I didn't try it yet, but my idea would be to
1st define what the trigger for the DMA should be.
2nd. Connect a DMA from counter to SRAM storing data in an array. Verify working
3nd. Connect a DMA from a SRAM array to the shift-register and verify working.
4th discard one of the DMAs and set the parameters accordingly into the second DMA
Now this should work.
give it a try
The problem is, that I do not know the correct counter register for dma transfer.
Which one should it been?