Re: [PATCH v2 1/2] usb: dwc3: gadget: Bail out in pullup if soft reset timeout happens

[Krishna Kurapati PSSNV]

On 3/29/2023 2:50 AM, Thinh Nguyen wrote:
> Hi,
>
> On Tue, Mar 28, 2023, Krishna Kurapati wrote:
> > If the core soft reset timeout happens, avoid setting up event
> > buffers and starting gadget as the writes to these registers
> > may not reflect when in reset and setting the run stop bit
> > can lead the controller to access wrong event buffer address
> > resulting in a crash.
> >
> > Signed-off-by: Krishna Kurapati <quic_kriskura@xxxxxxxxxxx>
> > ---
> >   drivers/usb/dwc3/gadget.c | 5 ++++-
> >   1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> > index 3c63fa97a680..f0472801d9a5 100644
> > --- a/drivers/usb/dwc3/gadget.c
> > +++ b/drivers/usb/dwc3/gadget.c
> > @@ -2620,13 +2620,16 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
> >   		 * device-initiated disconnect requires a core soft reset
> >   		 * (DCTL.CSftRst) before enabling the run/stop bit.
> >   		 */
> > -		dwc3_core_soft_reset(dwc);
> > +		ret = dwc3_core_soft_reset(dwc);
> > +		if (ret)
> > +			goto done;
> >   
> >   		dwc3_event_buffers_setup(dwc);
> >   		__dwc3_gadget_start(dwc);
> >   		ret = dwc3_gadget_run_stop(dwc, true, false);
> >   	}
> >   
> > +done:
> >   	pm_runtime_put(dwc->dev);
> >   
> >   	return ret;
> > --
> > 2.40.0
>
> I think there's one more place that may needs this check. Can you also
> add this check in __dwc3_set_mode()?

Hi Thinh,

  Sure. Will do it.
Will the below be good enough ? Or would it be good to add an error/warn 
log there>

kriskura@hu-kriskura-hyd:/local/mnt/workspace/krishna/skales2/skales/kernel$ 
git diff drivers/usb/
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 476b63618511..8d1d213d1dcd 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -210,7 +210,9 @@ static void __dwc3_set_mode(struct work_struct *work)
                }
                break;
        case DWC3_GCTL_PRTCAP_DEVICE:
-               dwc3_core_soft_reset(dwc);
+               ret = dwc3_core_soft_reset(dwc);
+               if (ret)
+                       goto out;

                dwc3_event_buffers_setup(dwc);

Regards,
Krishna,