Split of L1 interface to be used with OpenBTS or sysmo-BTS

The OpenBTS socket functions are moved from main to pcu_l1_if.cpp.

New sysmo_l1_if.cpp is introduced. It used special unix socket interface
to connect to sysmo-BTS. This is required to access CCCH/RACH and info
about cell layout. Traffic is also forwarded via this interface, but
it direct access of L1 baseband DSP will be added soon.

In order to handle ready-to-send requests above l1_if, the transmit
queue (for downlink blocks) is moved to gprs_rlcmac.cpp.

The TBF instance additionally holds TRX and TS info, but this is only
a hack currently. TBF instance requires more details about allocated
ressources in the future.

1 files changed, 87 insertions, 21 deletions

diff --git a/src/gprs_rlcmac.cpp b/src/gprs_rlcmac.cpp
index 7e9a0321..c50e7aec 100644
--- a/src/gprs_rlcmac.cpp
+++ b/src/gprs_rlcmac.cpp
@@ -24,6 +24,7 @@
 
 LLIST_HEAD(gprs_rlcmac_tbfs);
 void *rlcmac_tall_ctx;
+LLIST_HEAD(block_queue);
 
 int tfi_alloc()
 {
@@ -47,7 +48,7 @@ int tfi_alloc()
 }
 
 /* lookup TBF Entity (by TFI) */
-static struct gprs_rlcmac_tbf *tbf_by_tfi(uint8_t tfi)
+struct gprs_rlcmac_tbf *tbf_by_tfi(uint8_t tfi)
 {
 	struct gprs_rlcmac_tbf *tbf;
 
@@ -58,7 +59,7 @@ static struct gprs_rlcmac_tbf *tbf_by_tfi(uint8_t tfi)
 	return NULL;
 }
 
-static struct gprs_rlcmac_tbf *tbf_by_tlli(uint32_t tlli)
+struct gprs_rlcmac_tbf *tbf_by_tlli(uint32_t tlli)
 {
 	struct gprs_rlcmac_tbf *tbf;
 	llist_for_each_entry(tbf, &gprs_rlcmac_tbfs, list) {
@@ -68,7 +69,7 @@ static struct gprs_rlcmac_tbf *tbf_by_tlli(uint32_t tlli)
 	return NULL;
 }
 
-struct gprs_rlcmac_tbf *tbf_alloc(uint8_t tfi)
+struct gprs_rlcmac_tbf *tbf_alloc(uint8_t tfi, uint8_t trx, uint8_t ts)
 {
 	struct gprs_rlcmac_tbf *tbf;
 
@@ -77,12 +78,16 @@ struct gprs_rlcmac_tbf *tbf_alloc(uint8_t tfi)
 		return NULL;
 
 	tbf->tfi = tfi;
+	tbf->trx = trx;
+	tbf->ts = ts;
+	tbf->arfcn = pcu_l1if_bts.trx[trx].arfcn;
+	tbf->tsc = pcu_l1if_bts.trx[trx].ts[ts].tsc;
 	llist_add(&tbf->list, &gprs_rlcmac_tbfs);
 
 	return tbf;
 }
 
-static void tbf_free(struct gprs_rlcmac_tbf *tbf)
+void tbf_free(struct gprs_rlcmac_tbf *tbf)
 {
 	llist_del(&tbf->list);
 	talloc_free(tbf);
@@ -154,6 +159,13 @@ static void tbf_gsm_timer_start(struct gprs_rlcmac_tbf *tbf, unsigned int fT,
 	osmo_gsm_timer_schedule(&tbf->gsm_timer, frames);
 }
 
