On Tue, Feb 3, 2015 at 9:37 AM, Russell King - ARM Linux linux@arm.linux.org.uk wrote:
On Tue, Feb 03, 2015 at 09:04:03AM -0500, Rob Clark wrote:
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
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