ASCI: Control uplink access bursts detection of physical interface

An MPH-INFO message is used to turn detection of uplink access bursts on
or off. Whenever the uplink on a voice group channel is free, the uplink
access burst detection is turned on. When the uplink access is granted
to a talker or when the calling subscriber has been assigned to the
channel, the uplink access burst detection is turned off until the
uplink becomes free again.

Related: OS#4851
Depends: libosmocore.git Ibd6a1d468a70126a8f67e944fcb916969cc3c36b
Change-Id: I92d6773a3a463eb747143c85aa149e54c1fda122

6 files changed, 62 insertions, 11 deletions

diff --git a/include/osmo-bts/asci.h b/include/osmo-bts/asci.h
index 59b48b27..99802962 100644
--- a/include/osmo-bts/asci.h
+++ b/include/osmo-bts/asci.h
@@ -11,11 +11,13 @@ enum {
 
 void vgcs_rach(struct gsm_lchan *lchan, uint8_t ra, uint8_t acc_delay, uint32_t fn);
 
+void vgcs_lchan_activate(struct gsm_lchan *lchan);
+
 void vgcs_lchan_react(struct gsm_lchan *lchan);
 
 void vgcs_talker_frame(struct gsm_lchan *lchan);
 
-void vgcs_talker_reset(struct gsm_lchan *lchan);
+void vgcs_talker_reset(struct gsm_lchan *lchan, bool ul_access);
 
 void vgcs_listener_reset(struct gsm_lchan *lchan);
 
diff --git a/include/osmo-bts/l1sap.h b/include/osmo-bts/l1sap.h
index 353fc905..34259bd3 100644
--- a/include/osmo-bts/l1sap.h
+++ b/include/osmo-bts/l1sap.h
@@ -102,6 +102,7 @@ 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);
+int l1sap_uplink_access(struct gsm_lchan *lchan, bool active);
 
 enum l1sap_common_sapi {
 	L1SAP_COMMON_SAPI_UNKNOWN,
diff --git a/src/common/asci.c b/src/common/asci.c
index ccaacd8e..88d40e78 100644
--- a/src/common/asci.c
+++ b/src/common/asci.c
@@ -126,9 +126,9 @@ void vgcs_rach(struct gsm_lchan *lchan, uint8_t ra, uint8_t acc_delay, uint32_t
 
 		/* Stop RACH detection, wait for valid frame */
 		lchan->asci.talker_active = VGCS_TALKER_WAIT_FRAME;
-		if (l1sap_chan_modify(lchan->ts->trx, gsm_lchan2chan_nr(lchan)) != 0) {
-			LOGPLCHAN(lchan, DASCI, LOGL_ERROR, "failed to modify channel after TALKER DET\n");
-			rsl_tx_conn_fail(lchan, RSL_ERR_TALKER_ACC_FAIL);
+		if (l1sap_uplink_access(lchan, false) != 0) {
+			LOGPLCHAN(lchan, DASCI, LOGL_ERROR, "Failed to deactivate uplink access after TALKER DET.\n");
+			rsl_tx_conn_fail(lchan, RSL_ERR_EQUIPMENT_FAIL);
 			lchan->asci.talker_active = VGCS_TALKER_NONE;
 			return;
 		}
@@ -151,11 +151,25 @@ void vgcs_rach(struct gsm_lchan *lchan, uint8_t ra, uint8_t acc_delay, uint32_t
 	}
 }
 
+/* Received channel activation. */
+void vgcs_lchan_activate(struct gsm_lchan *lchan)
+{
+	LOGPLCHAN(lchan, DASCI, LOGL_INFO, "Channel is activated.\n");
+	if (l1sap_uplink_access(lchan, true) != 0) {
+		LOGPLCHAN(lchan, DASCI, LOGL_ERROR, "Failed to activate uplink access after channel activation.\n");
+		rsl_tx_conn_fail(lchan, RSL_ERR_EQUIPMENT_FAIL);
+	}
+}
+
 /* Received channel reactivation. (for assignment) */
 void vgcs_lchan_react(struct gsm_lchan *lchan)
 {
 	LOGPLCHAN(lchan, DASCI, LOGL_INFO, "Channel is activated for assignment.\n");
 	lchan->asci.talker_active = VGCS_TALKER_WAIT_FRAME;
+	if (l1sap_uplink_access(lchan, false) != 0) {
+		LOGPLCHAN(lchan, DASCI, LOGL_ERROR, "Failed to deactivate uplink access for assignment.\n");
+		rsl_tx_conn_fail(lchan, RSL_ERR_EQUIPMENT_FAIL);
+	}
 	radio_link_timeout_reset(lchan);
 }
 
@@ -169,7 +183,7 @@ void vgcs_talker_frame(struct gsm_lchan *lchan)
 }
 
 /* Release VGCS Talker state. */
-void vgcs_talker_reset(struct gsm_lchan *lchan)
+void vgcs_talker_reset(struct gsm_lchan *lchan, bool ul_access)
 {
 	if (lchan->asci.talker_active == VGCS_TALKER_NONE)
 		return;
@@ -179,8 +193,15 @@ void vgcs_talker_reset(struct gsm_lchan *lchan)
 	/* Stop T3115 */
 	osmo_timer_del(&lchan->asci.t3115);
 
