Bluetooth: Controller: Separate SDU interval for C_to_P and P_to_C

Support for separate SDU interval for C_to_P and P_to_C directions when setting CIG parameters. Signed-off-by: Vinayak Kariappa Chettimada <[email protected]>
zephyrproject-rtos · Jul 30, 2024 · ca4c50a · ca4c50a
1 parent 3bcaa6f
commit ca4c50a
Showing 1 changed file with 40 additions and 19 deletions.
diff --git a/subsys/bluetooth/controller/ll_sw/ull_central_iso.c b/subsys/bluetooth/controller/ll_sw/ull_central_iso.c
@@ -73,9 +73,9 @@ static void mfy_cis_offset_get(void *param);
 static void ticker_op_cb(uint32_t status, void *param);
 #endif /* CONFIG_BT_CTLR_CENTRAL_SPACING  == 0 */
 
-static void set_bn_max_pdu(bool framed, uint32_t iso_interval,
-			   uint32_t sdu_interval, uint16_t max_sdu, uint8_t *bn,
-			   uint8_t *max_pdu);
+static uint32_t set_bn_max_pdu(bool framed, uint32_t iso_interval,
+			       uint32_t iso_interval_cig, uint32_t sdu_interval,
+			       uint16_t max_sdu, uint8_t *bn, uint8_t *max_pdu);
 static uint8_t ll_cig_parameters_validate(void);
 static uint8_t ll_cis_parameters_validate(uint8_t cis_idx, uint8_t cis_id,
 					  uint16_t c_sdu, uint16_t p_sdu,
@@ -154,6 +154,7 @@ uint8_t ll_cig_parameters_commit(uint8_t cig_id, uint16_t *handles)
 	uint16_t cis_created_handles[STREAMS_PER_GROUP];
 	struct ll_conn_iso_stream *cis;
 	struct ll_conn_iso_group *cig;
+	uint32_t iso_interval_cig_us;
 	uint32_t iso_interval_us;
 	uint32_t cig_sync_delay;
 	uint32_t max_se_length;
@@ -228,19 +229,19 @@ uint8_t ll_cig_parameters_commit(uint8_t cig_id, uint16_t *handles)
 		 * handle the throughput. For unframed these must be divisible, if they're not,
 		 * framed mode must be forced.
 		 */
-		cig->iso_interval = cig->c_sdu_interval / ISO_INT_UNIT_US;
+		iso_interval_us = cig->c_sdu_interval;
 
-		if (cig->iso_interval < BT_HCI_ISO_INTERVAL_MIN) {
+		if (iso_interval_us < 5000U) {
 			/* ISO_Interval is below minimum (5 ms) */
-			cig->iso_interval = BT_HCI_ISO_INTERVAL_MIN;
+			iso_interval_us = 5000U;
 		}
 
 #if defined(CONFIG_BT_CTLR_CONN_ISO_AVOID_SEGMENTATION)
 		/* Check if this is a HAP usecase which requires higher link bandwidth to ensure
 		 * segmentation is not invoked in ISO-AL.
 		 */
 		if (cig->central.framing && cig->c_sdu_interval == 10000U) {
-			cig->iso_interval = 6; /* 7500 us */
+			iso_interval_us = 7500U; /* us */
 		}
 #endif
 
@@ -252,8 +253,7 @@ uint8_t ll_cig_parameters_commit(uint8_t cig_id, uint16_t *handles)
 		}
 	}
 
