Modify EGPRS DL TBF flow to support Split block

Modify the EGPRS DL TBF flow to support Split block during
Retx.

5 files changed, 178 insertions, 44 deletions

diff --git a/src/gprs_coding_scheme.h b/src/gprs_coding_scheme.h
index fb3a191..d283c87 100644
--- a/src/gprs_coding_scheme.h
+++ b/src/gprs_coding_scheme.h
@@ -113,7 +113,8 @@ public:
 
 	static const char *modeName(Mode mode);
 	static Scheme get_retx_mcs(const GprsCodingScheme &mcs,
-				const GprsCodingScheme &retx_mcs);
+				const GprsCodingScheme &retx_mcs,
+				const unsigned char arq_type);
 
 	static enum Scheme egprs_mcs_retx_tbl[MAX_NUM_ARQ]
 			[MAX_NUM_MCS][MAX_NUM_MCS];
@@ -232,10 +233,12 @@ inline bool operator >=(GprsCodingScheme a, GprsCodingScheme b)
 {
 	return a == b || a > b;
 }
+
 inline GprsCodingScheme::Scheme GprsCodingScheme::get_retx_mcs(
 				const GprsCodingScheme &mcs,
-				const GprsCodingScheme &demanded_mcs)
+				const GprsCodingScheme &demanded_mcs,
+				const unsigned char arq_type)
 {
-	return egprs_mcs_retx_tbl[EGPRS_ARQ2][mcs.to_num() - 1]
+	return egprs_mcs_retx_tbl[arq_type][mcs.to_num() - 1]
 			[demanded_mcs.to_num() - 1];
 }
diff --git a/src/rlc.cpp b/src/rlc.cpp
index 6770043..dc1db3e 100644
--- a/src/rlc.cpp
+++ b/src/rlc.cpp
@@ -285,7 +285,8 @@ bool gprs_rlc_ul_window::invalidate_bsn(const uint16_t bsn)
 }
 
 static void gprs_rlc_data_header_init(struct gprs_rlc_data_info *rlc,
-	GprsCodingScheme cs, bool with_padding, unsigned int header_bits)
+	GprsCodingScheme cs, bool with_padding, unsigned int header_bits,
+	unsigned int spb = 0)
 {
 	unsigned int i;
 	unsigned int padding_bits = with_padding ? cs.optionalPaddingBits() : 0;
@@ -300,7 +301,7 @@ static void gprs_rlc_data_header_init(struct gprs_rlc_data_info *rlc,
 
 	for (i = 0; i < rlc->num_data_blocks; i++) {
 		gprs_rlc_data_block_info_init(&rlc->block_info[i], cs,
-			with_padding);
+			with_padding, spb);
 
 		rlc->data_offs_bits[i] =
 			header_bits + padding_bits +
@@ -310,10 +311,10 @@ static void gprs_rlc_data_header_init(struct gprs_rlc_data_info *rlc,
 }
 
 void gprs_rlc_data_info_init_dl(struct gprs_rlc_data_info *rlc,
-	GprsCodingScheme cs, bool with_padding)
+	GprsCodingScheme cs, bool with_padding, unsigned int spb)
 {
 	return gprs_rlc_data_header_init(rlc, cs, with_padding,
-		cs.numDataHeaderBitsDL());
+		cs.numDataHeaderBitsDL(), spb);
 }
 
 void gprs_rlc_data_info_init_ul(struct gprs_rlc_data_info *rlc,
@@ -324,7 +325,7 @@ void gprs_rlc_data_info_init_ul(struct gprs_rlc_data_info *rlc,
 }
 
 void gprs_rlc_data_block_info_init(struct gprs_rlc_data_block_info *rdbi,
-	GprsCodingScheme cs, bool with_padding)
+	GprsCodingScheme cs, bool with_padding, unsigned int spb)
 {
 	unsigned int data_len = cs.maxDataBlockBytes();
 	if (with_padding)
@@ -336,7 +337,7 @@ void gprs_rlc_data_block_info_init(struct gprs_rlc_data_block_info *rdbi,
 	rdbi->e   = 1;
 	rdbi->cv  = 15;
 	rdbi->pi  = 0;
-	rdbi->spb = 0;
+	rdbi->spb = spb;
 }
 
