PCI: add Intel USB specific reset method

Handle device specific reset requirements (i.e. vendor reg for reset
along with appropriate timeout).

Signed-off-by: Yu Zhao <yu.zhao@intel.com>
Signed-off-by: Dexuan Cui <dexuan.cui@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/quirks.c

@@ -2642,7 +2642,31 @@ fs_initcall_sync(pci_apply_final_quirks);
  * reset a single function if other methods (e.g. FLR, PM D0->D3) are
  * not available.
  */
+static int reset_intel_generic_dev(struct pci_dev *dev, int probe)
+{
+	int pos;
+
+	/* only implement PCI_CLASS_SERIAL_USB at present */
+	if (dev->class == PCI_CLASS_SERIAL_USB) {
+		pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
+		if (!pos)
+			return -ENOTTY;
+
+		if (probe)
+			return 0;
+
+		pci_write_config_byte(dev, pos + 0x4, 1);
+		msleep(100);
+
+		return 0;
+	} else {
+		return -ENOTTY;
+	}
+}
+
 struct pci_dev_reset_methods pci_dev_reset_methods[] = {
+	{ PCI_VENDOR_ID_INTEL, PCI_ANY_ID,
+		reset_intel_generic_dev },
 	{ 0 }
 };
 #else