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

Roger Quadros
2023-05-03T09:30:59Z

On 03/05/2023 00:18, Thinh Nguyen wrote:
> 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:

As we don't pick the first patch, we will need to check for dwc->softconnect
here.

I'll send a follow up patch.

>> + /*
>> + * 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

cheers,
-roger