diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index b497daa..0a7a1b4 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -5,6 +5,7 @@
  *
  * PCI Express I/O Virtualization (IOV) support.
  *   Single Root IOV 1.0
+ *   Address Translation Service 1.0
  */
 
 #include <linux/pci.h>
@@ -679,3 +680,107 @@ irqreturn_t pci_sriov_migration(struct pci_dev *dev)
 	return sriov_migration(dev) ? IRQ_HANDLED : IRQ_NONE;
 }
 EXPORT_SYMBOL_GPL(pci_sriov_migration);
+
+static int ats_alloc_one(struct pci_dev *dev, int ps)
+{
+	int pos;
+	u16 cap;
+	struct pci_ats *ats;
+
+	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
+	if (!pos)
+		return -ENODEV;
+
+	ats = kzalloc(sizeof(*ats), GFP_KERNEL);
+	if (!ats)
+		return -ENOMEM;
+
+	ats->pos = pos;
+	ats->stu = ps;
+	pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);
+	ats->qdep = PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
+					    PCI_ATS_MAX_QDEP;
+	dev->ats = ats;
+
+	return 0;
+}
+
+static void ats_free_one(struct pci_dev *dev)
+{
+	kfree(dev->ats);
+	dev->ats = NULL;
+}
+
+/**
+ * pci_enable_ats - enable the ATS capability
+ * @dev: the PCI device
+ * @ps: the IOMMU page shift
+ *
+ * Returns 0 on success, or negative on failure.
+ */
+int pci_enable_ats(struct pci_dev *dev, int ps)
+{
+	int rc;
+	u16 ctrl;
+
+	BUG_ON(dev->ats);
+
+	if (ps < PCI_ATS_MIN_STU)
+		return -EINVAL;
+
+	rc = ats_alloc_one(dev, ps);
+	if (rc)
+		return rc;
+
+	ctrl = PCI_ATS_CTRL_ENABLE;
+	ctrl |= PCI_ATS_CTRL_STU(ps - PCI_ATS_MIN_STU);
+	pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
+
+	return 0;
+}
+
+/**
+ * pci_disable_ats - disable the ATS capability
+ * @dev: the PCI device
+ */
+void pci_disable_ats(struct pci_dev *dev)
+{
+	u16 ctrl;
+
+	BUG_ON(!dev->ats);
+
+	pci_read_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, &ctrl);
+	ctrl &= ~PCI_ATS_CTRL_ENABLE;
+	pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
+
+	ats_free_one(dev);
+}
+
+/**
+ * pci_ats_queue_depth - query the ATS Invalidate Queue Depth
+ * @dev: the PCI device
+ *
+ * Returns the queue depth on success, or negative on failure.
+ *
+ * The ATS spec uses 0 in the Invalidate Queue Depth field to
+ * indicate that the function can accept 32 Invalidate Request.
+ * But here we use the `real' values (i.e. 1~32) for the Queue
+ * Depth.
+ */
+int pci_ats_queue_depth(struct pci_dev *dev)
+{
+	int pos;
+	u16 cap;
+
+	if (dev->ats)
+		return dev->ats->qdep;
+
+	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
+	if (!pos)
+		return -ENODEV;
+
+	pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);
+
+	return PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
+				       PCI_ATS_MAX_QDEP;
+}
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index d03f6b9..3c2ec64 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -229,6 +229,13 @@ struct pci_sriov {
 	u8 __iomem *mstate;	/* VF Migration State Array */
 };
 
