[PATCH] usb: cdns3: exit cdns3_gadget_udc_start if FAST_REG_ACCESS cannot be set

[PATCH] usb: cdns3: exit cdns3_gadget_udc_start if FAST_REG_ACCESS cannot be set

[Siddharth Vadapalli]

When the device is in a low power state, access to the following
registers takes a long time:
- EP_CFG
- EP_TRADDR
- EP_CMD
- EP_SEL
- EP_STS
- USB_CONF

To address this, the fast register access feature can be enabled by
setting PUSB_PWR_FST_REG_ACCESS bit of the USB_PWR register, which
allows quick access by software. Software is expected to poll on
PUSB_PWR_FST_REG_ACCESS_STAT to ensure that fast register access has
been enabled by the controller. Attempting to access any of the
aforementioned registers after setting PUSB_PWR_FST_REG_ACCESS but
before PUSB_PWR_FST_REG_ACCESS_STAT has been set will result in
undefined behavior and potentially result in system hang.

Hence, poll on PUSB_PWR_FST_REG_ACCESS_STAT before proceeding with
gadget configuration, and exit if it cannot be enabled.

Fixes: b5148d946f45 ("usb: cdns3: gadget: set fast access bit")
Cc: <stable@vger.kernel.org>
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
---

Hello,

This patch is based on commit
92514ef226f5 Merge tag 'for-6.14-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
of Mainline Linux.

Regards,
Siddharth.

 drivers/usb/cdns3/cdns3-gadget.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
index fd1beb10bba7..b62691944272 100644
--- a/drivers/usb/cdns3/cdns3-gadget.c
+++ b/drivers/usb/cdns3/cdns3-gadget.c
@@ -2971,8 +2971,6 @@ static void cdns3_gadget_config(struct cdns3_device *priv_dev)
 	/* enable generic interrupt*/
 	writel(USB_IEN_INIT, &regs->usb_ien);
 	writel(USB_CONF_CLK2OFFDS | USB_CONF_L1DS, &regs->usb_conf);
-	/*  keep Fast Access bit */
-	writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);
 
 	cdns3_configure_dmult(priv_dev, NULL);
 }
@@ -2990,6 +2988,8 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
 	struct cdns3_device *priv_dev = gadget_to_cdns3_device(gadget);
 	unsigned long flags;
 	enum usb_device_speed max_speed = driver->max_speed;
+	int ret;
+	u32 reg;
 
 	spin_lock_irqsave(&priv_dev->lock, flags);
 	priv_dev->gadget_driver = driver;
@@ -2997,6 +2997,20 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
 	/* limit speed if necessary */
 	max_speed = min(driver->max_speed, gadget->max_speed);
 
+	/*  keep Fast Access bit */
+	writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);
+	reg = readl(&priv_dev->regs->usb_pwr);
+	if (!(reg & PUSB_PWR_FST_REG_ACCESS_STAT)) {
+		ret = readl_poll_timeout_atomic(&priv_dev->regs->usb_pwr, reg,
+						(reg & PUSB_PWR_FST_REG_ACCESS_STAT),
+						10, 1000);
+		if (ret) {
+			dev_err(priv_dev->dev, "Failed to enable fast access\n");
+			spin_unlock_irqrestore(&priv_dev->lock, flags);
+			return ret;
+		}
+	}
+
 	switch (max_speed) {
 	case USB_SPEED_FULL:
 		writel(USB_CONF_SFORCE_FS, &priv_dev->regs->usb_conf);
-- 
2.43.0

Re: [PATCH] usb: cdns3: exit cdns3_gadget_udc_start if FAST_REG_ACCESS cannot be set

[Peter Chen]

