Bluetooth: BAP: Dont discover ASE CP if ASE not found

Added a check in unicast_client_ase_discover_cb that if
no ASE was discovered, then it would stop the discovery
there instead of attempting to call
unicast_client_ase_cp_discover to discover the control point
which would not be useful to use anyhow.

This terminates the discovery earlier in case of the remote
side not supporting the audio direction we are discovering.

Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>

subsys/bluetooth/audio/bap_unicast_client.c

@@ -66,6 +66,7 @@ BUILD_ASSERT(CONFIG_BT_BAP_UNICAST_CLIENT_ASE_SRC_COUNT == 0 ||
 LOG_MODULE_REGISTER(bt_bap_unicast_client, CONFIG_BT_BAP_UNICAST_CLIENT_LOG_LEVEL);
 
 #define PAC_DIR_UNUSED(dir) ((dir) != BT_AUDIO_DIR_SINK && (dir) != BT_AUDIO_DIR_SOURCE)
+#define BAP_HANDLE_UNUSED   0x0000U
 struct bt_bap_unicast_client_ep {
 	uint16_t handle;
 	uint16_t cp_handle;
@@ -1521,7 +1522,7 @@ static uint8_t unicast_client_cp_notify(struct bt_conn *conn,
 
 	if (!data) {
 		LOG_DBG("Unsubscribed");
-		params->value_handle = 0x0000;
+		params->value_handle = BAP_HANDLE_UNUSED;
 		return BT_GATT_ITER_STOP;
 	}
 
@@ -1760,7 +1761,7 @@ static uint8_t unicast_client_ep_notify(struct bt_conn *conn,
 
 	if (!data) {
 		LOG_DBG("Unsubscribed");
-		params->value_handle = 0x0000;
+		params->value_handle = BAP_HANDLE_UNUSED;
 		return BT_GATT_ITER_STOP;
 	}
 
@@ -2231,8 +2232,8 @@ static void unicast_client_reset(struct bt_bap_ep *ep, uint8_t reason)
 	(void)k_work_cancel_delayable(&client_ep->ase_read_work);
 	(void)memset(ep, 0, sizeof(*ep));
 
-	client_ep->cp_handle = 0U;
-	client_ep->handle = 0U;
+	client_ep->cp_handle = BAP_HANDLE_UNUSED;
+	client_ep->handle = BAP_HANDLE_UNUSED;
 	(void)memset(&client_ep->discover, 0, sizeof(client_ep->discover));
 	client_ep->release_requested = false;
 	client_ep->cp_ntf_pending = false;
@@ -3694,6 +3695,27 @@ static uint8_t unicast_client_ase_read_func(struct bt_conn *conn, uint8_t err,
 	return BT_GATT_ITER_STOP;
 }
 
+static bool any_ases_found(const struct unicast_client *client)
+{
+	/* We always allocate ases from 0 to X, so to verify if any sink or source ASEs have been
+	 * found we can just check the first index
+	 */
+#if CONFIG_BT_BAP_UNICAST_CLIENT_ASE_SNK_COUNT > 0
+	if (client->dir == BT_AUDIO_DIR_SINK && client->snks[0].handle == BAP_HANDLE_UNUSED) {
+		LOG_DBG("No sink ASEs found");
+		return false;
+	}
+#endif /* CONFIG_BT_BAP_UNICAST_CLIENT_ASE_SNK_COUNT > 0 */
+#if CONFIG_BT_BAP_UNICAST_CLIENT_ASE_SRC_COUNT > 0
+	if (client->dir == BT_AUDIO_DIR_SOURCE && client->srcs[0].handle == BAP_HANDLE_UNUSED) {
+		LOG_DBG("No source ASEs found");
+		return false;
+	}
+#endif /* CONFIG_BT_BAP_UNICAST_CLIENT_ASE_SRC_COUNT > 0 */
+
+	return true;
+}
+
 static uint8_t unicast_client_ase_discover_cb(struct bt_conn *conn,
 					      const struct bt_gatt_attr *attr,
 					      struct bt_gatt_discover_params *discover)
@@ -3703,12 +3725,18 @@ static uint8_t unicast_client_ase_discover_cb(struct bt_conn *conn,
 	uint16_t value_handle;
 	int err;
 
+	client = &uni_cli_insts[bt_conn_index(conn)];
+
 	if (attr == NULL) {
-		err = unicast_client_ase_cp_discover(conn);
-		if (err != 0) {
-			LOG_ERR("Unable to discover ASE Control Point");
+		if (!any_ases_found(client)) {
+			unicast_client_discover_complete(conn, BT_ATT_ERR_ATTRIBUTE_NOT_FOUND);
+		} else {
+			err = unicast_client_ase_cp_discover(conn);
+			if (err != 0) {
+				LOG_ERR("Unable to discover ASE Control Point");
 
-			unicast_client_discover_complete(conn, err);
+				unicast_client_discover_complete(conn, err);
+			}
 		}
 
 		return BT_GATT_ITER_STOP;
@@ -3718,8 +3746,6 @@ static uint8_t unicast_client_ase_discover_cb(struct bt_conn *conn,
 	value_handle = chrc->value_handle;
 	memset(discover, 0, sizeof(*discover));
 
-	client = &uni_cli_insts[bt_conn_index(conn)];
-
 	LOG_DBG("conn %p attr %p handle 0x%04x dir %s", conn, attr, value_handle,
 		bt_audio_dir_str(client->dir));
 
@@ -3814,7 +3840,7 @@ static uint8_t unicast_client_pacs_avail_ctx_notify_cb(struct bt_conn *conn,
 
 	if (!data) {
 		LOG_DBG("Unsubscribed");
-		params->value_handle = 0x0000;
+		params->value_handle = BAP_HANDLE_UNUSED;
 		return BT_GATT_ITER_STOP;
 	}
 
@@ -3990,7 +4016,7 @@ static uint8_t unicast_client_pacs_location_notify_cb(struct bt_conn *conn,
 
 	if (!data) {
 		LOG_DBG("Unsubscribed");
-		params->value_handle = 0x0000;
+		params->value_handle = BAP_HANDLE_UNUSED;
 		return BT_GATT_ITER_STOP;
 	}