PCI: support device-specific reset methods

Add a new type of quirk for resetting devices at pci_dev_reset time.
This is necessary to handle device with nonstandard reset procedures,
especially useful for guest drivers.

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

@@ -2636,6 +2636,15 @@ static int __init pci_apply_final_quirks(void)
 }
 
 fs_initcall_sync(pci_apply_final_quirks);
+
+/*
+ * Followings are device-specific reset methods which can be used to
+ * reset a single function if other methods (e.g. FLR, PM D0->D3) are
+ * not available.
+ */
+struct pci_dev_reset_methods pci_dev_reset_methods[] = {
+	{ 0 }
+};
 #else
 void pci_fixup_device(enum pci_fixup_pass pass, struct pci_dev *dev) {}
 #endif