On DSP-side, can DSPLINK RingIO work in the SWI mode

Wei:

   From a cursory look at the source code, it appears RingIO APIs should be callable from SWI level.

   When calling RingIO_setNotifier(), you pass a callback that get's called from ISR context (from NOTIFY module).  Instead of that callback posting a SEM, post a SWI instead that will do the work for you.   Of course, you will need to create a SWI first (or SWIs: maybe one for the reader, one for the writer) which will run and do the necessary RingIO_acquire()/_release() calls when it gets posted.

  Note: RingIO work cannot be done from the callback itself:  from the DSPLink Programmer's Guide:

8.2 Don'ts
8.2.2 Do not call any DSP/BIOS Link API from a registered callback function
No DSP/BIOS Link API should be called from a callback function registered through
the RingIO or NOTIFY module. On DSP-side or on operating systems such as PrOS,
the callback functions are run from ISR context and must not perform any operations
that may take a lock or block, which is done by most DSPLink APIs. Minimum
functionality must be used in the callback functions, most often limited to posting a
semaphore on which application is waiting, posting SWI etc.

  See the BIOS5 documentation on usage of SWIs and examples.