Hi Finn,
On Fri, Aug 15, 2014 at 2:09 PM, Finn Thain <[email protected]> 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 > > -- -- To unsubscribe from this list: send the line "unsubscribe linux-m68k" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
