TRX: Add support for EFR transcoding

8 files changed, 194 insertions, 15 deletions

diff --git a/src/osmo-bts-trx/gsm0503_coding.c b/src/osmo-bts-trx/gsm0503_coding.c
index 5ceb1d58..3f4ae159 100644
--- a/src/osmo-bts-trx/gsm0503_coding.c
+++ b/src/osmo-bts-trx/gsm0503_coding.c
@@ -300,7 +300,7 @@ int pdtch_encode(ubit_t *bursts, uint8_t *l2_data, uint8_t l2_len)
 
 
 /*
- * GSM TCH/F FR transcoding
+ * GSM TCH/F FR/EFR transcoding
  */
 
 static void tch_fr_reassemble(uint8_t *tch_data, ubit_t *b_bits, int net_order)
@@ -338,6 +338,35 @@ static void tch_fr_reassemble(uint8_t *tch_data, ubit_t *b_bits, int net_order)
 	}
 }
 
+static void tch_efr_reassemble(uint8_t *tch_data, ubit_t *b_bits)
+{
+	int i, j;
+
+	tch_data[0] = 0xc << 4;
+	memset(tch_data + 1, 0, 30);
+
+	i = 0; /* counts bits */
+	j = 4; /* counts output bits */
+	while (i < 244) {
+		tch_data[j>>3] |= (b_bits[i] << (7-(j&7)));
+		i++;
+		j++;
+	}
+}
+
+static void tch_efr_disassemble(ubit_t *b_bits, uint8_t *tch_data)
+{
+	int i, j;
+
+	i = 0; /* counts bits */
+	j = 4; /* counts output bits */
+	while (i < 244) {
+		b_bits[i] = (tch_data[j>>3] >> (7-(j&7))) & 1;
+		i++;
+		j++;
+	}
+}
+
 static void tch_fr_disassemble(ubit_t *b_bits, uint8_t *tch_data, int net_order)
 {
 	int i, j, k, l, o;
@@ -386,6 +415,30 @@ static void tch_fr_b_to_d(ubit_t *d_bits, ubit_t *b_bits)
 		d_bits[i] = b_bits[gsm610_bitorder[i]];
 }
 
+static void tch_efr_d_to_w(ubit_t *b_bits, ubit_t *d_bits)
+{
+	int i;
+
+	for (i = 0; i < 260; i++)
+		b_bits[gsm660_bitorder[i]] = d_bits[i];
+}
+
+static void tch_efr_w_to_d(ubit_t *d_bits, ubit_t *b_bits)
+{
+	int i;
+
+	for (i = 0; i < 260; i++)
+		d_bits[i] = b_bits[gsm660_bitorder[i]];
+}
+
+static void tch_efr_protected(ubit_t *s_bits, ubit_t *b_bits)
+{
+	int i;
+
+	for (i = 0; i < 65; i++)
+		b_bits[i] = s_bits[gsm0503_gsm_efr_protected_bits[i]-1];
+}
+
 static void tch_fr_unreorder(ubit_t *d, ubit_t *p, ubit_t *u)
 {
 	int i;
@@ -410,10 +463,43 @@ static void tch_fr_reorder(ubit_t *u, ubit_t *d, ubit_t *p)
 		u[91+i] = p[i];
 }
 
-int tch_fr_decode(uint8_t *tch_data, sbit_t *bursts, int net_order)
+static void tch_efr_reorder(ubit_t *w, ubit_t *s, ubit_t *p)
+{
+	memcpy(w, s, 71);
+	w[71] = w[72] = s[69];
+	memcpy(w+73, s+71, 50);
+	w[123] = w[124] = s[119];
+	memcpy(w+125, s+121, 53);
+	w[178] = w[179] = s[172];
+	memcpy(w+180, s+174, 50);
+	w[230] = w[231] = s[222];
+	memcpy(w+232, s+224, 20);
+	memcpy(w+252, p, 8);
+}
+
+static void tch_efr_unreorder(ubit_t *s, ubit_t *p, ubit_t *w)
+{
+	int sum;
+
+	memcpy(s, w, 71);
+	sum = s[69] + w[71] + w[72];
+	s[69] = (sum > 2);
+	memcpy(s+71, w+73, 50);
+	sum = s[119] + w[123] + w[124];
+	s[119] = (sum > 2);
+	memcpy(s+121, w+125, 53);
+	sum = s[172] + w[178] + w[179];
+	s[172] = (sum > 2);
+	memcpy(s+174, w+180, 50);
+	sum = s[220] + w[230] + w[231];
+	s[222] = (sum > 2);
+	memcpy(s+224, w+232, 20);
+	memcpy(p, w+252, 8);
+}
+int tch_fr_decode(uint8_t *tch_data, sbit_t *bursts, int net_order, int efr)
 {
 	sbit_t iB[912], cB[456], h;
-	ubit_t conv[185], b[260], d[260], p[3];
+	ubit_t conv[185], s[244], w[260], b[65], d[260], p[8];
 	int i, rv, len, steal = 0;
 