 unsigned int gprs_rlc_mcs_cps(GprsCodingScheme cs,
@@ -411,8 +412,15 @@ void gprs_rlc_mcs_cps_decode(unsigned int cps,
 enum egprs_puncturing_values gprs_get_punct_scheme(
 	enum egprs_puncturing_values punct,
 	const GprsCodingScheme &cs,
-	const GprsCodingScheme &cs_current)
+	const GprsCodingScheme &cs_current,
+	unsigned int spb)
 {
+	/* If it is second segment of the split block
+	* dont change the puncturing scheme
+	*/
+	if (spb == 3)
+		return punct;
+
 	/* TS  44.060 9.3.2.1.1 */
 	if ((GprsCodingScheme::Scheme(cs) == GprsCodingScheme::MCS9) &&
 	(GprsCodingScheme::Scheme(cs_current) == GprsCodingScheme::MCS6)) {
diff --git a/src/rlc.h b/src/rlc.h
index dfeb262..e4511e2 100644
--- a/src/rlc.h
+++ b/src/rlc.h
@@ -165,18 +165,19 @@ struct gprs_rlc_data {
 };
 
 void gprs_rlc_data_info_init_dl(struct gprs_rlc_data_info *rlc,
-	GprsCodingScheme cs, bool with_padding);
+	GprsCodingScheme cs, bool with_padding, unsigned int spb = 0);
 void gprs_rlc_data_info_init_ul(struct gprs_rlc_data_info *rlc,
 	GprsCodingScheme cs, bool with_padding);
 void gprs_rlc_data_block_info_init(struct gprs_rlc_data_block_info *rdbi,
-	GprsCodingScheme cs, bool with_padding);
+	GprsCodingScheme cs, bool with_padding, unsigned int spb = 0);
 unsigned int gprs_rlc_mcs_cps(GprsCodingScheme cs, enum egprs_puncturing_values
 	punct, enum egprs_puncturing_values punct2, int with_padding);
 void gprs_rlc_mcs_cps_decode(unsigned int cps, GprsCodingScheme cs,
 	int *punct, int *punct2, int *with_padding);
 enum egprs_puncturing_values gprs_get_punct_scheme(enum egprs_puncturing_values
 	punct, const GprsCodingScheme &cs,
-	const GprsCodingScheme &cs_current_trans);
+	const GprsCodingScheme &cs_current_trans,
+	unsigned int spb);
 void gprs_update_punct_scheme(enum egprs_puncturing_values *punct,
 	const GprsCodingScheme &cs);
 /*
diff --git a/src/tbf.h b/src/tbf.h
index 54c605f..a825b4f 100644
--- a/src/tbf.h
+++ b/src/tbf.h
@@ -420,6 +420,9 @@ protected:
 	void start_llc_timer();
 	int analyse_errors(char *show_rbb, uint8_t ssn, ana_result *res);
 	void schedule_next_frame();
+	void egprs_dl_spb_status_get_data_buffer(int bsn, uint8_t **block_data);
+	unsigned int get_egprs_dl_spb_status(int bsn);
+	unsigned int get_egprs_dl_spb_value(int bsn);
 
 	struct osmo_timer_list m_llc_timer;
 };
diff --git a/src/tbf_dl.cpp b/src/tbf_dl.cpp
index eae6968..f6c48c4 100644
--- a/src/tbf_dl.cpp
+++ b/src/tbf_dl.cpp
@@ -382,13 +382,8 @@ int gprs_rlcmac_dl_tbf::take_next_bsn(uint32_t fn,
 		if (is_egprs_enabled()) {
 			m_rlc.block(bsn)->cs_current_trans =
 				GprsCodingScheme::get_retx_mcs(
-				m_rlc.block(bsn)->cs, ms()->current_cs_dl());
-
-			LOGP(DRLCMACDL, LOGL_DEBUG,
-			"- current_cs_dl(%d) demanded_mcs(%d) cs_trans(%d)\n",
-			m_rlc.block(bsn)->cs.to_num(),
-			ms()->current_cs_dl().to_num(),
-			m_rlc.block(bsn)->cs_current_trans.to_num());
+				m_rlc.block(bsn)->cs, ms()->current_cs_dl(),
+				bts->bts_data()->arq_type);
 