-	iso_interval_us = cig->iso_interval * ISO_INT_UNIT_US;
-	cig->lll.iso_interval_us = iso_interval_us;
+	iso_interval_cig_us = iso_interval_us;
 
 	lll_hdr_init(&cig->lll, cig);
 	max_se_length = 0U;
@@ -360,29 +360,43 @@ uint8_t ll_cig_parameters_commit(uint8_t cig_id, uint16_t *handles)
 			 * directions
 			 */
 			if (tx) {
+				uint32_t iso_interval_adjust_us;
 				uint8_t max_pdu;
 				uint8_t bn;
 
 				bn = cis->lll.tx.bn;
 				max_pdu = cis->lll.tx.max_pdu;
-				set_bn_max_pdu(cis->framed, iso_interval_us,
-					       cig->c_sdu_interval,
-					       cis->c_max_sdu, &bn, &max_pdu);
+				iso_interval_adjust_us =
+					set_bn_max_pdu(cis->framed, iso_interval_us,
+						       iso_interval_cig_us, cig->c_sdu_interval,
+						       cis->c_max_sdu, &bn, &max_pdu);
+				if (iso_interval_adjust_us != iso_interval_us) {
+					iso_interval_us = iso_interval_adjust_us;
+
+					goto ll_cig_parameters_commit_retry;
+				}
 				cis->lll.tx.bn = bn;
 				cis->lll.tx.max_pdu = max_pdu;
 			} else {
 				cis->lll.tx.bn = 0U;
 			}
 
 			if (rx) {
+				uint32_t iso_interval_adjust_us;
 				uint8_t max_pdu;
 				uint8_t bn;
 
 				bn = cis->lll.rx.bn;
 				max_pdu = cis->lll.rx.max_pdu;
-				set_bn_max_pdu(cis->framed, iso_interval_us,
-					       cig->p_sdu_interval,
-					       cis->p_max_sdu, &bn, &max_pdu);
+				iso_interval_adjust_us =
+					set_bn_max_pdu(cis->framed, iso_interval_us,
+						       iso_interval_cig_us, cig->p_sdu_interval,
+						       cis->p_max_sdu, &bn, &max_pdu);
+				if (iso_interval_adjust_us != iso_interval_us) {
+					iso_interval_us = iso_interval_adjust_us;
+
+					goto ll_cig_parameters_commit_retry;
+				}
 				cis->lll.rx.bn = bn;
 				cis->lll.rx.max_pdu = max_pdu;
 			} else {
@@ -402,6 +416,9 @@ uint8_t ll_cig_parameters_commit(uint8_t cig_id, uint16_t *handles)
 					(cis->central.p_rtn + 1) * cis->lll.rx.bn);
 	}
 
+	cig->lll.iso_interval_us = iso_interval_us;
+	cig->iso_interval = iso_interval_us / ISO_INT_UNIT_US;
+
 	handle_iter = UINT16_MAX;
 	total_time = 0U;
 
@@ -1170,9 +1187,9 @@ static void ticker_op_cb(uint32_t status, void *param)
 }
 #endif /* CONFIG_BT_CTLR_CENTRAL_SPACING  == 0 */
 
-static void set_bn_max_pdu(bool framed, uint32_t iso_interval,
-			   uint32_t sdu_interval, uint16_t max_sdu, uint8_t *bn,
-			   uint8_t *max_pdu)
+static uint32_t set_bn_max_pdu(bool framed, uint32_t iso_interval,
+			       uint32_t iso_interval_cig, uint32_t sdu_interval,
+			       uint16_t max_sdu, uint8_t *bn, uint8_t *max_pdu)
 {
 	if (framed) {
 		uint32_t max_drift_us;
@@ -1222,13 +1239,17 @@ static void set_bn_max_pdu(bool framed, uint32_t iso_interval,
 		}
 	} else {
 		/* For unframed, ISO_Interval must be N x SDU_Interval */
-		LL_ASSERT(iso_interval % sdu_interval == 0);
+		if ((iso_interval % sdu_interval) != 0) {
+			iso_interval += iso_interval_cig;
+		}
 
 		/* Core 5.3 Vol 6, Part G section 2.1:
 		 * BN >= ceil(Max_SDU/Max_PDU * ISO_Interval/SDU_Interval)
 		 */
 		*bn = DIV_ROUND_UP(max_sdu * iso_interval, (*max_pdu) * sdu_interval);
 	}
+
+	return iso_interval;
 }
 
 static uint8_t ll_cig_parameters_validate(void)