Re: [RFC v4 2/5] usb: dwc3: core: Refactor PHY logic to support Multiport Controller

From: Thinh Nguyen
Date: Wed Jan 25 2023 - 17:28:37 EST


On Wed, Jan 25, 2023, Jack Pham wrote:
> On Wed, Jan 25, 2023 at 07:08:10PM +0000, Thinh Nguyen wrote:
>
> <snip>
>
> > > + /*
> > > + * If the controller is not host-only, then it must be a
> > > + * single port controller.
> > > + */
>
> Thinh, is this a correct assumption? Is it possible for the IP to be
> synthesized to support both dual-role and multiple ports? We know that
> when operating in device mode only the first port can be used but the
> additional ports would be usable when in host.
>

Yes. Maybe we should rephrase it a bit. Perhaps something like this:
"Currently, only host mode supports multi-port"

In case this may change in the future.

BR,
Thinh


>
> > > + temp = readl(regs + DWC3_GHWPARAMS0);
> > > + hw_mode = DWC3_GHWPARAMS0_MODE(temp);
> > > + if (hw_mode != DWC3_GHWPARAMS0_MODE_HOST) {
> > > + dwc->num_ports = 1;
> > > + dwc->num_ss_ports = 1;
> > > + return 0;
> > > + }
> >
> > This check should be done before we get into this function.