[mm PATCH v3 08/23] arch/m68k: Add option to skip DMA sync as a part of mapping
From: Alexander Duyck <hidden>
Date: 2016-11-10 17:36:11
Also in:
linux-mm, lkml
Subsystem:
m68k architecture, the rest · Maintainers:
Geert Uytterhoeven, 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 later via a sync_for_cpu or sync_for_device call. Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: linux-m68k@lists.linux-m68k.org Signed-off-by: Alexander Duyck <redacted> --- arch/m68k/kernel/dma.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/m68k/kernel/dma.c b/arch/m68k/kernel/dma.c
index 8cf97cb..0707006 100644
--- a/arch/m68k/kernel/dma.c
+++ b/arch/m68k/kernel/dma.c@@ -134,7 +134,9 @@ static dma_addr_t m68k_dma_map_page(struct device *dev, struct page *page, { dma_addr_t handle = page_to_phys(page) + offset; - dma_sync_single_for_device(dev, handle, size, dir); + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + dma_sync_single_for_device(dev, handle, size, dir); + return handle; }
@@ -146,6 +148,10 @@ static int m68k_dma_map_sg(struct device *dev, struct scatterlist *sglist, for_each_sg(sglist, sg, nents, i) { sg->dma_address = sg_phys(sg); + + if (attrs & DMA_ATTR_SKIP_CPU_SYNC) + continue; + dma_sync_single_for_device(dev, sg->dma_address, sg->length, dir); }