this code makes equal sense for memory and I/O space, prefer to map
the PCI front end via memory space (conditionalized on a patchable kernel
variable), and do a bit of other random NetBSD-specific cleanup. (These
changes were sent to Justin Gibbs on March 28.)
- No more distinction between i/o-mapped and memory-mapped
devices. It's all "bus space" now, and space tags
differentiate the space with finer grain than the
bus chipset tag.
- Add memory barrier methods.
- Implement space alloc/free methods.
- Implement region read/write methods (like memcpy to/from
bus space).
This interface provides a better abstraction for dealing with
machine-independent chipset drivers.
cgd