enabled on amd64). Add a dmat64 field to various PCI attach structures,
and pass it down where needed. Implement a simple new function called
pci_dma64_available(pa) to test if 64bit DMA addresses may be used.
This returns 1 iff _PCI_HAVE_DMA64 is defined in <machine/pci_machdep.h>,
and there is more than 4G of memory.
The first board to be included here is the port to the 405GP-based
Walnut evaluation board, which up until now lived in arch/walnut.
arch/walnut will go away soon, once all the remaining walnut-isms
in the tree have been dealt with.
kleink