Bluetooth: BAP: Unicast client Split start and connect

doc/connectivity/bluetooth/api/audio/shell/bap.rst

@@ -34,6 +34,7 @@ Commands
       stream_qos             : interval [framing] [latency] [pd] [sdu] [phy] [rtn]
       qos                    : Send QoS configure for Unicast Group
       enable                 : [context]
+      connect                : Connect the CIS of the stream
       stop
       list
       print_ase_info         : Print ASE info for default connection
@@ -62,10 +63,8 @@ Commands
                                     [extended <meta>]
                                     [vendor <meta>]]
       send                   : Send to Audio Stream [data]
-      start_sine             : Start sending a LC3 encoded sine wave [all]
-      stop_sine              : Stop sending a LC3 encoded sine wave [all]
-      recv_stats             : Sets or gets the receive statistics reporting interval
-                              in # of packets
+      bap_stats              : Sets or gets the statistics reporting interval in # of
+                              packets
       set_location           : <direction: sink, source> <location bitmask>
       set_context            : <direction: sink, source><context bitmask> <type:
                               supported, available>
@@ -80,19 +79,19 @@ Commands
    "config","discover","idle/codec-configured/qos-configured","codec-configured"
    "qos","config","codec-configured/qos-configured","qos-configured"
    "enable","qos","qos-configured","enabling"
-   "[start]","enable","enabling","streaming"
+   "connect","qos/enable","qos-configured/enabling","qos-configured/enabling"
+   "[start]","enable/connect","enabling","streaming"
    "disable","enable", "enabling/streaming","disabling"
    "[stop]","disable","disabling","qos-configure/idle"
    "release","config","any","releasing/codec-configure/idle"
    "list","none","any","none"
    "select_unicast","none","any","none"
-   "connect","discover","idle/codec-configured/qos-configured","codec-configured"
    "send","enable","streaming","none"
 
 Example Central
 ***************
 
-Connect and establish a stream:
+Connect and establish a sink stream:
 
 .. code-block:: console
 
@@ -104,17 +103,22 @@ Connect and establish a stream:
    uart:~$ bap config sink 0
    uart:~$ bap qos
    uart:~$ bap enable
+   uart:~$ bap connect
 
-Or using connect command:
+Connect and establish a source stream:
 
 .. code-block:: console
 
    uart:~$ bt init
    uart:~$ bap init
    uart:~$ bt connect <address>
    uart:~$ gatt exchange-mtu
-   uart:~$ bap discover sink
-   uart:~$ bap connect sink 0
+   uart:~$ bap discover source
+   uart:~$ bap config source 0
+   uart:~$ bap qos
+   uart:~$ bap enable
+   uart:~$ bap connect
+   uart:~$ bap start
 
 Disconnect and release:
 
@@ -479,8 +483,7 @@ parameters.
 Enable
 ******
 
-The :code:`enable` command attempts to enable the stream previously configured,
-if the remote peer accepts then the ISO connection procedure is also initiated.
+The :code:`enable` command attempts to enable the stream previously configured.
 
 .. csv-table:: State Machine Transitions
    :header: "Depends", "Allowed States", "Next States"
@@ -493,17 +496,33 @@ if the remote peer accepts then the ISO connection procedure is also initiated.
    uart:~$ bap enable [context]
    uart:~$ bap enable Media
 
+Connect
+*******
+
+The :code:`connect` command attempts to connect the stream previously configured.
+Sink streams will have to be started by the unicast server, and source streams will have to be
+started by the unicast client.
+
+.. csv-table:: State Machine Transitions
+   :header: "Depends", "Allowed States", "Next States"
+   :widths: auto
+
+   "qos/enable","qos-configured/enabling","qos-configured/enabling"
+
+.. code-block:: console
+
+   uart:~$ bap connect
+
 Start
 *****
 
-The :code:`start` command is only necessary when acting as a sink as it
-indicates to the source the stack is ready to start receiving data.
+The :code:`start` command is only necessary when starting a source stream.
 
 .. csv-table:: State Machine Transitions
    :header: "Depends", "Allowed States", "Next States"
    :widths: auto
 
-   "enable","enabling","streaming"
+   "enable/connect","enabling","streaming"
 
 .. code-block:: console
 

doc/releases/migration-guide-3.7.rst

@@ -447,6 +447,10 @@ Bluetooth Audio
   This needs to be added to all instances of CAP discovery callback functions defined.
   (:github:`72797`)
 
