Merge tag 'pci-v4.13-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci

Pull PCI fix from Bjorn Helgaas:
"Work around Renesas uPD72020x 32-bit DMA issue"

* tag 'pci-v4.13-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
xhci: Reset Renesas uPD72020x USB controller for 32-bit DMA issue
PCI: Add pci_reset_function_locked()

drivers/pci/pci.c

···
 EXPORT_SYMBOL_GPL(pci_reset_function);
 
 /**
+ * pci_reset_function_locked - quiesce and reset a PCI device function
+ * @dev: PCI device to reset
+ *
+ * Some devices allow an individual function to be reset without affecting
+ * other functions in the same device.  The PCI device must be responsive
+ * to PCI config space in order to use this function.
+ *
+ * This function does not just reset the PCI portion of a device, but
+ * clears all the state associated with the device.  This function differs
+ * from __pci_reset_function() in that it saves and restores device state
+ * over the reset.  It also differs from pci_reset_function() in that it
+ * requires the PCI device lock to be held.
+ *
+ * Returns 0 if the device function was successfully reset or negative if the
+ * device doesn't support resetting a single function.
+ */
+int pci_reset_function_locked(struct pci_dev *dev)
+{
+	int rc;
+
+	rc = pci_probe_reset_function(dev);
+	if (rc)
+		return rc;
+
+	pci_dev_save_and_disable(dev);
+
+	rc = __pci_reset_function_locked(dev);
+
+	pci_dev_restore(dev);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(pci_reset_function_locked);
+
+/**
  * pci_try_reset_function - quiesce and reset a PCI device function
  * @dev: PCI device to reset
  *

drivers/usb/host/pci-quirks.c

···
 }
 DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_ANY_ID, PCI_ANY_ID,
 			PCI_CLASS_SERIAL_USB, 8, quirk_usb_early_handoff);
+
+bool usb_xhci_needs_pci_reset(struct pci_dev *pdev)
+{
+	/*
+	 * Our dear uPD72020{1,2} friend only partially resets when
+	 * asked to via the XHCI interface, and may end up doing DMA
+	 * at the wrong addresses, as it keeps the top 32bit of some
+	 * addresses from its previous programming under obscure
+	 * circumstances.
+	 * Give it a good wack at probe time. Unfortunately, this
+	 * needs to happen before we've had a chance to discover any
+	 * quirk, or the system will be in a rather bad state.
+	 */
+	if (pdev->vendor == PCI_VENDOR_ID_RENESAS &&
+	    (pdev->device == 0x0014 || pdev->device == 0x0015))
+		return true;
+
+	return false;
+}
+EXPORT_SYMBOL_GPL(usb_xhci_needs_pci_reset);

drivers/usb/host/pci-quirks.h

···
 void usb_enable_intel_xhci_ports(struct pci_dev *xhci_pdev);
 void usb_disable_xhci_ports(struct pci_dev *xhci_pdev);
 void sb800_prefetch(struct device *dev, int on);
+bool usb_xhci_needs_pci_reset(struct pci_dev *pdev);
 #else
 struct pci_dev;
 static inline void usb_amd_quirk_pll_disable(void) {}

drivers/usb/host/xhci-pci.c

···
 
 	driver = (struct hc_driver *)id->driver_data;
 
+	/* For some HW implementation, a XHCI reset is just not enough... */
+	if (usb_xhci_needs_pci_reset(dev)) {
+		dev_info(&dev->dev, "Resetting\n");
+		if (pci_reset_function_locked(dev))
+			dev_warn(&dev->dev, "Reset failed");
+	}
+
 	/* Prevent runtime suspending between USB-2 and USB-3 initialization */
 	pm_runtime_get_noresume(&dev->dev);
 

include/linux/pci.h

···
 int __pci_reset_function(struct pci_dev *dev);
 int __pci_reset_function_locked(struct pci_dev *dev);
 int pci_reset_function(struct pci_dev *dev);
+int pci_reset_function_locked(struct pci_dev *dev);
 int pci_try_reset_function(struct pci_dev *dev);
 int pci_probe_reset_slot(struct pci_slot *slot);
 int pci_reset_slot(struct pci_slot *slot);