On Tue, Feb 3, 2015 at 9:37 AM, Russell King - ARM Linux
[off-list ref] wrote:

On Tue, Feb 03, 2015 at 09:04:03AM -0500, Rob Clark wrote:

quoted

Since I'm stuck w/ an iommu, instead of built in mmu, my plan was to
drop use of dma-mapping entirely (incl the current call to dma_map_sg,
which I just need until we can use drm_cflush on arm), and
attach/detach iommu domains directly to implement context switches.
At that point, dma_addr_t really has no sensible meaning for me.

So how do you intend to import from a subsystem which only gives you
the dma_addr_t?

If you aren't passing system memory, you have no struct page.  You can't
fake up a struct page.  What this means is that struct scatterlist can't
represent it any other way.

Tell the exporter to stop using carveouts, and give me proper memory
instead.. ;-)

Well, at least on these SoC's, I think the only valid use for carveout
memory is the bootloader splashscreen.  And I was planning on just
hanging on to that for myself for fbdev scanout buffer or other
internal (non shared) usage..

BR,
-R

--
FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up
according to speedtest.net.