+* :c:func:`bt_bap_stream_start` no longer connects the CIS. To connect the CIS,
+  the :c:func:`bt_bap_stream_connect` shall now be called before :c:func:`bt_bap_stream_start`.
+  (:github:`73032`)
+
 * All occurrences of ``set_sirk`` have been changed to just ``sirk`` as the ``s`` in ``sirk`` stands
   for set. (:github:`73413`)
 

include/zephyr/bluetooth/audio/bap.h

@@ -2,7 +2,7 @@
  *  @brief Header for Bluetooth BAP.
  *
  * Copyright (c) 2020 Bose Corporation
- * Copyright (c) 2021-2023 Nordic Semiconductor ASA
+ * Copyright (c) 2021-2024 Nordic Semiconductor ASA
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -715,20 +715,43 @@ int bt_bap_stream_metadata(struct bt_bap_stream *stream, const uint8_t meta[], s
  */
 int bt_bap_stream_disable(struct bt_bap_stream *stream);
 
+/**
+ * @brief Connect unicast audio stream
+ *
+ * This procedure is used by a unicast client to connect the connected isochronous stream (CIS)
+ * associated with the audio stream. If two audio streams share a CIS, then this only needs to be
+ * done once for those streams. This can only be done for streams in the QoS configured or enabled
+ * states.
+ *
+ * The bt_bap_stream_ops.connected() callback will be called on the streams once this has finished.
+ *
+ * This shall only be called for unicast streams, and only as the unicast client
+ * (@kconfig{CONFIG_BT_BAP_UNICAST_CLIENT}).
+ *
+ * @param stream Stream object
+ *
+ * @retval 0 in case of success
+ * @retval -EINVAL if the stream, endpoint, ISO channel or connection is NULL
+ * @retval -EBADMSG if the stream or ISO channel is in an invalid state for connection
+ * @retval -EOPNOTSUPP if the role of the stream is not @ref BT_HCI_ROLE_CENTRAL
+ * @retval -EALREADY if the ISO channel is already connecting or connected
+ * @retval -EBUSY if another ISO channel is connecting
+ * @retval -ENOEXEC if otherwise rejected by the ISO layer
+ */
+int bt_bap_stream_connect(struct bt_bap_stream *stream);
+
 /**
  * @brief Start Audio Stream
  *
  * This procedure is used by a unicast client or unicast server to make a stream start streaming.
  *
- * For the unicast client, this will connect the CIS for the stream before
- * sending the start command.
+ * For the unicast client, this will send the receiver start ready command to the unicast server for
+ * @ref BT_AUDIO_DIR_SOURCE ASEs. The CIS is required to be connected first by
+ * bt_bap_stream_connect() before the command can be sent.
  *
- * For the unicast server, this will put a @ref BT_AUDIO_DIR_SINK stream into the streaming state if
- * the CIS is connected (initialized by the unicast client). If the CIS is not connected yet, the
- * stream will go into the streaming state as soon as the CIS is connected.
- * @ref BT_AUDIO_DIR_SOURCE streams will go into the streaming state when the unicast client sends
- * the Receiver Start Ready operation, which will trigger the @ref bt_bap_unicast_server_cb.start()
- * callback.
+ * For the unicast server, this will execute the receiver start ready command on the unicast server
+ * for @ref BT_AUDIO_DIR_SINK ASEs. If the CIS is not connected yet, the stream will go into the
+ * streaming state as soon as the CIS is connected.
  *
  * This shall only be called for unicast streams.
  *

samples/bluetooth/bap_unicast_client/src/main.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2023 Nordic Semiconductor ASA
+ * Copyright (c) 2021-2024 Nordic Semiconductor ASA
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -59,6 +59,7 @@ static K_SEM_DEFINE(sem_stream_configured, 0, 1);
 static K_SEM_DEFINE(sem_stream_qos, 0, ARRAY_SIZE(sinks) + ARRAY_SIZE(sources));
 static K_SEM_DEFINE(sem_stream_enabled, 0, 1);
 static K_SEM_DEFINE(sem_stream_started, 0, 1);
+static K_SEM_DEFINE(sem_stream_connected, 0, 1);
 
 #define AUDIO_DATA_TIMEOUT_US 1000000UL /* Send data every 1 second */
 
@@ -518,9 +519,9 @@ static void stream_enabled(struct bt_bap_stream *stream)
 	k_sem_give(&sem_stream_enabled);
 }
 
-static void stream_started(struct bt_bap_stream *stream)
+static void stream_connected_cb(struct bt_bap_stream *stream)
 {
-	printk("Audio Stream %p started\n", stream);
+	printk("Audio Stream %p connected\n", stream);
 
 	/* Reset sequence number for sinks */
 	for (size_t i = 0U; i < configured_sink_stream_count; i++) {
@@ -530,6 +531,13 @@ static void stream_started(struct bt_bap_stream *stream)
 		}
 	}
 
