android蓝牙移植,Android Bluetooth 移植
Android's Bluetooth stack uses BlueZ for GAP, SDP, and RFCOMM
profiles, and is a SIG-qualified Bluetooth stack.
Bluez is GPL licensed, so the Android framework interacts with
userspace bluez code through D-BUS IPC to avoid proprietary
code.
Headset and Handsfree (v1.5) profiles are implemented in the
Android framework and are both tightly coupled with the Phone App.
These profiles are also SIG qualified.
The diagram below offers a library-oriented view of the
Bluetooth stack. Click Bluetooth Process Diagram for a process-oriented view.
Solid elements represent Android blocks and dashed elements
represent partner-specific blocks.
Porting
BlueZ is Bluetooth 2.1 compatible and should work with any 2.1
chipset and is backward compatibile with older Bluetooth versions.
There are two integration points:
UART driver
Bluetooth Power On / Off
UART Driver
The BlueZ kernel sub-system attaches to your hardware-specific
UART driver using the hciattach daemon.
For example, for MSM7201A, this is
drivers/serial/msm_serial.c. You may also need to edit
command line options to hciattach via
init.rc.
Bluetooth Power On / Off
The method for powering on and off your bluetooth chip varies
from Android V 1.0 to post 1.0.
1.0: Android framework writes a 0 or 1 to
/sys/modules/board_[PLATFORM]/parameters/bluetooth_power_on.
Post 1.0: Android framework uses the linux
rfkill API. See
arch/arm/mach-msm/board-trout-rfkill.c for an
example.
Compiling
To compile Android with Bluetooth support enabled, add the
following line to BoardConfig.mk.
BOARD_HAVE_BLUETOOTH := true
Troubleshooting
Debugging
To debug your bluetooth implementation, start by reading the
logs (adb logcat) and look for ERRROR and WARNING
messages regarding Bluetooth. Andoird uses Bluez, which comes with
some useful debugging tools. The snippet below provides examples in
a suggested order:
hciconfig -a # print BT chipset address and features. Useful to check if you can communicate with your BT chipset.
hcidump -XVt # print live HCI UART traffic.
hcitool scan # scan for local devices. Useful to check if RX/TX works.
l2ping ADDRESS # ping another BT device. Useful to check if RX/TX works.
sdptool records ADDRESS # request the SDP records of another BT device.
Deamon Logs
Deamon logs for hcid (STDOUT) and
hciattach (STDERR) are sent to
/dev/null by default. Edit init.rc and
init.PLATFORM.rc to run these daemons under
logwrapper, which redirects output to
logcat.
hciconfig -a and hcitool
If you compile your own system.img for Android, and
hciconfig -a works but hcitool scan
doesn't, try installing the firmware for the Bluetooth chipset.
This firmware isn't yet available in the open source codebase, but
you can adb pull and then adb pushit from
a stock T-Mobile G1 (located in
/etc/firmware/brf6300.bin).
Tools
BlueZ provides a rich set of command line tools for debugging
and interacting with the Bluetooth sub-system, including:
hciconfig
hcitool
hcidump
sdptool
dbus-send
dbus-monitor
Feature Support
This section provides a change history of Bluetooth features
added in each Android release and provides some rough guidance as
to future features.
