It is impossible to use the DMA/Message Unit to provide DMA for the SPI port.
We can program the MPC8313 DMA controller to write (read) character to the SPITD (from SPIRD) but there is no way to synchronize DMA and SPI port data rates. The MPC8313 SPI controller has very shallow FIFO (2 characters only). So it is more effective when core checks for the SPI NE/NF events and write/read characters to/from SPI data registers.
