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

[Thinh Nguyen]

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()?

Thanks,
Thinh