On Fri, 2015-02-20 at 19:35 +1100, Benjamin Herrenschmidt wrote: > @@ -149,14 +141,13 @@ static void dma_direct_unmap_sg(struct device *dev, > struct scatterlist *sg, > > static int dma_direct_dma_supported(struct device *dev, u64 mask) > { > -#ifdef CONFIG_PPC64 > - /* Could be improved so platforms can set the limit in case > - * they have limited DMA windows > - */ > - return mask >= get_dma_offset(dev) + (memblock_end_of_DRAM() - 1); > -#else > - return 1; > + u64 offset = get_dma_offset(dev); > + u64 limit = offset + memblock_end_of_DRAM() - 1; > + > +#if defined(CONFIG_ZONE_DMA32) > + limit = offset + dma_get_zone_limit(ZONE_DMA32); > #endif > + return mask >= limit; > }
I'm confused as to whether dma_supported() is supposed to be testing a coherent mask or regular mask... The above suggests coherent, as does the call to dma_supported() in dma_set_coherent_mask(), but if swiotlb is used, swiotlb_dma_supported() will only check for a mask that can accommodate io_tlb_end, without regard for coherent allocations. > static u64 dma_direct_get_required_mask(struct device *dev) > diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c > index f146ef0..a7f15e2 100644 > --- a/arch/powerpc/mm/mem.c > +++ b/arch/powerpc/mm/mem.c > @@ -277,6 +277,11 @@ int dma_pfn_limit_to_zone(u64 pfn_limit) > return -EPERM; > } > > +u64 dma_get_zone_limit(int zone) > +{ > + return max_zone_pfns[zone] << PAGE_SHIFT; > +} If you must do this in terms of bytes rather than pfn, cast to u64 before shifting -- and even then the result will be PAGE_SIZE - 1 too small. -Scott _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev