Re: Re: [PATCH v4 3/5] arm64: dts: allwinner: h6: Add GPU OPP table

Dne torek, 06. september 2022 ob 21:26:34 CEST je Clément Péron napisal(a):

Hi Jernej,

On Tue, 6 Sept 2022 at 21:10, Jernej Škrabec [off-list ref] 

wrote:

quoted

Dne torek, 06. september 2022 ob 17:30:32 CEST je Clément Péron 

napisal(a):

quoted

quoted

Add an Operating Performance Points table for the GPU to
enable Dynamic Voltage & Frequency Scaling on the H6.

The voltage range is set with minimal voltage set to the target
and the maximal voltage set to 1.2V. This allow DVFS framework to
work properly on board with fixed regulator.

Signed-off-by: Clément Péron <redacted>
---

 .../boot/dts/allwinner/sun50i-h6-gpu-opp.dtsi | 87 +++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 arch/arm64/boot/dts/allwinner/sun50i-h6-gpu-opp.dtsi

diff --git a/arch/arm64/boot/dts/allwinner/sun50i-h6-gpu-opp.dtsi

b/arch/arm64/boot/dts/allwinner/sun50i-h6-gpu-opp.dtsi new file mode
100644
index 000000000000..b48049c4fc85

--- /dev/null
+++ b/arch/arm64/boot/dts/allwinner/sun50i-h6-gpu-opp.dtsi

@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+// Copyright (C) 2022 Clément Péron <peron.clem@gmail.com>
+
+/ {
+     gpu_opp_table: opp-table-gpu {
+             compatible = "operating-points-v2";
+
+             opp-216000000 {
+                     opp-hz = /bits/ 64 <216000000>;
+                     opp-microvolt = <810000 810000 1200000>;
+             };
+
+             opp-264000000 {
+                     opp-hz = /bits/ 64 <264000000>;
+                     opp-microvolt = <810000 810000 1200000>;
+             };

As mentioned in clock patch review, rates below 288 MHz are deemed
unstable on GPU PLL by vendor GPU kernel driver. At least in the BSP
version that I have. Did you test these points? If not, better to drop
them.

I changed the governor to userspace and set the freq to 216MHz / 264MHz
Run glmark2 and didn't observe any glitch nor issue.

I'm not sure if it's enough to say it's stable but I didn't observe
any strange behavior.

Ok then.

Forgot to ask, where did you get 1.2 V as an upper limit? H6 datasheet lists 
max. GPU voltage as 1.08 V.

Best regards,
Jernej

Regards,
Clement

quoted

Best regards,
Jernej

quoted

+
+             opp-312000000 {
+                     opp-hz = /bits/ 64 <312000000>;
+                     opp-microvolt = <810000 810000 1200000>;
+             };
+
+             opp-336000000 {
+                     opp-hz = /bits/ 64 <336000000>;
+                     opp-microvolt = <810000 810000 1200000>;
+             };
+
+             opp-360000000 {
+                     opp-hz = /bits/ 64 <360000000>;
+                     opp-microvolt = <820000 820000 1200000>;
+             };
+
+             opp-384000000 {
+                     opp-hz = /bits/ 64 <384000000>;
+                     opp-microvolt = <830000 830000 1200000>;
+             };
+
+             opp-408000000 {
+                     opp-hz = /bits/ 64 <408000000>;
+                     opp-microvolt = <840000 840000 1200000>;
+             };
+
+             opp-420000000 {
+                     opp-hz = /bits/ 64 <420000000>;
+                     opp-microvolt = <850000 850000 1200000>;
+             };
+
+             opp-432000000 {
+                     opp-hz = /bits/ 64 <432000000>;
+                     opp-microvolt = <860000 860000 1200000>;
+             };
+
+             opp-456000000 {
+                     opp-hz = /bits/ 64 <456000000>;
+                     opp-microvolt = <870000 870000 1200000>;
+             };
+
+             opp-504000000 {
+                     opp-hz = /bits/ 64 <504000000>;
+                     opp-microvolt = <890000 890000 1200000>;
+             };
+
+             opp-540000000 {
+                     opp-hz = /bits/ 64 <540000000>;
+                     opp-microvolt = <910000 910000 1200000>;
+             };
+
+             opp-576000000 {
+                     opp-hz = /bits/ 64 <576000000>;
+                     opp-microvolt = <930000 930000 1200000>;
+             };
+
+             opp-624000000 {
+                     opp-hz = /bits/ 64 <624000000>;
+                     opp-microvolt = <950000 950000 1200000>;
+             };
+
+             opp-756000000 {
+                     opp-hz = /bits/ 64 <756000000>;
+                     opp-microvolt = <1040000 1040000 1200000>;
+             };
+     };
+};
+
+&gpu {
+     operating-points-v2 = <&gpu_opp_table>;
+};
--
2.34.1

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