Re: [PATCH v1 07/10] arm64: dts: qcom: ipq5332: populate the opp table based on the eFuse

From: Varadarajan Narayanan
Date: Thu Oct 05 2023 - 12:35:02 EST


On Thu, Oct 05, 2023 at 02:39:43PM +0300, Dmitry Baryshkov wrote:
> On Thu, 5 Oct 2023 at 12:58, Varadarajan Narayanan
> <quic_varada@xxxxxxxxxxx> wrote:
> >
> > On Thu, Sep 07, 2023 at 04:59:28PM +0300, Dmitry Baryshkov wrote:
> > > On Thu, 7 Sept 2023 at 08:23, Varadarajan Narayanan
> > > <quic_varada@xxxxxxxxxxx> wrote:
> > > >
> > > > IPQ53xx have different OPPs available for the CPU based on
> > > > SoC variant. This can be determined through use of an eFuse
> > > > register present in the silicon.
> > > >
> > > > Add support to read the eFuse and populate the OPPs based on it.
> > > >
> > > > Signed-off-by: Kathiravan T <quic_kathirav@xxxxxxxxxxx>
> > > > Signed-off-by: Varadarajan Narayanan <quic_varada@xxxxxxxxxxx>
> > > > ---
> > > > arch/arm64/boot/dts/qcom/ipq5332.dtsi | 34 +++++++++++++++++++++++++++++++---
> > > > 1 file changed, 31 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git a/arch/arm64/boot/dts/qcom/ipq5332.dtsi b/arch/arm64/boot/dts/qcom/ipq5332.dtsi
> > > > index 82761ae..3ca3f34 100644
> > > > --- a/arch/arm64/boot/dts/qcom/ipq5332.dtsi
> > > > +++ b/arch/arm64/boot/dts/qcom/ipq5332.dtsi
> > > > @@ -91,11 +91,34 @@
> > > > };
> > > >
> > > > cpu_opp_table: opp-table-cpu {
> > > > - compatible = "operating-points-v2";
> > > > + compatible = "operating-points-v2-kryo-cpu";
> > > > opp-shared;
> > > > + nvmem-cells = <&cpu_speed_bin>;
> > > > + nvmem-cell-names = "speed_bin";
> > > > +
> > > > + /*
> > > > + * Listed all supported CPU frequencies and opp-supported-hw
> > > > + * values to select CPU frequencies based on the limits fused.
> > > > + * ------------------------------------------------------------
> > > > + * Frequency BIT3 BIT2 BIT1 BIT0 opp-supported-hw
> > > > + * 1.0GHz 1.2GHz 1.5GHz No Limit
> > > > + * ------------------------------------------------------------
> > > > + * 1100000000 1 1 1 1 0xF
> > > > + * 1500000000 0 0 1 1 0x3
> > > > + * -----------------------------------------------------------
> > > > + */
> > >
> > > This can probably go to the commit message instead.
> >
> > Ok
> >
> > > > +
> > > > + opp-1100000000 {
> > > > + opp-hz = /bits/ 64 <1100000000>;
> > >
> > > But your table shows 1.0 GHz and 1.2 GHz instead of 1.1 GHz
> >
> > Will update it.
> >
> > > > + opp-microvolt = <850000>;
> > > > + opp-supported-hw = <0xF>;
> > > > + clock-latency-ns = <200000>;
> > > > + };
> > > >
> > > > - opp-1488000000 {
> > > > - opp-hz = /bits/ 64 <1488000000>;
> > > > + opp-1500000000 {
> > > > + opp-hz = /bits/ 64 <1500000000>;
> > >
> > > So, 1.488 GHz or 1.5 GHz?
> >
> > 1.5 GHz
> >
> > > > + opp-microvolt = <950000>;
> > >
> > > Which regulator is controlled by this microvolt?
> >
> > Based on the SKU, the XBL sets up the regulator to provide 950000uV
> > on CPUs capable of running 1.5G and 850000uV on other SKUs. Linux
> > doesn't control it.
>
> Then why do you need this property here in the first place?

I get these errors without this property

[ 1.018065] cpu cpu0: opp_parse_microvolt: opp-microvolt missing although OPP managing regulators
[ 1.018074] cpu cpu0: _of_add_opp_table_v2: Failed to add OPP, -22

Thanks
Varada