sparc64: Enable 64-bit DMA

ATU 64bit addressing allows PCIe devices with 64bit DMA capabilities
to use ATU for 64bit DMA.
Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com>
Reviewed-by: chris hyser <chris.hyser@oracle.com>
Acked-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/Kconfig

@@ -93,6 +93,10 @@ config ARCH_ATU
 	bool
 	default y if SPARC64
 
+config ARCH_DMA_ADDR_T_64BIT
+	bool
+	default y if ARCH_ATU
+
 config IOMMU_HELPER
 	bool
 	default y if SPARC64

arch/sparc/kernel/iommu.c

@@ -760,8 +760,12 @@ int dma_supported(struct device *dev, u64 device_mask)
 	struct iommu *iommu = dev->archdata.iommu;
 	u64 dma_addr_mask = iommu->dma_addr_mask;
 
-	if (device_mask >= (1UL << 32UL))
+	if (device_mask > DMA_BIT_MASK(32)) {
+		if (iommu->atu)
+			dma_addr_mask = iommu->atu->dma_addr_mask;
+		else
 			return 0;
+	}
 
 	if ((device_mask & dma_addr_mask) == dma_addr_mask)
 		return 1;