linux-kernel - Re: [PATCH v2 1/3] usb: dwc3: gadget: Refactor EP0 forced stall/restart into a separate API

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Date:   Sat, 8 Apr 2023 01:45:01 +0000
From:   Thinh Nguyen <Thinh.Nguyen@...opsys.com>
To:     Wesley Cheng <quic_wcheng@...cinc.com>
CC:     "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "quic_jackp@...cinc.com" <quic_jackp@...cinc.com>,
        "quic_ugoswami@...cinc.com" <quic_ugoswami@...cinc.com>
Subject: Re: [PATCH v2 1/3] usb: dwc3: gadget: Refactor EP0 forced
 stall/restart into a separate API

On Fri, Apr 07, 2023, Wesley Cheng wrote:
> Several sequences utilize the same routine for forcing the control endpoint
> back into the SETUP phase.  This is required, because those operations need
> to ensure that EP0 is back in the default state.
> 
> Fixes: c96683798e27 ("usb: dwc3: ep0: Don't prepare beyond Setup stage")

Refactor patch should have no functional change. Why is there fixes tag?

BR,
Thinh

> Signed-off-by: Wesley Cheng <quic_wcheng@...cinc.com>
> ---
>  drivers/usb/dwc3/gadget.c | 44 ++++++++++++++++++---------------------
>  1 file changed, 20 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 3c63fa97a680..320e30476c88 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -139,6 +139,24 @@ int dwc3_gadget_set_link_state(struct dwc3 *dwc, enum dwc3_link_state state)
>  	return -ETIMEDOUT;
>  }
>  
> +static void dwc3_ep0_reset_state(struct dwc3 *dwc)
> +{
> +	unsigned int	dir;
> +
> +	if (dwc->ep0state != EP0_SETUP_PHASE) {
> +		dir = !!dwc->ep0_expect_in;
> +		if (dwc->ep0state == EP0_DATA_PHASE)
> +			dwc3_ep0_end_control_data(dwc, dwc->eps[dir]);
> +		else
> +			dwc3_ep0_end_control_data(dwc, dwc->eps[!dir]);
> +
> +		dwc->eps[0]->trb_enqueue = 0;
> +		dwc->eps[1]->trb_enqueue = 0;
> +
> +		dwc3_ep0_stall_and_restart(dwc);
> +	}
> +}
> +
>  /**
>   * dwc3_ep_inc_trb - increment a trb index.
>   * @index: Pointer to the TRB index to increment.
> @@ -3821,16 +3839,7 @@ static void dwc3_gadget_disconnect_interrupt(struct dwc3 *dwc)
>  	dwc->setup_packet_pending = false;
>  	usb_gadget_set_state(dwc->gadget, USB_STATE_NOTATTACHED);
>  
> -	if (dwc->ep0state != EP0_SETUP_PHASE) {
> -		unsigned int    dir;
> -
> -		dir = !!dwc->ep0_expect_in;
> -		if (dwc->ep0state == EP0_DATA_PHASE)
> -			dwc3_ep0_end_control_data(dwc, dwc->eps[dir]);
> -		else
> -			dwc3_ep0_end_control_data(dwc, dwc->eps[!dir]);
> -		dwc3_ep0_stall_and_restart(dwc);
> -	}
> +	dwc3_ep0_reset_state(dwc);
>  }
>  
>  static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc)
> @@ -3884,20 +3893,7 @@ static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc)
>  	 * phase. So ensure that EP0 is in setup phase by issuing a stall
>  	 * and restart if EP0 is not in setup phase.
>  	 */
> -	if (dwc->ep0state != EP0_SETUP_PHASE) {
> -		unsigned int	dir;
> -
> -		dir = !!dwc->ep0_expect_in;
> -		if (dwc->ep0state == EP0_DATA_PHASE)
> -			dwc3_ep0_end_control_data(dwc, dwc->eps[dir]);
> -		else
> -			dwc3_ep0_end_control_data(dwc, dwc->eps[!dir]);
> -
> -		dwc->eps[0]->trb_enqueue = 0;
> -		dwc->eps[1]->trb_enqueue = 0;
> -
> -		dwc3_ep0_stall_and_restart(dwc);
> -	}
> +	dwc3_ep0_reset_state(dwc);
>  
>  	/*
>  	 * In the Synopsis DesignWare Cores USB3 Databook Rev. 3.30a