 			/* TODO: Need to remove this check when MCS-8 -> MCS-6
 			 * transistion is handled
@@ -396,6 +391,14 @@ int gprs_rlcmac_dl_tbf::take_next_bsn(uint32_t fn,
 			if (m_rlc.block(bsn)->cs == GprsCodingScheme::MCS8)
 				m_rlc.block(bsn)->cs_current_trans =
 					GprsCodingScheme::MCS8;
+
+			LOGP(DRLCMACDL, LOGL_DEBUG,
+			"- current_cs_dl(%d) demanded_mcs(%d)"
+			"cs_trans(%d) arq_type(%d) bsn(%d)\n",
+			m_rlc.block(bsn)->cs.to_num(),
+			ms()->current_cs_dl().to_num(),
+			m_rlc.block(bsn)->cs_current_trans.to_num(),
+			bts->bts_data()->arq_type, bsn);
 		} else
 			m_rlc.block(bsn)->cs_current_trans =
 					m_rlc.block(bsn)->cs;
@@ -526,6 +529,8 @@ int gprs_rlcmac_dl_tbf::create_new_bsn(const uint32_t fn, GprsCodingScheme cs)
 	data = rlc_data->prepare(block_data_len);
 	rlc_data->cs = cs;
 	rlc_data->cs_current_trans = cs;
+	rlc_data->block_status_dl = EGPRS_RESEG_DL_DEFAULT;
+	rlc_data->cs_init = cs;
 	rlc_data->len = block_data_len;
 
 	rdbi = &(rlc_data->block_info);
@@ -612,6 +617,7 @@ struct msgb *gprs_rlcmac_dl_tbf::create_dl_acked_block(
 	unsigned num_bsns;
 	enum egprs_puncturing_values punct[ARRAY_SIZE(rlc.block_info)];
 	bool need_padding = false;
+	unsigned int spb = 0;
 
 	/*
 	 * TODO: This is an experimental work-around to put 2 BSN into
@@ -622,6 +628,7 @@ struct msgb *gprs_rlcmac_dl_tbf::create_dl_acked_block(
 	 * the current limit.
 	 */
 	cs = m_rlc.block(index)->cs_current_trans;
+	GprsCodingScheme &cs_init = m_rlc.block(index)->cs_init;
 	bsns[0] = index;
 	num_bsns = 1;
 
@@ -630,7 +637,15 @@ struct msgb *gprs_rlcmac_dl_tbf::create_dl_acked_block(
 		num_bsns += 1;
 	}
 
-	if (num_bsns == 1) {
+	if ((GprsCodingScheme::Scheme(cs_init) == GprsCodingScheme::MCS8) &&
+		(GprsCodingScheme::Scheme(cs) == GprsCodingScheme::MCS6 ||
+		GprsCodingScheme::Scheme(cs) == GprsCodingScheme::MCS3)) {
+		if ((get_egprs_dl_spb_status(index) ==
+			EGPRS_RESEG_DL_DEFAULT) ||
+			(get_egprs_dl_spb_status(index) ==
+			EGPRS_RESEG_SECOND_SEG_SENT))
+			need_padding  = true;
+	} else if (num_bsns == 1) {
 		/* TODO: remove the conditional when MCS-6 padding isn't
 		 * failing to be decoded by MEs anymore */
 		/* TODO: support of MCS-8 -> MCS-6 transition should be
@@ -640,7 +655,14 @@ struct msgb *gprs_rlcmac_dl_tbf::create_dl_acked_block(
 			cs.decToSingleBlock(&need_padding);
 	}
 
