[ARM] dma: provide a better dma_map_page() implementation

We can translate a struct page directly to a DMA address using
page_to_dma().  No need to use page_address() followed by
virt_to_dma().

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 10 insertions, 1 deletions

diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index eff954852c2b..856ee1bdee57 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -227,13 +227,22 @@ extern dma_addr_t dma_map_single(struct device *,void *, size_t, enum dma_data_d
  * can regain ownership by calling dma_unmap_page() or
  * dma_sync_single_for_cpu().
  */
+#ifndef CONFIG_DMABOUNCE
 static inline dma_addr_t
 dma_map_page(struct device *dev, struct page *page,
              unsigned long offset, size_t size,
              enum dma_data_direction dir)
 {
-        return dma_map_single(dev, page_address(page) + offset, size, dir);
+        if (!arch_is_coherent())
+                dma_cache_maint(page_address(page) + offset, size, dir);
+
+        return page_to_dma(dev, page) + offset;
 }
+#else
+extern dma_addr_t dma_map_page(struct device *dev, struct page *page,
+                        unsigned long offset, size_t size,
+                        enum dma_data_direction dir);
+#endif
 
 /**
  * dma_unmap_single - unmap a single buffer previously mapped