Hi All,
On Wed, Jan 3, 2018 at 6:49 PM, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
Hi Michael,
On Wed, Jan 3, 2018 at 7:24 AM, Michael Ellerman <mpe@xxxxxxxxxxxxxx> wrote:
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.
OK, didn't know about the offset.
Then "linear" is what we tend to use, right?
If this is indeed a linear mapping, can we just remove this and
replace it with the new "generic" mapping being introduced by this
patchset?
Thanks,
--
Julian Calaby
Email: julian.calaby@xxxxxxxxx
Profile: http://www.google.com/profiles/julian.calaby/
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