2 files changed, 142 insertions, 0 deletions

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index b497daab3d4a..0a7a1b40286f 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 d03f6b99f292..3c2ec64f78e9 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 */