[net-next PATCH RFC 16/26] arch/parisc: Add option to skip DMA sync as a part of map and unmap
From: Alexander Duyck <hidden>
Date: 2016-10-24 18:06:32
Also in:
linux-mm, lkml
Subsystem:
parisc architecture, the rest · Maintainers:
"James E.J. Bottomley", Helge Deller, Linus Torvalds
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. Cc: "James E.J. Bottomley" <redacted> Cc: Helge Deller <deller@gmx.de> Cc: linux-parisc@vger.kernel.org Signed-off-by: Alexander Duyck <redacted> --- arch/parisc/kernel/pci-dma.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/arch/parisc/kernel/pci-dma.c b/arch/parisc/kernel/pci-dma.c
index 02d9ed0..be55ede 100644
--- a/arch/parisc/kernel/pci-dma.c
+++ b/arch/parisc/kernel/pci-dma.c@@ -459,7 +459,9 @@ static dma_addr_t pa11_dma_map_page(struct device *dev, struct page *page, 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 device *dev, dma_addr_t dma_handle, { 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 device *dev, dma_addr_t dma_handle, */ 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 *dev, struct scatterlist *sglist, 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 device *dev, struct scatterlist *sglist, 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, --
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