dma-mapping: Provide write-combine allocations

Provide an implementation for dma_{alloc,free,mmap}_writecombine() when
the architecture supports DMA attributes.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

arch/arm/include/asm/dma-mapping.h

@@ -265,22 +265,6 @@ extern int arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
 			void *cpu_addr, dma_addr_t dma_addr, size_t size,
 			struct dma_attrs *attrs);
 
-static inline void *dma_alloc_writecombine(struct device *dev, size_t size,
-				       dma_addr_t *dma_handle, gfp_t flag)
-{
-	DEFINE_DMA_ATTRS(attrs);
-	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
-	return dma_alloc_attrs(dev, size, dma_handle, flag, &attrs);
-}
-
-static inline void dma_free_writecombine(struct device *dev, size_t size,
-				     void *cpu_addr, dma_addr_t dma_handle)
-{
-	DEFINE_DMA_ATTRS(attrs);
-	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
-	return dma_free_attrs(dev, size, cpu_addr, dma_handle, &attrs);
-}
-
 /*
  * This can be called during early boot to increase the size of the atomic
  * coherent DMA pool above the default value of 256KiB. It must be called

include/asm-generic/dma-mapping-common.h

@@ -205,14 +205,6 @@ dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma, void *cpu_addr,
 
 #define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, NULL)
 
-static inline int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,
-		      void *cpu_addr, dma_addr_t dma_addr, size_t size)
-{
-	DEFINE_DMA_ATTRS(attrs);
-	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
-	return dma_mmap_attrs(dev, vma, cpu_addr, dma_addr, size, &attrs);
-}
-
 int
 dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
 		       void *cpu_addr, dma_addr_t dma_addr, size_t size);

include/linux/dma-mapping.h

@@ -263,6 +263,32 @@ struct dma_attrs;
 #define dma_unmap_sg_attrs(dev, sgl, nents, dir, attrs) \
 	dma_unmap_sg(dev, sgl, nents, dir)
 
+#else
+static inline void *dma_alloc_writecombine(struct device *dev, size_t size,
+					   dma_addr_t *dma_addr, gfp_t gfp)
+{
+	DEFINE_DMA_ATTRS(attrs);
+	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
+	return dma_alloc_attrs(dev, size, dma_addr, gfp, &attrs);
+}
+
+static inline void dma_free_writecombine(struct device *dev, size_t size,
+					 void *cpu_addr, dma_addr_t dma_addr)
+{
+	DEFINE_DMA_ATTRS(attrs);
+	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
+	return dma_free_attrs(dev, size, cpu_addr, dma_addr, &attrs);
+}
+
+static inline int dma_mmap_writecombine(struct device *dev,
+					struct vm_area_struct *vma,
+					void *cpu_addr, dma_addr_t dma_addr,
+					size_t size)
+{
+	DEFINE_DMA_ATTRS(attrs);
+	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
+	return dma_mmap_attrs(dev, vma, cpu_addr, dma_addr, size, &attrs);
+}
 #endif /* CONFIG_HAVE_DMA_ATTRS */
 
 #ifdef CONFIG_NEED_DMA_MAP_STATE