diff --git a/plat/st/stm32mp1/stm32mp1_topology.c b/plat/st/stm32mp1/stm32mp1_topology.c
new file mode 100644
index 0000000..405aa33
--- /dev/null
+++ b/plat/st/stm32mp1/stm32mp1_topology.c
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <platform_def.h>
+#include <platform.h>
+#include <psci.h>
+
+/* 1 cluster, all cores into */
+static const unsigned char stm32mp1_power_domain_tree_desc[] = {
+	PLATFORM_CLUSTER_COUNT,
+	PLATFORM_CORE_COUNT,
+};
+
+/* This function returns the platform topology */
+const unsigned char *plat_get_power_domain_tree_desc(void)
+{
+	return stm32mp1_power_domain_tree_desc;
+}
+
+/*******************************************************************************
+ * This function implements a part of the critical interface between the psci
+ * generic layer and the platform that allows the former to query the platform
+ * to convert an MPIDR to a unique linear index. An error code (-1) is returned
+ * in case the MPIDR is invalid.
+ ******************************************************************************/
+int plat_core_pos_by_mpidr(u_register_t mpidr)
+{
+	unsigned int cluster_id, cpu_id;
+	u_register_t mpidr_copy = mpidr;
+
+	mpidr_copy &= MPIDR_AFFINITY_MASK;
+
+	if ((mpidr_copy & ~(MPIDR_CLUSTER_MASK | MPIDR_CPU_MASK)) != 0U) {
+		return -1;
+	}
+
+	cluster_id = (mpidr_copy >> MPIDR_AFF1_SHIFT) & MPIDR_AFFLVL_MASK;
+	cpu_id = (mpidr_copy >> MPIDR_AFF0_SHIFT) & MPIDR_AFFLVL_MASK;
+
+	if (cluster_id >= PLATFORM_CLUSTER_COUNT) {
+		return -1;
+	}
+
+	/*
+	 * Validate cpu_id by checking whether it represents a CPU in one
+	 * of the two clusters present on the platform.
+	 */
+	if (cpu_id >= PLATFORM_CORE_COUNT) {
+		return -1;
+	}
+
+	return (int)cpu_id;
+}