Re: [PATCH v2 2/2] [RFC] CPUFreq: Add support for cpu-perf-dependencies

Sudeep Holla
2020-10-12T16:03:01Z

On Mon, Oct 12, 2020 at 11:22:57AM +0100, Lukasz Luba wrote:
[...]

>
> True, the SCMI clock does not support discovery of clock tree:
> (from 4.6.1 Clock management protocol background)
> 'The protocol does not cover discovery of the clock tree, which must be
> described through firmware tables instead.' [1]
>

By firmware, spec refers to DT or ACPI, just to be clear.

> In this situation, would it make sense, instead of this binding from
> patch 1/2, create a binding for internal firmware/scmi node?
>

Why ? I prefer to solve this in a generic way and make it not scmi
specific issue. If OPP idea Viresh suggested can be made to work, that
would be good.

> Something like:
>
> firmware {
> scmi {
> ...
> scmi-perf-dep {
> compatible = "arm,scmi-perf-dependencies";
> cpu-perf-dep0 {
> cpu-perf-affinity = <&CPU0>, <&CPU1>;
> };
> cpu-perf-dep1 {
> cpu-perf-affinity = <&CPU3>, <&CPU4>;
> };
> cpu-perf-dep2 {
> cpu-perf-affinity = <&CPU7>;
> };
> };
> };
> };
>
> The code which is going to parse the binding would be inside the
> scmi perf protocol code and used via API by scmi-cpufreq.c.
>

Not completely against it, just need to understand how is this solved
or will be solved for any DT(non SCMI) and why it can be generic.

--
Regards,
Sudeep