Bluetooth: CSIP: Add support for dynamically setting set size

The set size can now be dynamically set and notified.
The rank is added as a argument in the case that changing
the set size, also affects the device's rank, as ranks
in a coordinated set needs to be continuous.

The set coordinator implementation has been updated
to support receiving the new set size, and providing
this information to the upper layers.

This commit adds a babblesim test for the new API,
as well as a shell command.

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

Author: Thalley

doc/connectivity/bluetooth/shell/audio/csip.rst

@@ -144,15 +144,18 @@ Using the Set Member
 
    csip_set_member --help
    csip_set_member - Bluetooth CSIP set member shell commands
-   Subcommands:
-      register      :Initialize the service and register callbacks [size <int>]
-                     [rank <int>] [not-lockable] [sirk <data>]
-      lock          :Lock the set
-      release       :Release the set [force]
-      sirk          :Set the currently used SIRK <sirk>
-      get_sirk      :Get the currently used SIRK
-      sirk_rsp      :Set the response used in SIRK requests <accept, accept_enc,
-                     reject, oob>
+      Subcommands:
+      register           : Initialize the service and register callbacks [size
+                           <int>] [rank <int>] [not-lockable] [sirk <data>]
+      lock               : Lock the set
+      release            : Release the set [force]
+      sirk               : Set the currently used SIRK <sirk>
+      set_size_and_rank  : Set the currently used size and rank <size> <rank>
+      get_info           : Get service info
+      sirk_rsp           : Set the response used in SIRK requests <accept,
+                           accept_enc, reject, oob>
+
+
 
 Example Usage
 =============
@@ -179,14 +182,32 @@ clients.
    uart:~$ csip_set_member sirk 00112233445566778899aabbccddeeff
    SIRK updated
 
-Getting the current SIRK
+Setting a new set size and rank
+-------------------------------
+
+This command can modify the set size and rank of a service instance.
+This shall be done for all device in the set at the same time,
+and all devices shall have the same set size.
+The rank will be ignored if the set is not lockable, else the rank shall be <= the set size,
+and shall be unique for this device in the set.
+
+.. code-block:: console
+
+   uart:~$ csip_set_member set_size_and_rank 1 1
+   Set size and rank updated to 1 and 1
+
+Getting the current info
 ------------------------
 
-This command can get the currently used SIRK.
+This command can get the currently used set info.
 
 .. code-block:: console
 
-   uart:~$ csip_set_member get_sirk
-   SIRK
-   36 04 9a dc 66 3a a1 a1 |6...f:..
-   1d 9a 2f 41 01 73 3e 01 |../A.s>.
+   uart:~$ csip_set_member get_info
+   Info for 0x2003b0c8
+           SIRK
+   00000000: 20 37 0a 00 95 c4 04 20  00 00 00 00 f1 79 09 00 | 7.....  .....y..|
+           Set size: 2
+           Rank: 1
+           Lockable: true
+           Locked: false

doc/releases/release-notes-4.2.rst

@@ -80,6 +80,8 @@ New APIs and options
     * :c:macro:`BT_BAP_ADV_PARAM_BROADCAST_SLOW`
     * :c:macro:`BT_BAP_PER_ADV_PARAM_BROADCAST_FAST`
     * :c:macro:`BT_BAP_PER_ADV_PARAM_BROADCAST_SLOW`
+    * :c:func:`bt_csip_set_member_set_size_and_rank`
+    * :c:func:`bt_csip_set_member_get_info`
 
   * Host
 

include/zephyr/bluetooth/audio/csip.h

@@ -32,6 +32,7 @@
 #include <stdint.h>
 
 #include <zephyr/autoconf.h>
+#include <zephyr/bluetooth/addr.h>
 #include <zephyr/bluetooth/bluetooth.h>
 #include <zephyr/bluetooth/conn.h>
 #include <zephyr/bluetooth/gap.h>
@@ -237,6 +238,70 @@ int bt_csip_set_member_sirk(struct bt_csip_set_member_svc_inst *svc_inst,
 int bt_csip_set_member_get_sirk(struct bt_csip_set_member_svc_inst *svc_inst,
 				uint8_t sirk[BT_CSIP_SIRK_SIZE]);
 
