WIP Algorithm B UL (TODO)

Select UL slot based on slot usage (similar to algorithm A)

1 files changed, 109 insertions, 63 deletions

diff --git a/src/gprs_rlcmac_ts_alloc.cpp b/src/gprs_rlcmac_ts_alloc.cpp
index 7da07673..1e0f539b 100644
--- a/src/gprs_rlcmac_ts_alloc.cpp
+++ b/src/gprs_rlcmac_ts_alloc.cpp
@@ -101,11 +101,12 @@ static inline int8_t find_free_usf(struct gprs_rlcmac_pdch *pdch)
 }
 
 static int find_possible_pdchs(struct gprs_rlcmac_trx *trx,
-	enum gprs_rlcmac_tbf_direction dir,
+	enum gprs_rlcmac_tbf_direction dir, size_t max_slots,
 	uint8_t mask, const char *mask_reason)
 {
 	unsigned ts;
 	int valid_ts_set = 0;
+	int8_t last_tsc = -1; /* must be signed */
 
 	for (ts = 0; ts < ARRAY_SIZE(trx->pdch); ts++) {
 		struct gprs_rlcmac_pdch *pdch;
@@ -125,12 +126,53 @@ static int find_possible_pdchs(struct gprs_rlcmac_trx *trx,
 			continue;
 		}
 
+		if (max_slots > 1) {
+		/* check if TSC changes */
+			if (last_tsc < 0)
+				last_tsc = pdch->tsc;
+			else if (last_tsc != pdch->tsc) {
+				LOGP(DRLCMAC, LOGL_ERROR,
+					"Skipping TS %d of TRX=%d, because it "
+					"has different TSC than lower TS of TRX. "
+					"In order to allow multislot, all "
+					"slots must be configured with the same "
+					"TSC!\n", ts, trx->trx_no);
+				continue;
+			}
+		}
+
 		valid_ts_set |= 1 << ts;
 	}
 
 	return valid_ts_set;
 }
 
+static uint8_t filter_ts(uint8_t current, uint8_t mask, const char *mask_reason)
+{
+	unsigned ts;
+	uint8_t result;
+	uint8_t invalid;
+
+	result = current & mask;
+
+	if (result == current || !mask_reason)
+		return result;
+
+	invalid = current & ~result;
+
+	for (ts = 0; ts < 8; ts++) {
+		if (((1 << ts) & invalid) == 0)
+			continue;
+
+		if (mask_reason)
+			LOGP(DRLCMAC, LOGL_DEBUG,
+				"- Skipping TS %d, because %s\n",
+				ts, mask_reason);
+	}
+
+	return result;
+}
+
 static int find_least_busy_pdch(struct gprs_rlcmac_trx *trx,
 	enum gprs_rlcmac_tbf_direction dir,
 	uint8_t mask,
@@ -326,7 +368,7 @@ int alloc_algorithm_a(struct gprs_rlcmac_bts *bts,
 		mask_reason = "need to reuse TS";
 	else if ((ref_tbf = ms->tbf(reverse(tbf->direction))))
 		mask_reason = ref_tbf->direction == GPRS_RLCMAC_UL_TBF ?
-			"not an uplink TBF" : "not a downlink TBF";
+			"not an uplink slot" : "not a downlink slot";
 
 	if (ref_tbf)
 		ts = ref_tbf->first_common_ts;
@@ -334,7 +376,7 @@ int alloc_algorithm_a(struct gprs_rlcmac_bts *bts,
 	if (ts >= 0)
 		mask = 1 << ts;
 
-	mask = find_possible_pdchs(tbf->trx, tbf->direction, mask, mask_reason);
+	mask = find_possible_pdchs(tbf->trx, tbf->direction, 1, mask, mask_reason);
 	if (!mask)
 		return -EINVAL;
 
@@ -597,76 +639,80 @@ static void tx_win_from_rx(const int ms_type,
  * slots.
  */
 static int select_ul_slots(gprs_rlcmac_trx *trx,
-		const int ms_type, const int ms_max_txslots,
+		const int ms_type, int ms_max_txslots,
 		uint8_t tx_win_min, uint8_t tx_range,
 		int8_t *usf, int8_t *first_common_ts, uint8_t rx_window)
 {
-	int tsc = -1;
 	uint8_t tx_window = 0;
-	int i;
-	uint8_t ts_no;
+	int ts;
+	uint16_t mask;
+	int first_ts;
+	int first_usf;
 
-	for (ts_no = tx_win_min, i = 0; i < tx_range; ts_no = (ts_no + 1) & 7, i++) {
-		gprs_rlcmac_pdch *pdch = &trx->pdch[ts_no];
+	mask = ((1 << tx_range) - 1) << tx_win_min;
+	tx_window = mask | (mask >> 8); /* wrap upper byte */
 
