diff --git a/include/plat/arm/common/plat_arm.h b/include/plat/arm/common/plat_arm.h
index 044e18e..aadf58d 100644
--- a/include/plat/arm/common/plat_arm.h
+++ b/include/plat/arm/common/plat_arm.h
@@ -149,6 +149,7 @@
 			    psci_power_state_t *req_state);
 int arm_validate_ns_entrypoint(uintptr_t entrypoint);
 void arm_system_pwr_domain_resume(void);
+void arm_program_trusted_mailbox(uintptr_t address);
 
 /* Topology utility function */
 int arm_check_mpidr(u_register_t mpidr);