[mm PATCH v3 09/23] arch/metag: Add option to skip DMA sync as a part of map and unmap
From: Alexander Duyck <hidden>
Date: 2016-11-10 17:36:45
Also in:
lkml, netdev
Subsystem:
the rest · Maintainer:
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 Hogan <redacted> Cc: linux-metag@vger.kernel.org Signed-off-by: Alexander Duyck <redacted> --- arch/metag/kernel/dma.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/arch/metag/kernel/dma.c b/arch/metag/kernel/dma.c
index 0db31e2..91968d9 100644
--- a/arch/metag/kernel/dma.c
+++ b/arch/metag/kernel/dma.c@@ -484,8 +484,9 @@ static dma_addr_t metag_dma_map_page(struct device *dev, struct page *page, unsigned long offset, size_t size, enum dma_data_direction direction, unsigned long attrs) { - dma_sync_for_device((void *)(page_to_phys(page) + offset), size, - direction); + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + dma_sync_for_device((void *)(page_to_phys(page) + offset), + size, direction); return page_to_phys(page) + offset; }
@@ -493,7 +494,8 @@ static void metag_dma_unmap_page(struct device *dev, dma_addr_t dma_address, size_t size, enum dma_data_direction direction, unsigned long attrs) { - dma_sync_for_cpu(phys_to_virt(dma_address), size, direction); + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + dma_sync_for_cpu(phys_to_virt(dma_address), size, direction); } static int metag_dma_map_sg(struct device *dev, struct scatterlist *sglist,
@@ -507,6 +509,10 @@ static int metag_dma_map_sg(struct device *dev, struct scatterlist *sglist, BUG_ON(!sg_page(sg)); sg->dma_address = sg_phys(sg); + + if (attrs & DMA_ATTR_SKIP_CPU_SYNC) + continue; + dma_sync_for_device(sg_virt(sg), sg->length, direction); }
@@ -525,6 +531,10 @@ static void metag_dma_unmap_sg(struct device *dev, struct scatterlist *sglist, BUG_ON(!sg_page(sg)); sg->dma_address = sg_phys(sg); + + if (attrs & DMA_ATTR_SKIP_CPU_SYNC) + continue; + dma_sync_for_cpu(sg_virt(sg), sg->length, direction); } } --
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