MIPS: loongson: remove loongson_dma_supported

Christoph Hellwig · paulburton · commit e799de3efb9d · 2018-06-24T09:26:02.000-07:00
swiotlb_dma_supported will always return true for a mask large enough to cover the DMA addresses for all physical memory, which is the right thing to do for swiotlb based dma ops. This function returned false if the mask was bigger than a firmware set dma_mask_bits that apparently can be either 32 or 64, and which seems completely buggys if it actually is not 64, as the false return negates the whole point of swiotlb. Signed-off-by: Christoph Hellwig <hch@lst.de> Patchwork: https://patchwork.linux-mips.org/patch/19533/ Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: David Daney <david.daney@cavium.com> Cc: Kevin Cernekee <cernekee@gmail.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: Tom Bogendoerfer <tsbogend@alpha.franken.de> Cc: Huacai Chen <chenhc@lemote.com> Cc: iommu@lists.linux-foundation.org Cc: linux-mips@linux-mips.org
diff --git a/arch/mips/loongson64/common/dma-swiotlb.c b/arch/mips/loongson64/common/dma-swiotlb.c
@@ -56,13 +56,6 @@ static void loongson_dma_sync_sg_for_device(struct device *dev,
 	mb();
 }
 
-static int loongson_dma_supported(struct device *dev, u64 mask)
-{
-	if (mask > DMA_BIT_MASK(loongson_sysconf.dma_mask_bits))
-		return 0;
-	return swiotlb_dma_supported(dev, mask);
-}
-
 dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
 {
 	long nid;
@@ -99,7 +92,7 @@ static const struct dma_map_ops loongson_dma_map_ops = {
 	.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
 	.sync_sg_for_device = loongson_dma_sync_sg_for_device,
 	.mapping_error = swiotlb_dma_mapping_error,
-	.dma_supported = loongson_dma_supported,
+	.dma_supported = swiotlb_dma_supported,
 };
 
 void __init plat_swiotlb_setup(void)
