Re: [PATCH v7 0/4] qcom-cpufreq-hw: Add CPU clock provider support

From: Manivannan Sadhasivam
Date: Mon Nov 21 2022 - 01:45:17 EST


On Mon, Nov 21, 2022 at 10:49:59AM +0530, Viresh Kumar wrote:
> On 17-11-22, 11:01, Manivannan Sadhasivam wrote:
> > Hello,
> >
> > This series adds clock provider support to the Qcom CPUFreq driver for
> > supplying the clocks to the CPU cores in Qcom SoCs.
> >
> > The Qualcomm platforms making use of CPUFreq HW Engine (EPSS/OSM) supply
> > clocks to the CPU cores. But this is not represented clearly in devicetree.
> > There is no clock coming out of the CPUFreq HW node to the CPU. This created
> > an issue [1] with the OPP core when a recent enhancement series was submitted.
> > Eventhough the issue got fixed in the OPP framework in the meantime, that's
> > not a proper solution and this series aims to fix it properly.
> >
> > There was also an attempt made by Viresh [2] to fix the issue by moving the
> > clocks supplied to the CPUFreq HW node to the CPU. But that was not accepted
> > since those clocks belong to the CPUFreq HW node only.
> >
> > The proposal here is to add clock provider support to the Qcom CPUFreq HW
> > driver to supply clocks to the CPUs that comes out of the EPSS/OSM block.
> > This correctly reflects the hardware implementation.
> >
> > The clock provider is a simple one that just provides the frequency of the
> > clocks supplied to each frequency domain in the SoC using .recalc_rate()
> > callback. The frequency supplied by the driver will be the actual frequency
> > that comes out of the EPSS/OSM block after the DCVS operation. This frequency
> > is not same as what the CPUFreq framework has set but it is the one that gets
> > supplied to the CPUs after throttling by LMh.
> >
> > This series has been tested on SM8450 based dev board with the OPP hack removed
> > and hence there is a DTS change only for that platform. Once this series gets
> > accepted, rest of the platform DTS can also be modified and finally the hack on
> > the OPP core can be dropped.
>
> Applied. Thanks.
>
> If you get review comments later on, please send incremental patches
> for that.
>

Sure thing.

Thanks,
Mani

> --
> viresh

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