mbed-os/features/cryptocell/FEATURE_CRYPTOCELL310

Guidelines for porting Cryptocell to Mbed OS

Cryptocell (CC) 310 is a hardware accelerator that can be ported to several boards, assuming these boards have CC 310 embedded in their hardware.

The CC 310 driver consists of three libraries:

• A common core library(libcc_core.a).
• A platform-specific TRNG library, containing TRNG-related information, for sampling sufficient entropy on the specific platform(libcc_trng.a).
• A platform-specific library containing extra information, such as the CC register's base addresses on the specific board. (libcc_ext.a)

To port your CC 310 driver to Mbed OS on your specific target, do the following:

1. In targets.json add the following to your target:
   • MBEDTLS_CONFIG_HW_SUPPORT to macros_add key. This instructs Mbed TLS to look for an alternative cryptographic implementation.
   • CRYPTOCELL310 to feature. Use this in your common code that you need to remove from compilation in case CC exists in your board. Use #if !defined(FEATURE_CRYPTOCELL310) and #if defined(FEATURE_CRYPTOCELL310).
2. In objects.h, include objects_cryptocell.h. You can use the FEATURE_CRYPTOCELL310 precompilation check as defined above.
3. In features/cryptocell/FEATURE_CRYPTOCELL310/TARGET_<target name>, add your platform-specific libraries for all toolchains in TOOLCHAIN_ARM, TOOLCHAIN_GCC_ARM and TOOLCHAIN_IAR respectively.
4. Add your CC setup code:
   • Implement cc_platform_setup() and cc_platform_terminate() to enable CC on your platform, in case you have board-specific setup functionality, required for CC setup. These functions can be empty.
   • Define cc_platform_ctx in cc_platform.h in a way that suits your implementation.