[PATCH 2/2] ARM: use cached memory in dma_alloc_coherent() if possible

@@ -579,6 +579,34 @@ int coherent_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 }
 
 /*
+ * For fully coherent systems/devices we can use normal, cached memory so just
+ * get some free pages.
+ */
+static void *coherent_alloc(struct device *dev, size_t size,
+			    dma_addr_t *dma_handle, gfp_t gfp)
+{
+	void *ret;
+	u64 mask = get_coherent_dma_mask(dev);
+
+	if (!dev || mask >= 0xffffffffUL)
+		gfp &= ~GFP_DMA;
+
+	ret = (void *)__get_free_pages(gfp, get_order(size));
+	if (ret) {
+		memset(ret, 0, size);
+		*dma_handle = virt_to_phys(ret);
+	}
+
+	return ret;
+}
+
+static void coherent_free(struct device *dev, size_t size, void *virt,
+			  dma_addr_t dma_handle)
+{
+	free_pages((unsigned long)dma_handle, get_order(size));
+}
+
+/*
  * Coherent DMA ops. These can either be used for the whole system
  * automatically if arch_is_coherent() is true or on a per device basis if the
  * device is connected to the ACP port to provide coherency for that device.

@@ -586,6 +614,8 @@ int coherent_map_sg(struct device *dev, struct scatterlist *sg, int nents,
  * dev->archdata.dma_ops
  */
 struct dma_map_ops coherent_dma_ops = {
+	.alloc_coherent		= coherent_alloc,
+	.free_coherent		= coherent_free,
 	.map_page		= coherent_map_page,
 	.map_sg			= coherent_map_sg,
 };