-	gprs_rlc_data_info_init_dl(&rlc, cs, need_padding);
+	spb = get_egprs_dl_spb_value(index);
+
+	LOGP(DRLCMACDL, LOGL_DEBUG, "- need_padding %d spb_status %d spb %d"
+			"(BSN1 %d BSN2 %d)\n",
+			need_padding,
+			get_egprs_dl_spb_status(index), spb, index, index2);
+
+	gprs_rlc_data_info_init_dl(&rlc, cs, need_padding, spb);
 
 	rlc.usf = 7; /* will be set at scheduler */
 	rlc.pr = 0; /* FIXME: power reduction */
@@ -659,10 +681,8 @@ struct msgb *gprs_rlcmac_dl_tbf::create_dl_acked_block(
 		data_block_idx++)
 	{
 		int bsn;
-		GprsCodingScheme cs_enc;
 		uint8_t *block_data;
 		gprs_rlc_data_block_info *rdbi, *block_info;
-		enum egprs_puncturing_values punct_scheme;
 
 		/* Check if there are more blocks than BSNs */
 		if (data_block_idx < num_bsns)
@@ -670,38 +690,34 @@ struct msgb *gprs_rlcmac_dl_tbf::create_dl_acked_block(
 		else
 			bsn = bsns[0];
 
-		cs_enc = m_rlc.block(bsn)->cs_current_trans;
-
-		/* get data and header from current block */
-		block_data = m_rlc.block(bsn)->block;
-
 		/* Get current puncturing scheme from block */
-		punct_scheme = gprs_get_punct_scheme(
-			m_rlc.block(bsn)->next_ps,
-			m_rlc.block(bsn)->cs, cs);
+		m_rlc.block(bsn)->next_ps = gprs_get_punct_scheme(
+				m_rlc.block(bsn)->next_ps,
+				m_rlc.block(bsn)->cs, cs, spb);
 
 		if (cs.isEgprs()) {
-			OSMO_ASSERT(punct_scheme >= EGPRS_PS_1);
-			OSMO_ASSERT(punct_scheme <= EGPRS_PS_3);
+			OSMO_ASSERT(m_rlc.block(bsn)->next_ps >= EGPRS_PS_1);
+			OSMO_ASSERT(m_rlc.block(bsn)->next_ps <= EGPRS_PS_3);
 		}
-		punct[data_block_idx] = punct_scheme;
+		punct[data_block_idx] = m_rlc.block(bsn)->next_ps;
 
 		rdbi = &rlc.block_info[data_block_idx];
 		block_info = &m_rlc.block(bsn)->block_info;
 
-		if(rdbi->data_len != m_rlc.block(bsn)->len) {
-			LOGP(DRLCMACDL, LOGL_ERROR,
-				"ERROR: Expected len = %d for %s instead of "
-				"%d in data unit %d (BSN %d, %s)\n",
-				rdbi->data_len, cs.name(), m_rlc.block(bsn)->len,
-				data_block_idx, bsn, cs_enc.name());
-			OSMO_ASSERT(rdbi->data_len == m_rlc.block(bsn)->len);
-		}
+		egprs_dl_spb_status_get_data_buffer(bsn, &block_data);
 
 		/* TODO: Need to handle 2 same bsns
 		 * in header type 1
 		 */
-		gprs_update_punct_scheme(&m_rlc.block(bsn)->next_ps,
+		/*
+		 * If it is first segment of the split block set the state of
+		 * bsn to nacked. If it is the first segment dont update the
+		 * next ps value of bsn
+		 */
+		if (spb == 2)
+			m_window.m_v_b.mark_nacked(bsn);
+		else
+			gprs_update_punct_scheme(&m_rlc.block(bsn)->next_ps,
 					cs);
 
