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>

1 files changed, 26 insertions, 0 deletions

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 931b70986272..d5d388160f42 100644
--- a/include/linux/dma-mapping.h
+++ b/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