Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> writes:
On Tue, Jan 2, 2018 at 10:45 AM, Michael Ellerman <mpe@xxxxxxxxxxxxxx> wrote:
Christoph Hellwig <hch@xxxxxx> writes:
We want to use the dma_direct_ namespace for a generic implementation,
so rename powerpc to the second best choice: dma_nommu_.
I'm not a fan of "nommu". Some of the users of direct ops *are* using an
IOMMU, they're just setting up a 1:1 mapping once at init time, rather
than mapping dynamically.
Though I don't have a good idea for a better name, maybe "1to1",
"linear", "premapped" ?
"identity"?
I think that would be wrong, but thanks for trying to help :)
The address on the device side is sometimes (often?) offset from the CPU
address. So eg. the device can DMA to RAM address 0x0 using address
0x800000000000000.
Identity would imply 0 == 0 etc.
I think "bijective" is the correct term, but that's probably a bit
esoteric.
cheers
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