Bluetooth: controller: llcp: update rx parameters upon receipt of PDU

According to specification, when executing a remote procedure the
rx parameters used need to be updated when the REQ from the peer
is received. Currently this is done only when an ACK is
received on the RSP PDU send out.
This commit updates the RX parameters upon receipt of the REQ PDU

Signed-off-by: Andries Kruithof <andries.kruithof@nordicsemi.no>

subsys/bluetooth/controller/ll_sw/ull_conn.c

@@ -8141,40 +8141,75 @@ void ull_dle_max_time_get(struct ll_conn *conn, uint16_t *max_rx_time,
 	return dle_max_time_get(conn, max_rx_time, max_tx_time);
 }
 
+/*
+ * TODO: this probably can be optimised for ex. by creating a macro for the
+ * ull_dle_update_eff function
+ */
 uint8_t ull_dle_update_eff(struct ll_conn *conn)
 {
 	uint8_t dle_changed = 0U;
 
-	const uint16_t eff_tx_octets =
+	/* Note that we must use bitwise or and not logical or */
-		MAX(MIN(conn->lll.dle.local.max_tx_octets, conn->lll.dle.remote.max_rx_octets),
+	dle_changed = ull_dle_update_eff_rx(conn);
-		    PDU_DC_PAYLOAD_SIZE_MIN);
+	dle_changed |= ull_dle_update_eff_tx(conn);
+
+	return dle_changed;
+}
+
+uint8_t ull_dle_update_eff_rx(struct ll_conn *conn)
+{
+	uint8_t dle_changed = 0U;
+
 	const uint16_t eff_rx_octets =
 		MAX(MIN(conn->lll.dle.local.max_rx_octets, conn->lll.dle.remote.max_tx_octets),
 		    PDU_DC_PAYLOAD_SIZE_MIN);
 
 #if defined(CONFIG_BT_CTLR_PHY)
-	unsigned int min_eff_tx_time = (conn->lll.phy_tx == PHY_CODED) ?
-			PDU_DC_PAYLOAD_TIME_MIN_CODED : PDU_DC_PAYLOAD_TIME_MIN;
 	unsigned int min_eff_rx_time = (conn->lll.phy_rx == PHY_CODED) ?
 			PDU_DC_PAYLOAD_TIME_MIN_CODED : PDU_DC_PAYLOAD_TIME_MIN;
 
-	const uint16_t eff_tx_time =
-		MAX(MIN(conn->lll.dle.local.max_tx_time, conn->lll.dle.remote.max_rx_time),
-		    min_eff_tx_time);
 	const uint16_t eff_rx_time =
 		MAX(MIN(conn->lll.dle.local.max_rx_time, conn->lll.dle.remote.max_tx_time),
 		    min_eff_rx_time);
 
-	if (eff_tx_time != conn->lll.dle.eff.max_tx_time) {
-		conn->lll.dle.eff.max_tx_time = eff_tx_time;
-		dle_changed = 1;
-	}
 	if (eff_rx_time != conn->lll.dle.eff.max_rx_time) {
 		conn->lll.dle.eff.max_rx_time = eff_rx_time;
 		dle_changed = 1;
 	}
 #else
 	conn->lll.dle.eff.max_rx_time = PDU_DC_MAX_US(eff_rx_octets, PHY_1M);
+#endif
+
+	if (eff_rx_octets != conn->lll.dle.eff.max_rx_octets) {
+		conn->lll.dle.eff.max_rx_octets = eff_rx_octets;
+		dle_changed = 1;
+	}
+
+	return dle_changed;
+}
+
+uint8_t ull_dle_update_eff_tx(struct ll_conn *conn)
+
+{
+	uint8_t dle_changed = 0U;
+
+	const uint16_t eff_tx_octets =
+		MAX(MIN(conn->lll.dle.local.max_tx_octets, conn->lll.dle.remote.max_rx_octets),
+		    PDU_DC_PAYLOAD_SIZE_MIN);
+
+#if defined(CONFIG_BT_CTLR_PHY)
+	unsigned int min_eff_tx_time = (conn->lll.phy_tx == PHY_CODED) ?
+			PDU_DC_PAYLOAD_TIME_MIN_CODED : PDU_DC_PAYLOAD_TIME_MIN;
+
+	const uint16_t eff_tx_time =
+		MAX(MIN(conn->lll.dle.local.max_tx_time, conn->lll.dle.remote.max_rx_time),
+		    min_eff_tx_time);
+
+	if (eff_tx_time != conn->lll.dle.eff.max_tx_time) {
+		conn->lll.dle.eff.max_tx_time = eff_tx_time;
+		dle_changed = 1;
+	}
+#else
 	conn->lll.dle.eff.max_tx_time = PDU_DC_MAX_US(eff_tx_octets, PHY_1M);
 #endif
 
