Re: [RFC PATCH 1/2] usb: ehci: Add option to override ehci_readl()/ehci_writel()

From: Alan Stern

Date: Mon Jul 13 2026 - 12:20:19 EST


On Tue, Jul 14, 2026 at 12:07:11AM +0900, Daniel Palmer wrote:
> Hi Alan,
>
> On Mon, 13 Jul 2026 at 23:46, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> >
> > On Mon, Jul 13, 2026 at 11:37:19PM +0900, Daniel Palmer wrote:
> > > Hi Alan,
> > >
> > > On Mon, 13 Jul 2026 at 23:21, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> > > > > +config HAVE_BROKEN_EHCI_HCD
> > > > > + bool
> > > >
> > > > That is not a good choice of name; it's far too generic. EHCI
> > > > controllers can be broken in so many different ways...
> > > >
> > > > How about USB_EHCI_MMIO_OVERRIDES instead?
> > >
> > > Noted. Based on that we'd have a config for each piece that needs to
> > > be overridden so drivers can pick the ones they need?
> >
> > Maybe. What other things will need to be overridden? It's hard to tell
> > what you're planning from just a single sample.
>
> For the fotg210 at least the location of the port status register
> needs to be overridden, it doesn't support sITDs so that has to be
> blocked, and the hardware has a bug where the length of ITDs is broken
> so it needs to have a workaround to write the value it wants.

Okay. I think it makes sense to have a separate CONFIG flag for each of
these.

Alan Stern