In I wrote:
there is no "Direct access to data FIFO RAM" in 'L4's RM. It's a pity, an extra kilobyte of RAM may come handy at times, even if it is potentially slower and "there is plenty RAM anyway".
An experiment proved this is available in 'L476.
Please add the CSR memory map FIgure (as is Fig.395 in RM0090 rev.15) into RM0351 - that is the way how to tell about that direct access.