Android 1.0 release
Platform features
Based on Bluez 3.36 and Linux Kernel 2.6.25
Bluetooth 2.0+EDR host stack
Headset Profile 1.0 in Audio Gateway role
Handsfree Profile 1.5 in Audio Gateway role
Three-way calling
Phonebook over AT commands
Qualifications
QDID B014524: Host stack (SDP, L2CAP, GAP, RFCOMM, SPP)
QDID B014624: EPL for HTC Dream (HSP, HFP)
Example products
HTC Dream / T-Mobile G1
Android 1.1 release
No Bluetooth changes since 1.0
Android 1.5 release (cupcake)
Platform features
Based on Bluez 3.36 with Linux Kernel 2.6.27
Bluetooth 2.0+EDR host stack
Support for auto-pairing with '0000' devices
Headset Profile 1.1 in Audio Gateway role
Handsfree Profile 1.5 in Audio Gateway role
Three-way calling
Phonebook over AT commands
Volume synchronization
eSCO
Extensive bug fixes and compatibility improvements
Stereo Bluetooth (A2DP 1.2) in Source role
AVDTP 1.2 in Acceptor and Initiator roles
GAVDTP 1.0 in Acceptor and Initiator roles
44.1 khz, stereo, software SBC codec
Remote Control (AVRCP 1.0) in Target role
AVCTP 1.3 in Target role
play/pause/stop/prev/next
Qualifications
QDID B015261: Host stack (SDP, L2CAP, GAP, RFCOMM, SPP, AVCTP,
AVRCP, GAVDP, AVDTP, A2DP)
QDID B015262: EPL for HTC Sapphire (HSP, HFP)
Android 2.0/2.1 release (eclair)
Platform features
Based on Bluez 4.47 with Linux Kernel 2.6.29
Bluetooth 2.1+EDR host stack
Support for auto-pairing with '0000' devices
Support for Simple Secure Pairing
Headset Profile 1.1 in Audio Gateway role
Handsfree Profile 1.5 in Audio Gateway role
Three-way calling
Phonebook over AT commands
Volume synchronization
eSCO
Extensive bug fixes and compatibility improvements
Stereo Bluetooth (A2DP 1.2) in Source role
AVDTP 1.2 in Acceptor and Initiator roles
GAVDTP 1.0 in Acceptor and Initiator roles
44.1 khz, stereo, software SBC codec
Remote Control (AVRCP 1.0) in Target role
AVCTP 1.3 in Target role
play/pause/stop/prev/next
Object Push Profile version 1.1
Adds ability to transfer pictures, videos
Transfer of contacts using vCard is not supported in this
release.
Phone Book Address Profile version 1.0
Phone Book Server Equipment (PSE) role supported
Using Java Bluetooth APIs, an Android application can peform
the following:
Scan for other Bluetooth devices
Query the local Bluetooth adapter for paired Bluetooth
devices
Establish RFCOMM channels
Connect to other devices through service discovery
Transfer data to and from other devices
Manage multiple connections
Support for Bluetooth enabled car and desk docks
Framework support for routing Phone Call Audio and A2DP
streaming using car and desk docks.
Android 2.2 release (Froyo)
Platform features
Based on Bluez 4.47 with Linux Kernel 2.6.32
No new profiles added.
Added ability to share contacts using vCard
Added ability to export all contacts - useful to transfer
contacts to car kits
Improved compatibility with headsets and car kits.
Future releases
This section offers a rough guide of which features the team is
developing for the next release. This feature list may change
without notice. It isn't possible to post scheduling advice to the
mailing lists.
More profiles...
Improved compatibility with headsets and car kits
Bluetooth emulator support
Bluetooth Low Energy
Development Notes
HID Support Cupcake features some early
work—Bluez has an HID plugin,
external/bluez/utils/input/Android.mk, which gets
compiled.
You can interact directly with this plugin using
dbus-send and dbus-monitor. While not
officially supported, you should be able to connect and use a HID
keyboard and mouse using the Bluez HID plugin API. Next steps
include plumbing the plugin API in the Android Java framework and
offering better support for HID input methods (new keymaps and
mouse support).
Tethering - DUN and PAN Support
Cupcake features some early work—Bluez has has DUN and PAN daemons
which get compiled and external/bluez/utils/dun/Android.mk
external/bluez/utils/pan/Android.mk BNEP support is compiled
into the kernel with cupcake.
While not officially supported, you should be able to run
dund or pand daemons and, using
pppd or iptables, test tethering support.
Next steps include plubming the DBUS APIs to these daemons up into
the Android Java framework and adding code to setup the network
paths via pppd and / or
iptables.