Relevant modifications:
1. Support degrading QSPI0/1 to SPI4/5 for normal SPI transfer
2. Fix with BSP crypto driver API change
3. Fix with BSP PDMA driver API change
4. Make necessary modifications to pass FPGA CI Test Shield tests
5. Don't distinguish pinmap among parts e.g. M480 LG. Application users must take care.
Reimplement atomic code in inline assembly. This can improve
optimisation, and avoids potential architectural problems with using
LDREX/STREX intrinsics.
API further extended:
* Bitwise operations (fetch_and/fetch_or/fetch_xor)
* fetch_add and fetch_sub (like incr/decr, but returning old value -
aligning with C++11)
* compare_exchange_weak
* Explicit memory order specification
* Basic freestanding template overloads for C++
This gives our existing C implementation essentially all the functionality
needed by C++11.
An actual Atomic<T> template based upon these C functions could follow.
1. For SHA AC, use atomic flag to manage its ownership.
(1) Nuvoton SHA AC doesn't support SHA context save & restore, so S/W
SHA fallback has been supported before. To make non-blocking 'acquire'
semantics clearer, introduce 'try_acquire' to substitute for 'acquire'.
(2) No biting CPU due to mechanism above.
(3) No deadlock due to mechanism above.
2. For AES/DES/ECC AC, change to mutex to manage their ownership.
(1) Change crypto-misc.c to crypto-misc.cpp to utilize C++ SingletonPtr
which guarantees thread-safe mutex construct-on-first-use.
(2) With change to crypto-misc.cpp, add 'extern "C"' modifier to CRYPTO_IRQHandler()
to avoid name mangling in C++.
(3) No priority inversion because mutex has osMutexPrioInherit attribute
bit set.
(4) No deadlock because these AC are all locked for a short sequence
of operations rather than the whole lifetime of mbedtls context.
(5) For double mbedtls_internal_ecp_init() issue, it has been fixed in upper
mbedtls layer. So no need to change ecc init/free flow.
Currently, trng_api.c is located in targets/ and AES/DES/SHA alter. are located in mbedtls/.
They have shared crypto code.
If they could locate at same location e.g. mbedtls/, the shared crypto code placement would be more reasonable.
Chun-Chieh Li
Kevin Bracey