+/* Address Translation Service */
+struct pci_ats {
+	int pos;	/* capability position */
+	int stu;	/* Smallest Translation Unit */
+	int qdep;	/* Invalidate Queue Depth */
+};
+
 #ifdef CONFIG_PCI_IOV
 extern int pci_iov_init(struct pci_dev *dev);
 extern void pci_iov_release(struct pci_dev *dev);
@@ -236,6 +243,20 @@ extern int pci_iov_resource_bar(struct pci_dev *dev, int resno,
 				enum pci_bar_type *type);
 extern void pci_restore_iov_state(struct pci_dev *dev);
 extern int pci_iov_bus_range(struct pci_bus *bus);
+
+extern int pci_enable_ats(struct pci_dev *dev, int ps);
+extern void pci_disable_ats(struct pci_dev *dev);
+extern int pci_ats_queue_depth(struct pci_dev *dev);
+/**
+ * pci_ats_enabled - query the ATS status
+ * @dev: the PCI device
+ *
+ * Returns 1 if ATS capability is enabled, or 0 if not.
+ */
+static inline int pci_ats_enabled(struct pci_dev *dev)
+{
+	return !!dev->ats;
+}
 #else
 static inline int pci_iov_init(struct pci_dev *dev)
 {
@@ -257,6 +278,22 @@ static inline int pci_iov_bus_range(struct pci_bus *bus)
 {
 	return 0;
 }
+
+static inline int pci_enable_ats(struct pci_dev *dev, int ps)
+{
+	return -ENODEV;
+}
+static inline void pci_disable_ats(struct pci_dev *dev)
+{
+}
+static inline int pci_ats_queue_depth(struct pci_dev *dev)
+{
+	return -ENODEV;
+}
+static inline int pci_ats_enabled(struct pci_dev *dev)
+{
+	return 0;
+}
 #endif /* CONFIG_PCI_IOV */
 
 #endif /* DRIVERS_PCI_H */
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 72698d8..bd3e4a7 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -188,6 +188,7 @@ struct pci_cap_saved_state {
 struct pcie_link_state;
 struct pci_vpd;
 struct pci_sriov;
+struct pci_ats;
 
 /*
  * The pci_dev structure is used to describe PCI devices.
@@ -285,6 +286,7 @@ struct pci_dev {
 		struct pci_sriov *sriov;	/* SR-IOV capability related */
 		struct pci_dev *physfn;	/* the PF this VF is associated with */
 	};
+	struct pci_ats	*ats;	/* Address Translation Service */
 #endif
 };
 
diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h
index 616bf8b..243cd5b 100644
--- a/include/linux/pci_regs.h
+++ b/include/linux/pci_regs.h
@@ -502,6 +502,7 @@
 #define PCI_EXT_CAP_ID_DSN	3
 #define PCI_EXT_CAP_ID_PWR	4
 #define PCI_EXT_CAP_ID_ARI	14
+#define PCI_EXT_CAP_ID_ATS	15
 #define PCI_EXT_CAP_ID_SRIOV	16
 
 /* Advanced Error Reporting */
@@ -620,6 +621,15 @@
 #define  PCI_ARI_CTRL_ACS	0x0002	/* ACS Function Groups Enable */
 #define  PCI_ARI_CTRL_FG(x)	(((x) >> 4) & 7) /* Function Group */
 
+/* Address Translation Service */
+#define PCI_ATS_CAP		0x04	/* ATS Capability Register */
+#define  PCI_ATS_CAP_QDEP(x)	((x) & 0x1f)	/* Invalidate Queue Depth */
+#define  PCI_ATS_MAX_QDEP	32	/* Max Invalidate Queue Depth */
+#define PCI_ATS_CTRL		0x06	/* ATS Control Register */
+#define  PCI_ATS_CTRL_ENABLE	0x8000	/* ATS Enable */
+#define  PCI_ATS_CTRL_STU(x)	((x) & 0x1f)	/* Smallest Translation Unit */
+#define  PCI_ATS_MIN_STU	12	/* shift of minimum STU block */
+
 /* Single Root I/O Virtualization */
 #define PCI_SRIOV_CAP		0x04	/* SR-IOV Capabilities */
 #define  PCI_SRIOV_CAP_VFM	0x01	/* VF Migration Capable */