+static void gprs_rlcmac_enqueue_block(bitvec *block, int len)
+{
+	struct msgb *msg = msgb_alloc(len, "rlcmac_dl");
+	bitvec_pack(block, msgb_put(msg, len));
+	msgb_enqueue(&block_queue, msg);
+}
+
 void  write_packet_downlink_assignment(bitvec * dest, uint8_t tfi, uint32_t tlli, uint8_t tn, uint8_t ta, uint8_t tsc)
 {
 	// TODO We should use our implementation of encode RLC/MAC Control messages.
@@ -259,7 +271,7 @@ void  write_packet_uplink_assignment(bitvec * dest, uint8_t tfi, uint32_t tlli)
 
 // GSM 04.08 9.1.18 Immediate assignment
 int write_immediate_assignment(bitvec * dest, uint8_t downlink, uint8_t ra, uint32_t fn,
-								uint8_t ta, uint8_t tfi = 0, uint32_t tlli = 0)
+								uint8_t ta, uint16_t arfcn, uint8_t ts, uint8_t tsc, uint8_t tfi = 0, uint32_t tlli = 0)
 {
 	unsigned wp = 0;
 
@@ -277,10 +289,10 @@ int write_immediate_assignment(bitvec * dest, uint8_t downlink, uint8_t ra, uint
 
 	// GSM 04.08 10.5.2.25a Packet Channel Description
 	bitvec_write_field(dest, wp,0x1,5);                               // Channel type
-	bitvec_write_field(dest, wp,(l1fh->fl1h)->channel_info.tn,3);     // TN
-	bitvec_write_field(dest, wp,(l1fh->fl1h)->channel_info.tsc,3);    // TSC
+	bitvec_write_field(dest, wp,ts,3);     // TN
+	bitvec_write_field(dest, wp,tsc,3);    // TSC
 	bitvec_write_field(dest, wp,0x0,3);                               // non-hopping RF channel configuraion
-	bitvec_write_field(dest, wp,(l1fh->fl1h)->channel_info.arfcn,10); // ARFCN
+	bitvec_write_field(dest, wp,arfcn,10); // ARFCN
 
 	//10.5.2.30 Request Reference
 	bitvec_write_field(dest, wp,ra,8);                    // RA
@@ -418,7 +430,7 @@ void gprs_rlcmac_tx_ul_ack(uint8_t tfi, uint32_t tlli, RlcMacUplinkDataBlock_t *
 	LOGPC(DRLCMAC, LOGL_NOTICE, "\n");
 	LOGP(DRLCMAC, LOGL_NOTICE, "------------------------- TX : Packet Uplink Ack -------------------------\n");
 	free(packet_uplink_ack);
-	pcu_l1if_tx(packet_uplink_ack_vec, GsmL1_Sapi_Pacch);
+	gprs_rlcmac_enqueue_block(packet_uplink_ack_vec, 23);
 	bitvec_free(packet_uplink_ack_vec);
 }
 
@@ -589,7 +601,7 @@ int gprs_rlcmac_rcv_control_block(bitvec *rlc_block)
 	uint8_t tfi = 0;
 	uint32_t tlli = 0;
 	struct gprs_rlcmac_tbf *tbf;
-	struct gprs_rlcmac_tbf *ul_tbf;
+//	struct gprs_rlcmac_tbf *ul_tbf;
 
 	RlcMacUplink_t * ul_control_block = (RlcMacUplink_t *)malloc(sizeof(RlcMacUplink_t));
 	LOGP(DRLCMAC, LOGL_NOTICE, "+++++++++++++++++++++++++ RX : Uplink Control Block +++++++++++++++++++++++++\n");
@@ -642,26 +654,79 @@ void gprs_rlcmac_rcv_block(bitvec *rlc_block)
 	}
 }
 