 	for (i=0; i<8; i++) {
@@ -444,11 +530,28 @@ int tch_fr_decode(uint8_t *tch_data, sbit_t *bursts, int net_order)
 		return -1;
 
 
-	tch_fr_d_to_b(b, d);
+	if (efr) {
+		tch_efr_d_to_w(w, d);
 
-	tch_fr_reassemble(tch_data, b, net_order);
+		tch_efr_unreorder(s, p, w);
 
-	len = 33;
+		tch_efr_protected(s, b);
+
+		rv = osmo_crc8gen_check_bits(&gsm0503_tch_efr_crc8, b,
+			65, p);
+		if (rv)
+			return -1;
+
+		tch_efr_reassemble(tch_data, s);
+
+		len = 31;
+	} else {
+		tch_fr_d_to_b(w, d);
+
+		tch_fr_reassemble(tch_data, w, net_order);
+
+		len = 33;
+	}
 
 	return len;
 }
@@ -456,15 +559,29 @@ int tch_fr_decode(uint8_t *tch_data, sbit_t *bursts, int net_order)
 int tch_fr_encode(ubit_t *bursts, uint8_t *tch_data, int len, int net_order)
 {
 	ubit_t iB[912], cB[456], h;
-	ubit_t conv[185], w[260], d[260], p[8];
+	ubit_t conv[185], w[260], b[65], s[244], d[260], p[8];
 	int i;
 
 	switch (len) {
+	case 31: /* TCH EFR */
+
+		tch_efr_disassemble(s, tch_data);
+
+		tch_efr_protected(s, b);
+
+		osmo_crc8gen_set_bits(&gsm0503_tch_efr_crc8, b, 65, p);
+
+		tch_efr_reorder(w, s, p);
+
+		tch_efr_w_to_d(d, w);
+
+		goto coding_efr_fr;
 	case 33: /* TCH FR */
 		tch_fr_disassemble(w, tch_data, net_order);
 
 		tch_fr_b_to_d(d, w);
 
+coding_efr_fr:
 		osmo_crc8gen_set_bits(&gsm0503_tch_fr_crc3, d, 50, p);
 
 		tch_fr_reorder(conv, d, p);
diff --git a/src/osmo-bts-trx/gsm0503_coding.h b/src/osmo-bts-trx/gsm0503_coding.h
index 240b2c07..96b162f3 100644
--- a/src/osmo-bts-trx/gsm0503_coding.h
+++ b/src/osmo-bts-trx/gsm0503_coding.h
@@ -5,7 +5,7 @@ int xcch_decode(uint8_t *l2_data, sbit_t *bursts);
 int xcch_encode(ubit_t *bursts, uint8_t *l2_data);
 int pdtch_decode(uint8_t *l2_data, sbit_t *bursts, uint8_t *usf_p);
 int pdtch_encode(ubit_t *bursts, uint8_t *l2_data, uint8_t l2_len);
-int tch_fr_decode(uint8_t *tch_data, sbit_t *bursts, int net_order);
+int tch_fr_decode(uint8_t *tch_data, sbit_t *bursts, int net_order, int efr);
 int tch_fr_encode(ubit_t *bursts, uint8_t *tch_data, int len, int net_order);
 int rach_decode(uint8_t *ra, sbit_t *burst, uint8_t bsic);
 int rach_encode(ubit_t *burst, uint8_t *ra, uint8_t bsic);
diff --git a/src/osmo-bts-trx/gsm0503_parity.c b/src/osmo-bts-trx/gsm0503_parity.c
index 1ecadcc7..cbb2bf0b 100644
--- a/src/osmo-bts-trx/gsm0503_parity.c
+++ b/src/osmo-bts-trx/gsm0503_parity.c
@@ -75,3 +75,16 @@ const struct osmo_crc8gen_code gsm0503_tch_fr_crc3 = {
 	.remainder = 0x7,
 };
 
