Hello,
I am trying to make DMA transfers on an M5485EVB under Linux, with zero success atm.
My goal is to use the DMA to transfer data from/to the DSPI.
The problem I am having is dual (or -2 does not work because of -1):

-1) When I call MCD_startDma, the processor freezes shortly after, for a long duration (like 10-15 secs). After that delay, the execution continues.
MCD_dmaStatus returns immediately 6 (DMA_DONE), but of course nothing has happened, even if I use mem-to-mem transfers (also, see point 2).
I thought it could be caused by an unhandled interrupt (i guessed that the delay starts as soon as the transfer ends) but all relevant interrupts are masked in the IMR...

-2) I can't figure out the address that must be passed to MCD_startDma. I tried kernel addresses and physical addresses (gotten via virt_to_phys(ptr)). Neither of them does work on memory-to-memory transfers. Also, I really don't know if addresses in the MBAR region should be translated to physical or not.
I checked the FEC driver and it seems that memory addresses should be translated via "virt_to_phys", while peripheral registers should not, but i'm not sure of that, as there seems to be no effect.

Does anybody have a clue? (or pointers? *pun inteded* )
Thanks a lot in advance for the help,

Luca Burelli
DEI-University of Padua (Italy)