diff --git a/include/osmocom/gprs/gprs_bssgp.h b/include/osmocom/gprs/gprs_bssgp.h
index 4eb9df4..e962b44 100644
--- a/include/osmocom/gprs/gprs_bssgp.h
+++ b/include/osmocom/gprs/gprs_bssgp.h
@@ -163,7 +163,7 @@
 			 uint16_t cid);
 
 /* Wrapper around TLV parser to parse BSSGP IEs */
-static inline int bssgp_tlv_parse(struct tlv_parsed *tp, uint8_t *buf, int len)
+static inline int bssgp_tlv_parse(struct tlv_parsed *tp, const uint8_t *buf, int len)
 {
 	return tlv_parse(tp, &tvlv_att_def, buf, len, 0, 0);
 }