On Tuesday 14 August 2012, Catalin Marinas wrote: > +static struct dma_map_ops arm64_swiotlb_dma_ops = { > + .alloc = arm64_swiotlb_alloc_coherent, > + .free = arm64_swiotlb_free_coherent, > + .map_page = arm64_swiotlb_map_page, > + .unmap_page = arm64_swiotlb_unmap_page, > + .map_sg = arm64_swiotlb_map_sg_attrs, > + .unmap_sg = arm64_swiotlb_unmap_sg_attrs, > + .sync_single_for_cpu = arm64_swiotlb_sync_single_for_cpu, > + .sync_single_for_device = arm64_swiotlb_sync_single_for_device, > + .sync_sg_for_cpu = arm64_swiotlb_sync_sg_for_cpu, > + .sync_sg_for_device = arm64_swiotlb_sync_sg_for_device, > + .dma_supported = swiotlb_dma_supported, > + .mapping_error = swiotlb_dma_mapping_error, > +}; > + > +void __init swiotlb_init_with_default_size(size_t default_size, int verbose); > + > +void __init arm64_swiotlb_init(size_t max_size) > +{ > + dma_ops = &arm64_swiotlb_dma_ops; > + swiotlb_init_with_default_size(min((size_t)SZ_64M, max_size), 1); > +} Why is swiotlb the default? I would expect that most devices can in fact use the entire 64 bit address space, so you can use a simple linear implementation for those. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html