arm: dma mapping: Export a dma ops function arm_dma_set_mask

Expose another DMA operations function: arm_dma_set_mask. This
function will be added to a custom DMA ops for Armada 370/XP.
Depending of its configuration Armada 370/XP can be set as a "nearly"
coherent architecture. In this case the DMA ops is made of:
- specific functions for this architecture
- already exposed arm DMA related functions
- the arm_dma_set_mask which was not exposed yet.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>

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

@@ -111,6 +111,8 @@ static inline void dma_free_noncoherent(struct device *dev, size_t size,
 
 extern int dma_supported(struct device *dev, u64 mask);
 
+extern int arm_dma_set_mask(struct device *dev, u64 dma_mask);
+
 /**
  * arm_dma_alloc - allocate consistent memory for DMA
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices

arch/arm/mm/dma-mapping.c

@@ -124,8 +124,6 @@ static void arm_dma_sync_single_for_device(struct device *dev,
 	__dma_page_cpu_to_dev(page, offset, size, dir);
 }
 
-static int arm_dma_set_mask(struct device *dev, u64 dma_mask);
-
 struct dma_map_ops arm_dma_ops = {
 	.alloc			= arm_dma_alloc,
 	.free			= arm_dma_free,
@@ -971,7 +969,7 @@ int dma_supported(struct device *dev, u64 mask)
 }
 EXPORT_SYMBOL(dma_supported);
 
-static int arm_dma_set_mask(struct device *dev, u64 dma_mask)
+int arm_dma_set_mask(struct device *dev, u64 dma_mask)
 {
 	if (!dev->dma_mask || !dma_supported(dev, dma_mask))
 		return -EIO;