DSPI does not have any embedded RAM region.
FEC MIB RAM is small memory ampped area 0xFFF4_C200h–0xFFF4_C3FFh and it can only be accessed by 32-bit.
FEC FIFO RAM does not seems to be possible to access directly.
That fec mib ram region where does it defined in the reference manual
Br,
Indra
It is not explicitly mentioned as memory mapped RAM as its purpose is not to use it as general purporse RAM.