diff --git a/include/osmocom/gsm/l1sap.h b/include/osmocom/gsm/l1sap.h
new file mode 100644
index 0000000..9547c32
--- /dev/null
+++ b/include/osmocom/gsm/l1sap.h
@@ -0,0 +1,53 @@
+#ifndef _OSMOCOM_L1SAP_H
+#define _OSMOCOM_L1SAP_H
+
+#include <osmocom/core/prim.h>
+
+/*! \brief LAPDm related primitives (L1<->L2 SAP) */
+enum osmo_ph_prim {
+	PRIM_PH_DATA,		/*!< \brief PH-DATA */
+	PRIM_PH_RACH,		/*!< \brief PH-RANDOM_ACCESS */
+	PRIM_PH_CONN,		/*!< \brief PH-CONNECT */
+	PRIM_PH_EMPTY_FRAME,	/*!< \brief PH-EMPTY_FRAME */
+	PRIM_PH_RTS,		/*!< \brief PH-RTS */
+};
+
+/*! \brief for PH-RANDOM_ACCESS.req */
+struct ph_rach_req_param {
+	uint8_t ra;		/*!< \brief Random Access */
+	uint8_t ta;		/*!< \brief Timing Advance */
+	uint8_t tx_power;	/*!< \brief Transmit Power */
+	uint8_t is_combined_ccch;/*!< \brief Are we using a combined CCCH? */
+	uint16_t offset;	/*!< \brief Timing Offset */
+};
+
+/*! \brief for PH-RANDOM_ACCESS.ind */
+struct ph_rach_ind_param {
+	uint8_t ra;		/*!< \brief Random Access */
+	uint8_t acc_delay;	/*!< \brief Delay in bit periods */
+	uint32_t fn;		/*!< \brief GSM Frame Number at time of RA */
+};
+
+/*! \brief for PH-[UNIT]DATA.{req,ind} */
+struct ph_data_param {
+	uint8_t link_id;	/*!< \brief Link Identifier (Like RSL) */
+	uint8_t chan_nr;	/*!< \brief Channel Number (Like RSL) */
+};
+
+/*! \brief for PH-CONN.ind */
+struct ph_conn_ind_param {
+	uint32_t fn;		/*!< \brief GSM Frame Number */
+};
+
+/*! \brief primitive header for LAPDm PH-SAP primitives */
+struct osmo_phsap_prim {
+	struct osmo_prim_hdr oph; /*!< \brief generic primitive header */
+	union {
+		struct ph_data_param data;
+		struct ph_rach_req_param rach_req;
+		struct ph_rach_ind_param rach_ind;
+		struct ph_conn_ind_param conn_ind;
+	} u;			/*!< \brief request-specific data */
+};
+
+#endif /* _OSMOCOM_L1SAP_H */
diff --git a/include/osmocom/gsm/lapdm.h b/include/osmocom/gsm/lapdm.h
index 571fd46..a6e4ad7 100644
--- a/include/osmocom/gsm/lapdm.h
+++ b/include/osmocom/gsm/lapdm.h
@@ -1,6 +1,7 @@
 #ifndef _OSMOCOM_LAPDM_H
 #define _OSMOCOM_LAPDM_H
 
+#include <osmocom/gsm/l1sap.h>
 #include <osmocom/gsm/lapd_core.h>
 
 /*! \defgroup lapdm LAPDm implementation according to GSM TS 04.06
@@ -9,55 +10,6 @@
 
 /*! \file lapdm.h */
 
-/* primitive related sutff */
-
-/*! \brief LAPDm related primitives (L1<->L2 SAP) */
-enum osmo_ph_prim {
-	PRIM_PH_DATA,		/*!< \brief PH-DATA */
-	PRIM_PH_RACH,		/*!< \brief PH-RANDOM_ACCESS */
-	PRIM_PH_CONN,		/*!< \brief PH-CONNECT */
-	PRIM_PH_EMPTY_FRAME,	/*!< \brief PH-EMPTY_FRAME */
-	PRIM_PH_RTS,		/*!< \brief PH-RTS */
-};
-
-/*! \brief for PH-RANDOM_ACCESS.req */
-struct ph_rach_req_param {
-	uint8_t ra;		/*!< \brief Random Access */
-	uint8_t ta;		/*!< \brief Timing Advance */
-	uint8_t tx_power;	/*!< \brief Transmit Power */
-	uint8_t is_combined_ccch;/*!< \brief Are we using a combined CCCH? */
-	uint16_t offset;	/*!< \brief Timing Offset */
-};
-
-/*! \brief for PH-RANDOM_ACCESS.ind */
-struct ph_rach_ind_param {
-	uint8_t ra;		/*!< \brief Random Access */
-	uint8_t acc_delay;	/*!< \brief Delay in bit periods */
-	uint32_t fn;		/*!< \brief GSM Frame Number at time of RA */
-};
-
-/*! \brief for PH-[UNIT]DATA.{req,ind} */
-struct ph_data_param {
-	uint8_t link_id;	/*!< \brief Link Identifier (Like RSL) */
-	uint8_t chan_nr;	/*!< \brief Channel Number (Like RSL) */
-};
-
-/*! \brief for PH-CONN.ind */
-struct ph_conn_ind_param {
-	uint32_t fn;		/*!< \brief GSM Frame Number */
-};
-
-/*! \brief primitive header for LAPDm PH-SAP primitives */
-struct osmo_phsap_prim {
-	struct osmo_prim_hdr oph; /*!< \brief generic primitive header */
-	union {
-		struct ph_data_param data;
-		struct ph_rach_req_param rach_req;
-		struct ph_rach_ind_param rach_ind;
-		struct ph_conn_ind_param conn_ind;
-	} u;			/*!< \brief request-specific data */
-};
-
 /*! \brief LAPDm mode/role */
 enum lapdm_mode {
 	LAPDM_MODE_MS,		/*!< \brief behave like a MS (mobile phone) */