linux-kernel - [net-next PATCH 09/27] arch/frv: Add option to skip sync on DMA map

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Date:   Tue, 25 Oct 2016 11:37:36 -0400
From:   Alexander Duyck <alexander.h.duyck@...el.com>
To:     netdev@...r.kernel.org, intel-wired-lan@...ts.osuosl.org,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:     davem@...emloft.net, brouer@...hat.com
Subject: [net-next PATCH 09/27] arch/frv: Add option to skip sync on DMA map

The use of DMA_ATTR_SKIP_CPU_SYNC was not consistent across all of the DMA
APIs in the arch/arm folder.  This change is meant to correct that so that
we get consistent behavior.

Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
---
 arch/frv/mb93090-mb00/pci-dma-nommu.c |   14 ++++++++++----
 arch/frv/mb93090-mb00/pci-dma.c       |    9 +++++++--
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/arch/frv/mb93090-mb00/pci-dma-nommu.c b/arch/frv/mb93090-mb00/pci-dma-nommu.c
index 90f2e4c..1876881 100644
--- a/arch/frv/mb93090-mb00/pci-dma-nommu.c
+++ b/arch/frv/mb93090-mb00/pci-dma-nommu.c
@@ -109,16 +109,19 @@ static int frv_dma_map_sg(struct device *dev, struct scatterlist *sglist,
 		int nents, enum dma_data_direction direction,
 		unsigned long attrs)
 {
-	int i;
 	struct scatterlist *sg;
+	int i;
+
+	BUG_ON(direction == DMA_NONE);
+
+	if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+		return nents;
 
 	for_each_sg(sglist, sg, nents, i) {
 		frv_cache_wback_inv(sg_dma_address(sg),
 				    sg_dma_address(sg) + sg_dma_len(sg));
 	}
 
-	BUG_ON(direction == DMA_NONE);
-
 	return nents;
 }
 
@@ -127,7 +130,10 @@ static dma_addr_t frv_dma_map_page(struct device *dev, struct page *page,
 		enum dma_data_direction direction, unsigned long attrs)
 {
 	BUG_ON(direction == DMA_NONE);
-	flush_dcache_page(page);
+
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		flush_dcache_page(page);
+
 	return (dma_addr_t) page_to_phys(page) + offset;
 }
 
diff --git a/arch/frv/mb93090-mb00/pci-dma.c b/arch/frv/mb93090-mb00/pci-dma.c
index f585745..dba7df9 100644
--- a/arch/frv/mb93090-mb00/pci-dma.c
+++ b/arch/frv/mb93090-mb00/pci-dma.c
@@ -40,13 +40,16 @@ static int frv_dma_map_sg(struct device *dev, struct scatterlist *sglist,
 		int nents, enum dma_data_direction direction,
 		unsigned long attrs)
 {
+	struct scatterlist *sg;
 	unsigned long dampr2;
 	void *vaddr;
 	int i;
-	struct scatterlist *sg;
 
 	BUG_ON(direction == DMA_NONE);
 
+	if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+		return nents;
+
 	dampr2 = __get_DAMPR(2);
 
 	for_each_sg(sglist, sg, nents, i) {
@@ -70,7 +73,9 @@ static dma_addr_t frv_dma_map_page(struct device *dev, struct page *page,
 		unsigned long offset, size_t size,
 		enum dma_data_direction direction, unsigned long attrs)
 {
-	flush_dcache_page(page);
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		flush_dcache_page(page);
+
 	return (dma_addr_t) page_to_phys(page) + offset;
 }