[PATCH v2 0/2] usb: dwc3: gadget: Improve dwc3_gadget_suspend/resume

[PATCH v2 0/2] usb: dwc3: gadget: Improve dwc3_gadget_suspend/resume

[Roger Quadros]

Hi,

This series improves suspend/resume handling
- check for error condition .suspend
- avoid Timeout error and delay in .suspend

Changelog:
v2:
- rebase on greg/usb-next
- split into 2 patches. Add Fixes tag and cc stable.
- do not check for !softconnect in error condition in dwc3_gadget_suspend()

Roger Quadros (2):
  usb: dwc3: gadget: Avoid controller stop in .suspend if !softconnect
  usb: dwc3: gadget: Improve dwc3_gadget_suspend() and
    dwc3_gadget_resume()

 drivers/usb/dwc3/gadget.c | 68 +++++++++++++++++++--------------------
 1 file changed, 34 insertions(+), 34 deletions(-)

-- 
2.34.1

[PATCH v2 1/2] usb: dwc3: gadget: Avoid controller stop in .suspend if !softconnect

[Roger Quadros]

If softconnect is not set it means the controller has not started,
so no point in stopping it in dwc3_gadget_suspend()

Cc: stable@vger.kernel.org # 5.16
Fixes: 8217f07a5023 ("usb: dwc3: gadget: Avoid starting DWC3 gadget during UDC unbind")
Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/usb/dwc3/gadget.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index c0ca4d12f95d..b5170374cd18 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -4656,7 +4656,7 @@ int dwc3_gadget_suspend(struct dwc3 *dwc)
 {
 	unsigned long flags;
 
-	if (!dwc->gadget_driver)
+	if (!dwc->gadget_driver || !dwc->softconnect)
 		return 0;
 
 	dwc3_gadget_run_stop(dwc, false);
-- 
2.34.1

Re: [PATCH v2 1/2] usb: dwc3: gadget: Avoid controller stop in .suspend if !softconnect

[Thinh Nguyen]

On Tue, May 02, 2023, Roger Quadros wrote:
> If softconnect is not set it means the controller has not started,
> so no point in stopping it in dwc3_gadget_suspend()
> 
> Cc: stable@vger.kernel.org # 5.16
> Fixes: 8217f07a5023 ("usb: dwc3: gadget: Avoid starting DWC3 gadget during UDC unbind")

If the reason for this patch is as mentioned in the commit message, then
I don't think this is a fix patch that needs to be backported to stable.
The reason why we needed to check both dwc->gadget_driver and
dwc->softconnect is because of a potential race between resume and
unbind. Would there be a similar case in dwc_gadget_suspend where a
potential race may occur? If not, I don't think we need this patch.

Thanks,
Thinh

> Signed-off-by: Roger Quadros <rogerq@kernel.org>
> ---
>  drivers/usb/dwc3/gadget.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index c0ca4d12f95d..b5170374cd18 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -4656,7 +4656,7 @@ int dwc3_gadget_suspend(struct dwc3 *dwc)
>  {
>  	unsigned long flags;
>  
> -	if (!dwc->gadget_driver)
> +	if (!dwc->gadget_driver || !dwc->softconnect)
>  		return 0;
>  
>  	dwc3_gadget_run_stop(dwc, false);
> -- 
> 2.34.1
> 

Re: [PATCH v2 1/2] usb: dwc3: gadget: Avoid controller stop in .suspend if !softconnect

[Roger Quadros]

On 03/05/2023 00:17, Thinh Nguyen wrote:
> On Tue, May 02, 2023, Roger Quadros wrote:
>> If softconnect is not set it means the controller has not started,
>> so no point in stopping it in dwc3_gadget_suspend()
>>
>> Cc: stable@vger.kernel.org # 5.16
>> Fixes: 8217f07a5023 ("usb: dwc3: gadget: Avoid starting DWC3 gadget during UDC unbind")
> 
> If the reason for this patch is as mentioned in the commit message, then
> I don't think this is a fix patch that needs to be backported to stable.
> The reason why we needed to check both dwc->gadget_driver and
> dwc->softconnect is because of a potential race between resume and
> unbind. Would there be a similar case in dwc_gadget_suspend where a
> potential race may occur? If not, I don't think we need this patch.

OK. I agree.

> 
> Thanks,
> Thinh
> 
>> Signed-off-by: Roger Quadros <rogerq@kernel.org>
>> ---
>>  drivers/usb/dwc3/gadget.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
>> index c0ca4d12f95d..b5170374cd18 100644
>> --- a/drivers/usb/dwc3/gadget.c
>> +++ b/drivers/usb/dwc3/gadget.c
>> @@ -4656,7 +4656,7 @@ int dwc3_gadget_suspend(struct dwc3 *dwc)
>>  {
>>  	unsigned long flags;
>>  
>> -	if (!dwc->gadget_driver)
>> +	if (!dwc->gadget_driver || !dwc->softconnect)
>>  		return 0;
>>  
>>  	dwc3_gadget_run_stop(dwc, false);
>> -- 
>> 2.34.1

cheers,
-roger

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

[Roger Quadros]

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

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

[Thinh Nguyen]

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

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

[Roger Quadros]

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