+/* Program PCIE MaxPayload setting on device: ensure parent maxpayload <= device */
+static int pci_set_payload(struct pci_dev *dev)
+{
+ int pos, ppos;
+ u16 pctl, psz;
+ u16 dctl, dsz, dcap, dmax;
+ struct pci_dev *parent;
+
+ parent = dev->bus->self;
+ pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
+ if (!pos)
+ return 0;
+
+ /* Read Device MaxPayload capability and setting */
+ pci_read_config_word(dev, pos + PCI_EXP_DEVCTL, &dctl);
+ pci_read_config_word(dev, pos + PCI_EXP_DEVCAP, &dcap);
+ dsz = (dctl & PCI_EXP_DEVCTL_PAYLOAD) >> 5;
+ dmax = (dcap & PCI_EXP_DEVCAP_PAYLOAD);
+
+ /* Read Parent MaxPayload setting */
+ ppos = pci_find_capability(parent, PCI_CAP_ID_EXP);
+ if (!ppos)
+ return 0;
+ pci_read_config_word(parent, ppos + PCI_EXP_DEVCTL, &pctl);
+ psz = (pctl & PCI_EXP_DEVCTL_PAYLOAD) >> 5;
+
+ /* If parent payload > device max payload -> error
+ * If parent payload > device payload -> set speed
+ * If parent payload <= device payload -> do nothing
+ */
+ if (psz > dmax)
+ return -1;
+ else if (psz > dsz) {
+ dev_info(&dev->dev, "Setting MaxPayload to %d\n", 128 << psz);
+ pci_write_config_word(dev, pos + PCI_EXP_DEVCTL,
+ (dctl & ~PCI_EXP_DEVCTL_PAYLOAD) +
+ (psz << 5));
+ }
+ return 0;
+}
+