osmo-bts-trx: migrate to new generic ECU abstraction

libosmocodec has recently introduced a generic ECU abstraction layer
which supports (pluggable) Error Concealment Units for not only the
FR codec, but potentially any other codec, too.

Change-Id: I001005aae6de76d4e045b8dc572239f057bb150d
Depends: libosmocore I4d33c9c7c2d4c7462ff38a49c178b65accae1915

3 files changed, 78 insertions, 30 deletions

diff --git a/src/common/gsm_data_shared.c b/src/common/gsm_data_shared.c
index 1ba43aa6..f0f5ae20 100644
--- a/src/common/gsm_data_shared.c
+++ b/src/common/gsm_data_shared.c
@@ -31,6 +31,7 @@
 #include <osmocom/gsm/gsm_utils.h>
 #include <osmocom/gsm/abis_nm.h>
 #include <osmocom/core/statistics.h>
+#include <osmocom/codec/ecu.h>
 
 #include <osmo-bts/gsm_data.h>
 
@@ -807,3 +808,24 @@ const struct value_string lchan_ciph_state_names[] = {
 	{ LCHAN_CIPH_RXTX_CONF,	"RXTX_CONF" },
 	{ 0, NULL }
 };
+
+/* determine the ECU codec constant for the codec used by given lchan */
+int lchan2ecu_codec(const struct gsm_lchan *lchan)
+{
+	struct gsm_bts_trx_ts *ts = lchan->ts;
+
+	switch (lchan->tch_mode) {
+	case GSM48_CMODE_SPEECH_V1:
+		if (ts_pchan(ts) == GSM_PCHAN_TCH_H)
+			return OSMO_ECU_CODEC_HR;
+		else
+			return OSMO_ECU_CODEC_FR;
+		break;
+	case GSM48_CMODE_SPEECH_EFR:
+		return OSMO_ECU_CODEC_EFR;
+	case GSM48_CMODE_SPEECH_AMR:
+		return OSMO_ECU_CODEC_AMR;
+	default:
+		return -1;
+	}
+}
diff --git a/src/osmo-bts-trx/l1_if.c b/src/osmo-bts-trx/l1_if.c
index 22ef2d73..db53d4c6 100644
--- a/src/osmo-bts-trx/l1_if.c
+++ b/src/osmo-bts-trx/l1_if.c
@@ -29,6 +29,7 @@
 
 #include <osmocom/core/talloc.h>
 #include <osmocom/core/bits.h>
+#include <osmocom/codec/ecu.h>
 #include <osmocom/gsm/abis_nm.h>
 
 #include <osmo-bts/logging.h>
@@ -626,6 +627,9 @@ int bts_model_l1sap_down(struct gsm_bts_trx *trx, struct osmo_phsap_prim *l1sap)
 					break;
 				}
 
+				/* attempt to allocate an Error Concealment Unit instance, if available */
+				lchan->ecu_state = osmo_ecu_init(trx, lchan2ecu_codec(lchan));
+
 				/* trx_chan_desc[] in scheduler.c uses the RSL_CHAN_OSMO_PDCH cbits
 				 * (0xc0) to indicate the need for PDTCH and PTCCH SAPI activation.
 				 * However, 0xc0 is a cbits pattern exclusively used for Osmocom style
@@ -671,6 +675,10 @@ int bts_model_l1sap_down(struct gsm_bts_trx *trx, struct osmo_phsap_prim *l1sap)
 				break;
 			}
 			if (l1sap->u.info.type == PRIM_INFO_MODIFY) {
+				/* ECU for possibly new codec */
+				if (lchan->ecu_state)
+					osmo_ecu_destroy(lchan->ecu_state);
+				lchan->ecu_state = osmo_ecu_init(trx, lchan2ecu_codec(lchan));
 				/* change mode */
 				trx_sched_set_mode(&l1h->l1s, chan_nr,
 					lchan->rsl_cmode, lchan->tch_mode,
@@ -689,6 +697,11 @@ int bts_model_l1sap_down(struct gsm_bts_trx *trx, struct osmo_phsap_prim *l1sap)
 					"chan_nr 0x%02x\n", chan_nr);
 				break;
 			}
+			/* clear ECU state (if any) */
+			if (lchan->ecu_state) {
+				osmo_ecu_destroy(lchan->ecu_state);
+				lchan->ecu_state = NULL;
+			}
 			/* deactivate associated channel */
 			bts_model_lchan_deactivate_sacch(lchan);
 			if (!l1sap->u.info.u.act_req.sacch_only) {
diff --git a/src/osmo-bts-trx/scheduler_trx.c b/src/osmo-bts-trx/scheduler_trx.c
index 12490539..45fc7012 100644
--- a/src/osmo-bts-trx/scheduler_trx.c
+++ b/src/osmo-bts-trx/scheduler_trx.c
@@ -1236,16 +1236,19 @@ int rx_tchf_fn(struct l1sched_trx *l1t, enum trx_chan_type chan,
 			"Received bad data (%u/%u)\n",
 			bi->fn % l1ts->mf_period, l1ts->mf_period);
 		bfi_flag = true;
-		goto bfi;
-	}
-	if (rc < 4) {
+	} else if (rc < 4) {
 		LOGL1S(DL1P, LOGL_NOTICE, l1t, bi->tn, chan, bi->fn,
 			"Received bad data (%u/%u) with invalid codec mode %d\n",
 			bi->fn % l1ts->mf_period, l1ts->mf_period, rc);
 		bfi_flag = true;
-		goto bfi;
 	}
 
