README.md

Add MCU Supports

To add a support for another MCU, please do as the following steps.

1. Create a new directory under supports directory with the name of your target board

   mkdir target # please change target as the name of your board

2. In the direcotry of your target MCU, the following three files must be included:

   file name	description
   target_hal.c	Initialization code of the target board
   target.ld	Linker script
   CMakeLists.txt	Bulid script for CMAKE

3. Implement the following functions HARM_HAL_Device_Init, HARM_HAL_SecureRNG_Init, HARM_HAL_SecureRNG_GetNext in target_hal.c.

   • void HARM_HAL_Device_Init(void): Initialize the target board, including memory partitioning, access permission enforcement, clock configuration and so on.

   • void HARM_HAL_SecureRNG_Init(void): Initialize the random number generator (RNG).

   • int HARM_HAL_SecureRNG_GetNext(void): Get a random number from the RNG.

   Template of target_hal.c:

   /* Include your header files */
   ...
   void HARM_HAL_Device_Init(void)
   {
       /* Code for memory partitioning, access permission enforcement*/
       ...
       /* Code for clock configuration */
       ...
       /* Code for debug console initialization */
       ...
   }
   
   void HARM_HAL_SecureRNG_Init(void)
   {
       /* Code for RNG initializaion*/
   }
   
   int HARM_HAL_SecureRNG_GetNext(void)
   {
       /* Code for getting a random number from RNG pool */
   }

4. Describe the memory layout in the linker script file target.ld. NOTE: .gnu.sgstubs section must be contained to place the non-secure callable (NSC) veneer table.

   SECTIONS
   {
       ...  /* other sections */
       .gnu.sgstubs:
       {
           __start_sg__ = .
           *(.gnu.sgstubs*)
           __end_sg__ .
       } > FLASH
       ... /* other sections */
   }

5. Edit CMakeLists.txt:

   project(<target_name>)
   ...
   include_directories(...)
   add_definitions(-DFOO -DBAR ...)
   aux_source_directory(... LIB_SRCS)
   ...
   add_library(${PROJECT_NAME} ${LIB_SRCS})
   

6. Edit CMakeLists.txt in the root directory:

   ...
   option(TARGET_<YOUR_BOARD_NAME> "Target your board" Off)
   
   if (TARGET_YOUR_BOARD_NAME)
       add_subdirectory(supports/<target_name>)
       set(EXTRA_LIBS ${EXTRA_LIBS} <target_name>)
   endif (TARGET_<YOUR_BOARD_NAME>)
   ...