Bluetooth: host: Add API to run conn CTE response HCI command

Add host API to allow execution of HCI_LE_Connection_CTE_Response_-
Enable HCI command.

Signed-off-by: Piotr Pryga <piotr.pryga@nordicsemi.no>

include/bluetooth/direction.h

@@ -142,6 +142,7 @@ struct bt_df_conn_iq_samples_report {
 	/** Pinter to IQ samples data. */
 	struct bt_hci_le_iq_sample const *sample;
 };
+
 /**
  * @brief Set or update the Constant Tone Extension parameters for periodic advertising set.
  *
@@ -217,4 +218,26 @@ int bt_df_conn_cte_rx_enable(struct bt_conn *conn, const struct bt_df_conn_cte_r
  */
 int bt_df_conn_cte_rx_disable(struct bt_conn *conn);
 
+/**
+ * @brief Enable Constant Tone Extension response procedure for a connection.
+ *
+ * The function is available if @kconfig{CONFIG_BT_DF_CONNECTION_CTE_RSP} is enabled.
+ *
+ * @param conn   Connection object.
+ *
+ * @return Zero in case of success, other value in case of failure.
+ */
+int bt_df_conn_cte_rsp_enable(struct bt_conn *conn);
+
+/**
+ * @brief Disable Constant Tone Extension response procedure for a connection.
+ *
+ * The function is available if @kconfig{CONFIG_BT_DF_CONNECTION_CTE_RSP} is enabled.
+ *
+ * @param conn   Connection object.
+ *
+ * @return Zero in case of success, other value in case of failure.
+ */
+int bt_df_conn_cte_rsp_disable(struct bt_conn *conn);
+
 #endif /* ZEPHYR_INCLUDE_BLUETOOTH_DF_H_ */

subsys/bluetooth/host/Kconfig

@@ -546,26 +546,39 @@ config BT_DF
 	  It will allow to: get information about antennae, configure
 	  Constant Tone Extension, transmit CTE and sample incoming CTE.
 
+if BT_DF
+
 config BT_DF_CONNECTIONLESS_CTE_RX
 	bool "Enable support for receive of CTE in connectionless mode"
-	depends on BT_DF
 	help
 	  Enable support for reception and sampling of Constant Tone Extension
 	  in connectionless mode.
 
 config BT_DF_CONNECTION_CTE_RX
 	bool "Enable support for receive of CTE in connection mode"
-	depends on BT_DF
 	help
 	  Enable support for reception and sampling of Constant Tone Extension
 	  in connection mode.
 
+config BT_DF_CONNECTION_CTE_TX
+	bool "Enable support for transmission of CTE in connection mode"
+	help
+	  Enable support for transmission of Constant Tone Extension in
+	  connection mode.
+
+config BT_DF_CONNECTION_CTE_RSP
+	bool "Enable support for CTE request procedure in connection mode"
+	depends on BT_DF_CONNECTION_CTE_TX
+	help
+	  Enable support for request of Constant Tone Extension in connection
+	  mode.
+
 config BT_DEBUG_DF
 	bool "Bluetooth Direction Finding debug"
-	depends on BT_DF
 	help
 	  This option enables debug support for Bluetooth Direction Finding
 
+endif # BT_DF
 endif # BT_HCI_HOST
 
 config BT_ECC

subsys/bluetooth/host/conn_internal.h

@@ -44,6 +44,8 @@ enum {
 	BT_CONN_AUTO_DATA_LEN_COMPLETE,
 
 	BT_CONN_CTE_RX_ENABLED,          /* CTE receive and sampling is enabled */
+	BT_CONN_CTE_TX_PARAMS_SET,       /* CTE transmission parameters are set */
+	BT_CONN_CTE_RSP_ENABLED,         /* CTE response procedure is enabled */
 
