Re: [PATCH v4 2/2] ARM: dts: sun8i-r40: add opp table for cpu

[qianfan]

在 2022/5/16 16:53, Maxime Ripard 写道:
> On Mon, May 16, 2022 at 10:15:16AM +0800, qianfanguijin@xxxxxxx wrote:
> > From: qianfan Zhao <qianfanguijin@xxxxxxx>
> >
> > OPP table value is get from allwinner lichee linux-3.10 kernel driver
> >
> > Signed-off-by: qianfan Zhao <qianfanguijin@xxxxxxx>
> > ---
> >   arch/arm/boot/dts/sun8i-r40.dtsi | 42 ++++++++++++++++++++++++++++++++
> >   1 file changed, 42 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/sun8i-r40.dtsi b/arch/arm/boot/dts/sun8i-r40.dtsi
> > index 291f4784e86c..8949153eb0eb 100644
> > --- a/arch/arm/boot/dts/sun8i-r40.dtsi
> > +++ b/arch/arm/boot/dts/sun8i-r40.dtsi
> > @@ -54,6 +54,36 @@ / {
> >   	#size-cells = <1>;
> >   	interrupt-parent = <&gic>;
> >   
> > +	cpu0_opp_table: opp_table0 {
> > +		compatible = "operating-points-v2";
> > +		opp-shared;
> > +
> > +		opp-720000000 {
> > +			opp-hz = /bits/ 64 <720000000>;
> > +			opp-microvolt = <1000000 1000000 1300000>;
> > +			clock-latency-ns = <2000000>;
> > +		};
> > +
> > +		opp-912000000 {
> > +			opp-hz = /bits/ 64 <912000000>;
> > +			opp-microvolt = <1100000 1100000 1300000>;
> > +			clock-latency-ns = <2000000>;
> > +		};
> > +
> > +		opp-1008000000 {
> > +			opp-hz = /bits/ 64 <1008000000>;
> > +			opp-microvolt = <1160000 1160000 1300000>;
> > +			clock-latency-ns = <2000000>;
> > +		};
> > +
> > +		/* The opp table of the cpu frequency that exceeds 1G
> > +		 * is not defined here. They require higher operating
> > +		 * current, which may exceed the 500mA limited if the
> > +		 * system is powered by USB. You can add them to the
> > +		 * board's DTS is you make sure.
> > +		 */
> That's not the issue though. The issue is that the board is setup with a
> CPU voltage at 1160mV, and if we raise the frequency to a higher OPP
> without raising the voltage as well, the CPU will crash.
Yes, this is a issue and if the dts doesn't has "cpu-supply" node.
The comment above is found while testing. 100% cpu load @ 4x1.2G
will consume about 800mA@5V current, the board will reboot if it
is powered by USB. So I leave those comments.

I am thinking your suggestion to write the opp part to a dtsi like
A64. Should I adding all supported freq?

I am preparing a new version which including cpu cooling.
> Maxime