powerpc/dma: remove dma_nommu_get_required_mask

This function is identical to the generic dma_direct_get_required_mask,
except that the generic version also takes the bus_dma_mask account,
which could lead to incorrect results in the powerpc 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

@@ -32,7 +32,6 @@ 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);
-u64 dma_nommu_get_required_mask(struct device *dev);
 
 #ifdef CONFIG_NOT_COHERENT_CACHE
 /*

arch/powerpc/kernel/dma-iommu.c

@@ -152,7 +152,7 @@ u64 dma_iommu_get_required_mask(struct device *dev)
 		return 0;
 
 	if (dev_is_pci(dev)) {
-		u64 bypass_mask = dma_nommu_get_required_mask(dev);
+		u64 bypass_mask = dma_direct_get_required_mask(dev);
 
 		if (dma_iommu_bypass_supported(dev, bypass_mask))
 			return bypass_mask;

arch/powerpc/kernel/dma.c

@@ -145,18 +145,6 @@ static void dma_nommu_unmap_sg(struct device *dev, struct scatterlist *sgl,
 		__dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
 }
 
-u64 dma_nommu_get_required_mask(struct device *dev)
-{
-	u64 end, mask;
-
-	end = memblock_end_of_DRAM() + get_dma_offset(dev);
-
-	mask = 1ULL << (fls64(end) - 1);
-	mask += mask - 1;
-
-	return mask;
-}
-
 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)
@@ -205,7 +193,7 @@ const struct dma_map_ops dma_nommu_ops = {
 	.dma_supported			= dma_nommu_dma_supported,
 	.map_page			= dma_nommu_map_page,
 	.unmap_page			= dma_nommu_unmap_page,
-	.get_required_mask		= dma_nommu_get_required_mask,
+	.get_required_mask		= dma_direct_get_required_mask,
 #ifdef CONFIG_NOT_COHERENT_CACHE
 	.sync_single_for_cpu 		= dma_nommu_sync_single,
 	.sync_single_for_device 	= dma_nommu_sync_single,