powerpc/dma: remove dma_nommu_dma_supported

This function is largely identical to the generic version used
everywhere else.  Replace it with the generic version.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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

@@ -31,7 +31,6 @@ int dma_nommu_map_sg(struct device *dev, struct scatterlist *sgl,
 dma_addr_t dma_nommu_map_page(struct device *dev, struct page *page,
 		unsigned long offset, size_t size,
 		enum dma_data_direction dir, unsigned long attrs);
-int dma_nommu_dma_supported(struct device *dev, u64 mask);
 
 #ifdef CONFIG_NOT_COHERENT_CACHE
 /*

arch/powerpc/kernel/dma-iommu.c

@@ -21,7 +21,7 @@
 static inline bool dma_iommu_alloc_bypass(struct device *dev)
 {
 	return dev->archdata.iommu_bypass && !iommu_fixed_is_weak &&
-		dma_nommu_dma_supported(dev, dev->coherent_dma_mask);
+		dma_direct_supported(dev, dev->coherent_dma_mask);
 }
 
 static inline bool dma_iommu_map_bypass(struct device *dev,

arch/powerpc/kernel/dma.c

@@ -39,29 +39,6 @@ static u64 __maybe_unused get_pfn_limit(struct device *dev)
 	return pfn;
 }
 
-int dma_nommu_dma_supported(struct device *dev, u64 mask)
-{
-#ifdef CONFIG_PPC64
-	u64 limit = phys_to_dma(dev, (memblock_end_of_DRAM() - 1));
-
-	/* Limit fits in the mask, we are good */
-	if (mask >= limit)
-		return 1;
-
-#ifdef CONFIG_FSL_SOC
-	/*
-	 * Freescale gets another chance via ZONE_DMA, however
-	 * that will have to be refined if/when they support iommus
-	 */
-	return 1;
-#endif
-	/* Sorry ... */
-	return 0;
-#else
-	return 1;
-#endif
-}
-
 #ifndef CONFIG_NOT_COHERENT_CACHE
 void *__dma_nommu_alloc_coherent(struct device *dev, size_t size,
 				  dma_addr_t *dma_handle, gfp_t flag,
@@ -190,7 +167,7 @@ const struct dma_map_ops dma_nommu_ops = {
 	.free				= __dma_nommu_free_coherent,
 	.map_sg				= dma_nommu_map_sg,
 	.unmap_sg			= dma_nommu_unmap_sg,
-	.dma_supported			= dma_nommu_dma_supported,
+	.dma_supported			= dma_direct_supported,
 	.map_page			= dma_nommu_map_page,
 	.unmap_page			= dma_nommu_unmap_page,
 	.get_required_mask		= dma_direct_get_required_mask,