smscb: Base cell operational life cycle on CBCH being operative

This allows running CBCH/ETWS related procedures only when the CBCH
towards MS under that cell is operative.
This also allows providing awarness of per-cell status to the CBSP peer
as required per specs.

Related: SYS#5910
Change-Id: Ia93919be94132fc010acb5bbfef0a6fd51c42981

include/osmocom/bsc/smscb.h

@@ -9,6 +9,7 @@
 struct bsc_cbc_link;
 
 /* smscb.c */
+void smscb_global_init(void);
 void bts_smscb_del(struct bts_smscb_message *smscb, struct bts_smscb_chan_state *cstate,
 		   const char *reason);
 const char *bts_smscb_msg2str(const struct bts_smscb_message *smscb);
@@ -25,7 +26,9 @@ struct bts_smscb_page *bts_smscb_pull_page(struct bts_smscb_chan_state *cstate);
 void bts_smscb_page_done(struct bts_smscb_chan_state *cstate, struct bts_smscb_page *page);
 int bts_smscb_rx_cbch_load_ind(struct gsm_bts *bts, bool cbch_extended, bool is_overflow,
 			       uint8_t slot_count);
+void bts_cbch_init(struct gsm_bts *bts);
 void bts_cbch_timer_schedule(struct gsm_bts *bts);
+void bts_cbch_timer_cb(void *data);
 
 enum bsc_cbc_link_mode {
 	BSC_CBC_LINK_MODE_DISABLED = 0,
@@ -64,7 +67,6 @@ int bsc_cbc_link_restart(void);
 int cbsp_tx_decoded(struct bsc_cbc_link *cbc, struct osmo_cbsp_decoded *decoded);
 
 void bts_etws_init(struct gsm_bts *bts);
-void bts_etws_bootstrap(struct gsm_bts *bts);
 
 /* smscb_vty.c: */
 void smscb_vty_init(void);

src/osmo-bsc/bts.c

@@ -93,12 +93,6 @@ const char *btstype2str(enum gsm_bts_type type)
 	return get_value_string(bts_type_names, type);
 }
 
-static void bts_init_cbch_state(struct bts_smscb_chan_state *cstate, struct gsm_bts *bts)
-{
-	cstate->bts = bts;
-	INIT_LLIST_HEAD(&cstate->messages);
-}
-
 static LLIST_HEAD(bts_models);
 
 struct gsm_bts_model *bts_model_find(enum gsm_bts_type type)
@@ -152,6 +146,8 @@ static int gsm_bts_talloc_destructor(struct gsm_bts *bts)
 {
 	paging_destructor(bts);
 
+	osmo_timer_del(&bts->cbch_timer);
+
 	bts->site_mgr->bts[0] = NULL;
 
 	if (bts->gprs.cell.mo.fi) {
@@ -429,8 +425,7 @@ struct gsm_bts *gsm_bts_alloc(struct gsm_network *net, struct gsm_bts_sm *bts_sm
 	memcpy(&bts->mr_half.bts_mode[0], &amr_hr_ms_bts_mode[0], sizeof(amr_hr_ms_bts_mode));
 	bts->mr_half.num_modes = ARRAY_SIZE(amr_hr_ms_bts_mode);
 
-	bts_init_cbch_state(&bts->cbch_basic, bts);
-	bts_init_cbch_state(&bts->cbch_extended, bts);
+	bts_cbch_init(bts);
 	bts_etws_init(bts);
 
 	acc_mgr_init(&bts->acc_mgr, bts);

src/osmo-bsc/cbch_scheduler.c

@@ -246,7 +246,7 @@ static void bts_cbch_send_one(struct bts_smscb_chan_state *cstate)
 	bts_smscb_page_done(cstate, page);
 }
 
-static void bts_cbch_timer_cb(void *data)
+void bts_cbch_timer_cb(void *data)
 {
 	struct gsm_bts *bts = (struct gsm_bts *)data;
 
@@ -259,7 +259,6 @@ static void bts_cbch_timer_cb(void *data)
 /* There is one SMSCB message (page) per eight 51-multiframes, i.e. 1.882 seconds */
 void bts_cbch_timer_schedule(struct gsm_bts *bts)
 {
-	osmo_timer_setup(&bts->cbch_timer, &bts_cbch_timer_cb, bts);
 	osmo_timer_schedule(&bts->cbch_timer, 1, 882920);
 }
 

src/osmo-bsc/osmo_bsc_main.c

@@ -359,14 +359,6 @@ static void bootstrap_rsl(struct gsm_bts_trx *trx)
 		osmo_fsm_inst_dispatch(ts->fi, TS_EV_RSL_READY, NULL);
 	}
 