-int gprs_rlcmac_rcv_rach(uint8_t ra, uint32_t Fn, uint16_t ta)
+struct msgb *gen_dummy_msg(void)
+{
+	struct msgb *msg = msgb_alloc(23, "rlcmac_dl_idle");
+	// RLC/MAC filler with USF=1
+	bitvec *filler = bitvec_alloc(23);
+	bitvec_unhex(filler, "41942b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b");
+	bitvec_pack(filler, msgb_put(msg, 23));
+	bitvec_free(filler);
+	return msg;
+}
+
+void gprs_rlcmac_rcv_rts_block(uint8_t trx, uint8_t ts, uint16_t arfcn,
+	uint32_t fn, uint8_t block_nr)
+{
+	struct msgb *msg;
+	
+	set_current_fn(fn);
+	msg = msgb_dequeue(&block_queue);
+	if (!msg)
+		msg = gen_dummy_msg();
+	pcu_l1if_tx_pdtch(msg, trx, ts, arfcn, fn, block_nr);
+}
+
+int select_pdch(uint8_t *_trx, uint8_t *_ts)
+{
+	uint8_t trx, ts;
+
+	for (trx = 0; trx < 8; trx++) {
+		for (ts = 0; ts < 8; ts++) {
+			if (pcu_l1if_bts.trx[trx].ts[ts].enable) {
+				*_trx = trx;
+				*_ts = ts;
+				return 0;
+			}
+		}
+	}
+
+	return -EBUSY;
+}
+
+int gprs_rlcmac_rcv_rach(uint8_t ra, uint32_t Fn, int16_t qta)
 {
 	struct gprs_rlcmac_tbf *tbf;
+	uint8_t trx, ts;
 
+	if (select_pdch(&trx, &ts)) {
+		LOGP(DRLCMAC, LOGL_NOTICE, "No PDCH ressource\n");
+		/* FIXME: send reject */
+		return -EBUSY;
+	}
 	// Create new TBF
 	int tfi = tfi_alloc();
 	if (tfi < 0) {
 		return tfi;
 	}
-	tbf = tbf_alloc(tfi);
+	tbf = tbf_alloc(tfi, trx, ts);
+	if (qta < 0)
+		qta = 0;
+	if (qta > 252)
+		qta = 252;
+	tbf->ta = qta >> 2;
 	tbf->direction = GPRS_RLCMAC_UL_TBF;
 	tbf->state = GPRS_RLCMAC_WAIT_DATA_SEQ_START;
 	LOGP(DRLCMAC, LOGL_NOTICE, "TBF: [UPLINK] START TFI: %u\n", tbf->tfi);
-	LOGP(DRLCMAC, LOGL_NOTICE, "RX: [PCU <- BTS] TFI: %u RACH\n", tbf->tfi);
+	LOGP(DRLCMAC, LOGL_NOTICE, "RX: [PCU <- BTS] TFI: %u RACH qbit-ta=%d ra=%d, Fn=%d (%d,%d,%d)\n", tbf->tfi, qta, ra, Fn, (Fn / (26 * 51)) % 32, Fn % 51, Fn % 26);
 	LOGP(DRLCMAC, LOGL_NOTICE, "TX: [PCU -> BTS] TFI: %u Packet Immidiate Assignment\n", tbf->tfi);
 	bitvec *immediate_assignment = bitvec_alloc(23);
 	bitvec_unhex(immediate_assignment, "2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b");
-	int len = write_immediate_assignment(immediate_assignment, 0, ra, Fn, ta, tbf->tfi);
-	pcu_l1if_tx(immediate_assignment, GsmL1_Sapi_Agch, len);
+	int len = write_immediate_assignment(immediate_assignment, 0, ra, Fn, tbf->ta, tbf->arfcn, tbf->ts, tbf->tsc, tbf->tfi);
+	pcu_l1if_tx_agch(immediate_assignment, len);
 	bitvec_free(immediate_assignment);
+
+	return 0;
 }
 
