Re: [net-next PATCH RFC 07/26] arch/c6x: Add option to skip sync on DMA map and unmap
From: Mark Salter <hidden>
Date: 2016-10-28 14:59:04
Also in:
linux-mm, lkml
On Mon, 2016-10-24 at 08:05 -0400, Alexander Duyck wrote:
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: Mark Salter <redacted> Cc: Aurelien Jacquiot <redacted> Cc: linux-c6x-dev@linux-c6x.org Signed-off-by: Alexander Duyck <redacted> ---
Acked-by: Mark Salter <redacted>
quoted hunk ↗ jump to hunk
arch/c6x/kernel/dma.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)diff --git a/arch/c6x/kernel/dma.c b/arch/c6x/kernel/dma.c index db4a6a3..d28df74 100644 --- a/arch/c6x/kernel/dma.c +++ b/arch/c6x/kernel/dma.c@@ -42,14 +42,17 @@ static dma_addr_t c6x_dma_map_page(struct device *dev, struct page *page,{ dma_addr_t handle = virt_to_phys(page_address(page) + offset); - c6x_dma_sync(handle, size, dir); + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + c6x_dma_sync(handle, size, dir); + return handle; } static void c6x_dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir, unsigned long attrs) { - c6x_dma_sync(handle, size, dir); + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + c6x_dma_sync(handle, size, dir); } static int c6x_dma_map_sg(struct device *dev, struct scatterlist *sglist,@@ -60,7 +63,8 @@ static int c6x_dma_map_sg(struct device *dev, struct scatterlist *sglist,for_each_sg(sglist, sg, nents, i) { sg->dma_address = sg_phys(sg); - c6x_dma_sync(sg->dma_address, sg->length, dir); + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + c6x_dma_sync(sg->dma_address, sg->length, dir); } return nents;@@ -72,8 +76,10 @@ static void c6x_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,struct scatterlist *sg; int i; - for_each_sg(sglist, sg, nents, i) - c6x_dma_sync(sg_dma_address(sg), sg->length, dir); + for_each_sg(sglist, sg, nents, i) { + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + c6x_dma_sync(sg_dma_address(sg), sg->length, dir); + } }