diff --git a/drivers/arm/css/scp/css_pm_scmi.c b/drivers/arm/css/scp/css_pm_scmi.c
index 097d2eb..aeb7eda 100644
--- a/drivers/arm/css/scp/css_pm_scmi.c
+++ b/drivers/arm/css/scp/css_pm_scmi.c
@@ -224,8 +224,8 @@
 
 	SCMI_SET_PWR_STATE_MAX_PWR_LVL(scmi_pwr_state, lvl - 1);
 
-	core_pos = plat_core_pos_by_mpidr(mpidr);
-	assert(core_pos >= 0 && (core_pos < PLATFORM_CORE_COUNT));
+	core_pos = (unsigned int)plat_core_pos_by_mpidr(mpidr);
+	assert(core_pos < PLATFORM_CORE_COUNT);
 
 	css_scp_core_pos_to_scmi_channel(core_pos, &domain_id,
 			&channel_id);
@@ -256,8 +256,8 @@
 		return PSCI_E_INVALID_PARAMS;
 	}
 
-	cpu_idx = plat_core_pos_by_mpidr(mpidr);
-	assert(cpu_idx > -1);
+	cpu_idx = (unsigned int)plat_core_pos_by_mpidr(mpidr);
+	assert(cpu_idx < PLATFORM_CORE_COUNT);
 
 	css_scp_core_pos_to_scmi_channel(cpu_idx, &domain_id, &channel_id);
 	ret = scmi_pwr_state_get(scmi_handles[channel_id],