 	/* Total number of flags - must be at the end of the enum */
 	BT_CONN_NUM_FLAGS,

subsys/bluetooth/host/direction.c

@@ -593,6 +593,52 @@ int hci_df_prepare_connection_iq_report(struct net_buf *buf,
 }
 #endif /* CONFIG_BT_DF_CONNECTION_CTE_RX */
 
+#if defined(CONFIG_BT_DF_CONNECTION_CTE_RSP)
+static void prepare_conn_cte_rsp_enable_cmd_params(struct net_buf *buf, const struct bt_conn *conn,
+						   bool enable)
+{
+	struct bt_hci_cp_le_conn_cte_rsp_enable *cp;
+
+	cp = net_buf_add(buf, sizeof(*cp));
+	(void)memset(cp, 0, sizeof(*cp));
+
+	cp->handle = sys_cpu_to_le16(conn->handle);
+	cp->enable = enable ? 1U : 0U;
+}
+
+static int hci_df_set_conn_cte_rsp_enable(struct bt_conn *conn, bool enable)
+{
+	struct bt_hci_rp_le_conn_cte_rsp_enable *rp;
+	struct bt_hci_cmd_state_set state;
+	struct net_buf *buf, *rsp;
+	int err;
+
+	buf = bt_hci_cmd_create(BT_HCI_OP_LE_CONN_CTE_RSP_ENABLE,
+				sizeof(struct bt_hci_cp_le_conn_cte_rsp_enable));
+	if (!buf) {
+		return -ENOBUFS;
+	}
+
+	prepare_conn_cte_rsp_enable_cmd_params(buf, conn, enable);
+
+	bt_hci_cmd_state_set_init(buf, &state, conn->flags, BT_CONN_CTE_RSP_ENABLED, enable);
+
+	err = bt_hci_cmd_send_sync(BT_HCI_OP_LE_CONN_CTE_RSP_ENABLE, buf, &rsp);
+	if (err) {
+		return err;
+	}
+
+	rp = (void *)rsp->data;
+	if (conn->handle != sys_le16_to_cpu(rp->handle)) {
+		err = -EIO;
+	}
+
+	net_buf_unref(rsp);
+
+	return err;
+}
+#endif /* CONFIG_BT_DF_CONNECTION_CTE_RSP */
+
 /* @brief Function initializes Direction Finding in Host
  *
  * @return Zero in case of success, other value in case of failure.
@@ -767,3 +813,39 @@ int bt_df_conn_cte_rx_disable(struct bt_conn *conn)
 	return bt_df_set_conn_cte_rx_enable(conn, false, NULL);
 }
 #endif /* CONFIG_BT_DF_CONNECTION_CTE_RX */
+
+#if defined(CONFIG_BT_DF_CONNECTION_CTE_RSP)
+static int bt_df_set_conn_cte_rsp_enable(struct bt_conn *conn, bool enable)
+{
+	CHECKIF(!conn) {
+		return -EINVAL;
+	}
+
+	if (!BT_FEAT_LE_CONNECTION_CTE_RESP(bt_dev.le.features)) {
+		BT_WARN("CTE response procedure is not supported");
+		return -ENOTSUP;
+	}
+
+	if (conn->state != BT_CONN_CONNECTED) {
+		BT_ERR("not connected");
+		return -ENOTCONN;
+	}
+
+	if (!atomic_test_bit(conn->flags, BT_CONN_CTE_TX_PARAMS_SET)) {
+		BT_ERR("Can't start CTE response procedure before CTE TX params setup");
+		return -EINVAL;
+	}
+
+	return hci_df_set_conn_cte_rsp_enable(conn, enable);
+}
+
+int bt_df_conn_cte_rsp_enable(struct bt_conn *conn)
+{
+	return bt_df_set_conn_cte_rsp_enable(conn, true);
+}
+
+int bt_df_conn_cte_rsp_disable(struct bt_conn *conn)
+{
+	return bt_df_set_conn_cte_rsp_enable(conn, false);
+}
+#endif /* CONFIG_BT_DF_CONNECTION_CTE_RSP */