-	/* Start CBCH transmit timer if CBCH is present */
-	if (trx->nr == 0 && gsm_bts_get_cbch(trx->bts))
-		bts_cbch_timer_schedule(trx->bts);
-
-	/* Start ETWS/PWS Primary Notification, if active */
-	if (trx->nr == 0)
-		bts_etws_bootstrap(trx->bts);
-
 	/* Drop all expired channel requests in the list */
 	abis_rsl_chan_rqd_queue_flush(trx->bts);
 }
@@ -469,8 +461,6 @@ static int inp_sig_cb(unsigned int subsys, unsigned int signal,
 			rate_ctr_inc(rate_ctr_group_get_ctr(trx->bts->bts_ctrs, BTS_CTR_BTS_RSL_FAIL));
 			acc_ramp_abort(&trx->bts->acc_ramp);
 			gsm_trx_all_ts_dispatch(trx, TS_EV_RSL_DOWN, NULL);
-			if (trx->nr == 0)
-				osmo_timer_del(&trx->bts->cbch_timer);
 		}
 
 		gsm_bts_sm_mo_reset(trx->bts->site_mgr);
@@ -935,6 +925,7 @@ int main(int argc, char **argv)
 	lb_init();
 	acc_ramp_global_init();
 	paging_global_init();
+	smscb_global_init();
 
 	/* Read the config */
 	rc = bsc_network_configure(config_file);

src/osmo-bsc/smscb.c

@@ -27,6 +27,7 @@
 #include <osmocom/core/msgb.h>
 #include <osmocom/core/talloc.h>
 #include <osmocom/core/byteswap.h>
+#include <osmocom/core/signal.h>
 
 #include <osmocom/gsm/cbsp.h>
 #include <osmocom/gsm/protocol/gsm_23_041.h>
@@ -42,6 +43,7 @@
 #include <osmocom/bsc/lchan_fsm.h>
 #include <osmocom/bsc/abis_rsl.h>
 #include <osmocom/bsc/bts.h>
+#include <osmocom/bsc/signal.h>
 
 /*********************************************************************************
  * Helper Functions
@@ -74,6 +76,19 @@ static int gen_etws_primary_notification(uint8_t *out, uint16_t serial_nr, uint1
 	return ETWS_PRIM_NOTIF_SIZE;
 }
 
+static void bts_cbch_init_state(struct bts_smscb_chan_state *cstate, struct gsm_bts *bts)
+{
+	cstate->bts = bts;
+	INIT_LLIST_HEAD(&cstate->messages);
+}
+
+void bts_cbch_init(struct gsm_bts *bts)
+{
+	bts_cbch_init_state(&bts->cbch_basic, bts);
+	bts_cbch_init_state(&bts->cbch_extended, bts);
+	osmo_timer_setup(&bts->cbch_timer, &bts_cbch_timer_cb, bts);
+}
+
 /*! Obtain SMSCB Channel State for given BTS (basic or extended CBCH) */
 struct bts_smscb_chan_state *bts_get_smscb_chan(struct gsm_bts *bts, bool extended)
 {
@@ -1033,8 +1048,64 @@ void bts_etws_init(struct gsm_bts *bts)
 }
 
 /* BSC is bootstrapping a BTS; install any currently active ETWS PN */
-void bts_etws_bootstrap(struct gsm_bts *bts)
+static void bts_etws_bootstrap(struct gsm_bts *bts)
 {
 	if (bts->etws.active)
 		bts_send_etws(bts);
 }
+
+/* Callback function to be called every time we receive a signal from NM */
+static int nm_sig_cb(unsigned int subsys, unsigned int signal,
+		     void *handler_data, void *signal_data)
+{
+	struct nm_running_chg_signal_data *nsd;
+	struct gsm_bts *bts;
+	struct gsm_bts_trx *trx;
+
+	if (signal != S_NM_RUNNING_CHG)
+		return 0;
+
+	nsd = signal_data;
+	bts = nsd->bts;
+
+	switch (nsd->obj_class) {
+	case NM_OC_RADIO_CARRIER:
+		trx = (struct gsm_bts_trx *)nsd->obj;
+		break;
+	case NM_OC_BASEB_TRANSC:
+		trx = gsm_bts_bb_trx_get_trx((struct gsm_bts_bb_trx *)nsd->obj);
+		break;
+	default:
+		return 0;
+	}
+
+	struct gsm_lchan *cbch = gsm_bts_get_cbch(bts);
+	if (!cbch)
+		return 0;
+	/* We only care about state changes of TRX holding the CBCH. */
+	if (trx != cbch->ts->trx)
+		return 0;
+
+	if (nsd->running) {
+		if (trx_is_usable(trx)) {
+			LOG_BTS(bts, DCBS, LOGL_INFO, "BTS becomes available for CBCH\n");
+			/* Start CBCH transmit timer if CBCH is present */
+			bts_cbch_timer_schedule(trx->bts);
+			/* Start ETWS/PWS Primary Notification, if active */
+			bts_etws_bootstrap(trx->bts);
+		}
+	} else {
+		if (osmo_timer_pending(&bts->cbch_timer)) {
+			/* If timer is ongoing it means CBCH was available */
+			LOG_BTS(bts, DCBS, LOGL_INFO, "BTS becomes unavailable for CBCH\n");
+			osmo_timer_del(&bts->cbch_timer);
+		} /* else: CBCH was already unavailable before */
+	}
+	return 0;
+}
+
+/* To be called once at startup of the process: */
+void smscb_global_init(void)
+{
+	osmo_signal_register_handler(SS_NM, nm_sig_cb, NULL);
+}