diff --git a/src/soc/intel/skylake/acpi.c b/src/soc/intel/skylake/acpi.c
index 9bbfec3cd5..4794a998f9 100644
--- a/src/soc/intel/skylake/acpi.c
+++ b/src/soc/intel/skylake/acpi.c
@@ -128,7 +128,7 @@ static int cstate_set_non_s0ix[] = {
 	C_STATE_C7S_LONG_LAT,
 };
 
-acpi_cstate_t *soc_get_cstate_map(size_t *entries)
+const acpi_cstate_t *soc_get_cstate_map(size_t *entries)
 {
 	static acpi_cstate_t map[MAX(ARRAY_SIZE(cstate_set_s0ix),
 				ARRAY_SIZE(cstate_set_non_s0ix))];