[PATCH v2] arm64: dts: xilinx: versal-net: Remove CPU idle states
Jay Buddhabhatti
jay.buddhabhatti at amd.com
Wed Oct 7 05:19:32 PDT 2026
The sleep state powers down the CPU core, and the wake-up time cannot be
guaranteed because the firmware may be busy handling other tasks at the
time of the wake-up request. This leads to unpredictable and potentially
high wake-up latency during CPU idle.
Remove the sleep state to avoid this dependency on firmware. The default
backend CPU idle state simply puts core in WFI and retains its context
without being powered off. Since wake-up from WFI is handled entirely in
hardware, it is effectively immediate (a few cycles) and does not depend
on firmware availability.
Signed-off-by: Jay Buddhabhatti <jay.buddhabhatti at amd.com>
---
Changes in v2:
- Remove the idle state instead of replacing it with a retention state.
- Update the subject and commit description.
Link to v1: https://lore.kernel.org/all/20260727121842.3410495-1-jay.buddhabhatti@amd.com/
---
arch/arm64/boot/dts/xilinx/versal-net.dtsi | 29 ----------------------
1 file changed, 29 deletions(-)
diff --git a/arch/arm64/boot/dts/xilinx/versal-net.dtsi b/arch/arm64/boot/dts/xilinx/versal-net.dtsi
index 21bb917bcba1..9b74e59fd64a 100644
--- a/arch/arm64/boot/dts/xilinx/versal-net.dtsi
+++ b/arch/arm64/boot/dts/xilinx/versal-net.dtsi
@@ -103,7 +103,6 @@ cpu0: cpu at 0 {
enable-method = "psci";
reg = <0>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -133,7 +132,6 @@ cpu100: cpu at 100 {
enable-method = "psci";
reg = <0x100>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -163,7 +161,6 @@ cpu200: cpu at 200 {
enable-method = "psci";
reg = <0x200>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -193,7 +190,6 @@ cpu300: cpu at 300 {
enable-method = "psci";
reg = <0x300>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -223,7 +219,6 @@ cpu10000: cpu at 10000 {
enable-method = "psci";
reg = <0x10000>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -253,7 +248,6 @@ cpu10100: cpu at 10100 {
enable-method = "psci";
reg = <0x10100>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -283,7 +277,6 @@ cpu10200: cpu at 10200 {
enable-method = "psci";
reg = <0x10200>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -313,7 +306,6 @@ cpu10300: cpu at 10300 {
enable-method = "psci";
reg = <0x10300>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -343,7 +335,6 @@ cpu20000: cpu at 20000 {
enable-method = "psci";
reg = <0x20000>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -373,7 +364,6 @@ cpu20100: cpu at 20100 {
enable-method = "psci";
reg = <0x20100>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -403,7 +393,6 @@ cpu20200: cpu at 20200 {
enable-method = "psci";
reg = <0x20200>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -433,7 +422,6 @@ cpu20300: cpu at 20300 {
enable-method = "psci";
reg = <0x20300>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -463,7 +451,6 @@ cpu30000: cpu at 30000 {
enable-method = "psci";
reg = <0x30000>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -493,7 +480,6 @@ cpu30100: cpu at 30100 {
enable-method = "psci";
reg = <0x30100>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -523,7 +509,6 @@ cpu30200: cpu at 30200 {
enable-method = "psci";
reg = <0x30200>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -553,7 +538,6 @@ cpu30300: cpu at 30300 {
enable-method = "psci";
reg = <0x30300>;
operating-points-v2 = <&cpu_opp_table>;
- cpu-idle-states = <&CPU_SLEEP_0>;
d-cache-size = <0x10000>; /* 64kB */
d-cache-line-size = <64>;
/* 4 ways set associativity */
@@ -632,19 +616,6 @@ llc: l4-cache { /* LLC inside CMN */
cache-size = <0x1000000>; /* 16MB */
cache-unified;
};
-
- idle-states {
- entry-method = "psci";
-
- CPU_SLEEP_0: cpu-sleep-0 {
- compatible = "arm,idle-state";
- arm,psci-suspend-param = <0x40000000>;
- local-timer-stop;
- entry-latency-us = <300>;
- exit-latency-us = <600>;
- min-residency-us = <10000>;
- };
- };
};
cpu_opp_table: opp-table {
--
2.34.1
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