 		m_rlc.block(bsn)->cs = cs;
@@ -1167,3 +1183,106 @@ bool gprs_rlcmac_dl_tbf::keep_open(unsigned fn) const
 	keep_time_frames = msecs_to_frames(bts_data()->dl_tbf_idle_msec);
 	return frames_since_last_drain(fn) <= keep_time_frames;
 }
+
+/*
+ * This function returns the pointer to data which needs
+ * to be copied. Also updates the status of the block related to
+ * Split block handling in the RLC/MAC block.
+ */
+void gprs_rlcmac_dl_tbf::egprs_dl_spb_status_get_data_buffer(int bsn,
+	uint8_t **block_data)
+{
+	struct gprs_rlc_data *rlc_data = m_rlc.block(bsn);
+
+	GprsCodingScheme &cs_current_trans = m_rlc.block(bsn)->cs_current_trans;
+	GprsCodingScheme &cs_init = m_rlc.block(bsn)->cs_init;
+
+	/*
+	 * Table 10.3a.0.1 of 44.060
+	 * MCS6,9: second segment starts at 74/2 = 37
+	 * MCS5,7: second segment starts at 56/2 = 28
+	 * MCS8: second segment starts at 31
+	 * MCS4: second segment starts at 44/2 = 22
+	 */
+	if (cs_current_trans.headerTypeData() ==
+			GprsCodingScheme::HEADER_EGPRS_DATA_TYPE_3) {
+		if (rlc_data->block_status_dl == EGPRS_RESEG_FIRST_SEG_SENT) {
+			switch (GprsCodingScheme::Scheme(cs_init)) {
+			case GprsCodingScheme::MCS6 :
+			case GprsCodingScheme::MCS9 :
+				*block_data = &rlc_data->block[37];
+			break;
+			case GprsCodingScheme::MCS7 :
+			case GprsCodingScheme::MCS5 :
+				*block_data = &rlc_data->block[28];
+			break;
+			case GprsCodingScheme::MCS8 :
+				*block_data = &rlc_data->block[31];
+			break;
+			case GprsCodingScheme::MCS4 :
+			*block_data = &rlc_data->block[22];
+			break;
+			default:
+				OSMO_ASSERT(false);
+			break;
+
+			}
+			rlc_data->block_status_dl = EGPRS_RESEG_SECOND_SEG_SENT;
+			return;
+		} else if ((cs_init.headerTypeData() ==
+				GprsCodingScheme::HEADER_EGPRS_DATA_TYPE_1) ||
+			(cs_init.headerTypeData() ==
+				GprsCodingScheme::HEADER_EGPRS_DATA_TYPE_2)) {
+			rlc_data->block_status_dl =
+					EGPRS_RESEG_FIRST_SEG_SENT;
+		} else if ((GprsCodingScheme::Scheme(cs_init) ==
+					GprsCodingScheme::MCS4) &&
+				(GprsCodingScheme::Scheme(cs_current_trans) ==
+					GprsCodingScheme::MCS1)) {
+			rlc_data->block_status_dl = EGPRS_RESEG_FIRST_SEG_SENT;
+		}
+	}
+	*block_data = &rlc_data->block[0];
+}
+
+/*
+ * This function returns the status of split block
+ * for RLC/MAC block.
+ */
+unsigned int gprs_rlcmac_dl_tbf::get_egprs_dl_spb_status(int bsn)
+{
+	struct gprs_rlc_data *rlc_data = m_rlc.block(bsn);
+
+	return rlc_data->block_status_dl;
+}
+
+/*
+ * This function returns the spb value to be sent OTA
+ * for RLC/MAC block.
+ */
+unsigned int gprs_rlcmac_dl_tbf::get_egprs_dl_spb_value(int bsn)
+{
+	struct gprs_rlc_data *rlc_data = m_rlc.block(bsn);
+
+	GprsCodingScheme &cs_current_trans = m_rlc.block(bsn)->cs_current_trans;
+	GprsCodingScheme &cs_init = m_rlc.block(bsn)->cs_init;
+
+	/* Table 10.4.8b.1 of 44.060 */
+	if (cs_current_trans.headerTypeData() ==
+			GprsCodingScheme::HEADER_EGPRS_DATA_TYPE_3) {
+		if (rlc_data->block_status_dl == EGPRS_RESEG_FIRST_SEG_SENT) {
+			return 3;
+		} else if ((cs_init.headerTypeData() ==
+				GprsCodingScheme::HEADER_EGPRS_DATA_TYPE_1) ||
+			(cs_init.headerTypeData() ==
+				GprsCodingScheme::HEADER_EGPRS_DATA_TYPE_2)) {
+			return 2;
+		} else if ((GprsCodingScheme::Scheme(cs_init) ==
+					GprsCodingScheme::MCS4) &&
+				(GprsCodingScheme::Scheme(cs_current_trans) ==
+					GprsCodingScheme::MCS1)) {
+			return 2;
+		}
+	}
+	return 0;
+}