From: Alexander Duyck <alexander.h.duyck@xxxxxxxxx> Subject: arch/parisc: add option to skip DMA sync as a part of map and unmap This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to avoid invoking cache line invalidation if the driver will just handle it via a sync_for_cpu or sync_for_device call. Link: http://lkml.kernel.org/r/20161110113529.76501.44762.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx> Cc: "James E.J. Bottomley" <jejb@xxxxxxxxxxxxxxxx> Cc: Helge Deller <deller@xxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/parisc/kernel/pci-dma.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff -puN arch/parisc/kernel/pci-dma.c~arch-parisc-add-option-to-skip-dma-sync-as-a-part-of-map-and-unmap arch/parisc/kernel/pci-dma.c --- a/arch/parisc/kernel/pci-dma.c~arch-parisc-add-option-to-skip-dma-sync-as-a-part-of-map-and-unmap +++ a/arch/parisc/kernel/pci-dma.c @@ -459,7 +459,9 @@ static dma_addr_t pa11_dma_map_page(stru void *addr = page_address(page) + offset; BUG_ON(direction == DMA_NONE); - flush_kernel_dcache_range((unsigned long) addr, size); + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + flush_kernel_dcache_range((unsigned long) addr, size); + return virt_to_phys(addr); } @@ -469,8 +471,11 @@ static void pa11_dma_unmap_page(struct d { BUG_ON(direction == DMA_NONE); + if (attrs & DMA_ATTR_SKIP_CPU_SYNC) + return; + if (direction == DMA_TO_DEVICE) - return; + return; /* * For PCI_DMA_FROMDEVICE this flush is not necessary for the @@ -479,7 +484,6 @@ static void pa11_dma_unmap_page(struct d */ flush_kernel_dcache_range((unsigned long) phys_to_virt(dma_handle), size); - return; } static int pa11_dma_map_sg(struct device *dev, struct scatterlist *sglist, @@ -496,6 +500,10 @@ static int pa11_dma_map_sg(struct device sg_dma_address(sg) = (dma_addr_t) virt_to_phys(vaddr); sg_dma_len(sg) = sg->length; + + if (attrs & DMA_ATTR_SKIP_CPU_SYNC) + continue; + flush_kernel_dcache_range(vaddr, sg->length); } return nents; @@ -510,14 +518,16 @@ static void pa11_dma_unmap_sg(struct dev BUG_ON(direction == DMA_NONE); + if (attrs & DMA_ATTR_SKIP_CPU_SYNC) + return; + if (direction == DMA_TO_DEVICE) - return; + return; /* once we do combining we'll need to use phys_to_virt(sg_dma_address(sglist)) */ for_each_sg(sglist, sg, nents, i) flush_kernel_vmap_range(sg_virt(sg), sg->length); - return; } static void pa11_dma_sync_single_for_cpu(struct device *dev, _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
