Add header file of PH-/MPH-/TCH-SAP interface to common part of osmo-bts

Instead of handling primitives directly at layer 1 specific code,
osmo-bts handles primitives at common code.

When all primitive are moved, the l1sap interface will:
- receive PH-DATA indications and forward them to layer 2.
- check for RF link loss and notify BSC.
- receive TCH indications and forward them via RTP.
- receive PH-RTS indications and send PH-DATA requests with content
  according to its logical channel.
- receive TCH-RTS indications and send TCH requests with content
  received via RTP or loopback from TCH indications.
- send MPH-INFO requests to activate, deactivate and modify logical
  channels and handle their confirms.
- receive MPH-INFO indications with measurements from tranceiver.
- forward received and transmitted PH-DATA to GSMTAP.

2 files changed, 72 insertions, 1 deletions

diff --git a/include/osmo-bts/Makefile.am b/include/osmo-bts/Makefile.am
index 67fd2bf..cd3d8c0 100644
--- a/include/osmo-bts/Makefile.am
+++ b/include/osmo-bts/Makefile.am
@@ -1,3 +1,3 @@
 noinst_HEADERS = abis.h bts.h bts_model.h gsm_data.h logging.h measurement.h \
 		 oml.h paging.h rsl.h signal.h vty.h amr.h pcu_if.h pcuif_proto.h \
-		 handover.h msg_utils.h tx_power.h control_if.h cbch.h
+		 handover.h msg_utils.h tx_power.h control_if.h cbch.h l1sap.h
diff --git a/include/osmo-bts/l1sap.h b/include/osmo-bts/l1sap.h
new file mode 100644
index 0000000..a1dc303
--- /dev/null
+++ b/include/osmo-bts/l1sap.h
@@ -0,0 +1,71 @@
+#ifndef L1SAP_H
+#define L1SAP_H
+
+/* timeslot and subslot from chan_nr */
+#define L1SAP_CHAN2TS(chan_nr) (chan_nr & 7)
+#define L1SAP_CHAN2SS_TCHH(chan_nr) ((chan_nr >> 3) & 1)
+#define L1SAP_CHAN2SS_SDCCH4(chan_nr) ((chan_nr >> 3) & 3)
+#define L1SAP_CHAN2SS_SDCCH8(chan_nr) ((chan_nr >> 3) & 7)
+
+/* logical channel from chan_nr + link_id */
+#define L1SAP_IS_LINK_SACCH(link_id) ((link_id & 0xC0) == 0x40)
+#define L1SAP_IS_CHAN_TCHF(chan_nr) ((chan_nr & 0xf8) == 0x08)
+#define L1SAP_IS_CHAN_TCHH(chan_nr) ((chan_nr & 0xf0) == 0x10)
+#define L1SAP_IS_CHAN_SDCCH4(chan_nr) ((chan_nr & 0xe0) == 0x20)
+#define L1SAP_IS_CHAN_SDCCH8(chan_nr) ((chan_nr & 0xc0) == 0x40)
+#define L1SAP_IS_CHAN_BCCH(chan_nr) ((chan_nr & 0xf8) == 0x80)
+#define L1SAP_IS_CHAN_RACH(chan_nr) ((chan_nr & 0xf8) == 0x88)
+#define L1SAP_IS_CHAN_AGCH_PCH(chan_nr) ((chan_nr & 0xf8) == 0x90)
+
+/* rach type from ra */
+#define L1SAP_IS_PACKET_RACH(ra) ((ra & 0xf0) == 0x70)
+
+/* CCCH block from frame number */
+#define L1SAP_FN2CCCHBLOCK(fn) ((fn % 51) / 5 - 1)
+
+/* PTCH layout from frame number */
+#define L1SAP_FN2MACBLOCK(fn) ((fn % 52) / 4)
+#define L1SAP_FN2PTCCHBLOCK(fn) ((fn / 52) & 7)
+#define L1SAP_IS_PTCCH(fn) ((fn % 52) == 12)
+
+/* subslot from any chan_nr */
+static inline uint8_t l1sap_chan2ss(uint8_t chan_nr)
+{
+	if (L1SAP_IS_CHAN_SDCCH8(chan_nr))
+		return L1SAP_CHAN2SS_SDCCH8(chan_nr);
+	if (L1SAP_IS_CHAN_SDCCH4(chan_nr))
+		return L1SAP_CHAN2SS_SDCCH4(chan_nr);
+	if (L1SAP_IS_CHAN_TCHH(chan_nr))
+		return L1SAP_CHAN2SS_TCHH(chan_nr);
+	return 0;
+}
+
+
+/* allocate a msgb containing a osmo_phsap_prim + optional l2 data */
+struct msgb *l1sap_msgb_alloc(unsigned int l2_len);
+
+/* any L1 prim received from bts model */
+int l1sap_up(struct gsm_bts_trx *trx, struct osmo_phsap_prim *l1sap);
+
+/* pcu (socket interface) sends us a data request primitive */
+int l1sap_pdch_req(struct gsm_bts_trx_ts *ts, int is_ptcch, uint32_t fn,
+	uint16_t arfcn, uint8_t block_nr, uint8_t *data, uint8_t len);
+
+/* call-back function for incoming RTP */
+void l1sap_rtp_rx_cb(struct osmo_rtp_socket *rs, const uint8_t *rtp_pl,
+	unsigned int rtp_pl_len);
+
+/* channel control */
+int l1sap_chan_act(struct gsm_bts_trx *trx, uint8_t chan_nr);
+int l1sap_chan_rel(struct gsm_bts_trx *trx, uint8_t chan_nr);
+int l1sap_chan_deact_sacch(struct gsm_bts_trx *trx, uint8_t chan_nr);
+int l1sap_chan_modify(struct gsm_bts_trx *trx, uint8_t chan_nr);
+
+extern const struct value_string gsmtap_sapi_names[];
+extern struct gsmtap_inst *gsmtap;
+extern uint32_t gsmtap_sapi_mask;
+extern uint8_t gsmtap_sapi_acch;
+
+#define msgb_l1sap_prim(msg) ((struct osmo_phsap_prim *)(msg)->l1h)
+
+#endif /* L1SAP_H */