Converting FreeRTOS labs TCP stack to FreeRTOS

lciummo wrote on Monday, August 24, 2015:

I was doing some porting of components to SafeRTOS (the IEC 62304 certified version of FreeRTOS), and I noticed the pvPortMalloc and pvPortFree calls are no longer supported. SafeRTOS does not support (or need) any dynamic ram.

Given I want to use the FreeRTOS TCP stack on SafeRTOS, should I write a network allocator heap_xxx.c for my networkInterface code to use that allocates a fixed number of buffers?

Anything else in the stack that will make this port difficult/impossible?


rtel wrote on Monday, August 24, 2015:

SafeRTOS does not use dynamic memory allocation because, generally speaking, it is frowned upon in safety critical aps (non-deterministic and fragmentation being the main concerns).

There are not many places in the +TCP code that uses pvPortMalloc(). The main one is the allocation of network buffers, but there is already an option to allocated them statically instead.

After that there are some small allocations being made in FreeRTOS_socket() and vDNSSetCallBack(). It might be that you don’t use vDNSSetCallBack(), and as you suggest you could provide your own trivial implementation for FreeRTOS_socket() as it will only ever allocated two different sizes - one size of UDP sockets and one size for TCP sockets.