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arch/arm: add option to skip sync on DMA map and unmap
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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.

Link: http://lkml.kernel.org/r/20161110113424.76501.2715.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@torvalds
Alexander Duyck authored and torvalds committed Dec 15, 2016
1 parent 8a3385d commit fc1b138
Showing 1 changed file with 10 additions and 6 deletions.
16 changes: 10 additions & 6 deletions arch/arm/common/dmabounce.c
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Original file line number Diff line number Diff line change
Expand Up @@ -243,7 +243,8 @@ static int needs_bounce(struct device *dev, dma_addr_t dma_addr, size_t size)
}

static inline dma_addr_t map_single(struct device *dev, void *ptr, size_t size,
enum dma_data_direction dir)
enum dma_data_direction dir,
unsigned long attrs)
{
struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
struct safe_buffer *buf;
Expand All @@ -262,7 +263,8 @@ static inline dma_addr_t map_single(struct device *dev, void *ptr, size_t size,
__func__, buf->ptr, virt_to_dma(dev, buf->ptr),
buf->safe, buf->safe_dma_addr);

if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) {
if ((dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) &&
!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
dev_dbg(dev, "%s: copy unsafe %p to safe %p, size %d\n",
__func__, ptr, buf->safe, size);
memcpy(buf->safe, ptr, size);
Expand All @@ -272,7 +274,8 @@ static inline dma_addr_t map_single(struct device *dev, void *ptr, size_t size,
}

static inline void unmap_single(struct device *dev, struct safe_buffer *buf,
size_t size, enum dma_data_direction dir)
size_t size, enum dma_data_direction dir,
unsigned long attrs)
{
BUG_ON(buf->size != size);
BUG_ON(buf->direction != dir);
Expand All @@ -283,7 +286,8 @@ static inline void unmap_single(struct device *dev, struct safe_buffer *buf,

DO_STATS(dev->archdata.dmabounce->bounce_count++);

if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) {
if ((dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) &&
!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
void *ptr = buf->ptr;

dev_dbg(dev, "%s: copy back safe %p to unsafe %p size %d\n",
Expand Down Expand Up @@ -334,7 +338,7 @@ static dma_addr_t dmabounce_map_page(struct device *dev, struct page *page,
return DMA_ERROR_CODE;
}

return map_single(dev, page_address(page) + offset, size, dir);
return map_single(dev, page_address(page) + offset, size, dir, attrs);
}

/*
Expand All @@ -357,7 +361,7 @@ static void dmabounce_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t
return;
}

unmap_single(dev, buf, size, dir);
unmap_single(dev, buf, size, dir, attrs);
}

static int __dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
Expand Down

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