[PATCH] arm64: dts: qcom: shikra: Switch CPU ETMs to MMIO-based probing

From: Jie Gan

Date: Mon Sep 21 2026 - 23:10:04 EST


The etm0-etm3 nodes are declared with "arm,coresight-etm4x-sysreg"
but do not implement self-hosted system-register trace access on
this SoC: ID_AA64DFR0_EL1.TraceVer reads as 0 on the affected CPUs,
so etm4_init_sysreg_access() correctly reports the access mechanism
as unavailable and the ETMv4 driver fails to probe with -EINVAL.

The CPU ETMs have a memory-mapped aperture, so switch each node to
the standard "arm,coresight-etm4x", "arm,primecell" compatible with
its MMIO reg range.

Fixes: eed738c6dd0c ("arm64: dts: qcom: shikra: Add coresight nodes")
Signed-off-by: Jie Gan <jie.gan@xxxxxxxxxxxxxxxx>
---
Signed-off-by: Jie Gan <jiegan@xxxxxxxxxxxxxxxx>
---
arch/arm64/boot/dts/qcom/shikra.dtsi | 140 ++++++++++++++++++-----------------
1 file changed, 72 insertions(+), 68 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/shikra.dtsi b/arch/arm64/boot/dts/qcom/shikra.dtsi
index c1f06f692f66..62bacf749241 100644
--- a/arch/arm64/boot/dts/qcom/shikra.dtsi
+++ b/arch/arm64/boot/dts/qcom/shikra.dtsi
@@ -164,74 +164,6 @@ eud_in: endpoint {
};
};

- etm0 {
- compatible = "arm,coresight-etm4x-sysreg";
-
- clocks = <&rpmcc RPM_SMD_QDSS_CLK>;
- clock-names = "apb_pclk";
- cpu = <&cpu0>;
- qcom,skip-power-up;
-
- out-ports {
- port {
- etm0_out: endpoint {
- remote-endpoint = <&funnel_cpuss0_in0>;
- };
- };
- };
- };
-
- etm1 {
- compatible = "arm,coresight-etm4x-sysreg";
-
- clocks = <&rpmcc RPM_SMD_QDSS_CLK>;
- clock-names = "apb_pclk";
- cpu = <&cpu1>;
- qcom,skip-power-up;
-
- out-ports {
- port {
- etm1_out: endpoint {
- remote-endpoint = <&funnel_cpuss0_in1>;
- };
- };
- };
- };
-
- etm2 {
- compatible = "arm,coresight-etm4x-sysreg";
-
- clocks = <&rpmcc RPM_SMD_QDSS_CLK>;
- clock-names = "apb_pclk";
- cpu = <&cpu2>;
- qcom,skip-power-up;
-
- out-ports {
- port {
- etm2_out: endpoint {
- remote-endpoint = <&funnel_cpuss0_in2>;
- };
- };
- };
- };
-
- etm3 {
- compatible = "arm,coresight-etm4x-sysreg";
-
- clocks = <&rpmcc RPM_SMD_QDSS_CLK>;
- clock-names = "apb_pclk";
- cpu = <&cpu3>;
- qcom,skip-power-up;
-
- out-ports {
- port {
- etm3_out: endpoint {
- remote-endpoint = <&funnel_cpuss0_in3>;
- };
- };
- };
- };
-
firmware {
scm {
compatible = "qcom,scm-shikra", "qcom,scm";
@@ -3218,6 +3150,24 @@ cti@9020000 {
label = "cti_apss_pe0";
};

+ etm@9040000 {
+ compatible = "arm,coresight-etm4x", "arm,primecell";
+ reg = <0x0 0x09040000 0x0 0x1000>;
+
+ clocks = <&rpmcc RPM_SMD_QDSS_CLK>;
+ clock-names = "apb_pclk";
+ cpu = <&cpu0>;
+ qcom,skip-power-up;
+
+ out-ports {
+ port {
+ etm0_out: endpoint {
+ remote-endpoint = <&funnel_cpuss0_in0>;
+ };
+ };
+ };
+ };
+
cti@90e0000 {
compatible = "arm,coresight-cti", "arm,primecell";
reg = <0x0 0x090e0000 0x0 0x1000>;
@@ -3236,6 +3186,24 @@ cti@9120000 {
label = "cti_apss_pe1";
};

+ etm@9140000 {
+ compatible = "arm,coresight-etm4x", "arm,primecell";
+ reg = <0x0 0x09140000 0x0 0x1000>;
+
+ clocks = <&rpmcc RPM_SMD_QDSS_CLK>;
+ clock-names = "apb_pclk";
+ cpu = <&cpu1>;
+ qcom,skip-power-up;
+
+ out-ports {
+ port {
+ etm1_out: endpoint {
+ remote-endpoint = <&funnel_cpuss0_in1>;
+ };
+ };
+ };
+ };
+
cti@9220000 {
compatible = "arm,coresight-cti", "arm,primecell";
reg = <0x0 0x09220000 0x0 0x1000>;
@@ -3245,6 +3213,24 @@ cti@9220000 {
label = "cti_apss_pe2";
};

+ etm@9240000 {
+ compatible = "arm,coresight-etm4x", "arm,primecell";
+ reg = <0x0 0x09240000 0x0 0x1000>;
+
+ clocks = <&rpmcc RPM_SMD_QDSS_CLK>;
+ clock-names = "apb_pclk";
+ cpu = <&cpu2>;
+ qcom,skip-power-up;
+
+ out-ports {
+ port {
+ etm2_out: endpoint {
+ remote-endpoint = <&funnel_cpuss0_in2>;
+ };
+ };
+ };
+ };
+
cti@9320000 {
compatible = "arm,coresight-cti", "arm,primecell";
reg = <0x0 0x09320000 0x0 0x1000>;
@@ -3254,6 +3240,24 @@ cti@9320000 {
label = "cti_apss_pe3";
};

+ etm@9340000 {
+ compatible = "arm,coresight-etm4x", "arm,primecell";
+ reg = <0x0 0x09340000 0x0 0x1000>;
+
+ clocks = <&rpmcc RPM_SMD_QDSS_CLK>;
+ clock-names = "apb_pclk";
+ cpu = <&cpu3>;
+ qcom,skip-power-up;
+
+ out-ports {
+ port {
+ etm3_out: endpoint {
+ remote-endpoint = <&funnel_cpuss0_in3>;
+ };
+ };
+ };
+ };
+
funnel@9800000 {
compatible = "arm,coresight-dynamic-funnel", "arm,primecell";
reg = <0x0 0x09800000 0x0 0x1000>;

---
base-commit: 5c4d4169604b335c38bbc79bc1fc03042981fc6f
change-id: 20260922-fix-etm-probe-issue-on-shikra-5a624f583975

Best regards,
--
Jie Gan <jie.gan@xxxxxxxxxxxxxxxx>