A Machine-Independent DMA Framework for Net BSD

One of the challenges in implementing a portable kernel is finding good abstractions for semanticallysimilar operations which often have very machinedependent implementations. This is especially important on modern machines which share common architectural features, e.g. the PCI bus.

This paper describes why a machine-independent DMA mapping abstraction is needed, the design considerations for such an abstraction, and the implementation of this abstraction in the NetBSD/alpha and NetBSD/i386 kernels.