Bluetooth: controller: Fix ISO broadcaster pre-transmission groups > 1

For pre-transmission groups > 1, the broadcaster link layer would fetch
incorrect payloads from the TX node queue.

Update payload index calculation to reference correct TX payload. Fix
PTO FIXMEs and range checks.

Signed-off-by: Morten Priess <mtpr@oticon.com>

subsys/bluetooth/controller/ll_sw/nordic/lll/lll_adv_iso.c

@@ -627,9 +627,24 @@ static void isr_tx_common(void *param,
 	if (!pdu) {
 		uint8_t payload_index;
 
-		payload_index = (lll->bn_curr - 1U) +
-				(lll->ptc_curr * lll->pto);
-		payload_count = lll->payload_count + payload_index - lll->bn;
+		if (lll->ptc_curr) {
+			uint8_t ptx_idx = lll->ptc_curr - 1;
+			uint8_t ptx_payload_idx;
+			uint32_t ptx_group_mult;
+			uint8_t ptx_group_idx;
+
+			/* Calculate group index and multiplier for deriving
+			 * pre-transmission payload index.
+			 */
+			ptx_group_idx = ptx_idx / lll->bn;
+			ptx_payload_idx = ptx_idx - ptx_group_idx * lll->bn;
+			ptx_group_mult = (ptx_group_idx + 1) * lll->pto;
+			payload_index = ptx_payload_idx + ptx_group_mult * lll->bn;
+		} else {
+			payload_index  = lll->bn_curr - 1U;
+		}
+
+		payload_count = lll->payload_count - lll->bn + payload_index;
 
 #if !TEST_WITH_DUMMY_PDU
 		struct lll_adv_iso_stream *stream;

subsys/bluetooth/controller/ll_sw/ull_adv_iso.c

@@ -201,12 +201,11 @@ static uint8_t big_create(uint8_t big_handle, uint8_t adv_handle, uint8_t num_bi
 				return BT_HCI_ERR_INVALID_PARAM;
 			}
 
-			/* FIXME: PTO is currently limited to BN */
-			if (!IN_RANGE(pto, 0x00, bn /*0x0F*/)) {
+			if (!IN_RANGE(pto, 0x00, 0x0F)) {
 				return BT_HCI_ERR_INVALID_PARAM;
 			}
 
-			if (bn * irc + pto < nse) {
+			if (pto && !(bn * irc < nse)) {
 				return BT_HCI_ERR_INVALID_PARAM;
 			}
 		} else {
@@ -1162,10 +1161,8 @@ static uint8_t ptc_calc(const struct lll_adv_iso *lll, uint32_t event_spacing,
 		       (lll->sub_interval * lll->bn * lll->num_bis)) *
 		      lll->bn;
 
-		/* FIXME: Here we restrict to a maximum of BN Pre-Transmission
-		 * subevents per BIS
-		 */
-		ptc = MIN(ptc, lll->bn);
+		/* Restrict PTC to number of available subevents */
+		ptc = MIN(ptc, lll->nse - lll->bn * lll->irc);
 
 		return ptc;
 	}