PCI: Prevent xHCI driver from claiming AMD Nolan USB3 DRD device

[mirror_ubuntu-zesty-kernel.git] / drivers / pci / quirks.c

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 90acb32c85b1c637aa918a13b236c17c015b73c8..ed6f89b6efe5c2cab127dd15613cab59be736fd7 100644 (file)
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -378,6 +378,26 @@ static void quirk_ati_exploding_mce(struct pci_dev *dev)
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI,     PCI_DEVICE_ID_ATI_RS100,   quirk_ati_exploding_mce);
 
+/*
+ * In the AMD NL platform, this device ([1022:7912]) has a class code of
+ * PCI_CLASS_SERIAL_USB_XHCI (0x0c0330), which means the xhci driver will
+ * claim it.
+ * But the dwc3 driver is a more specific driver for this device, and we'd
+ * prefer to use it instead of xhci. To prevent xhci from claiming the
+ * device, change the class code to 0x0c03fe, which the PCI r3.0 spec
+ * defines as "USB device (not host controller)". The dwc3 driver can then
+ * claim it based on its Vendor and Device ID.
+ */
+static void quirk_amd_nl_class(struct pci_dev *pdev)
+{
+       /*
+        * Use 'USB Device' (0x0c03fe) instead of PCI header provided
+        */
+       pdev->class = 0x0c03fe;
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_NL_USB,
+               quirk_amd_nl_class);
+
 /*
  * Let's make the southbridge information explicit instead
  * of having to worry about people probing the ACPI areas,