add dma support for PolarFire SoC

[jrosberg]

Summary

Initial basic DMA support.
This version don't have any fancy channel allocation support etc. To be done later.
note: PDMA on MPFS is memory-to-memory only.

Impact

None - new code

Testing

Tested with Icicles board.

[jrosberg]

what's the best way to handle styling of this long line: (nxstyle don't like it)

EXTERN uint64_t mpfs_dma_get_current_destination(enum mpfs_dma_channel_e channel);

rename function?
or split the line (from where?)

[patacongo]

what's the best way to handle styling of this long line: (nxstyle don't like it)

EXTERN uint64_t mpfs_dma_get_current_destination(enum mpfs_dma_channel_e channel);

rename function?
or split the line (from where?)

First, I would try to remove the EXTERN. That is not normally present and not necessary unless called from C++ (which is shouldn't be) and it is not also enclosed int EXTERN "C" {}

It is also fairly common to divide a line between the return type and the function name like:

EXTERN uint64_t
mpfs_dma_get_current_destination(enum mpfs_dma_channel_e channel);

curr and dest and also very standard shortenings of current and destination.

[jrosberg]

Removed that channel enum. I like it more this way.