On Tue, Oct 28, 2014 at 03:06:31PM +0300, Sergei Shtylyov wrote:
> Hello.
>
> On 10/28/2014 2:54 PM, Huang Rui wrote:
>
> >The AMD Nolan (NL) SoC contains a DesignWare USB3 Dual-Role Device that can
> >be operated either as a USB Host or a USB Device. 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.
>
> >Suggested-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> >Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> >Cc: Jason Chang <jason.chang@xxxxxxx>
> >Signed-off-by: Huang Rui <ray.huang@xxxxxxx>
> >---
> > drivers/pci/quirks.c | 20 ++++++++++++++++++++
> > 1 file changed, 20 insertions(+)
>
> >diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> >index 90acb32..1152bef 100644
> >--- a/drivers/pci/quirks.c
> >+++ b/drivers/pci/quirks.c
> >@@ -379,6 +379,26 @@ 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' (0x0x03fe) instead of PCI header provided
>
> 0x0c03fe, you mean?
Yes. That's a typo, 'USB Device' class code should be 0x0c03fe, will
update.
>
> >+ */
> >+ pdev->class = 0x0c03fe;
> >+}
> >+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_NL_USB,
>
> I'm not sure it was a good idea to declare the ID in pci_ids.h --
> it's been long discouraged.
>
You're right. But PCI_DEVICE_ID_AMD_NL_USB will be used on two
drivers(pci and dwc3). It also might be used for identifying AMD NL
chip for another drivers in future.
Thanks,
Rui
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