New API for non cache coherent ppc cpu's

[Paul Mackerras]

Armin Kuster writes:

> To all NOT_COHERENT_CACHE users
>
> About a month ago a new API made its way into the ppc,
> consistent_sync_page.  For CONFIG_NOT_COHERENT_CACHE  processors,
> requires
> proper flushing of the page being used.  Please review and provide feed
> back

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.

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).

Paul.

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