+	if (rc != GSM_MACBLOCK_LEN && lchan->ecu_state)
+		osmo_ecu_frame_in(lchan->ecu_state, bfi_flag, tch_data, rc);
+
+	if (bfi_flag)
+		goto bfi;
+
 	/* FACCH */
 	if (rc == GSM_MACBLOCK_LEN) {
 		uint16_t ber10k = compute_ber10k(n_bits_total, n_errors);
@@ -1260,21 +1263,22 @@ int rx_tchf_fn(struct l1sched_trx *l1t, enum trx_chan_type chan,
 bfi:
 		if (rsl_cmode == RSL_CMOD_SPD_SPEECH) {
 			/* indicate bad frame */
-			switch (tch_mode) {
-			case GSM48_CMODE_SPEECH_V1: /* FR */
-				if (lchan->tch.dtx.ul_sid) {
-					/* DTXu: pause in progress. Push empty payload to upper layers */
-					rc = 0;
-					goto compose_l1sap;
-				}
+			if (lchan->tch.dtx.ul_sid) {
+				/* DTXu: pause in progress. Push empty payload to upper layers */
+				rc = 0;
+				goto compose_l1sap;
+			}
 
-				/* Perform error concealment if possible */
-				rc = osmo_ecu_fr_conceal(&lchan->ecu_state.fr, tch_data);
-				if (rc) {
-					memset(tch_data, 0, GSM_FR_BYTES);
-					tch_data[0] = 0xd0;
-				}
+			/* If there is an ECU active on this channel, use its output */
+			if (lchan->ecu_state) {
+				rc = osmo_ecu_frame_out(lchan->ecu_state, tch_data);
+				goto compose_l1sap;
+			}
 
+			switch (tch_mode) {
+			case GSM48_CMODE_SPEECH_V1: /* FR */
+				memset(tch_data, 0, GSM_FR_BYTES);
+				tch_data[0] = 0xd0;
 				rc = GSM_FR_BYTES;
 				break;
 			case GSM48_CMODE_SPEECH_EFR: /* EFR */
@@ -1306,10 +1310,6 @@ bfi:
 	if (rsl_cmode != RSL_CMOD_SPD_SPEECH)
 		return 0;
 
-	/* Reset ECU with a good frame */
-	if (!bfi_flag && tch_mode == GSM48_CMODE_SPEECH_V1)
-		osmo_ecu_fr_reset(&lchan->ecu_state.fr, tch_data);
-
 	/* TCH or BFI */
 compose_l1sap:
 	return _sched_compose_tch_ind(l1t, bi->tn,
@@ -1332,6 +1332,7 @@ int rx_tchh_fn(struct l1sched_trx *l1t, enum trx_chan_type chan,
 	uint8_t tch_data[128]; /* just to be safe */
 	int rc, amr = 0;
 	int n_errors, n_bits_total;
+	bool bfi_flag = false;
 	struct gsm_lchan *lchan =
 		get_lchan_by_chan_nr(l1t->trx, trx_chan_desc[chan].chan_nr | bi->tn);
 	/* Note on FN-10: If we are at FN 10, we decoded an even aligned
@@ -1444,15 +1445,20 @@ int rx_tchh_fn(struct l1sched_trx *l1t, enum trx_chan_type chan,
 		LOGL1S(DL1P, LOGL_NOTICE, l1t, bi->tn, chan, bi->fn,
 			"Received bad data (%u/%u)\n",
 			bi->fn % l1ts->mf_period, l1ts->mf_period);
-		goto bfi;
-	}
-	if (rc < 4) {
+		bfi_flag = true;
+	} else if (rc < 4) {
 		LOGL1S(DL1P, LOGL_NOTICE, l1t, bi->tn, chan, bi->fn,
 			"Received bad data (%u/%u) with invalid codec mode %d\n",
 			bi->fn % l1ts->mf_period, l1ts->mf_period, rc);
-		goto bfi;
+		bfi_flag = true;
 	}
 
+	if (rc != GSM_MACBLOCK_LEN && lchan->ecu_state)
+		osmo_ecu_frame_in(lchan->ecu_state, bfi_flag, tch_data, rc);
+
+	if (bfi_flag)
+		goto bfi;
+
 	/* FACCH */
 	if (rc == GSM_MACBLOCK_LEN) {
 		chan_state->ul_ongoing_facch = 1;
@@ -1470,13 +1476,20 @@ bfi:
 		 * so we actually need to send two bad frame indications! */
 		if (rsl_cmode == RSL_CMOD_SPD_SPEECH) {
 			/* indicate bad frame */
+			if (lchan->tch.dtx.ul_sid) {
+				/* DTXu: pause in progress. Push empty payload to upper layers */
+				rc = 0;
+				goto compose_l1sap;
+			}
+
+			/* If there is an ECU active on this channel, use its output */
+			if (lchan->ecu_state) {
+				rc = osmo_ecu_frame_out(lchan->ecu_state, tch_data);
+				goto compose_l1sap;
+			}
+
 			switch (tch_mode) {
 			case GSM48_CMODE_SPEECH_V1: /* HR */
-				if (lchan->tch.dtx.ul_sid) {
-					/* DTXu: pause in progress. Push empty payload to upper layers */
-					rc = 0;
-					goto compose_l1sap;
-				}
 				tch_data[0] = 0x70; /* F = 0, FT = 111 */
 				memset(tch_data + 1, 0, 14);
 				rc = 15;