AMD IOMMU: add dma_supported callback

This function determines if the AMD IOMMU implementation is responsible
for a given device. So the DMA layer can get this information from the
driver.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 25 insertions, 0 deletions

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 0cb8fd2359f5..a6a6f8ed1cf5 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -1205,6 +1205,30 @@ free_mem:
 }
 
 /*
+ * This function is called by the DMA layer to find out if we can handle a
+ * particular device. It is part of the dma_ops.
+ */
+static int amd_iommu_dma_supported(struct device *dev, u64 mask)
+{
+        u16 bdf;
+        struct pci_dev *pcidev;
+
+        /* No device or no PCI device */
+        if (!dev || dev->bus != &pci_bus_type)
+                return 0;
+
+        pcidev = to_pci_dev(dev);
+
+        bdf = calc_devid(pcidev->bus->number, pcidev->devfn);
+
+        /* Out of our scope? */
+        if (bdf > amd_iommu_last_bdf)
+                return 0;
+
+        return 1;
+}
+
+/*
  * The function for pre-allocating protection domains.
  *
  * If the driver core informs the DMA layer if a driver grabs a device
@@ -1247,6 +1271,7 @@ static struct dma_mapping_ops amd_iommu_dma_ops = {
         .unmap_single = unmap_single,
         .map_sg = map_sg,
         .unmap_sg = unmap_sg,
+        .dma_supported = amd_iommu_dma_supported,
 };
 
 /*