+static void pci_configure_ltr(struct pci_dev *dev)
+{
+#ifdef CONFIG_PCIEASPM
+ u32 cap;
+ struct pci_dev *bridge;
+
+ if (!pci_is_pcie(dev))
+ return;
+
+ pcie_capability_read_dword(dev, PCI_EXP_DEVCAP2, &cap);
+ if (!(cap & PCI_EXP_DEVCAP2_LTR))
+ return;
+
+ /*
+ * Software must not enable LTR in an Endpoint unless the Root
+ * Complex and all intermediate Switches indicate support for LTR.
+ * PCIe r3.1, sec 6.18.
+ */
+ if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
+ dev->ltr_path = 1;
+ else {
+ bridge = pci_upstream_bridge(dev);
+ if (bridge && bridge->ltr_path)
+ dev->ltr_path = 1;
+ }
+
+ if (dev->ltr_path)
+ pcie_capability_set_word(dev, PCI_EXP_DEVCTL2,
+ PCI_EXP_DEVCTL2_LTR_EN);
+#endif
+}
+