Merge pull request #6794 from RonEld/cc310_porting

Cryptocell 310 support

Author: Cruz Monrreal

.astyleignore

@@ -1,5 +1,6 @@
 BUILD
 cmsis
+features/cryptocell
 features/mbedtls
 features/FEATURE_LWIP/lwip
 rtos/TARGET_CORTEX/rtx4

doxyfile_options

@@ -841,6 +841,7 @@ EXCLUDE_PATTERNS       = */tools/* \
                          */BUILD/* \
                          */rtos/TARGET_CORTEX/rtx* \
                          */cmsis/* \
+                         */features/cryptocell/* \
                          */features/mbedtls/* \
                          */features/storage/* \
                          */features/unsupported/* \

features/cryptocell/FEATURE_CRYPTOCELL310/Readme.md

@@ -0,0 +1,21 @@
+# 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)`.
+1. In `objects.h`, include `objects_cryptocell.h`. You can use the `FEATURE_CRYPTOCELL310` precompilation check as defined above.
+1. 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.
+1. 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.
+