See:
./Drivers/STM32F4xx_HAL_Driver/LICENSE.txt
./Drivers/CMSIS/Device/ST/STM32F4xx/LICENSE.txt
./Drivers/CMSIS/Documentation/General/html/LICENSE.txt
./Drivers/CMSIS/LICENSE.txt
./Drivers/CMSIS/DSP/ComputeLibrary/LICENSE.txt

All other files may be treated as under BSD-3-Clause or Public Domain.
