New API for non cache coherent ppc cpu's

Roman Zippel zippel at
Fri Nov 23 10:50:07 EST 2001


Paul Mackerras wrote:

> If we have to have a consistent_sync_page, it should be purely a local
> function in our implementation of the official DMA mapping API - see
> Documentation/DMA-mapping.txt.  Drivers should be using functions such
> as pci_alloc_consistent, pci_map_single, pci_dma_sync_single,
> pci_unmap_single, etc.  The implementation of those routines should do
> the correct cache flushing - if it doesn't then we need to fix it.

This document only describes DMA _mappings_, it doesn't say anything
about cache coherency.

> If you're talking about non-PCI devices, use the pci DMA API but just
> pass NULL for the dev (we need to make sure that will work ok on the
> non-cache-coherent cpus).

That's the other problem, "non-PCI" sounds like ISA there, what about
other buses?

bye, Roman

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