Re: [PATCH] USB: OHCI: Add quirk for LS7A OHCI controller (rev 0x02)

[Huacai Chen]

On Wed, Mar 26, 2025 at 10:11 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Wed, Mar 26, 2025 at 06:23:55PM +0800, Huacai Chen wrote:
> > The OHCI controller (rev 0x02) under LS7A PCI host has a hardware flaw.
> > MMIO register with offset 0x60/0x64 is treated as legacy PS2-compatible
> > keyboard/mouse interface, which confuse the OHCI controller. Since OHCI
> > only use a 4KB BAR resource indeed, the LS7A OHCI controller's 32KB BAR
> > is wrapped around (the second 4KB BAR space is the same as the first 4KB
> > internally). So we can add an 4KB offset (0x1000) to the OHCI registers
> > (from the PCI BAR resource) as a quirk.
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Suggested-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > Tested-by: Mingcong Bai <jeffbai@xxxxxxx>
> > Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
> > ---
> >  drivers/usb/host/ohci-pci.c | 13 +++++++++++++
> >  1 file changed, 13 insertions(+)
> >
> > diff --git a/drivers/usb/host/ohci-pci.c b/drivers/usb/host/ohci-pci.c
> > index 900ea0d368e0..38e535aa09fe 100644
> > --- a/drivers/usb/host/ohci-pci.c
> > +++ b/drivers/usb/host/ohci-pci.c
> > @@ -165,6 +165,15 @@ static int ohci_quirk_amd700(struct usb_hcd *hcd)
> >       return 0;
> >  }
> >
> > +static int ohci_quirk_loongson(struct usb_hcd *hcd)
> > +{
> > +     struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
> > +
> > +     hcd->regs += (pdev->revision == 0x2) ? 0x1000 : 0x0;
>
> Please add a comment explaining why the quirk is needed and how it fixes
> the problem.
OK, I will do it in V2.

Huacai

>
> Alan Stern
>
> > +
> > +     return 0;
> > +}
> > +
> >  static int ohci_quirk_qemu(struct usb_hcd *hcd)
> >  {
> >       struct ohci_hcd *ohci = hcd_to_ohci(hcd);
> > @@ -224,6 +233,10 @@ static const struct pci_device_id ohci_pci_quirks[] = {
> >               PCI_DEVICE(PCI_VENDOR_ID_ATI, 0x4399),
> >               .driver_data = (unsigned long)ohci_quirk_amd700,
> >       },
> > +     {
> > +             PCI_DEVICE(PCI_VENDOR_ID_LOONGSON, 0x7a24),
> > +             .driver_data = (unsigned long)ohci_quirk_loongson,
> > +     },
> >       {
> >               .vendor         = PCI_VENDOR_ID_APPLE,
> >               .device         = 0x003f,
> > --
> > 2.47.1
> >