I figure there seems to have two CryptoCell 312 implementations within TF-M. One under lib/ext/cryptocell-312-runtime and the other under platform/ext/accelerator/cc312/cc312-rom. What are the difference between these two?

For lib/ext/cryptocell-312-runtime, it does not define MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG whereas /ext/accelerator/cc312/cc312-rom does.  Does that mean cryptocell-312-runtime is initiating RNG cryptodriver by using mbedtls_entropy_add_source whereas cc312-rom is using mbedtls_psa_external_get_random. If so, may I ask why these two cryptocells take two different approaches? I read from one of the documentation that mbedtls_psa_external_get_random is used when entropy is sufficient. So if entropy is sufficient, is it always preferred to have MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG defined and implements mbedtls_psa_external_get_random? What are the differences between the two approaches.

I also found cryptocell-312-runtime defines the entry point function cc3xx_init_random. But since PSA random number entry point funciton is not complete, the cc3xx_init_random is not being called anywhere, right?

I know random number generation PSA entry point function is in development, may I ask when that would be expected to complete?