-		/* check if enabled */
-		if (!pdch->is_enabled()) {
-			LOGP(DRLCMAC, LOGL_DEBUG, "- Skipping TS %d, "
-				"because not enabled\n", ts_no);
-			if (ms_type == 1 && tx_window)
-				goto inc_window;
-			continue;
-		}
-		/* check if used as downlink */
-		if (!(rx_window & (1 << ts_no))) {
-			LOGP(DRLCMAC, LOGL_DEBUG, "- Skipping TS %d, "
-				"because not a downlink slot\n", ts_no);
-			if (ms_type == 1 && tx_window)
-				goto inc_window;
-			continue;
-		}
-		/* check if TSC changes */
-		if (tsc < 0)
-			tsc = pdch->tsc;
-		else if (tsc != pdch->tsc) {
-			LOGP(DRLCMAC, LOGL_ERROR, "Skipping TS %d of "
-				"TRX=%d, because it has different TSC "
-				"than lower TS of TRX. In order to "
-				"allow multislot, all slots must be "
-				"configured with the same TSC!\n",
-				ts_no, trx->trx_no);
-			if (ms_type == 1)
-				goto inc_window;
-			continue;
-		}
-		/* check for free usf */
-		usf[ts_no] = find_free_usf(pdch);
-		if (usf[ts_no] < 0) {
-			LOGP(DRLCMAC, LOGL_DEBUG, "- Skipping TS %d, "
-			"because no USF available\n", ts_no);
-			if (ms_type == 1)
-				goto inc_window;
-			continue;
-		}
+	tx_window = find_possible_pdchs(trx, GPRS_RLCMAC_UL_TBF, ms_max_txslots,
+		tx_window, NULL);
 
-		if (!tx_window)
-			*first_common_ts = ts_no;
+	tx_window = filter_ts(tx_window, rx_window, "not a downlink slot");
 
-		tx_window |= (1 << ts_no);
-		LOGP(DRLCMAC, LOGL_DEBUG, "- Selected UL TS %d\n", ts_no);
+	if (ms_type == 1) {
+		ms_max_txslots = 1;
+		first_ts = find_least_busy_pdch(trx, GPRS_RLCMAC_UL_TBF,
+			tx_window, &first_usf);
 
-inc_window:
-		if (1 && ms_type == 1) { /* FIXME: multislot UL assignment */
-			LOGP(DRLCMAC, LOGL_DEBUG, "- Done, because "
-				"1 slot assigned\n");
-			break;
-		}
-		if (i+1 == ms_max_txslots) {
-			LOGP(DRLCMAC, LOGL_DEBUG, "- Done, because "
-				"slots / window reached maximum "
-				"allowed Tx size\n");
-			break;
+		LOGP(DRLCMAC, LOGL_DEBUG, "- Selected UL TS %d\n", first_ts);
+
+		tx_window = 1 << first_ts;
+		usf[first_ts] = first_usf;
+		*first_common_ts = first_ts;
+
+		/* FIXME: multislot UL assignment */
+		LOGP(DRLCMAC, LOGL_DEBUG, "- Done, because 1 slot assigned\n");
+	} else {
+		bool found = false;
+		mask = 0;
+		for (ts = tx_win_min; ts < tx_win_min + tx_range; ts++) {
+			gprs_rlcmac_pdch *pdch = &trx->pdch[ts];
+			bool ts_valid = tx_window & (1 << (ts % 8));
+
+			usf[ts] = -1;
+
+			if (!found && !ts_valid)
+				continue;
+
+			if (ts_valid) {
+				/* check for free usf */
+				usf[ts] = find_free_usf(pdch);
+				if (usf[ts] < 0) {
+					LOGP(DRLCMAC, LOGL_DEBUG,
+						"- Skipping TS %d, "
+						"because no USF available\n", ts);
+					continue;
+				}
+
+				if (!found)
+					*first_common_ts = ts;
+
+				found = true;
+				LOGP(DRLCMAC, LOGL_DEBUG,
+					"- Selected UL TS %d\n", ts);
+				mask |= 1 << ts;
+			}
+
+			ms_max_txslots -= 1;
+			if (ms_max_txslots == 0) {
+				LOGP(DRLCMAC, LOGL_DEBUG, "- Done, because "
+					"slots / window reached maximum "
+					"allowed Tx size\n");
+				break;
+			}
+
+			/* see 45.002, 6.4.2.2.1, note 0 */
 		}
+
+		tx_window = mask;
 	}
 
 	LOGP(DRLCMAC, LOGL_DEBUG, "- Selected TX window: "