Bluetooth: Audio: Add broadcast audio scan service (BASS)

Add the BASS as a standalone service. The service is
used for the scan delegator role, which has not been
fully implemented yet.

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

include/bluetooth/audio/bass.h

@@ -0,0 +1,97 @@
+/** @file
+ *  @brief Header for Bluetooth BASS.
+ *
+ * Copyright (c) 2020 Bose Corporation
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_BLUETOOTH_AUDIO_BASS_
+#define ZEPHYR_INCLUDE_BLUETOOTH_AUDIO_BASS_
+#include <zephyr/types.h>
+#include <bluetooth/conn.h>
+
+#if IS_ENABLED(CONFIG_BT_BASS)
+#define BT_BASS_MAX_METADATA_LEN CONFIG_BT_BASS_MAX_METADATA_LEN
+#define BT_BASS_MAX_SUBGROUPS    CONFIG_BT_BASS_MAX_SUBGROUPS
+#else
+#define BT_BASS_MAX_METADATA_LEN 0
+#define BT_BASS_MAX_SUBGROUPS    0
+#endif
+
+#define BT_BASS_BROADCAST_CODE_SIZE        16
+
+#define BT_BASS_PA_STATE_NOT_SYNCED        0x00
+#define BT_BASS_PA_STATE_INFO_REQ          0x01
+#define BT_BASS_PA_STATE_SYNCED            0x02
+#define BT_BASS_PA_STATE_FAILED            0x03
+#define BT_BASS_PA_STATE_NO_PAST           0x04
+
+#define BT_BASS_BIG_ENC_STATE_NO_ENC       0x00
+#define BT_BASS_BIG_ENC_STATE_BCODE_REQ    0x01
+#define BT_BASS_BIG_ENC_STATE_DEC          0x02
+#define BT_BASS_BIG_ENC_STATE_BAD_CODE     0x03
+
+#define BT_BASS_ERR_OPCODE_NOT_SUPPORTED   0x80
+#define BT_BASS_ERR_INVALID_SRC_ID         0x81
+
+#define BT_BASS_PA_INTERVAL_UNKNOWN        0xFFFF
+
+#define BT_BASS_BROADCAST_MAX_ID           0xFFFFFF
+
+#define BT_BASS_BIS_SYNC_NO_PREF           0xFFFFFFFF
+
+struct bt_bass_subgroup {
+	uint32_t bis_sync;
+	uint32_t requested_bis_sync;
+	uint8_t metadata_len;
+	uint8_t metadata[BT_BASS_MAX_METADATA_LEN];
+};
+
+/* TODO: Only expose this as an opaque type */
+struct bt_bass_recv_state {
+	uint8_t src_id;
+	bt_addr_le_t addr;
+	uint8_t adv_sid;
+	uint8_t req_pa_sync_value;
+	uint8_t pa_sync_state;
+	uint8_t encrypt_state;
+	uint32_t broadcast_id; /* 24 bits */
+	uint8_t bad_code[BT_BASS_BROADCAST_CODE_SIZE];
+	uint8_t num_subgroups;
+	struct bt_bass_subgroup subgroups[BT_BASS_MAX_SUBGROUPS];
+};
+
+struct bt_bass_cb {
+	void (*pa_synced)(struct bt_bass_recv_state *recv_state,
+			  const struct bt_le_per_adv_sync_synced_info *info);
+	void (*pa_term)(struct bt_bass_recv_state *recv_state,
+			const struct bt_le_per_adv_sync_term_info *info);
+	void (*pa_recv)(struct bt_bass_recv_state *recv_state,
+			const struct bt_le_per_adv_sync_recv_info *info,
+			struct net_buf_simple *buf);
+	void (*biginfo)(struct bt_bass_recv_state *recv_state,
+			const struct bt_iso_biginfo *biginfo);
+};
+
+/**
+ * @brief Registers the callbacks used by BASS.
+ */
+void bt_bass_register_cb(struct bt_bass_cb *cb);
+
+/**
+ * @brief Set the sync state of a receive state in the server
+ *
+ * @param src_id         The source id used to identify the receive state.
+ * @param pa_sync_state  The sync state of the PA.
+ * @param bis_synced     Array of bitfields to set the BIS sync state for each
+ *                       subgroup.
+ * @param encrypted      The BIG encryption state.
+ * @return int           Error value. 0 on success, ERRNO on fail.
+ */
+int bt_bass_set_sync_state(uint8_t src_id, uint8_t pa_sync_state,
+			   uint32_t bis_synced[BT_BASS_MAX_SUBGROUPS],
+			   uint8_t encrypted);
+
+#endif /* ZEPHYR_INCLUDE_BLUETOOTH_AUDIO_BASS_ */

subsys/bluetooth/audio/CMakeLists.txt

@@ -48,3 +48,4 @@ zephyr_library_sources_ifdef(CONFIG_BT_AUDIO_CAPABILITIES capabilities.c)
 zephyr_library_sources_ifdef(CONFIG_BT_AUDIO_UNICAST_CLIENT unicast_client.c)
 zephyr_library_sources_ifdef(CONFIG_BT_AUDIO_BROADCAST_SOURCE broadcast_source.c)
 zephyr_library_sources_ifdef(CONFIG_BT_AUDIO_BROADCAST_SINK broadcast_sink.c)
+zephyr_library_sources_ifdef(CONFIG_BT_BASS bass.c)

subsys/bluetooth/audio/Kconfig

@@ -32,5 +32,6 @@ rsource "Kconfig.vcs"
 rsource "Kconfig.mics"
 rsource "Kconfig.csis"
 rsource "Kconfig.mcs"
+rsource "Kconfig.bass"
 
