On Thu, Mar 08, 2018 at 04:03:12PM +0000, Robin Murphy wrote: >> Also fix the sta2x11 case. For that SOC the dma map ops need an >> additional physical to dma address translations. For swiotlb buffers >> that is done throught the phys_to_dma helper, but the sta2x11_dma_ops >> also added an additional translation on the return value from >> x86_swiotlb_alloc_coherent, which is only correct if that functions >> returns a direct allocation and not a swiotlb buffer. With the >> generic swiotlb and dma-direct code phys_to_dma is not always used >> and the separate sta2x11_dma_ops can be replaced with a simple >> bit that marks if the additional physical to dma address translation >> is needed. > > FWIW, last time I looked I got the impression that STA2x11 could just use > dma_pfn_offset - the comments and a2p/p2a logic in sta2x11-fixup.c > certainly imply that the underlying hardware situation is pretty much > exactly that for which dma_pfn_offset exists.
That probably is the case. But without access to the hardware I don't feel like doing this deeper surgery. And even without that this case provides a great simplification.
