diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 104333c2c8a3..4c15fae534f3 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1070,25 +1070,21 @@ static bool etm4_init_iomem_access(struct etmv4_drvdata *drvdata,
 				   struct csdev_access *csa)
 {
 	u32 devarch = readl_relaxed(drvdata->base + TRCDEVARCH);
-	u32 idr1 = readl_relaxed(drvdata->base + TRCIDR1);
 
 	/*
 	 * All ETMs must implement TRCDEVARCH to indicate that
-	 * the component is an ETMv4. To support any broken
-	 * implementations we fall back to TRCIDR1 check, which
-	 * is not really reliable.
+	 * the component is an ETMv4. Even though TRCIDR1 also
+	 * contains the information, it is part of the "Trace"
+	 * register and must be accessed with the OSLK cleared,
+	 * with MMIO. But we cannot touch the OSLK until we are
+	 * sure this is an ETM. So rely only on the TRCDEVARCH.
 	 */
-	if ((devarch & ETM_DEVARCH_ID_MASK) == ETM_DEVARCH_ETMv4x_ARCH) {
-		drvdata->arch = etm_devarch_to_arch(devarch);
-	} else {
-		pr_warn("CPU%d: ETM4x incompatible TRCDEVARCH: %x, falling back to TRCIDR1\n",
-			smp_processor_id(), devarch);
-
-		if (ETM_TRCIDR1_ARCH_MAJOR(idr1) != ETM_TRCIDR1_ARCH_ETMv4)
-			return false;
-		drvdata->arch = etm_trcidr_to_arch(idr1);
+	if ((devarch & ETM_DEVARCH_ID_MASK) != ETM_DEVARCH_ETMv4x_ARCH) {
+		pr_warn_once("TRCDEVARCH doesn't match ETMv4 architecture\n");
+		return false;
 	}
 
+	drvdata->arch = etm_devarch_to_arch(devarch);
 	*csa = CSDEV_ACCESS_IOMEM(drvdata->base);
 	return true;
 }
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
index 434f4e95ee17..27c8a9901868 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.h
+++ b/drivers/hwtracing/coresight/coresight-etm4x.h
@@ -753,14 +753,12 @@
  * TRCDEVARCH	- CoreSight architected register
  *                - Bits[15:12] - Major version
  *                - Bits[19:16] - Minor version
- * TRCIDR1	- ETM architected register
- *                - Bits[11:8] - Major version
- *                - Bits[7:4]  - Minor version
- * We must rely on TRCDEVARCH for the version information,
- * however we don't want to break the support for potential
- * old implementations which might not implement it. Thus
- * we fall back to TRCIDR1 if TRCDEVARCH is not implemented
- * for memory mapped components.
+ *
+ * We must rely only on TRCDEVARCH for the version information. Even though,
+ * TRCIDR1 also provides the architecture version, it is a "Trace" register
+ * and as such must be accessed only with Trace power domain ON. This may
+ * not be available at probe time.
+ *
  * Now to make certain decisions easier based on the version
  * we use an internal representation of the version in the
  * driver, as follows :
@@ -786,12 +784,6 @@ static inline u8 etm_devarch_to_arch(u32 devarch)
 				ETM_DEVARCH_REVISION(devarch));
 }
 
-static inline u8 etm_trcidr_to_arch(u32 trcidr1)
-{
-	return ETM_ARCH_VERSION(ETM_TRCIDR1_ARCH_MAJOR(trcidr1),
-				ETM_TRCIDR1_ARCH_MINOR(trcidr1));
-}
-
 enum etm_impdef_type {
 	ETM4_IMPDEF_HISI_CORE_COMMIT,
 	ETM4_IMPDEF_FEATURE_MAX,