BT Stack porting layer for Linux based Platform

Overview

The bluetooth-Linux is the adaptation layer (porting layer) between the Linux BT application code example and Infineon's btstack running on the Linux based platforms. The porting layer provides bluetooth stack initialization and implements platform interfaces to provide OS, memory services and enables communication between the BTSTACK and the BT controller.

Platform HCI transport config

Application shall call cy_platform_bluetooth_init( ) API to initialize the porting layer before calling any stack API. This API initializes and configures the UART device with parameters from application and opens the serial device specified by application to enable communication with the BT Controller. This API can also be used to download the firmware patch if needed by passing the patch file and the patch baudrate.

• API cy_platform_bluetooth_init( )

Debug configuration

Application shall call cy_bt_spy_comm_init( ) API with required parameters to collect the traces on BTSpy.

• API cy_bt_spy_comm_init( )

Design

• During stack initialization,function pointer of the platform interfaces gets registered with the stack to use the system resources i.e Memory, mutex. The porting layer also registers functions that send data from stack to controller.
• Porting layer send HCI command and data to the controller by calling SendCommandToBtHCI and SendAclToBtHCI functions.
• Porting layer receives HCI event and data from the BT controller by calling ProcessEventFromHCI and ProcessAclFromHCI functions and then passes the event/data to btstack using which does further processing.

How to build Linux porting layer

1. Create a directory under $HOME on the host PC and switch to the created directory. For example, use the following commands to switch:

   mkdir $HOME/Linux_BT
   cd $HOME/Linux_BT
   

2. Fetch the code example source code from GitHub.

   git clone https://github.com/Infineon/bluetooth-linux --branch release-v1.0.0
   

3. Clone the code example dependencies (BTSTACK library and Linux porting layer source code) using the following commands:

   git clone https://github.com/Infineon/btstack --branch release-v3.6.0
   

   Three different directories are created after cloning the code example and its dependencies as shown in the Figure 1.

   Figure 1. Code example directory structure

   

4. Create the build folder under the code example source folder and build the code example using the following commands:

   cd $HOME/Linux_BT/bluetooth-linux
   mkdir build && cd build
   cmake -DCMAKE_C_COMPILER:PATH=<GCC_CROSS_COMPILER> -DWICED_INCLUDE=../btstack/wiced_include ../ && make
   

   Where,

   • GCC_CROSS_COMPILER is the target cross compiler for GCC (generally /usr/bin/aarch64-linux-gnu-gcc for ARM64-based targets)

   The porting layer library is generated under the build folder: liblinux_stack_porting_layer.a.

Linux Audio

• linux-audio folder contains the ALSA lib header and the pre-build dynamic library for ARM64 and copy from GitHub alsa-lib
• This part is for Linux platform speaker and mic control using.
• you can go the ALSA project GitHub for getting more information.

Additional Information

For Bluetooth Host Stack Library APIs, refer to the BLE API reference manual.

For BTSTACK Library, refer to the BTSTACK Library.

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