Hi Finn,
On Fri, Aug 15, 2014 at 2:09 PM, Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx> wrote:
On Thu, 14 Aug 2014, Michael Schmitz wrote:
The DMA setup early on may save time if the next phase is indeed DATAIN
or DATAOUT - if a command disconnects the DMA just won't be started. I
would have thought the DMA setup could just as easily be done inside
NCR5380_transfer_dma instead of splitting it in DMA setup and DMA start
- any particular reason for this, Sammy?
Doing the DMA setup early on may not work for atari_NCR5380 given
merge_contiguous_buffers() takes place prior to NCR5380_transfer_dma() and
may alter the length of the tranfer. (sun3_NCR5380 doesn't have
merge_contiguous_buffers()).
Not only that - the DMA setup (on Falcon) will be trashed by
subsequent accesses to the NCR5380 (registers are accessed through the
ST-DMA, the NCR5380 is not directly connected to the CPU bus).
We'd need to do all DMA setup in NCR5380_transfer_dma instead.
Cheers,
Michael
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