+/*
+ * GSM TCH EFR parity
+ *
+ * g(x) = x^8 + x^4 + x^3 + x^2 + 1
+ */
+
+const struct osmo_crc8gen_code gsm0503_tch_efr_crc8 = {
+	.bits = 8,
+	.poly = 0x1d,
+	.init = 0x00,
+	.remainder = 0x00,
+};
+
diff --git a/src/osmo-bts-trx/gsm0503_parity.h b/src/osmo-bts-trx/gsm0503_parity.h
index 50d14bfc..e3678b22 100644
--- a/src/osmo-bts-trx/gsm0503_parity.h
+++ b/src/osmo-bts-trx/gsm0503_parity.h
@@ -6,5 +6,6 @@ const struct osmo_crc16gen_code gsm0503_cs234_crc16;
 const struct osmo_crc8gen_code gsm0503_rach_crc6;
 const struct osmo_crc16gen_code gsm0503_sch_crc10;
 const struct osmo_crc8gen_code gsm0503_tch_fr_crc3;
+const struct osmo_crc8gen_code gsm0503_tch_efr_crc8;
 
 #endif /* _0503_PARITY_H */
diff --git a/src/osmo-bts-trx/gsm0503_tables.c b/src/osmo-bts-trx/gsm0503_tables.c
index 8ab6060b..837cc68e 100644
--- a/src/osmo-bts-trx/gsm0503_tables.c
+++ b/src/osmo-bts-trx/gsm0503_tables.c
@@ -109,3 +109,15 @@ const uint8_t gsm0503_gsm_fr_map[76] = {
 	3, 3, 3, 3
 };
 
+/* this table describes the 65 most importaint bits from EFR coded
+ * bits as indicated in TS 05.03 (3.1.1.1) */
+const uint8_t gsm0503_gsm_efr_protected_bits[65] = {
+	 39, 40, 41, 42, 43, 44, 48, 87, 45,  2,
+	  3,  8, 10, 18, 19, 24, 46, 47,142,143,
+	144,145,146,147, 92, 93,195,196, 98,137,
+	148, 94,197,149,150, 95,198,  4,  5, 11,
+	 12, 16,  9,  6,  7, 13, 17, 20, 96,199,
+	  1, 14, 15, 21, 25, 26, 28,151,201,190,
+	240, 88,138,191,241
+};
+
diff --git a/src/osmo-bts-trx/gsm0503_tables.h b/src/osmo-bts-trx/gsm0503_tables.h
index 827fded4..66f325bf 100644
--- a/src/osmo-bts-trx/gsm0503_tables.h
+++ b/src/osmo-bts-trx/gsm0503_tables.h
@@ -9,5 +9,6 @@ extern const sbit_t gsm0503_usf2twelve_sbit[8][12];
 extern const uint8_t gsm0503_puncture_cs2[588];
 extern const uint8_t gsm0503_puncture_cs3[676];
 extern const uint8_t gsm0503_gsm_fr_map[76];
+extern const uint8_t gsm0503_gsm_efr_protected_bits[65];
 
