iommu/amd: Add amd_iommu_device_info() function

This function can be used to find out which features
necessary for IOMMUv2 usage are available on a given device.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index d5074f428423..03944e76b700 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -3565,3 +3565,46 @@ void amd_iommu_enable_device_erratum(struct pci_dev *pdev, u32 erratum)
         dev_data->errata |= (1 << erratum);
 }
 EXPORT_SYMBOL(amd_iommu_enable_device_erratum);
+
+int amd_iommu_device_info(struct pci_dev *pdev,
+                          struct amd_iommu_device_info *info)
+{
+        int max_pasids;
+        int pos;
+
+        if (pdev == NULL || info == NULL)
+                return -EINVAL;
+
+        if (!amd_iommu_v2_supported())
+                return -EINVAL;
+
+        memset(info, 0, sizeof(*info));
+
+        pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ATS);
+        if (pos)
+                info->flags |= AMD_IOMMU_DEVICE_FLAG_ATS_SUP;
+
+        pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
+        if (pos)
+                info->flags |= AMD_IOMMU_DEVICE_FLAG_PRI_SUP;
+
+        pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
+        if (pos) {
+                int features;
+
+                max_pasids = 1 << (9 * (amd_iommu_max_glx_val + 1));
+                max_pasids = min(max_pasids, (1 << 20));
+
+                info->flags |= AMD_IOMMU_DEVICE_FLAG_PASID_SUP;
+                info->max_pasids = min(pci_max_pasids(pdev), max_pasids);
+
+                features = pci_pasid_features(pdev);
+                if (features & PCI_PASID_CAP_EXEC)
+                        info->flags |= AMD_IOMMU_DEVICE_FLAG_EXEC_SUP;
+                if (features & PCI_PASID_CAP_PRIV)
+                        info->flags |= AMD_IOMMU_DEVICE_FLAG_PRIV_SUP;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL(amd_iommu_device_info);