 // Send RLC data to OpenBTS.
@@ -721,7 +786,7 @@ void gprs_rlcmac_tx_dl_data_block(uint32_t tlli, uint8_t tfi, uint8_t *pdu, int
 	encode_gsm_rlcmac_downlink_data(data_block_vector, data_block);
 	LOGP(DRLCMAC, LOGL_NOTICE, "------------------------- TX : Downlink Data Block -------------------------\n");
 	free(data_block);
-	pcu_l1if_tx(data_block_vector, GsmL1_Sapi_Pdtch);
+	gprs_rlcmac_enqueue_block(data_block_vector, BLOCK_LEN);
 	bitvec_free(data_block_vector);
 	
 	// Singular case, TS 44.060 10.4.14
@@ -780,6 +845,8 @@ int gprs_rlcmac_segment_llc_pdu(struct gprs_rlcmac_tbf *tbf)
 			start_index += block_data_len;
 		}
 	}
+
+	return 0;
 }
 
 /* Send Uplink unit-data to SGSN. */
@@ -812,8 +879,8 @@ void gprs_rlcmac_downlink_assignment(gprs_rlcmac_tbf *tbf)
 	LOGP(DRLCMAC, LOGL_NOTICE, "TX: [PCU -> BTS] TFI: %u TLLI: 0x%08x Immidiate Assignment (CCCH)\n", tbf->tfi, tbf->tlli);
 	bitvec *immediate_assignment = bitvec_alloc(23);
 	bitvec_unhex(immediate_assignment, "2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b");
-	int len = write_immediate_assignment(immediate_assignment, 1, 125, get_current_fn(), (l1fh->fl1h)->channel_info.ta, tbf->tfi, tbf->tlli);
-	pcu_l1if_tx(immediate_assignment, GsmL1_Sapi_Agch, len);
+	int len = write_immediate_assignment(immediate_assignment, 1, 125, get_current_fn(), tbf->ta, tbf->arfcn, tbf->ts, tbf->tsc, tbf->tfi, tbf->tlli);
+	pcu_l1if_tx_agch(immediate_assignment, len);
 	bitvec_free(immediate_assignment);
 	tbf_gsm_timer_start(tbf, 0, 120);
 }
@@ -823,15 +890,14 @@ void gprs_rlcmac_packet_downlink_assignment(gprs_rlcmac_tbf *tbf)
 	LOGP(DRLCMAC, LOGL_NOTICE, "TX: [PCU -> BTS] TFI: %u TLLI: 0x%08x Packet DL Assignment\n", tbf->tfi, tbf->tlli);
 	bitvec *packet_downlink_assignment_vec = bitvec_alloc(23);
 	bitvec_unhex(packet_downlink_assignment_vec, "2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b");
-	write_packet_downlink_assignment(packet_downlink_assignment_vec, tbf->tfi, tbf->tlli, (l1fh->fl1h)->channel_info.tn,
-                                                (l1fh->fl1h)->channel_info.ta, (l1fh->fl1h)->channel_info.tsc);
+	write_packet_downlink_assignment(packet_downlink_assignment_vec, tbf->tfi, tbf->tlli, tbf->ts, tbf->ta, tbf->tsc);
 	RlcMacDownlink_t * packet_downlink_assignment = (RlcMacDownlink_t *)malloc(sizeof(RlcMacDownlink_t));
 	LOGP(DRLCMAC, LOGL_NOTICE, "+++++++++++++++++++++++++ TX : Packet Downlink Assignment +++++++++++++++++++++++++\n");
 	decode_gsm_rlcmac_downlink(packet_downlink_assignment_vec, packet_downlink_assignment);
 	LOGPC(DRLCMAC, LOGL_NOTICE, "\n");
 	LOGP(DRLCMAC, LOGL_NOTICE, "------------------------- TX : Packet Downlink Assignment -------------------------\n");
 	free(packet_downlink_assignment);
-	pcu_l1if_tx(packet_downlink_assignment_vec, GsmL1_Sapi_Pacch);
+	gprs_rlcmac_enqueue_block(packet_downlink_assignment_vec, 23);
 	bitvec_free(packet_downlink_assignment_vec);
 	tbf_gsm_timer_start(tbf, 0, 120);
 }