Re: [PATCH v8 6/9] usb: dwc3: qcom: Add multiport controller support for qcom wrapper

Johan Hovold
2023-06-08T09:44:29Z

On Thu, Jun 08, 2023 at 01:25:25AM +0530, Krishna Kurapati PSSNV wrote:
> On 6/7/2023 5:14 PM, Johan Hovold wrote:
> > On Fri, May 26, 2023 at 08:55:22PM +0530, Krishna Kurapati PSSNV wrote:
> >> On 5/26/2023 8:25 AM, Bjorn Andersson wrote:
> >
> >>> We need to fix the dwc3 glue design, so that the glue and the core can
> >>> cooperate - and we have a few other use cases where this is needed (e.g.
> >>> usb_role_switch propagation to the glue code).
> >
> >> Thanks for the comments on this patch. I had some suggestions come in
> >> from the team internally:
> >>
> >> 1. To use the notifier call available in drivers/usb/core/notify.c and
> >> make sure that host mode is enabled. That way we can access dwc or xhci
> >> without any issue.
> >
> > I don't think this is a good idea and instead the callbacks should be
> > dedicated for the xhci and dwc3 drivers. A struct with callbacks can be
> > passed down to the child devices, which call back into the drivers of
> > their parents for notifications and when they need services from them
> > (e.g. during suspend or on role changes).

> While I agree with you that these notifications are to be used during
> role switch or suspend/resume, there is no restriction on using them for
> checking whether we are in host mode or not. IMO, it would be cleaner as
> we won't be dereferencing dwc driver data at all to check if we are in
> host mode or not.

I'm not sure I understand what you're saying here. Could you try to
rephrase it?

Johan