-	/* Talker detection done */
+	/* Talker released. */
 	lchan->asci.talker_active = VGCS_TALKER_NONE;
+	if (ul_access) {
+		if (l1sap_uplink_access(lchan, true) != 0) {
+			LOGPLCHAN(lchan, DASCI, LOGL_ERROR,
+				  "Failed to activate uplink access after uplink became free.\n");
+			rsl_tx_conn_fail(lchan, RSL_ERR_EQUIPMENT_FAIL);
+		}
+	}
 }
 
 /* Release VGCS Listener state. */
diff --git a/src/common/l1sap.c b/src/common/l1sap.c
index 844fdada..c5997260 100644
--- a/src/common/l1sap.c
+++ b/src/common/l1sap.c
@@ -2444,3 +2444,26 @@ int l1sap_chan_modify(struct gsm_bts_trx *trx, uint8_t chan_nr)
 
 	return l1sap_chan_act_dact_modify(trx, chan_nr, PRIM_INFO_MODIFY, 0);
 }
+
+int l1sap_uplink_access(struct gsm_lchan *lchan, bool active)
+{
+	uint8_t chan_nr = gsm_lchan2chan_nr(lchan);
+	struct osmo_phsap_prim l1sap;
+
+	if (lchan->state != LCHAN_S_ACTIVE && !rsl_chan_rt_is_asci(lchan->rsl_chan_rt)) {
+		LOGPLCHAN(lchan, DL1C, LOGL_ERROR, "Channel %s is not an active ASCI type channel.\n",
+			  rsl_chan_nr_str(chan_nr));
+		return -EINVAL;
+	}
+
+	LOGPLCHAN(lchan, DL1C, LOGL_INFO, "%s uplink access detection on channel %s\n",
+		  (active) ? "Activating" : "Deactivating", rsl_chan_nr_str(chan_nr));
+
+
+	memset(&l1sap, 0, sizeof(l1sap));
+	osmo_prim_init(&l1sap.oph, SAP_GSM_PH, PRIM_MPH_INFO, PRIM_OP_REQUEST, NULL);
+	l1sap.u.info.type = (active) ? PRIM_INFO_ACT_UL_ACC : PRIM_INFO_DEACT_UL_ACC;
+	l1sap.u.info.u.ulacc_req.chan_nr = chan_nr;
+
+	return l1sap_down(lchan->ts->trx, &l1sap);
+}
diff --git a/src/common/lchan.c b/src/common/lchan.c
index bd503497..6178200f 100644
--- a/src/common/lchan.c
+++ b/src/common/lchan.c
@@ -219,7 +219,7 @@ void gsm_lchan_release(struct gsm_lchan *lchan, enum lchan_rel_act_kind rel_kind
 
 	/* release handover, listener and talker states */
 	handover_reset(lchan);
-	vgcs_talker_reset(lchan);
+	vgcs_talker_reset(lchan, false);
 	vgcs_listener_reset(lchan);
 	vgcs_uplink_free_reset(lchan);
 
diff --git a/src/common/rsl.c b/src/common/rsl.c
index 09723bed..deeb255c 100644
--- a/src/common/rsl.c
+++ b/src/common/rsl.c
@@ -2207,8 +2207,12 @@ static int rsl_rx_chan_activ(struct msgb *msg)
 		lchan->top_acch_active = false;
 
 	/* set ASCI channel into right state */
-	if (reactivation && rsl_chan_rt_is_asci(lchan->rsl_chan_rt))
-		vgcs_lchan_react(lchan);
+	if (rsl_chan_rt_is_asci(lchan->rsl_chan_rt)) {
+		if (reactivation)
+			vgcs_lchan_react(lchan);
+		else
+			vgcs_lchan_activate(lchan);
+	}
 
 	/* on reactivation, the channel is already activated */
 	if (reactivation) {
@@ -3618,7 +3622,7 @@ static int rsl_rx_rll(struct gsm_bts_trx *trx, struct msgb *msg)
 
 	/* VGCS Uplink is released by MSC using REL-REQ. */
 	if (rh->c.msg_type == RSL_MT_REL_REQ)
-		vgcs_talker_reset(lchan);
+		vgcs_talker_reset(lchan, true);
 
 	LOGPLCHAN(lchan, DRLL, LOGL_DEBUG, "Rx RLL %s Abis -> LAPDm\n", rsl_msg_name(rh->c.msg_type));
 
@@ -3840,7 +3844,7 @@ int lapdm_rll_tx_cb(struct msgb *msg, struct lapdm_entity *le, void *ctx)
 
 		/* REL_IND handling */
 		if (rh->msg_type == RSL_MT_REL_IND && lchan_is_tch(lchan)) {
-			vgcs_talker_reset(lchan);
+			vgcs_talker_reset(lchan, true);
 			LOGPLCHAN(lchan, DRSL, LOGL_INFO,
 				  "Scheduling %s to L3 in next associated TCH-RTS.ind\n",
 				  rsl_msg_name(rh->msg_type));