Thanks a lot for Vincent Guittot careful work to find bug for 'CPU_NAP'
idle state. From ftrace log we can observe CA73 CPUs can be easily
waken up from 'CPU_NAP' state but the 'waken up' CPUs doesn't handle
anything and sleep again; so there have tons of trace events for CA73
CPUs entering and exiting idle state.
On Hi3660 CA73 has retention state 'CPU_NAP' for CPU idle, this state we
set its psci parameter as '0x0000001' and from this parameter it can
calculate state id is 1. Unfortunately ARM trusted firmware (ARM-TF)
takes 1 as a invalid value for state id, so the CPU cannot enter idle
state and directly bail out to kernel.
We want to create good practice for psci parameters platform definition,
so review the psci specification. The spec "ARM Power State Coordination
Interface - Platform Design Document (ARM DEN 0022D)" recommends state
ID in chapter "6.5 Recommended StateID Encoding". The recommended power
state IDs can be presented by below listed values; and it divides into
three fields, every field can use 4 bits to present power states
corresponding to core level, cluster level and system level:
0: Run
1: Standby
2: Retention
3: Powerdown
This commit changes psci parameter to compliance with the suggested
state ID in the doc. Except we change 'CPU_NAP' state psci parameter
to '0x0000002', this commit also changes 'CPU_SLEEP' and 'CLUSTER_SLEEP'
state parameters to '0x0010003' and '0x1010033' respectively.
Credits to Daniel, Sudeep and Soby for suggestion and consolidation.
Cc: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Cc: Sudeep Holla <sudeep.holla@xxxxxxx>
Cc: Soby Mathew <Soby.Mathew@xxxxxxx>
Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx>
---
arch/arm64/boot/dts/hisilicon/hi3660.dtsi | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/boot/dts/hisilicon/hi3660.dtsi b/arch/arm64/boot/dts/hisilicon/hi3660.dtsi
index ab0b95b..99d5a46 100644
--- a/arch/arm64/boot/dts/hisilicon/hi3660.dtsi
+++ b/arch/arm64/boot/dts/hisilicon/hi3660.dtsi
@@ -147,7 +147,7 @@
CPU_NAP: cpu-nap {
compatible = "arm,idle-state";
- arm,psci-suspend-param = <0x0000001>;
+ arm,psci-suspend-param = <0x0000002>;
entry-latency-us = <7>;
exit-latency-us = <2>;
min-residency-us = <15>;
@@ -156,7 +156,7 @@
CPU_SLEEP: cpu-sleep {
compatible = "arm,idle-state";
local-timer-stop;
- arm,psci-suspend-param = <0x0010000>;
+ arm,psci-suspend-param = <0x0010003>;
entry-latency-us = <40>;
exit-latency-us = <70>;
min-residency-us = <3000>;
@@ -165,7 +165,7 @@
CLUSTER_SLEEP_0: cluster-sleep-0 {
compatible = "arm,idle-state";
local-timer-stop;
- arm,psci-suspend-param = <0x1010000>;
+ arm,psci-suspend-param = <0x1010033>;
entry-latency-us = <500>;
exit-latency-us = <5000>;
min-residency-us = <20000>;
@@ -174,7 +174,7 @@
CLUSTER_SLEEP_1: cluster-sleep-1 {
compatible = "arm,idle-state";
local-timer-stop;
- arm,psci-suspend-param = <0x1010000>;
+ arm,psci-suspend-param = <0x1010033>;
entry-latency-us = <1000>;
exit-latency-us = <5000>;
min-residency-us = <20000>;
--
2.7.4
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