PCI: Add support for PASID capability

Devices supporting Process Address Space Identifiers
(PASIDs) can use an IOMMU to access multiple IO address
spaces at the same time. A PCIe device indicates support for
this feature by implementing the PASID capability. This
patch adds support for the capability to the Linux kernel.

Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/include/linux/pci-ats.h b/include/linux/pci-ats.h
index 0713952..e3d0b38 100644
--- a/include/linux/pci-ats.h
+++ b/include/linux/pci-ats.h
@@ -93,4 +93,35 @@
 }
 #endif /* CONFIG_PCI_PRI */
 
+#ifdef CONFIG_PCI_PASID
+
+extern int pci_enable_pasid(struct pci_dev *pdev, int features);
+extern void pci_disable_pasid(struct pci_dev *pdev);
+extern int pci_pasid_features(struct pci_dev *pdev);
+extern int pci_max_pasids(struct pci_dev *pdev);
+
+#else  /* CONFIG_PCI_PASID */
+
+static inline int pci_enable_pasid(struct pci_dev *pdev, int features)
+{
+	return -EINVAL;
+}
+
+static inline void pci_disable_pasid(struct pci_dev *pdev)
+{
+}
+
+static inline int pci_pasid_features(struct pci_dev *pdev)
+{
+	return -EINVAL;
+}
+
+static inline int pci_max_pasids(struct pci_dev *pdev)
+{
+	return -EINVAL;
+}
+
+#endif /* CONFIG_PCI_PASID */
+
+
 #endif /* LINUX_PCI_ATS_H*/
diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h
index 7fc32af..b5d9657 100644
--- a/include/linux/pci_regs.h
+++ b/include/linux/pci_regs.h
@@ -675,6 +675,14 @@
 #define PCI_PRI_MAX_REQ_OFF	0x08	/* Cap offset for max reqs supported */
 #define PCI_PRI_ALLOC_REQ_OFF	0x0c	/* Cap offset for max reqs allowed */
 
+/* PASID capability */
+#define PCI_PASID_CAP		0x1b    /* PASID capability ID */
+#define PCI_PASID_CAP_OFF	0x04    /* PASID feature register */
+#define PCI_PASID_CONTROL_OFF   0x06    /* PASID control register */
+#define PCI_PASID_ENABLE	0x01	/* Enable/Supported bit */
+#define PCI_PASID_EXEC		0x02	/* Exec permissions Enable/Supported */
+#define PCI_PASID_PRIV		0x04	/* Priviledge Mode Enable/Support */
+
 /* Single Root I/O Virtualization */
 #define PCI_SRIOV_CAP		0x04	/* SR-IOV Capabilities */
 #define  PCI_SRIOV_CAP_VFM	0x01	/* VF Migration Capable */