Adding direct access to DSP of sysmoBTS for PDTCH traffice

In order to use this feature, sysmoBTS requires option "-M", otherwise
the traffic is forwarded through socket interface.

This is essential, if PCU runs on processor of sysmoBTS. The reaction
time and delay of PDTCH frames could heavily degrade proper packet flow.

1 files changed, 353 insertions, 0 deletions

diff --git a/src/sysmo_l1_if.c b/src/sysmo_l1_if.c
new file mode 100644
index 00000000..7cb1d177
--- /dev/null
+++ b/src/sysmo_l1_if.c
@@ -0,0 +1,353 @@
+
+#include <string.h>
+#include <errno.h>
+
+#include <sysmocom/femtobts/superfemto.h>
+#include <sysmocom/femtobts/gsml1prim.h>
+#include <sysmocom/femtobts/gsml1const.h>
+#include <sysmocom/femtobts/gsml1types.h>
+
+#include <osmocom/core/gsmtap.h>
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/timer.h>
+#include <sysmo_l1_if.h>
+#include <gprs_debug.h>
+#include <pcu_l1_if.h>
+
+uint32_t l1if_ts_to_hLayer2(uint8_t trx, uint8_t ts)
+{
+	return (ts << 16) | (trx << 24);
+}
+
+/* allocate a msgb containing a GsmL1_Prim_t */
+struct msgb *l1p_msgb_alloc(void)
+{
+	struct msgb *msg = msgb_alloc(sizeof(GsmL1_Prim_t), "l1_prim");
+
+	if (msg)
+		msg->l1h = msgb_put(msg, sizeof(GsmL1_Prim_t));
+
+	return msg;
+}
+
+static int l1if_req_pdch(struct femtol1_hdl *fl1h, struct msgb *msg)
+{
+	struct osmo_wqueue *wqueue = &fl1h->write_q[MQ_PDTCH_WRITE];
+
+	osmo_wqueue_enqueue(wqueue, msg);
+
+	return 0;
+}
+
+static void *prim_init(GsmL1_Prim_t *prim, GsmL1_PrimId_t id, struct femtol1_hdl *gl1)
+{
+	prim->id = id;
+
+	/* for some reason the hLayer1 field is not always at the same position
+	 * in the GsmL1_Prim_t, so we have to have this ugly case statement here... */
+	switch (id) {
+	case GsmL1_PrimId_MphInitReq:
+		//prim->u.mphInitReq.hLayer1 = gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphCloseReq:
+		prim->u.mphCloseReq.hLayer1 = gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphConnectReq:
+		prim->u.mphConnectReq.hLayer1 = gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphDisconnectReq:
+		prim->u.mphDisconnectReq.hLayer1 = gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphActivateReq:
+		prim->u.mphActivateReq.hLayer1 = gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphDeactivateReq:
+		prim->u.mphDeactivateReq.hLayer1 = gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphConfigReq:
+		prim->u.mphConfigReq.hLayer1 = gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphMeasureReq:
+		prim->u.mphMeasureReq.hLayer1 = gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphInitCnf:
+	case GsmL1_PrimId_MphCloseCnf:
+	case GsmL1_PrimId_MphConnectCnf:
+	case GsmL1_PrimId_MphDisconnectCnf:
+	case GsmL1_PrimId_MphActivateCnf:
+	case GsmL1_PrimId_MphDeactivateCnf:
+	case GsmL1_PrimId_MphConfigCnf:
+	case GsmL1_PrimId_MphMeasureCnf:
+		break;
+	case GsmL1_PrimId_MphTimeInd:
+		break;
+	case GsmL1_PrimId_MphSyncInd:
+		break;
+	case GsmL1_PrimId_PhEmptyFrameReq:
+		prim->u.phEmptyFrameReq.hLayer1 = gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_PhDataReq:
+		prim->u.phDataReq.hLayer1 = gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_PhConnectInd:
+		break;
+	case GsmL1_PrimId_PhReadyToSendInd:
