Re: [PATCH v2 2/2] usb: dwc3: gadget: Improve dwc3_gadget_suspend() and dwc3_gadget_resume()

Thinh Nguyen
2023-05-02T21:19:34Z

On Tue, May 02, 2023, Roger Quadros wrote:
> Prevent -ETIMEDOUT error on .suspend().
> e.g. If gadget driver is loaded and we are connected to a USB host,
> all transfers must be stopped before stopping the controller else
> we will not get a clean stop i.e. dwc3_gadget_run_stop() will take
> several seconds to complete and will return -ETIMEDOUT.
>
> Handle error cases properly in dwc3_gadget_suspend().
> Simplify dwc3_gadget_resume() by using the introduced helper function.
>
> Fixes: 9f8a67b65a49 ("usb: dwc3: gadget: fix gadget suspend/resume")
> Cc: stable@vger.kernel.org
> Suggested-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
> Signed-off-by: Roger Quadros <rogerq@kernel.org>
> ---
> drivers/usb/dwc3/gadget.c | 66 +++++++++++++++++++--------------------
> 1 file changed, 33 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index b5170374cd18..869f1695565d 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -2699,6 +2699,21 @@ static int dwc3_gadget_soft_disconnect(struct dwc3 *dwc)
> return ret;
> }
>
> +static int dwc3_gadget_soft_connect(struct dwc3 *dwc)
> +{
> + /*
> + * In the Synopsys DWC_usb31 1.90a programming guide section
> + * 4.1.9, it specifies that for a reconnect after a
> + * device-initiated disconnect requires a core soft reset
> + * (DCTL.CSftRst) before enabling the run/stop bit.
> + */
> + dwc3_core_soft_reset(dwc);
> +
> + dwc3_event_buffers_setup(dwc);
> + __dwc3_gadget_start(dwc);
> + return dwc3_gadget_run_stop(dwc, true);
> +}
> +
> static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
> {
> struct dwc3 *dwc = gadget_to_dwc(g);
> @@ -2737,21 +2752,10 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
>
> synchronize_irq(dwc->irq_gadget);
>
> - if (!is_on) {
> + if (!is_on)
> ret = dwc3_gadget_soft_disconnect(dwc);
> - } else {
> - /*
> - * In the Synopsys DWC_usb31 1.90a programming guide section
> - * 4.1.9, it specifies that for a reconnect after a
> - * device-initiated disconnect requires a core soft reset
> - * (DCTL.CSftRst) before enabling the run/stop bit.
> - */
> - dwc3_core_soft_reset(dwc);
> -
> - dwc3_event_buffers_setup(dwc);
> - __dwc3_gadget_start(dwc);
> - ret = dwc3_gadget_run_stop(dwc, true);
> - }
> + else
> + ret = dwc3_gadget_soft_connect(dwc);
>
> pm_runtime_put(dwc->dev);
>
> @@ -4655,42 +4659,38 @@ void dwc3_gadget_exit(struct dwc3 *dwc)
> int dwc3_gadget_suspend(struct dwc3 *dwc)
> {
> unsigned long flags;
> + int ret;
>
> if (!dwc->gadget_driver || !dwc->softconnect)
> return 0;
>
> - dwc3_gadget_run_stop(dwc, false);
> + ret = dwc3_gadget_soft_disconnect(dwc);
> + if (ret)
> + goto err;
>
> spin_lock_irqsave(&dwc->lock, flags);
> dwc3_disconnect_gadget(dwc);
> - __dwc3_gadget_stop(dwc);
> spin_unlock_irqrestore(&dwc->lock, flags);
>
> return 0;
> +
> +err:
> + /*
> + * Attempt to reset the controller's state. Likely no
> + * communication can be established until the host
> + * performs a port reset.
> + */
> + dwc3_gadget_soft_connect(dwc);
> +
> + return ret;
> }
>
> int dwc3_gadget_resume(struct dwc3 *dwc)
> {
> - int ret;
> -
> if (!dwc->gadget_driver || !dwc->softconnect)
> return 0;
>
> - ret = __dwc3_gadget_start(dwc);
> - if (ret < 0)
> - goto err0;
> -
> - ret = dwc3_gadget_run_stop(dwc, true);
> - if (ret < 0)
> - goto err1;
> -
> - return 0;
> -
> -err1:
> - __dwc3_gadget_stop(dwc);
> -
> -err0:
> - return ret;
> + return dwc3_gadget_soft_connect(dwc);
> }
>
> void dwc3_gadget_process_pending_events(struct dwc3 *dwc)
> --
> 2.34.1
>

Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>

Thanks,
Thinh