CPU to Last Level Cache Controller (LLCC)
> > - Last Level Cache Controller (LLCC) to DDR
> >
> > Signed-off-by: Aaron Kling <webgeek1234@xxxxxxxxx>
> > ---
> > arm64: dts: qcom: sm8750: add cpu OPP table with DDR and LLCC bandwidths
> > ---
>
> [...]
>
> > +     cpu6_opp_table: opp-table-cpu6 {
> > +             compatible = "operating-points-v2";
> > +             opp-shared;
> > +
> > +             opp-1017600000 {
> > +                     opp-hz = /bits/ 64 <1017600000>;
> > +                     opp-peak-kBps = <(1353000 * 16) (350000 * 4)>;
>
> I think this should be * 4 in both cases since the interconnect driver
> ignores the channel count for a node in peak voting. We may have a bug
> in all other DTs here.

If this is confirmed, I can update this patch. I based the
calculations on my sm8550 copy of this change, which in turn was based
on the sm8650 change. If this is wrong, that means one piece is
scaling 4x too quickly? Making it a power consumption issue, not a
performance issue.

> BTW, are there no lower OPPs for the fast cores?

Not on cq8725s at least. These lists came from an AYN Odin 3 with that
soc. I don't have any sm8750 proper devices to see if that's any
different.

Aaron