Thread (5 messages) 5 messages, 3 authors, 2018-08-13

Re: [PATCH] arm64: dts: rockchip: Add idle-states to device tree for rk3399

From: Heiko Stuebner <hidden>
Date: 2018-08-09 20:10:06
Also in: linux-arm-kernel, linux-rockchip, lkml

Am Mittwoch, 6. Juli 2016, 10:20:54 CEST schrieb Caesar Wang:
As the rk3399 ATF had been supported on ARM github [0], so we can add
idle-states for rk3399.
This patch adds idle-states bindings data collected through tests
experiments (latency and energy consumption) on rk3399 evb2 board.

You can see detail idle-states definitions on document [1].

* arm,psci-suspend-param: power_state parameter to pass to the PSCI
  suspend call.
* entry-latency: Worst case latency required to enter the idle state. The
  exit-latency may be guaranteed only after entry-latency has passed.
* min-residency: Minimum period, including preparation and entry, for a
  given idle state to be worthwhile energywise
* min-residency: Minimum period, including preparation and entry, for a
  given idle state to be worthwhile energywise.

[0]:
https://github.com/ARM-software/arm-trusted-firmware
[1]:
Documentation/devicetree/bindings/arm/psci.txt
Documentation/devicetree/bindings/arm/idle-states.txt

Signed-off-by: Caesar Wang <redacted>
Looks like this patch slipped through the cracks and nobody reposted
them over time.

quoted hunk ↗ jump to hunk
 arch/arm64/boot/dts/rockchip/rk3399.dtsi | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
diff --git a/arch/arm64/boot/dts/rockchip/rk3399.dtsi b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
index a6dd623..12ce265 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
@@ -101,6 +101,18 @@
 			};
 		};
 
+		idle-states {
+			entry-method = "psci";
+			cpu_sleep: cpu-sleep-0 {
+				compatible = "arm,idle-state";
+				local-timer-stop;
+				arm,psci-suspend-param = <0x0010000>;
+				entry-latency-us = <350>;
+				exit-latency-us = <600>;
+				min-residency-us = <1150>;
Looking at the chromeos kernel, there are some more patches adapting
this idle-state to use different timings.

There also was a cluster-idle state added for a while but that seems to
cause audio issues according to the CrOS history.

In any case, I'll try to look at this shortly.


Heiko
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