diff --git a/services/std_svc/psci/psci_main.c b/services/std_svc/psci/psci_main.c
index e6cd3a3a4d0c9e39d59b689cd27fb7786cca13b6..68ad5f632e4bdeb25d906208075686bf40cd8d58 100644
--- a/services/std_svc/psci/psci_main.c
+++ b/services/std_svc/psci/psci_main.c
@@ -47,7 +47,6 @@ int psci_cpu_on(u_register_t target_cpu,
 
 {
 	int rc;
-	unsigned int end_pwrlvl;
 	entry_point_info_t ep;
 
 	/* Determine if the cpu exists of not */
@@ -64,11 +63,7 @@ int psci_cpu_on(u_register_t target_cpu,
 	 * To turn this cpu on, specify which power
 	 * levels need to be turned on
 	 */
-	end_pwrlvl = PLAT_MAX_PWR_LVL;
-	rc = psci_cpu_on_start(target_cpu,
-			    &ep,
-			    end_pwrlvl);
-	return rc;
+	return psci_cpu_on_start(target_cpu, &ep);
 }
 
 unsigned int psci_version(void)
diff --git a/services/std_svc/psci/psci_on.c b/services/std_svc/psci/psci_on.c
index 200e62225b9df5a15ad96e892065649e556b2c3a..c8c36cd0f0b4cd709d9dd0bbc906ca2573456486 100644
--- a/services/std_svc/psci/psci_on.c
+++ b/services/std_svc/psci/psci_on.c
@@ -67,13 +67,16 @@ static int cpu_on_validate_state(aff_info_state_t aff_state)
  * platform handler as it can return error.
  ******************************************************************************/
 int psci_cpu_on_start(u_register_t target_cpu,
-		      entry_point_info_t *ep,
-		      unsigned int end_pwrlvl)
+		      entry_point_info_t *ep)
 {
 	int rc;
 	unsigned int target_idx = plat_core_pos_by_mpidr(target_cpu);
 	aff_info_state_t target_aff_state;
 
+	/* Calling function must supply valid input arguments */
+	assert((int) target_idx >= 0);
+	assert(ep != NULL);
+
 	/*
 	 * This function must only be called on platforms where the
 	 * CPU_ON platform hooks have been implemented.
diff --git a/services/std_svc/psci/psci_private.h b/services/std_svc/psci/psci_private.h
index 4b91ad530b9ca7434e61d35895202a4325773ab4..8a671b39d7d3f0873d3c1387fd3ad7662a896b37 100644
--- a/services/std_svc/psci/psci_private.h
+++ b/services/std_svc/psci/psci_private.h
@@ -203,8 +203,7 @@ int psci_spd_migrate_info(u_register_t *mpidr);
 
 /* Private exported functions from psci_on.c */
 int psci_cpu_on_start(unsigned long target_cpu,
-		      entry_point_info_t *ep,
-		      unsigned int end_pwrlvl);
+		      entry_point_info_t *ep);
 
 void psci_cpu_on_finish(unsigned int cpu_idx,
 			psci_power_state_t *state_info);