 endif # BT_AUDIO

subsys/bluetooth/audio/Kconfig.bass

@@ -0,0 +1,58 @@
+# Bluetooth Audio - Broadcast Assistant configuration options
+#
+# Copyright (c) 2020 Bose Corporation
+# Copyright (c) 2021 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+if BT_AUDIO
+
+#####################  Broadcast Audio Scan Service #####################
+
+config BT_BASS
+	bool "Broadcast Audio Scan Service"
+	select BT_OBSERVER
+	select BT_EXT_ADV
+	select BT_PER_ADV_SYNC
+	select BT_SMP_SC_PAIR_ONLY
+	select BT_ISO_SYNC_RECEIVER
+	help
+	  This option enables support for the Broadcast Audio Scan Service.
+
+if BT_BASS
+
+config BT_BASS_RECV_STATE_COUNT
+	int "Broadcast Audio Scan Service Receive State Count"
+	default 1
+	range 1 3
+	help
+	  Sets the number of receive state characteristics present on the
+	  server. Each characteristic may hold information to sync to a
+	  periodic advertise or a broadcast isochronous stream.
+
+config BT_BASS_MAX_METADATA_LEN
+	int "Broadcast Audio Scan Service Maximum Metadata Length"
+	default 32
+	range 0 255
+	help
+	  The maximum metadata length support by the BASS server.
+
+config BT_BASS_MAX_SUBGROUPS
+	int "Broadcast Audio Scan Service Maximum Number of Subgroups support"
+	default 1
+	range 0 31
+	help
+	  The maximum number of BIS subgroups supported.
+
+############### DEBUG ###############
+
+config BT_DEBUG_BASS
+	bool "Broadcast Audio Scan Service debug"
+	help
+	  Use this option to enable Broadcast Audio Scan Service debug logs for
+	  the Bluetooth Audio functionality.
+
+endif # BT_BASS
+
+endif # BT_AUDIO

subsys/bluetooth/audio/bass_internal.h

@@ -0,0 +1,93 @@
+/** @file
+ *  @brief Internal header for Bluetooth BASS.
+ */
+
+/*
+ * Copyright (c) 2019 Bose Corporation
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/types.h>
+#include <bluetooth/conn.h>
+#include <bluetooth/audio/bass.h>
+
+#define BT_BASS_SCAN_STATE_NOT_SCANNING   0x00
+#define BT_BASS_SCAN_STATE_SCANNING       0x01
+
+#define BT_BASS_OP_SCAN_STOP              0x00
+#define BT_BASS_OP_SCAN_START             0x01
+#define BT_BASS_OP_ADD_SRC                0x02
+#define BT_BASS_OP_MOD_SRC                0x03
+#define BT_BASS_OP_BROADCAST_CODE         0x04
+#define BT_BASS_OP_REM_SRC                0x05
+
+#define BT_BASS_SCAN_STATE_IDLE           0x00
+#define BT_BASS_SCAN_STATE_SCANNING       0x01
+#define BT_BASS_SCAN_STATE_FAILED         0x02
+#define BT_BASS_SCAN_STATE_SYNCED         0x03
+
+#define BT_BASS_PA_REQ_NO_SYNC            0x00
+#define BT_BASS_PA_REQ_SYNC_PAST          0x01
+#define BT_BASS_PA_REQ_SYNC               0x02
+
+#define BT_BASS_BROADCAST_ID_SIZE          3
+
+#define BT_BASS_VALID_OPCODE(opcode) \
+	((opcode) >= BT_BASS_OP_SCAN_STOP && (opcode) <= BT_BASS_OP_REM_SRC)
+
+struct bt_bass_cp_scan_stop {
+	uint8_t opcode;
+} __packed;
+
+struct bt_bass_cp_scan_start {
+	uint8_t opcode;
+} __packed;
+
+struct bt_bass_cp_subgroup {
+	uint32_t bis_sync;
+	uint8_t metadata_len;
+	uint8_t metadata[0];
+} __packed;
+
+struct bt_bass_cp_add_src {
+	uint8_t opcode;
+	bt_addr_le_t addr;
+	uint8_t adv_sid;
+	uint8_t broadcast_id[BT_BASS_BROADCAST_ID_SIZE];
+	uint8_t pa_sync;
+	uint16_t pa_interval;
+	uint8_t num_subgroups;
+	struct bt_bass_cp_subgroup subgroups[0];
+} __packed;
+
+struct bt_bass_cp_mod_src {
+	uint8_t opcode;
+	uint8_t src_id;
+	uint8_t pa_sync;
+	uint16_t pa_interval;
+	uint8_t num_subgroups;
+	struct bt_bass_cp_subgroup subgroups[0];
+} __packed;
+
+struct bt_bass_cp_broadcase_code {
+	uint8_t opcode;
+	uint8_t src_id;
+	uint8_t broadcast_code[16];
+} __packed;
+
+struct bt_bass_cp_rem_src {
+	uint8_t opcode;
+	uint8_t src_id;
+} __packed;
+
+union bt_bass_cp {
+	uint8_t opcode;
+	struct bt_bass_cp_scan_stop scan_stop;
+	struct bt_bass_cp_scan_start scan_start;
+	struct bt_bass_cp_add_src add_src;
+	struct bt_bass_cp_mod_src mod_src;
+	struct bt_bass_cp_broadcase_code broadcast_code;
+	struct bt_bass_cp_rem_src rem_src;
+};