@@ -8182,10 +8217,6 @@ uint8_t ull_dle_update_eff(struct ll_conn *conn)
 		conn->lll.dle.eff.max_tx_octets = eff_tx_octets;
 		dle_changed = 1;
 	}
-	if (eff_rx_octets != conn->lll.dle.eff.max_rx_octets) {
-		conn->lll.dle.eff.max_rx_octets = eff_rx_octets;
-		dle_changed = 1;
-	}
 
 	return dle_changed;
 }
@@ -8258,7 +8289,7 @@ void ull_dle_init(struct ll_conn *conn, uint8_t phy)
 	 * Part B, section 4.5.10 we can call ull_dle_update_eff
 	 * for initialisation
 	 */
-	ull_dle_update_eff(conn);
+	(void)ull_dle_update_eff(conn);
 
 	/* Check whether the controller should perform a data length update after
 	 * connection is established

subsys/bluetooth/controller/ll_sw/ull_conn_internal.h

@@ -97,6 +97,8 @@ void ull_dle_max_time_get(struct ll_conn *conn, uint16_t *max_rx_time,
 				    uint16_t *max_tx_time);
 
 uint8_t ull_dle_update_eff(struct ll_conn *conn);
+uint8_t ull_dle_update_eff_tx(struct ll_conn *conn);
+uint8_t ull_dle_update_eff_rx(struct ll_conn *conn);
 
 void ull_dle_local_tx_update(struct ll_conn *conn, uint16_t tx_octets, uint16_t tx_time);
 

subsys/bluetooth/controller/ll_sw/ull_llcp_common.c

@@ -942,11 +942,12 @@ static void rp_comm_rx_decode(struct ll_conn *conn, struct proc_ctx *ctx, struct
 	case PDU_DATA_LLCTRL_TYPE_LENGTH_REQ:
 		llcp_pdu_decode_length_req(conn, pdu);
 		/* On reception of REQ mark RSP open for local piggy-back
-		 * Pause data tx, to ensure we can later (on RSP tx ack) update DLE without
+		 * Pause data tx, to ensure we can later (on RSP tx ack) update TX DLE without
 		 * conflicting with out-going LL Data PDUs
 		 * See BT Core 5.2 Vol6: B-4.5.10 & B-5.1.9
 		 */
 		llcp_tx_pause_data(conn, LLCP_TX_QUEUE_PAUSE_DATA_DATA_LENGTH);
+		ctx->data.dle.ntf_dle = ull_dle_update_eff_rx(conn);
 		break;
 #endif /* CONFIG_BT_CTLR_DATA_LENGTH */
 #if defined(CONFIG_BT_CTLR_DF_CONN_CTE_RSP)
@@ -1276,8 +1277,9 @@ static void rp_comm_st_wait_tx_ack(struct ll_conn *conn, struct proc_ctx *ctx, u
 #if defined(CONFIG_BT_CTLR_DATA_LENGTH)
 		case PROC_DATA_LENGTH_UPDATE: {
 			/* Apply changes in data lengths/times */
-			uint8_t dle_changed = ull_dle_update_eff(conn);
+			uint8_t dle_changed = ull_dle_update_eff_tx(conn);
 
+			dle_changed |= ctx->data.dle.ntf_dle;
 			llcp_tx_resume_data(conn, LLCP_TX_QUEUE_PAUSE_DATA_DATA_LENGTH);
 
 			if (dle_changed && !llcp_ntf_alloc_is_available()) {

subsys/bluetooth/controller/ll_sw/ull_llcp_internal.h

@@ -197,6 +197,12 @@ struct proc_ctx {
 		} pu;
 #endif /* CONFIG_BT_CTLR_PHY */
 
+#if defined(CONFIG_BT_CTLR_DATA_LENGTH)
+		struct {
+			uint8_t ntf_dle;
+		} dle;
+#endif
+
 		/* Connection Update & Connection Parameter Request */
 		struct {
 			uint8_t error;