 #endif /* _0503_TABLES_H */
diff --git a/src/osmo-bts-trx/scheduler.c b/src/osmo-bts-trx/scheduler.c
index 023be372..f1a0b629 100644
--- a/src/osmo-bts-trx/scheduler.c
+++ b/src/osmo-bts-trx/scheduler.c
@@ -779,7 +779,14 @@ static void tx_tch_common(struct trx_l1h *l1h, uint8_t tn, uint32_t fn,
 			memset(tch_data, 0, 33);
 			len = 33;
 			break;
+		case GSM48_CMODE_SPEECH_EFR: /* EFR */
+			if (chan != TRXC_TCHF)
+				goto inval_mode1;
+			memset(tch_data, 0, 31);
+			len = 31;
+			break;
 		default:
+inval_mode1:
 			LOGP(DL1C, LOGL_ERROR, "TCH mode invalid, please "
 				"fix!\n");
 			len = 0;
@@ -857,7 +864,21 @@ static void tx_tch_common(struct trx_l1h *l1h, uint8_t tn, uint32_t fn,
 				goto free_bad_msg;
 			}
 			break;
+		case GSM48_CMODE_SPEECH_EFR: /* EFR */
+			if (chan != TRXC_TCHF)
+				goto inval_mode2;
+			len = 31;
+			if (msgb_l2len(msg_tch) >= 1
+			 && (msg_tch->l2h[0] >> 4) != 0xc) {
+				LOGP(DL1C, LOGL_NOTICE, "%s Transmitting 'bad "
+					"EFR frame' trx=%u ts=%u at fn=%u.\n",
+					trx_chan_desc[chan].name,
+					l1h->trx->nr, tn, fn);
+				goto free_bad_msg;
+			}
+			break;
 		default:
+inval_mode2:
 			LOGP(DL1C, LOGL_ERROR, "TCH mode invalid, please "
 				"fix!\n");
 			goto free_bad_msg;
@@ -1185,7 +1206,10 @@ static int rx_tchf_fn(struct trx_l1h *l1h, uint8_t tn, uint32_t fn,
 	switch ((rsl_cmode != RSL_CMOD_SPD_SPEECH) ? GSM48_CMODE_SPEECH_V1
 								: tch_mode) {
 	case GSM48_CMODE_SPEECH_V1: /* FR */
-		rc = tch_fr_decode(tch_data, *bursts_p, 1);
+		rc = tch_fr_decode(tch_data, *bursts_p, 1, 0);
+		break;
+	case GSM48_CMODE_SPEECH_EFR: /* EFR */
+		rc = tch_fr_decode(tch_data, *bursts_p, 1, 1);
 		break;
 	default:
 		LOGP(DL1C, LOGL_ERROR, "TCH mode %u invalid, please fix!\n",
@@ -1217,6 +1241,10 @@ bfi:
 				memset(tch_data, 0, 33);
 				rc = 33;
 				break;
+			case GSM48_CMODE_SPEECH_EFR: /* EFR */
+				memset(tch_data, 0, 31);
+				rc = 31;
+				break;
 			default:
 				LOGP(DL1C, LOGL_ERROR, "TCH mode invalid, "
 					"please fix!\n");
diff --git a/tests/bursts/bursts_test.c b/tests/bursts/bursts_test.c
index e04899cc..935cbc6d 100644
--- a/tests/bursts/bursts_test.c
+++ b/tests/bursts/bursts_test.c
@@ -243,7 +243,7 @@ static void test_fr(uint8_t *speech, int len)
 	printd("%s\n", osmo_hexdump((uint8_t *)bursts_s + 59 + 812, 57));
 
 	/* decode */
-	rc = tch_fr_decode(result, bursts_s, 1);
+	rc = tch_fr_decode(result, bursts_s, 1, len == 31);
 
 	ASSERT_TRUE(rc == len);
 
@@ -349,7 +349,8 @@ uint8_t test_macblock[][54] = {
 	0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17 },
 };
 
-uint8_t test_speech[33];
+uint8_t test_speech_fr[33];
+uint8_t test_speech_efr[31];
 
 int main(int argc, char **argv)
 {
@@ -367,10 +368,16 @@ int main(int argc, char **argv)
 	for (i = 0; i < sizeof(test_l2) / sizeof(test_l2[0]); i++)
 		test_sch(test_l2[i]);
 
-	for (i = 0; i < sizeof(test_speech); i++)
-		test_speech[i] = i;
-	test_speech[0] = 0xd0;
-	test_fr(test_speech, sizeof(test_speech));
+	for (i = 0; i < sizeof(test_speech_fr); i++)
+		test_speech_fr[i] = i;
+	test_speech_fr[0] = 0xd0;
+	test_fr(test_speech_fr, sizeof(test_speech_fr));
+
+	for (i = 0; i < sizeof(test_speech_efr); i++)
+		test_speech_efr[i] = i;
+	test_speech_efr[0] = 0xc0;
+	test_fr(test_speech_efr, sizeof(test_speech_efr));
+
 	for (i = 0; i < sizeof(test_l2) / sizeof(test_l2[0]); i++)
 		test_fr(test_l2[i], sizeof(test_l2[0]));