[VAMOS] osmo-bts-trx: schedule bursts on 'shadow' timeslots

Change-Id: I3e0bdf8c03273f66991aa1764029ab1dd3528d7e
Related: SYS#4895, OS#4941

3 files changed, 45 insertions, 3 deletions

diff --git a/src/osmo-bts-trx/main.c b/src/osmo-bts-trx/main.c
index 6ec8dfc9..71349397 100644
--- a/src/osmo-bts-trx/main.c
+++ b/src/osmo-bts-trx/main.c
@@ -146,6 +146,7 @@ int bts_model_init(struct gsm_bts *bts)
 	osmo_bts_set_feature(bts->features, BTS_FEAT_HOPPING);
 	osmo_bts_set_feature(bts->features, BTS_FEAT_ACCH_REP);
 	osmo_bts_set_feature(bts->features, BTS_FEAT_MULTI_TSC);
+	osmo_bts_set_feature(bts->features, BTS_FEAT_VAMOS);
 
 	bts_internal_flag_set(bts, BTS_INTERNAL_FLAG_MEAS_PAYLOAD_COMB);
 
diff --git a/src/osmo-bts-trx/scheduler_trx.c b/src/osmo-bts-trx/scheduler_trx.c
index 4a23f117..1a4f03fa 100644
--- a/src/osmo-bts-trx/scheduler_trx.c
+++ b/src/osmo-bts-trx/scheduler_trx.c
@@ -149,6 +149,40 @@ static void bts_sched_flush_buffers(struct gsm_bts *bts)
 	}
 }
 
+/* schedule one frame for a shadow timeslot, merge bursts */
+static void _sched_dl_shadow_burst(const struct gsm_bts_trx_ts *ts,
+				   struct trx_dl_burst_req *br)
+{
+	struct l1sched_ts *l1ts = ts->priv;
+
+	/* For the shadow timeslots, physical channel type can be either
+	 * GSM_PCHAN_TCH_{F,H} or GSM_PCHAN_NONE.  Even if the primary
+	 * timeslot is a dynamic timeslot, it's always a concrete value. */
+	if (ts->pchan == GSM_PCHAN_NONE)
+		return;
+
+	struct trx_dl_burst_req sbr = {
+		.trx_num = br->trx_num,
+		.fn = br->fn,
+		.tn = br->tn,
+	};
+
+	_sched_dl_burst(l1ts, &sbr);
+
+	if (br->burst_len != 0 && sbr.burst_len != 0) { /* Both present */
+		memcpy(br->burst + GSM_BURST_LEN, sbr.burst, GSM_BURST_LEN);
+		br->burst_len = 2 * GSM_BURST_LEN;
+		br->mod = TRX_MOD_T_AQPSK;
+		/* FIXME: SCPIR is hard-coded to 0 */
+	} else if (br->burst_len == 0) {
+		/* No primary burst, send shadow burst alone */
+		memcpy(br, &sbr, sizeof(sbr));
+	} else if (sbr.burst_len == 0) {
+		/* No shadow burst, send primary burst alone */
+		return;
+	}
+}
+
 /* schedule all frames of all TRX for given FN */
 static void bts_sched_fn(struct gsm_bts *bts, const uint32_t fn)
 {
@@ -193,8 +227,11 @@ static void bts_sched_fn(struct gsm_bts *bts, const uint32_t fn)
 				br = &pinst->u.osmotrx.br[tn];
 			}
 
-			/* get burst for FN */
+			/* get burst for the primary timeslot */
 			_sched_dl_burst(l1ts, br);
+
+			/* get burst for the shadow timeslot */
+			_sched_dl_shadow_burst(ts->vamos.peer, br);
 		}
 	}
 
diff --git a/src/osmo-bts-trx/trx_if.c b/src/osmo-bts-trx/trx_if.c
index afd630f0..968c335e 100644
--- a/src/osmo-bts-trx/trx_if.c
+++ b/src/osmo-bts-trx/trx_if.c
@@ -755,6 +755,7 @@ static const uint8_t trx_data_rx_hdr_len[] = {
 static const uint8_t trx_data_mod_val[] = {
 	[TRX_MOD_T_GMSK]	= 0x00, /* .00xx... */
 	[TRX_MOD_T_8PSK]	= 0x20, /* .010x... */
+	[TRX_MOD_T_AQPSK]	= 0x60, /* .11xx... */
 };
 
 /* Header dissector for TRXDv0 (and part of TRXDv1) */
@@ -863,9 +864,12 @@ static int trx_data_handle_pdu_v2(struct phy_instance *phy_inst,
 	/* TDMA timeslot number (other bits are RFU) */
 	bi->tn = buf[0] & 0x07;
 
-	/* TRX (RF channel) number and BATCH.ind */
-	if (buf[1] & (1 << 7))
+	if (buf[1] & (1 << 7)) /* BATCH.ind */
 		bi->flags |= TRX_BI_F_BATCH_IND;
+	if (buf[1] & (1 << 6)) /* VAMOS.ind */
+		bi->flags |= TRX_BI_F_SHADOW_IND;
+
+	/* TRX (RF channel) number */
 	bi->trx_num = buf[1] & 0x3f;
 	bi->flags |= TRX_BI_F_TRX_NUM;