+		break;
+	case GsmL1_PrimId_PhDataInd:
+		break;
+	case GsmL1_PrimId_PhRaInd:
+		break;
+	default:
+		LOGP(DL1IF, LOGL_ERROR, "unknown L1 primitive %u\n", id);
+		break;
+	}
+	return &prim->u;
+}
+
+struct sapi_dir {
+	GsmL1_Sapi_t sapi;
+	GsmL1_Dir_t dir;
+};
+
+static const struct sapi_dir pdtch_sapis[] = {
+	{ GsmL1_Sapi_Pdtch,	GsmL1_Dir_TxDownlink },
+	{ GsmL1_Sapi_Pdtch,	GsmL1_Dir_RxUplink },
+	{ GsmL1_Sapi_Ptcch,	GsmL1_Dir_TxDownlink },
+	{ GsmL1_Sapi_Prach,	GsmL1_Dir_RxUplink },
+#if 0
+	{ GsmL1_Sapi_Ptcch,	GsmL1_Dir_RxUplink },
+	{ GsmL1_Sapi_Pacch,	GsmL1_Dir_TxDownlink },
+#endif
+};
+
+
+/* connect PDTCH */
+int l1if_connect_pdch(void *obj, uint8_t ts)
+{
+	struct femtol1_hdl *fl1h = obj;
+	struct msgb *msg = l1p_msgb_alloc();
+	GsmL1_MphConnectReq_t *cr;
+
+	cr = prim_init(msgb_l1prim(msg), GsmL1_PrimId_MphConnectReq, fl1h);
+	cr->u8Tn = ts;
+	cr->logChComb = GsmL1_LogChComb_XIII;
+	
+	return l1if_req_pdch(fl1h, msg);
+}
+
+static int handle_ph_readytosend_ind(struct femtol1_hdl *fl1h,
+				     GsmL1_PhReadyToSendInd_t *rts_ind)
+{
+	struct gsm_time g_time;
+	int rc = 0;
+
+	gsm_fn2gsmtime(&g_time, rts_ind->u32Fn);
+
+	DEBUGP(DL1IF, "Rx PH-RTS.ind %02u/%02u/%02u SAPI=%s\n",
+		g_time.t1, g_time.t2, g_time.t3,
+		get_value_string(femtobts_l1sapi_names, rts_ind->sapi));
+
+	switch (rts_ind->sapi) {
+	case GsmL1_Sapi_Pdtch:
+	case GsmL1_Sapi_Pacch:
+		rc = pcu_rx_rts_req_pdtch((long)fl1h->priv, rts_ind->u8Tn,
+			rts_ind->u16Arfcn, rts_ind->u32Fn, rts_ind->u8BlockNbr);
+	case GsmL1_Sapi_Ptcch:
+		// FIXME
+	default:
+		break;
+	}
+
+	return rc;
+}
+
+static int handle_ph_data_ind(struct femtol1_hdl *fl1h,
+	GsmL1_PhDataInd_t *data_ind, struct msgb *l1p_msg)
+{
+	int rc = 0;
+
+	gsmtap_send(fl1h->gsmtap, data_ind->u16Arfcn | GSMTAP_ARFCN_F_UPLINK,
+			data_ind->u8Tn, GSMTAP_CHANNEL_PACCH, 0,
+			data_ind->u32Fn, 0, 0, data_ind->msgUnitParam.u8Buffer,
+			data_ind->msgUnitParam.u8Size);
+
+	DEBUGP(DL1IF, "Rx PH-DATA.ind %s (hL2 %08x): %s",
+		get_value_string(femtobts_l1sapi_names, data_ind->sapi),
+		data_ind->hLayer2,
+		osmo_hexdump(data_ind->msgUnitParam.u8Buffer,
+			     data_ind->msgUnitParam.u8Size));
+
+	switch (data_ind->sapi) {
+	case GsmL1_Sapi_Pdtch:
+	case GsmL1_Sapi_Pacch:
+		/* drop incomplete UL block */
+		if (data_ind->msgUnitParam.u8Buffer[0]
+			!= GsmL1_PdtchPlType_Full)
+			break;
+		/* PDTCH / PACCH frame handling */
+		pcu_rx_data_ind_pdtch((long)fl1h->priv, data_ind->u8Tn,
+			data_ind->msgUnitParam.u8Buffer + 1,
+			data_ind->msgUnitParam.u8Size - 1,
+			data_ind->u32Fn);
+		break;
+	case GsmL1_Sapi_Ptcch:
+		// FIXME
+		break;
+	default:
+		LOGP(DL1IF, LOGL_NOTICE, "Rx PH-DATA.ind for unknown L1 SAPI %s\n",
+			get_value_string(femtobts_l1sapi_names, data_ind->sapi));
+		break;
+	}
+
+	return rc;
+}
+
+#define MIN_QUAL_RACH	5.0f
+
+static int handle_ph_ra_ind(struct femtol1_hdl *fl1h, GsmL1_PhRaInd_t *ra_ind)
+{
+	uint8_t acc_delay;
+
+	if (ra_ind->measParam.fLinkQuality < MIN_QUAL_RACH)
+		return 0;
+
+	DEBUGP(DL1IF, "Rx PH-RA.ind");
+
+	/* check for under/overflow / sign */
+	if (ra_ind->measParam.i16BurstTiming < 0)
+		acc_delay = 0;
+	else
+		acc_delay = ra_ind->measParam.i16BurstTiming >> 2;