On 25-02-06 18:29:36, Siddharth Vadapalli wrote:
> When the device is in a low power state, access to the following
> registers takes a long time:
> - EP_CFG
> - EP_TRADDR
> - EP_CMD
> - EP_SEL
> - EP_STS
> - USB_CONF
> 
> To address this, the fast register access feature can be enabled by
> setting PUSB_PWR_FST_REG_ACCESS bit of the USB_PWR register, which
> allows quick access by software. Software is expected to poll on
> PUSB_PWR_FST_REG_ACCESS_STAT to ensure that fast register access has
> been enabled by the controller. Attempting to access any of the
> aforementioned registers after setting PUSB_PWR_FST_REG_ACCESS but
> before PUSB_PWR_FST_REG_ACCESS_STAT has been set will result in
> undefined behavior and potentially result in system hang.
> 
> Hence, poll on PUSB_PWR_FST_REG_ACCESS_STAT before proceeding with
> gadget configuration, and exit if it cannot be enabled.
> 
> Fixes: b5148d946f45 ("usb: cdns3: gadget: set fast access bit")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
> ---
> 
> Hello,
> 
> This patch is based on commit
> 92514ef226f5 Merge tag 'for-6.14-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
> of Mainline Linux.
> 
> Regards,
> Siddharth.
> 
>  drivers/usb/cdns3/cdns3-gadget.c | 18 ++++++++++++++++--
>  1 file changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
> index fd1beb10bba7..b62691944272 100644
> --- a/drivers/usb/cdns3/cdns3-gadget.c
> +++ b/drivers/usb/cdns3/cdns3-gadget.c
> @@ -2971,8 +2971,6 @@ static void cdns3_gadget_config(struct cdns3_device *priv_dev)
>  	/* enable generic interrupt*/
>  	writel(USB_IEN_INIT, &regs->usb_ien);
>  	writel(USB_CONF_CLK2OFFDS | USB_CONF_L1DS, &regs->usb_conf);
> -	/*  keep Fast Access bit */
> -	writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);
>  
>  	cdns3_configure_dmult(priv_dev, NULL);
>  }
> @@ -2990,6 +2988,8 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
>  	struct cdns3_device *priv_dev = gadget_to_cdns3_device(gadget);
>  	unsigned long flags;
>  	enum usb_device_speed max_speed = driver->max_speed;
> +	int ret;
> +	u32 reg;
>  
>  	spin_lock_irqsave(&priv_dev->lock, flags);
>  	priv_dev->gadget_driver = driver;
> @@ -2997,6 +2997,20 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
>  	/* limit speed if necessary */
>  	max_speed = min(driver->max_speed, gadget->max_speed);
>  
> +	/*  keep Fast Access bit */
> +	writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);
> +	reg = readl(&priv_dev->regs->usb_pwr);
> +	if (!(reg & PUSB_PWR_FST_REG_ACCESS_STAT)) {
> +		ret = readl_poll_timeout_atomic(&priv_dev->regs->usb_pwr, reg,
> +						(reg & PUSB_PWR_FST_REG_ACCESS_STAT),
> +						10, 1000);
> +		if (ret) {
> +			dev_err(priv_dev->dev, "Failed to enable fast access\n");
> +			spin_unlock_irqrestore(&priv_dev->lock, flags);
> +			return ret;
> +		}
> +	}
> +
>  	switch (max_speed) {
>  	case USB_SPEED_FULL:
>  		writel(USB_CONF_SFORCE_FS, &priv_dev->regs->usb_conf);

Hi Siddharth,

Would you please keep this change at cdns3_gadget_config in case the
controller is power lost during the system suspend?

Peter

Re: [PATCH] usb: cdns3: exit cdns3_gadget_udc_start if FAST_REG_ACCESS cannot be set

[Siddharth Vadapalli]

On Fri, Feb 07, 2025 at 10:25:23AM +0800, Peter Chen wrote:

