Bluetooth: audio: Improve stream coupling for CIS as the unicast client

Allow  the streams to be paired when creating unicast group. This will
allow to reuse the same ISO for the paired streams.

Fixes: #51796
Signed-off-by: Mariusz Skamra <[email protected]>

Author: MariuszSkamra

include/zephyr/bluetooth/audio/audio.h

@@ -1946,32 +1946,33 @@ int bt_audio_stream_release(struct bt_audio_stream *stream);
 int bt_audio_stream_send(struct bt_audio_stream *stream, struct net_buf *buf,
 			 uint16_t seq_num, uint32_t ts);
 
-/** @brief Parameter struct for the unicast group functions
- *
- * Parameter struct for the bt_audio_unicast_group_create() and
- * bt_audio_unicast_group_add_streams() functions.
- */
 struct bt_audio_unicast_group_stream_param {
 	/** Pointer to a stream object. */
 	struct bt_audio_stream *stream;
 
-	/** The QoS settings for the @ref bt_audio_unicast_group_stream_param.stream. */
+	/** The QoS settings for the stream object. */
 	struct bt_codec_qos *qos;
+};
 
-	/** @brief The direction of the @ref bt_audio_unicast_group_stream_param.stream
-	 *
-	 * If two streams are being used for the same ACL connection but in
-	 * different directions, they may use the same CIS.
-	 */
-	enum bt_audio_dir dir;
+/** @brief Parameter struct for the unicast group functions
+ *
+ * Parameter struct for the bt_audio_unicast_group_create() and
+ * bt_audio_unicast_group_add_streams() functions.
+ */
+struct bt_audio_unicast_group_stream_pair_param {
+	/** Pointer to a receiving stream parameters. */
+	struct bt_audio_unicast_group_stream_param *rx_param;
+
+	/** Pointer to a transmiting stream parameters. */
+	struct bt_audio_unicast_group_stream_param *tx_param;
 };
 
 struct bt_audio_unicast_group_param {
 	/** The number of parameters in @p params */
 	size_t params_count;
 
 	/** Array of stream parameters */
-	struct bt_audio_unicast_group_stream_param *params;
+	struct bt_audio_unicast_group_stream_pair_param *params;
 
 	/** @brief Unicast Group packing mode.
 	 *
@@ -2020,7 +2021,7 @@ int bt_audio_unicast_group_create(struct bt_audio_unicast_group_param *param,
  *  @return 0 in case of success or negative value in case of error.
  */
 int bt_audio_unicast_group_add_streams(struct bt_audio_unicast_group *unicast_group,
-				       struct bt_audio_unicast_group_stream_param params[],
+				       struct bt_audio_unicast_group_stream_pair_param params[],
 				       size_t num_param);
 
 /** @brief Delete audio unicast group.

samples/bluetooth/unicast_audio_client/src/main.c

@@ -33,8 +33,10 @@ NET_BUF_POOL_FIXED_DEFINE(tx_pool, CONFIG_BT_AUDIO_UNICAST_CLIENT_ASE_SNK_COUNT,
 static struct bt_audio_stream streams[CONFIG_BT_AUDIO_UNICAST_CLIENT_ASE_SNK_COUNT +
 				      CONFIG_BT_AUDIO_UNICAST_CLIENT_ASE_SRC_COUNT];
 static size_t configured_sink_stream_count;
-static size_t configured_stream_count;
+static size_t configured_source_stream_count;
 
+#define configured_stream_count (configured_sink_stream_count + \
+				 configured_source_stream_count)
 
 /* Select a codec configuration to apply that is mandatory to support by both client and server.
  * Allows this sample application to work without logic to parse the codec capabilities of the
@@ -329,25 +331,6 @@ static void audio_timer_timeout(struct k_work *work)
 
 #endif
 
-
-static enum bt_audio_dir stream_dir(const struct bt_audio_stream *stream)
-{
-	for (size_t i = 0U; i < ARRAY_SIZE(sinks); i++) {
-		if (sinks[i].ep != NULL && stream->ep == sinks[i].ep) {
-			return BT_AUDIO_DIR_SINK;
-		}
-	}
-
-	for (size_t i = 0U; i < ARRAY_SIZE(sources); i++) {
-		if (sources[i] != NULL && stream->ep == sources[i]) {
-			return BT_AUDIO_DIR_SOURCE;
-		}
-	}
-
-	__ASSERT(false, "Invalid stream");
-	return 0;
-}
-
 static void print_hex(const uint8_t *ptr, size_t len)
 {
 	while (len-- != 0) {
@@ -880,7 +863,6 @@ static int configure_streams(void)
 		}
 
 		printk("Configured sink stream[%zu]\n", i);
-		configured_stream_count++;
 		configured_sink_stream_count++;
 	}
 
@@ -900,26 +882,42 @@ static int configure_streams(void)
 		}
 
 		printk("Configured source stream[%zu]\n", i);
-		configured_stream_count++;
+		configured_source_stream_count++;
 	}
 
 	return 0;
 }
 
 static int create_group(void)
 {
-	struct bt_audio_unicast_group_stream_param stream_params[ARRAY_SIZE(streams)];
+	const size_t params_count = MAX(configured_sink_stream_count,
+					configured_source_stream_count);
+	struct bt_audio_unicast_group_stream_pair_param pair_params[params_count];
+	struct bt_audio_unicast_group_stream_param stream_params[configured_stream_count];
 	struct bt_audio_unicast_group_param param;
 	int err;
 
 	for (size_t i = 0U; i < configured_stream_count; i++) {
 		stream_params[i].stream = &streams[i];
 		stream_params[i].qos = &codec_configuration.qos;
-		stream_params[i].dir = stream_dir(stream_params[i].stream);
 	}
 
-	param.params = stream_params;
-	param.params_count = configured_stream_count;
+	for (size_t i = 0U; i < params_count; i++) {
+		if (i < configured_sink_stream_count) {
+			pair_params[i].tx_param = &stream_params[i];
+		} else {
+			pair_params[i].tx_param = NULL;
+		}
+
+		if (i < configured_source_stream_count) {
+			pair_params[i].rx_param = &stream_params[i + configured_sink_stream_count];
+		} else {
+			pair_params[i].rx_param = NULL;
+		}
+	}
+
+	param.params = pair_params;
+	param.params_count = params_count;
 	param.packing = BT_ISO_PACKING_SEQUENTIAL;
 
 	err = bt_audio_unicast_group_create(&param, &unicast_group);
@@ -969,7 +967,7 @@ static int enable_streams(void)
 		init_lc3();
 	}
 
-	for (size_t i = 0; i < configured_stream_count; i++) {
+	for (size_t i = 0U; i < configured_stream_count; i++) {
 		int err;
 
 		err = bt_audio_stream_enable(&streams[i],
@@ -992,7 +990,7 @@ static int enable_streams(void)
 
 static int start_streams(void)
 {
-	for (size_t i = 0; i < configured_stream_count; i++) {
+	for (size_t i = 0U; i < configured_stream_count; i++) {
 		int err;
 
 		err = bt_audio_stream_start(&streams[i]);
@@ -1025,7 +1023,7 @@ static void reset_data(void)
 	k_sem_reset(&sem_stream_started);
 
 	configured_sink_stream_count = 0;
-	configured_stream_count = 0;
+	configured_source_stream_count = 0;
 }
 
 void main(void)