From 0f2980db15f3448533c8a978e71daffbde2cdbf2 Mon Sep 17 00:00:00 2001
From: Vinayak Kariappa Chettimada <vich@nordicsemi.no>
Date: Tue, 31 Jan 2023 12:30:49 +0530
Subject: [PATCH] Bluetooth: Controller: Maximize BIG event length and preempt
 PTO & CTRL

Maximize BIG event length to extend upto ISO interval, and
allow PTO and Control subevents to be pre-emptible.

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>
---
 .../bluetooth/controller/Kconfig.ll_sw_split  | 12 +++++
 .../bluetooth/controller/ll_sw/ull_adv_iso.c  | 53 +++++++++++++------
 2 files changed, 49 insertions(+), 16 deletions(-)

diff --git a/subsys/bluetooth/controller/Kconfig.ll_sw_split b/subsys/bluetooth/controller/Kconfig.ll_sw_split
index 5fb2c54d085..1fa9031d47f 100644
--- a/subsys/bluetooth/controller/Kconfig.ll_sw_split
+++ b/subsys/bluetooth/controller/Kconfig.ll_sw_split
@@ -386,6 +386,18 @@ config BT_CTLR_ADV_RESERVE_MAX
 	  corresponding to the Advertising Data present at the time of the
 	  start/enable of Advertising is used.
 
+config BT_CTLR_ADV_ISO_RESERVE_MAX
+	bool "Use maximum Broadcast ISO event time reservation"
+	depends on BT_CTLR_ADV_ISO
+	default y
+	help
+	  Use maximum Broadcast ISO event time reservation. If disabled, then
+	  time reservation does not include the pre-transmissions of the last
+	  BIS and any Control subevents. This will allow extended or periodic
+	  advertising events to preempt the BIG events but allow higher radio
+	  utilizations by allowing larger BIG events when not overlapping with
+	  extended or periodic advertising.
+
 config BT_CTLR_ADV_AUX_SYNC_OFFSET
 	int "Pre-defined offset between AUX_ADV_IND and AUX_SYNC_IND"
 	depends on BT_CTLR_ADV_PERIODIC
diff --git a/subsys/bluetooth/controller/ll_sw/ull_adv_iso.c b/subsys/bluetooth/controller/ll_sw/ull_adv_iso.c
index 4551fac228d..de78352baa2 100644
--- a/subsys/bluetooth/controller/ll_sw/ull_adv_iso.c
+++ b/subsys/bluetooth/controller/ll_sw/ull_adv_iso.c
@@ -282,27 +282,41 @@ uint8_t ll_big_create(uint8_t big_handle, uint8_t adv_handle, uint8_t num_bis,
 	event_spacing = latency_packing + ctrl_spacing +
 			EVENT_OVERHEAD_START_US + EVENT_OVERHEAD_END_US;
 
-	/* Calculate overheads due to extended advertising. */
-	aux = HDR_LLL2ULL(adv->lll.aux);
-	ticks_slot_aux = aux->ull.ticks_slot;
-	if (IS_ENABLED(CONFIG_BT_CTLR_LOW_LAT)) {
-		ticks_slot_overhead = MAX(aux->ull.ticks_active_to_start,
-					  aux->ull.ticks_prepare_to_start);
+	/* Check if aux context allocated before we are creating ISO */
+	if (adv->lll.aux) {
+		aux = HDR_LLL2ULL(adv->lll.aux);
 	} else {
-		ticks_slot_overhead = 0U;
+		aux = NULL;
+	}
+
+	/* Calculate overheads due to extended advertising. */
+	if (aux && aux->is_started) {
+		ticks_slot_aux = aux->ull.ticks_slot;
+		if (IS_ENABLED(CONFIG_BT_CTLR_LOW_LAT)) {
+			ticks_slot_overhead = MAX(aux->ull.ticks_active_to_start,
+						  aux->ull.ticks_prepare_to_start);
+		} else {
+			ticks_slot_overhead = 0U;
+		}
+		ticks_slot_aux += ticks_slot_overhead;
+	} else {
+		ticks_slot_aux = 0U;
 	}
-	ticks_slot_aux += ticks_slot_overhead;
 
 	/* Calculate overheads due to periodic advertising. */
 	sync = HDR_LLL2ULL(lll_adv_sync);
-	ticks_slot_sync = sync->ull.ticks_slot;
-	if (IS_ENABLED(CONFIG_BT_CTLR_LOW_LAT)) {
-		ticks_slot_overhead = MAX(sync->ull.ticks_active_to_start,
-					  sync->ull.ticks_prepare_to_start);
+	if (sync->is_started) {
+		ticks_slot_sync = sync->ull.ticks_slot;
+		if (IS_ENABLED(CONFIG_BT_CTLR_LOW_LAT)) {
+			ticks_slot_overhead = MAX(sync->ull.ticks_active_to_start,
+						  sync->ull.ticks_prepare_to_start);
+		} else {
+			ticks_slot_overhead = 0U;
+		}
+		ticks_slot_sync += ticks_slot_overhead;
 	} else {
-		ticks_slot_overhead = 0U;
+		ticks_slot_sync = 0U;
 	}
-	ticks_slot_sync += ticks_slot_overhead;
 
 	/* Calculate total overheads due to extended and periodic advertising */
 	if (CONFIG_BT_CTLR_ADV_AUX_SYNC_OFFSET > 0U) {
@@ -1008,8 +1022,15 @@ static uint32_t adv_iso_start(struct ll_adv_iso_set *adv_iso,
 		      EVENT_MSS_US;
 	ctrl_spacing = PDU_BIS_US(sizeof(struct pdu_big_ctrl), lll_iso->enc,
 				  lll_iso->phy, lll_iso->phy_flags);
-	slot_us = (pdu_spacing * lll_iso->nse * lll_iso->num_bis) +
-		  ctrl_spacing;
+
+	if (IS_ENABLED(CONFIG_BT_CTLR_ADV_ISO_RESERVE_MAX)) {
+		slot_us = (pdu_spacing * lll_iso->nse * lll_iso->num_bis) +
+			  ctrl_spacing;
+	} else {
+		slot_us = pdu_spacing * ((lll_iso->nse * lll_iso->num_bis) -
+					 lll_iso->ptc);
+	}
+
 	slot_us += EVENT_OVERHEAD_START_US + EVENT_OVERHEAD_END_US;
 
 	adv_iso->ull.ticks_active_to_start = 0U;