| BlueZ for Android |
| ***************** |
| |
| Since Android 4.2 there exists a well standardized HAL interface that the |
| Bluetooth stack is expected to provide and which enables the easy replacement |
| of the stack of choice on Android. Android BlueZ is intended as a drop-in |
| replacement to Android provided Bluetooth stack. |
| |
| More details about BlueZ for Android architecture and components can be found |
| in android/hal-ipc-api.txt file. |
| |
| Supported Android version: 4.4 |
| |
| =============================== |
| Building and running on Android |
| =============================== |
| |
| Steps needed to build and run Android Open Source Project 4.4.2 with |
| integrated BlueZ. |
| |
| Build requirements |
| ================== |
| |
| - GLib - Android 4.2 or later don't provide GLib and one must provide it in |
| 'external/bluetooth/glib' folder of Android tree. Sample Android GLib port |
| is available at https://code.google.com/p/aosp-bluez.glib/ |
| |
| - SBC - A2DP code requires SBC library (version 1.2 or higher) present in |
| 'external/bluetooth/sbc' directory. Library is build from Android.mk provided |
| by BlueZ. SBC code is available at git://git.kernel.org/pub/scm/bluetooth/sbc |
| |
| - Bionic support - Currently only 'master' branch available at |
| https://android.googlesource.com/platform/bionic provides all required |
| functionality and running BlueZ on release branch requires backporting missing |
| features (currently only epoll_create1 call for Android 4.4.2). Sample |
| Bionic for Android 4.4.2 with all required features backported is available at |
| https://code.google.com/p/aosp-bluez.platform-bionic/ |
| |
| Runtime requirements |
| ==================== |
| |
| BlueZ HAL library requires 'bluetoothd' and 'bluetoothd-snoop' services to be |
| available on Android system. Some permissions settings are also required. |
| |
| This can be done by importing init.bluetooth.rc file in init.rc file of targeted |
| board: |
| import init.bluetooth.rc |
| |
| For convenience examples are provided at: |
| https://code.google.com/p/aosp-bluez.device-lge-mako/ (Nexus 4) |
| https://code.google.com/p/aosp-bluez.device-asus-flo/ (Nexus 7 2013) |
| |
| Downloading and building |
| ======================== |
| |
| Building for Android requires full Android AOSP source tree. Sample Android |
| 4.4.2 tree with all required components present is available at |
| http://code.google.com/p/aosp-bluez/ |
| |
| This tree provides support for Nexus4 (target aosp_mako-userdebug) and |
| Nexus 7 2013 (target aosp_flo-userdebug). Tree does not provide binary blobs |
| needed to run Android on supported devices. Those can be obtained from |
| https://developers.google.com/android/nexus/drivers. Binary blobs needs to be |
| unpacked (EULA acceptance required) into 'vendor' directory of Android tree. |
| |
| Downloading: |
| repo init -u https://code.google.com/p/aosp-bluez.platform-manifest -b kitkat |
| repo sync |
| |
| Building: |
| source build/envsetup.sh |
| lunch aosp_mako-userdebug or lunch aosp_flo-userdebug |
| make -j8 |
| |
| Flashing: |
| adb reboot bootloader |
| fastboot flashall -w |
| |
| After full build is done it is possible to rebuild only BlueZ: |
| 'cd external/bluetooth/bluez/android/' |
| 'mm' (or 'mm -B' to force rebuilding of all files) |
| 'adb sync' to update target device. |
| |
| Linux Kernel requirements |
| ========================= |
| |
| BlueZ for Android uses Linux Bluetooth subsystem and it must be enabled in |
| kernel. Minimal required version of management interface is 1.3. This |
| corresponds to Linux 3.9 but latest available version is recommended. Other |
| requirements include UHID and network bridge support. |
| |
| Following kernel options should be enabled: |
| CONFIG_BT |
| CONFIG_BT_RFCOMM |
| CONFIG_BT_RFCOMM_TTY |
| CONFIG_BT_BNEP |
| CONFIG_BT_BNEP_MC_FILTER |
| CONFIG_BT_BNEP_PROTO_FILTER |
| CONFIG_BRIDGE |
| CONFIG_UHID |
| |
| Also BT chip driver needs to be enabled e.g: |
| CONFIG_BT_HCIBTUSB |
| |
| If it is not possible to use new enough Linux kernel one can use updated |
| bluetooth subsytem from Backports project. More information about Backports can |
| be found at https://backports.wiki.kernel.org. Sample kernels using backports |
| for running BlueZ on Android are available at |
| https://code.google.com/p/aosp-bluez. |
| |
| ============================= |
| Building and running on Linux |
| ============================= |
| |
| It is possible to build and test BlueZ for Android daemon on Linux (eg. PC). |
| Simply follow instructions available at README file in BlueZ top directory. |
| Android daemon binary is located at android/bluetoothd. See next section on |
| how to test Android daemon on Linux. |
| |
| ============ |
| Testing tool |
| ============ |
| |
| BT HAL test tools located in android/haltest is provided for HAL level testing |
| of both Android daemon and HAL library. Start it with '-n' parameter and type |
| 'bluetooth init' in prompt to initialize HAL library. Running without parameter |
| will make haltest try to initialize all services after start. On Android |
| required bluetoothd service will be started automatically. On Linux it is |
| required to start android/bluetoothd manually before init command timeout or |
| use provided android/system-emulator, which takes care of launching daemon |
| automatically on HAL library initialization. To deinitialize HAL library and |
| stop daemon type 'bluetooth cleanup'. Type 'help' for more information. Tab |
| completion is also supported. |
| |
| =========================== |
| Implementation shortcomings |
| =========================== |
| |
| It is possible that some of HAL functionality is missing implementation due to |
| reasons like feature feasibility or necessity for latest Android Framework. |
| This sections provides list of such deficiencies. Note that HAL library is |
| always expected to fully implement HAL API so missing implementation might |
| happen only in daemon. |
| |
| HAL Bluetooth |
| ============= |
| |
| methods: |
| dut_mode_send never called from Android Framework |
| le_test_mode never called from Android Framework |
| get_remote_service_record never called from Android Framework |
| |
| callbacks: |
| dut_mode_recv_cb |
| le_test_mode_cb |
| |
| properties: |
| BT_PROPERTY_SERVICE_RECORD not supported for adapter and device, for |
| device this property is to be returned as |
| response to get_remote_service_record, |
| not sure what to return on get_property |
| calls (records of all services?) |
| |
| BT_PROPERTY_REMOTE_VERSION_INFO information required by this property (LMP |
| information) are not accessible from mgmt |
| interface, also marking this property as |
| settable is probably a typo in HAL header |
| |
| Socket HAL |
| ========== |
| |
| Support only for BTSOCK_RFCOMM socket type. |