+#if 0
+	if (acc_delay > bts->max_ta) {
+		LOGP(DL1C, LOGL_INFO, "ignoring RACH request %u > max_ta(%u)\n",
+		     acc_delay, btsb->max_ta);
+		return 0;
+	}
+#endif
+
+	return 0;
+}
+
+
+/* handle any random indication from the L1 */
+int l1if_handle_l1prim(int wq, struct femtol1_hdl *fl1h, struct msgb *msg)
+{
+	GsmL1_Prim_t *l1p = msgb_l1prim(msg);
+	int rc = 0;
+
+	LOGP(DL1IF, LOGL_DEBUG, "Rx L1 prim %s on queue %d\n",
+		get_value_string(femtobts_l1prim_names, l1p->id), wq);
+
+	switch (l1p->id) {
+#if 0
+	case GsmL1_PrimId_MphTimeInd:
+		rc = handle_mph_time_ind(fl1h, &l1p->u.mphTimeInd);
+		break;
+	case GsmL1_PrimId_MphSyncInd:
+		break;
+	case GsmL1_PrimId_PhConnectInd:
+		break;
+#endif
+	case GsmL1_PrimId_PhReadyToSendInd:
+		rc = handle_ph_readytosend_ind(fl1h, &l1p->u.phReadyToSendInd);
+		break;
+	case GsmL1_PrimId_PhDataInd:
+		rc = handle_ph_data_ind(fl1h, &l1p->u.phDataInd, msg);
+		break;
+	case GsmL1_PrimId_PhRaInd:
+		rc = handle_ph_ra_ind(fl1h, &l1p->u.phRaInd);
+		break;
+	default:
+		break;
+	}
+
+	msgb_free(msg);
+
+	return rc;
+}
+
+int l1if_handle_sysprim(struct femtol1_hdl *fl1h, struct msgb *msg)
+{
+	return -ENOTSUP;
+}
+
+/* send packet data request to L1 */
+int l1if_pdch_req(void *obj, uint8_t ts, int is_ptcch, uint32_t fn,
+	uint16_t arfcn, uint8_t block_nr, uint8_t *data, uint8_t len)
+{
+	struct femtol1_hdl *fl1h = obj;
+	struct msgb *msg;
+	GsmL1_Prim_t *l1p;
+	GsmL1_PhDataReq_t *data_req;
+	GsmL1_MsgUnitParam_t *msu_param;
+	struct gsm_time g_time;
+
+	gsm_fn2gsmtime(&g_time, fn);
+
+	DEBUGP(DL1IF, "TX packet data %02u/%02u/%02u is_ptcch=%d ts=%d "
+		"block_nr=%d, arfcn=%d, len=%d\n", g_time.t1, g_time.t2,
+		g_time.t3, is_ptcch, ts, block_nr, arfcn, len);
+
+	msg = l1p_msgb_alloc();
+	l1p = msgb_l1prim(msg);
+	l1p->id = GsmL1_PrimId_PhDataReq;
+	data_req = &l1p->u.phDataReq;
+	data_req->hLayer1 = fl1h->hLayer1;
+	data_req->sapi = (is_ptcch) ? GsmL1_Sapi_Ptcch : GsmL1_Sapi_Pdtch;
+	data_req->subCh = GsmL1_SubCh_NA;
+	data_req->u8BlockNbr = block_nr;
+	data_req->u8Tn = ts;
+	data_req->u32Fn = fn;
+	msu_param = &data_req->msgUnitParam;
+	msu_param->u8Size = len;
+	memcpy(msu_param->u8Buffer, data, len);
+
+	gsmtap_send(fl1h->gsmtap, arfcn, data_req->u8Tn, GSMTAP_CHANNEL_PACCH,
+			0, data_req->u32Fn, 0, 0,
+			data_req->msgUnitParam.u8Buffer,
+			data_req->msgUnitParam.u8Size);
+
+
+	/* transmit */
+	osmo_wqueue_enqueue(&fl1h->write_q[MQ_PDTCH_WRITE], msg);
+
+	return 0;
+}
+
+void *l1if_open_pdch(void *priv, uint32_t hlayer1)
+{
+	struct femtol1_hdl *fl1h;
+	int rc;
+
+	fl1h = talloc_zero(priv, struct femtol1_hdl);
+	if (!fl1h)
+		return NULL;
+
+	fl1h->hLayer1 = hlayer1;
+	fl1h->priv = priv;
+	fl1h->clk_cal = 0;
+	/* default clock source: OCXO */
+	fl1h->clk_src = SuperFemto_ClkSrcId_Ocxo;
+
+	rc = l1if_transport_open(MQ_PDTCH_WRITE, fl1h);
+	if (rc < 0) {
+		talloc_free(fl1h);
+		return NULL;
+	}
+
+	fl1h->gsmtap = gsmtap_source_init("localhost", GSMTAP_UDP_PORT, 1);
+	if (fl1h->gsmtap)
+		gsmtap_source_add_sink(fl1h->gsmtap);
+
+	return fl1h;
+}
+
+static int l1if_close_pdch(void *obj)
+{
+	struct femtol1_hdl *fl1h = obj;
+	if (fl1h)
+		l1if_transport_close(MQ_PDTCH_WRITE, fl1h);
+	return 0;
+}
+