From: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org
[ Upstream commit 3f1dcaff642e75c1d2ad03f783fa8a3b1f56dd50 ]
The entry/exit latency and minimum residency in state for the idle states of MSM8998 were ..bad: first of all, for all of them the timings were written for CPU sleep but the min-residency-us param was miscalculated (supposedly, while porting this from downstream); Then, the power collapse states are setting PC on both the CPU cluster *and* the L2 cache, which have different timings: in the specific case of L2 the times are higher so these ones should be taken into account instead of the CPU ones.
This parameter misconfiguration was not giving particular issues because on MSM8998 there was no CPU scaling at all, so cluster/L2 power collapse was rarely (if ever) hit. When CPU scaling is enabled, though, the wrong timings will produce SoC unstability shown to the user as random, apparently error-less, sudden reboots and/or lockups.
This set of parameters are stabilizing the SoC when CPU scaling is ON and when power collapse is frequently hit.
Signed-off-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org Signed-off-by: Bjorn Andersson bjorn.andersson@linaro.org Link: https://lore.kernel.org/r/20210901183123.1087392-3-angelogioacchino.delregno... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm64/boot/dts/qcom/msm8998.dtsi | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/boot/dts/qcom/msm8998.dtsi b/arch/arm64/boot/dts/qcom/msm8998.dtsi index ccd535edbf4e1..dcb79003ca0e6 100644 --- a/arch/arm64/boot/dts/qcom/msm8998.dtsi +++ b/arch/arm64/boot/dts/qcom/msm8998.dtsi @@ -246,38 +246,42 @@ LITTLE_CPU_SLEEP_0: cpu-sleep-0-0 { compatible = "arm,idle-state"; idle-state-name = "little-retention"; + /* CPU Retention (C2D), L2 Active */ arm,psci-suspend-param = <0x00000002>; entry-latency-us = <81>; exit-latency-us = <86>; - min-residency-us = <200>; + min-residency-us = <504>; };
LITTLE_CPU_SLEEP_1: cpu-sleep-0-1 { compatible = "arm,idle-state"; idle-state-name = "little-power-collapse"; + /* CPU + L2 Power Collapse (C3, D4) */ arm,psci-suspend-param = <0x40000003>; - entry-latency-us = <273>; - exit-latency-us = <612>; - min-residency-us = <1000>; + entry-latency-us = <814>; + exit-latency-us = <4562>; + min-residency-us = <9183>; local-timer-stop; };
BIG_CPU_SLEEP_0: cpu-sleep-1-0 { compatible = "arm,idle-state"; idle-state-name = "big-retention"; + /* CPU Retention (C2D), L2 Active */ arm,psci-suspend-param = <0x00000002>; entry-latency-us = <79>; exit-latency-us = <82>; - min-residency-us = <200>; + min-residency-us = <1302>; };
BIG_CPU_SLEEP_1: cpu-sleep-1-1 { compatible = "arm,idle-state"; idle-state-name = "big-power-collapse"; + /* CPU + L2 Power Collapse (C3, D4) */ arm,psci-suspend-param = <0x40000003>; - entry-latency-us = <336>; - exit-latency-us = <525>; - min-residency-us = <1000>; + entry-latency-us = <724>; + exit-latency-us = <2027>; + min-residency-us = <9419>; local-timer-stop; }; };