Hello Peter,

> On 25-02-06 18:29:36, Siddharth Vadapalli wrote:
> > When the device is in a low power state, access to the following
> > registers takes a long time:
> > - EP_CFG
> > - EP_TRADDR
> > - EP_CMD
> > - EP_SEL
> > - EP_STS
> > - USB_CONF
> > 
> > To address this, the fast register access feature can be enabled by
> > setting PUSB_PWR_FST_REG_ACCESS bit of the USB_PWR register, which
> > allows quick access by software. Software is expected to poll on
> > PUSB_PWR_FST_REG_ACCESS_STAT to ensure that fast register access has
> > been enabled by the controller. Attempting to access any of the
> > aforementioned registers after setting PUSB_PWR_FST_REG_ACCESS but
> > before PUSB_PWR_FST_REG_ACCESS_STAT has been set will result in
> > undefined behavior and potentially result in system hang.
> > 
> > Hence, poll on PUSB_PWR_FST_REG_ACCESS_STAT before proceeding with
> > gadget configuration, and exit if it cannot be enabled.
> > 
> > Fixes: b5148d946f45 ("usb: cdns3: gadget: set fast access bit")
> > Cc: <stable@vger.kernel.org>
> > Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
> > ---
> > 
> > Hello,
> > 
> > This patch is based on commit
> > 92514ef226f5 Merge tag 'for-6.14-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
> > of Mainline Linux.
> > 
> > Regards,
> > Siddharth.
> > 
> >  drivers/usb/cdns3/cdns3-gadget.c | 18 ++++++++++++++++--
> >  1 file changed, 16 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
> > index fd1beb10bba7..b62691944272 100644
> > --- a/drivers/usb/cdns3/cdns3-gadget.c
> > +++ b/drivers/usb/cdns3/cdns3-gadget.c
> > @@ -2971,8 +2971,6 @@ static void cdns3_gadget_config(struct cdns3_device *priv_dev)
> >  	/* enable generic interrupt*/
> >  	writel(USB_IEN_INIT, &regs->usb_ien);
> >  	writel(USB_CONF_CLK2OFFDS | USB_CONF_L1DS, &regs->usb_conf);
> > -	/*  keep Fast Access bit */
> > -	writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);
> >  
> >  	cdns3_configure_dmult(priv_dev, NULL);
> >  }
> > @@ -2990,6 +2988,8 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
> >  	struct cdns3_device *priv_dev = gadget_to_cdns3_device(gadget);
> >  	unsigned long flags;
> >  	enum usb_device_speed max_speed = driver->max_speed;
> > +	int ret;
> > +	u32 reg;
> >  
> >  	spin_lock_irqsave(&priv_dev->lock, flags);
> >  	priv_dev->gadget_driver = driver;
> > @@ -2997,6 +2997,20 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
> >  	/* limit speed if necessary */
> >  	max_speed = min(driver->max_speed, gadget->max_speed);
> >  
> > +	/*  keep Fast Access bit */
> > +	writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);
> > +	reg = readl(&priv_dev->regs->usb_pwr);
> > +	if (!(reg & PUSB_PWR_FST_REG_ACCESS_STAT)) {
> > +		ret = readl_poll_timeout_atomic(&priv_dev->regs->usb_pwr, reg,
> > +						(reg & PUSB_PWR_FST_REG_ACCESS_STAT),
> > +						10, 1000);
> > +		if (ret) {
> > +			dev_err(priv_dev->dev, "Failed to enable fast access\n");
> > +			spin_unlock_irqrestore(&priv_dev->lock, flags);
> > +			return ret;
> > +		}
> > +	}
> > +
> >  	switch (max_speed) {
> >  	case USB_SPEED_FULL:
> >  		writel(USB_CONF_SFORCE_FS, &priv_dev->regs->usb_conf);
> 
> Hi Siddharth,
> 
> Would you please keep this change at cdns3_gadget_config in case the
> controller is power lost during the system suspend?

I did think of that initially, but the problem with doing so is that we
are already accessing USB_CONF above in the "switch(max_speed)" section.
The PUSB_PWR_FST_REG_ACCESS bit needs to be set before accessing any of:
- EP_CFG
- EP_TRADDR
- EP_CMD
- EP_SEL
- EP_STS
- USB_CONF

Please let me know if you have an alternate suggestion to address the
above.

Regards,
Siddharth.

Re: [PATCH] usb: cdns3: exit cdns3_gadget_udc_start if FAST_REG_ACCESS cannot be set

[Peter Chen]

