diff --git a/arch/arm/mach-stm32mp/dram_init.c b/arch/arm/mach-stm32mp/dram_init.c
index 78b12fc..6024959 100644
--- a/arch/arm/mach-stm32mp/dram_init.c
+++ b/arch/arm/mach-stm32mp/dram_init.c
@@ -6,6 +6,7 @@
 #define LOG_CATEGORY LOGC_ARCH
 
 #include <dm.h>
+#include <efi_loader.h>
 #include <image.h>
 #include <init.h>
 #include <lmb.h>
@@ -74,3 +75,14 @@
 
 	return reg + size;
 }
+
+void efi_add_known_memory(void)
+{
+	if (IS_ENABLED(CONFIG_EFI_LOADER))
+		/*
+		 * Memory over ram_top is reserved to OPTEE.
+		 * Declare to EFI only memory area below ram_top
+		 */
+		efi_add_memory_map(gd->ram_base, gd->ram_top - gd->ram_base,
+				   EFI_CONVENTIONAL_MEMORY);
+}