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Subject[net-next PATCH 17/27] arch/parisc: Add option to skip DMA sync as a part of map and unmap
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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" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
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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