V1 of a patch series to convert m68k Amiga WD33C93 drivers to the DMA API. This series was precipitated by Arnd removing CONFIG_VIRT_TO_BUS. The m68k WD33C93 still used virt_to_bus to convert virtual addresses to physical addresses suitable for the DMA engines (note m68k does not have an IOMMU and uses a direct mapping for DMA addresses). Arnd suggested to use dma_map_single() to set up dma mappings instead of open-coding much the same in every driver dma_setup() function. It appears that m68k (MMU, except for coldfire) will set up pages for DMA transfers as non-cacheable, thus obviating the need for explicit cache management. DMA setup on a3000 host adapters can be simplified to skip bounce buffer use (assuming SCSI buffers passed to the driver are cache line aligned; a safe bet except for maybe sg.c input). On gvp11 and a2091 host adapters, only the lowest 16 MB of physical memory can be directy addressed by DMA, and bounce buffers from that space must still be used (possibly allocated from chip RAM using the custom allocator) if buffers are located in the higher memory regions. The m68k VME mvme147 driver has no DMA addressing or alignment restrictions and can be converted in the same way as the Amiga a3000 one, but will require conversion to a platform device driver first. Only compile tested so far, and hardware testing might be hard to do. I'd appreciate someone giving this a thorough review. Thanks, and Cheers, Michael