+	k_sem_give(&sem_stream_connected);
+}
+
+static void stream_started(struct bt_bap_stream *stream)
+{
+	printk("Audio Stream %p started\n", stream);
+
 	k_sem_give(&sem_stream_started);
 }
 
@@ -576,7 +584,8 @@ static struct bt_bap_stream_ops stream_ops = {
 	.disabled = stream_disabled,
 	.stopped = stream_stopped,
 	.released = stream_released,
-	.recv = stream_recv
+	.recv = stream_recv,
+	.connected = stream_connected_cb,
 };
 
 static void add_remote_source(struct bt_bap_ep *ep)
@@ -1018,17 +1027,62 @@ static int enable_streams(void)
 	return 0;
 }
 
-static int start_streams(void)
+static int connect_streams(void)
 {
 	for (size_t i = 0U; i < configured_stream_count; i++) {
 		int err;
 
-		err = bt_bap_stream_start(&streams[i]);
-		if (err != 0) {
+		k_sem_reset(&sem_stream_connected);
+
+		err = bt_bap_stream_connect(&streams[i]);
+		if (err == -EALREADY) {
+			/* We have already connected a paired stream */
+			continue;
+		} else if (err != 0) {
 			printk("Unable to start stream: %d\n", err);
 			return err;
 		}
 
+		err = k_sem_take(&sem_stream_connected, K_FOREVER);
+		if (err != 0) {
+			printk("failed to take sem_stream_connected (err %d)\n", err);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static enum bt_audio_dir stream_dir(const struct bt_bap_stream *stream)
+{
+	struct bt_bap_ep_info ep_info;
+	int err;
+
+	err = bt_bap_ep_get_info(stream->ep, &ep_info);
+	if (err != 0) {
+		printk("Failed to get ep info for %p: %d\n", stream, err);
+		__ASSERT_NO_MSG(false);
+
+		return 0;
+	}
+
+	return ep_info.dir;
+}
+
+static int start_streams(void)
+{
+	for (size_t i = 0U; i < configured_stream_count; i++) {
+		struct bt_bap_stream *stream = &streams[i];
+		int err;
+
+		if (stream_dir(stream) == BT_AUDIO_DIR_SOURCE) {
+			err = bt_bap_stream_start(&streams[i]);
+			if (err != 0) {
+				printk("Unable to start stream: %d\n", err);
+				return err;
+			}
+		} /* Sink streams are started by the unicast server */
+
 		err = k_sem_take(&sem_stream_started, K_FOREVER);
 		if (err != 0) {
 			printk("failed to take sem_stream_started (err %d)\n", err);
@@ -1051,6 +1105,7 @@ static void reset_data(void)
 	k_sem_reset(&sem_stream_qos);
 	k_sem_reset(&sem_stream_enabled);
 	k_sem_reset(&sem_stream_started);
+	k_sem_reset(&sem_stream_connected);
 
 	configured_sink_stream_count = 0;
 	configured_source_stream_count = 0;
@@ -1131,6 +1186,13 @@ int main(void)
 		}
 		printk("Streams enabled\n");
 
+		printk("Connecting streams\n");
+		err = connect_streams();
+		if (err != 0) {
+			return 0;
+		}
+		printk("Streams connected\n");
+
 		printk("Starting streams\n");
 		err = start_streams();
 		if (err != 0) {

samples/bluetooth/tmap_peripheral/src/bap_unicast_sr.c

@@ -1,7 +1,7 @@
 /** @file
  *  @brief Bluetooth Basic Audio Profile (BAP) Unicast Server role.
  *
- *  Copyright (c) 2021-2023 Nordic Semiconductor ASA
+ *  Copyright (c) 2021-2024 Nordic Semiconductor ASA
  *  Copyright (c) 2022 Codecoup
  *  Copyright (c) 2023 NXP
  *
@@ -293,10 +293,23 @@ static void stream_recv(struct bt_bap_stream *stream, const struct bt_iso_recv_i
 
 static void stream_enabled(struct bt_bap_stream *stream)
 {
-	const int err = bt_bap_stream_start(stream);
+	struct bt_bap_ep_info ep_info;
+	int err;
 
+	err = bt_bap_ep_get_info(stream->ep, &ep_info);
 	if (err != 0) {
-		printk("Failed to start stream %p: %d", stream, err);
+		printk("Failed to get ep info: %d\n", err);
+		return;
+	}
+
+	/* The unicast server is responsible for starting the sink streams */
+	if (ep_info.dir == BT_AUDIO_DIR_SINK) {
+		/* Automatically do the receiver start ready operation */
+		err = bt_bap_stream_start(stream);
+
+		if (err != 0) {
+			printk("Failed to start stream %p: %d", stream, err);
+		}
 	}
 }