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

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>

diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index 301281645d086690f1935af86c99711b629e59d6..75055df1cda30f39c42863d9bdd4fdcc391ff8f1 100644 (file)
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -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;
@@ -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);
@@ -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);
@@ -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",
@@ -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);
 }
 
 /*
@@ -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,