+/**
+ * @brief Set a new size and rank for a service instance
+ *
+ * This function can be used to dynamically change the size and rank of a service instance.
+ * It is important to note that a set cannot have multiple devices with the same rank in a set,
+ * and it is up to the caller of this function to ensure that.
+ * Similarly, it is important that the size is updated on all devices in the set at the same time.
+ *
+ * If @kconfig{CONFIG_BT_CSIP_SET_MEMBER_SIZE_NOTIFIABLE} is enabled, this will also send a
+ * notification to all connected or bonded clients.
+ *
+ * @param svc_inst The service instance.
+ * @param size The new set size.
+ * @param rank The new rank. Ignored if the @p svc_inst is not lockable.
+ *
+ * @retval -EINVAL @p svc_inst is NULL, @p size is less than 1, @p rank is less than 1 or higher
+ *                 than @p size for a lockable @p svc_inst.
+ * @retval -EALREADY @p size and @p rank are already the provided values.
+ * @retval 0 Success.
+ */
+int bt_csip_set_member_set_size_and_rank(struct bt_csip_set_member_svc_inst *svc_inst, uint8_t size,
+					 uint8_t rank);
+
+/** Struct to hold information about a service instance */
+struct bt_csip_set_member_set_info {
+	/** The 16-octet SIRK */
+	uint8_t sirk[BT_CSIP_SIRK_SIZE];
+
+	/** The set size */
+	uint8_t set_size;
+
+	/**
+	 * @brief The rank
+	 *
+	 * May be 0 if the set is not lockable
+	 */
+	uint8_t rank;
+
+	/** Whether the set is lockable  */
+	bool lockable: 1;
+
+	/** Whether the set is currently locked */
+	bool locked: 1;
+
+	/**
+	 * @brief The address of the client that currently holds the lock
+	 *
+	 * Will be @ref BT_ADDR_LE_NONE if the server holds the lock
+	 */
+	bt_addr_le_t lock_client_addr;
+};
+
+/**
+ * @brief Get information about a service instances
+ *
+ * @param svc_inst The service instance.
+ * @param info Pointer to a struct to store the information in.
+ *
+ * @retval -EINVAL @p svc_inst or @p info is NULL.
+ * @retval 0 Success.
+ */
+int bt_csip_set_member_get_info(const struct bt_csip_set_member_svc_inst *svc_inst,
+				struct bt_csip_set_member_set_info *info);
+
 /**
  * @brief Generate the Resolvable Set Identifier (RSI) value.
  *
@@ -382,6 +447,24 @@ typedef void (*bt_csip_set_coordinator_lock_changed_cb)(
 typedef void (*bt_csip_set_coordinator_sirk_changed_cb)(
 	struct bt_csip_set_coordinator_csis_inst *inst);
 
+/**
+ * @typedef bt_csip_set_coordinator_size_changed_cb
+ * @brief Callback when the size of a set of a connected device changes.
+ *
+ * Since all devices in a set shall have the same set size value.
+ * Each connected device may send the same new size set in a notification,
+ * assuming that the remote device supports notifications of the set size.
+ *
+ * The rank of each device in the set may also change as part of this, so it is advisable to call
+ * bt_csip_set_coordinator_discover() to rediscover and read the characteristic values of the sets
+ * on each device.
+ *
+ * @param inst    The Coordinated Set Identification Service instance that was changed.
+ *                The new size is stored in the @p inst->info.size.
+ */
+typedef void (*bt_csip_set_coordinator_size_changed_cb)(
+	struct bt_conn *conn, const struct bt_csip_set_coordinator_csis_inst *inst);
+
 /**
  * @typedef bt_csip_set_coordinator_ordered_access_cb_t
  * @brief Callback for bt_csip_set_coordinator_ordered_access()
@@ -417,6 +500,8 @@ struct bt_csip_set_coordinator_cb {
 	bt_csip_set_coordinator_lock_changed_cb lock_changed;
 	/** Callback when a set's SIRK has changed */
 	bt_csip_set_coordinator_sirk_changed_cb sirk_changed;
+	/** Callback when a set's size has changed */
+	bt_csip_set_coordinator_size_changed_cb size_changed;
 	/** Callback for the ordered access procedure */
 	bt_csip_set_coordinator_ordered_access_cb_t ordered_access;
 

subsys/bluetooth/audio/Kconfig.csip

@@ -53,6 +53,11 @@ config BT_CSIP_SET_MEMBER_SIRK_NOTIFIABLE
 	help
 	  This option enables support for clients to be notified on SIRK changes.
 
+config BT_CSIP_SET_MEMBER_SIZE_NOTIFIABLE
+	bool "Set Size notifiable support"
+	help
+	  This option enables support for clients to be notified on Set Size changes.
+
 endif # BT_CSIP_SET_MEMBER
 
 #################### Coordinated Set Identification Client ####################

subsys/bluetooth/audio/csip_set_coordinator.c

@@ -312,6 +312,17 @@ static void sirk_changed(struct bt_csip_set_coordinator_csis_inst *inst)
 	}
 }
 
+static void size_changed(struct bt_conn *conn, struct bt_csip_set_coordinator_csis_inst *inst)
+{
+	struct bt_csip_set_coordinator_cb *listener;
+
+	SYS_SLIST_FOR_EACH_CONTAINER(&csip_set_coordinator_cbs, listener, _node) {
+		if (listener->size_changed != NULL) {
+			listener->size_changed(conn, inst);
+		}
+	}
+}
+
 static void release_set_complete(int err)
 {
 	struct bt_csip_set_coordinator_cb *listener;
@@ -468,17 +479,19 @@ static uint8_t size_notify_func(struct bt_conn *conn,
 
 	if (svc_inst != NULL) {
 		if (length == sizeof(set_size)) {
-			struct bt_csip_set_coordinator_inst *client;
 			struct bt_csip_set_coordinator_set_info *set_info;
+			struct bt_csip_set_coordinator_csis_inst *inst;
+			struct bt_csip_set_coordinator_inst *client;
 
 			client = &client_insts[bt_conn_index(conn)];
-			set_info = &client->set_member.insts[svc_inst->idx].info;
+			inst = &client->set_member.insts[svc_inst->idx];
+			set_info = &inst->info;
 
 			(void)memcpy(&set_size, data, length);
 			LOG_DBG("Set size updated from %u to %u", set_info->set_size, set_size);
 
 			set_info->set_size = set_size;
-			/* TODO: Notify app */
+			size_changed(conn, inst);
 		} else {
 			LOG_DBG("Invalid length %u", length);
 		}