On 25-02-07 11:12:50, Siddharth Vadapalli wrote:
> On Fri, Feb 07, 2025 at 10:25:23AM +0800, Peter Chen wrote:
> 
> Hello Peter,
> 
> > On 25-02-06 18:29:36, Siddharth Vadapalli wrote:
> > > When the device is in a low power state, access to the following
> > > registers takes a long time:
> > > - EP_CFG
> > > - EP_TRADDR
> > > - EP_CMD
> > > - EP_SEL
> > > - EP_STS
> > > - USB_CONF
> > > 
> > > To address this, the fast register access feature can be enabled by
> > > setting PUSB_PWR_FST_REG_ACCESS bit of the USB_PWR register, which
> > > allows quick access by software. Software is expected to poll on
> > > PUSB_PWR_FST_REG_ACCESS_STAT to ensure that fast register access has
> > > been enabled by the controller. Attempting to access any of the
> > > aforementioned registers after setting PUSB_PWR_FST_REG_ACCESS but
> > > before PUSB_PWR_FST_REG_ACCESS_STAT has been set will result in
> > > undefined behavior and potentially result in system hang.
> > > 
> > > Hence, poll on PUSB_PWR_FST_REG_ACCESS_STAT before proceeding with
> > > gadget configuration, and exit if it cannot be enabled.
> > > 
> > > Fixes: b5148d946f45 ("usb: cdns3: gadget: set fast access bit")
> > > Cc: <stable@vger.kernel.org>
> > > Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
> > > ---
> > > 
> > > Hello,
> > > 
> > > This patch is based on commit
> > > 92514ef226f5 Merge tag 'for-6.14-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
> > > of Mainline Linux.
> > > 
> > > Regards,
> > > Siddharth.
> > > 
> > >  drivers/usb/cdns3/cdns3-gadget.c | 18 ++++++++++++++++--
> > >  1 file changed, 16 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
> > > index fd1beb10bba7..b62691944272 100644
> > > --- a/drivers/usb/cdns3/cdns3-gadget.c
> > > +++ b/drivers/usb/cdns3/cdns3-gadget.c
> > > @@ -2971,8 +2971,6 @@ static void cdns3_gadget_config(struct cdns3_device *priv_dev)
> > >  	/* enable generic interrupt*/
> > >  	writel(USB_IEN_INIT, &regs->usb_ien);
> > >  	writel(USB_CONF_CLK2OFFDS | USB_CONF_L1DS, &regs->usb_conf);
> > > -	/*  keep Fast Access bit */
> > > -	writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);
> > >  
> > >  	cdns3_configure_dmult(priv_dev, NULL);
> > >  }
> > > @@ -2990,6 +2988,8 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
> > >  	struct cdns3_device *priv_dev = gadget_to_cdns3_device(gadget);
> > >  	unsigned long flags;
> > >  	enum usb_device_speed max_speed = driver->max_speed;
> > > +	int ret;
> > > +	u32 reg;
> > >  
> > >  	spin_lock_irqsave(&priv_dev->lock, flags);
> > >  	priv_dev->gadget_driver = driver;
> > > @@ -2997,6 +2997,20 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
> > >  	/* limit speed if necessary */
> > >  	max_speed = min(driver->max_speed, gadget->max_speed);
> > >  
> > > +	/*  keep Fast Access bit */
> > > +	writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);
> > > +	reg = readl(&priv_dev->regs->usb_pwr);
> > > +	if (!(reg & PUSB_PWR_FST_REG_ACCESS_STAT)) {
> > > +		ret = readl_poll_timeout_atomic(&priv_dev->regs->usb_pwr, reg,
> > > +						(reg & PUSB_PWR_FST_REG_ACCESS_STAT),
> > > +						10, 1000);
> > > +		if (ret) {
> > > +			dev_err(priv_dev->dev, "Failed to enable fast access\n");
> > > +			spin_unlock_irqrestore(&priv_dev->lock, flags);
> > > +			return ret;
> > > +		}
> > > +	}
> > > +
> > >  	switch (max_speed) {
> > >  	case USB_SPEED_FULL:
> > >  		writel(USB_CONF_SFORCE_FS, &priv_dev->regs->usb_conf);
> > 
> > Hi Siddharth,
> > 
> > Would you please keep this change at cdns3_gadget_config in case the
> > controller is power lost during the system suspend?
> 
> I did think of that initially, but the problem with doing so is that we
> are already accessing USB_CONF above in the "switch(max_speed)" section.
> The PUSB_PWR_FST_REG_ACCESS bit needs to be set before accessing any of:
> - EP_CFG
> - EP_TRADDR
> - EP_CMD
> - EP_SEL
> - EP_STS
> - USB_CONF
> 
> Please let me know if you have an alternate suggestion to address the
> above.
> 

How about move cdns3_gadget_config at the beginning of function
cdns3_gadget_udc_start, and add your changes at cdns3_gadget_config?

Regards,
Peter

Re: [PATCH] usb: cdns3: exit cdns3_gadget_udc_start if FAST_REG_ACCESS cannot be set

[Siddharth Vadapalli]

On Sat, Feb 08, 2025 at 01:39:44PM +0800, Peter Chen wrote:
> On 25-02-07 11:12:50, Siddharth Vadapalli wrote:
> > On Fri, Feb 07, 2025 at 10:25:23AM +0800, Peter Chen wrote:
> > 
> > Hello Peter,
> > 
> > > On 25-02-06 18:29:36, Siddharth Vadapalli wrote:
> > > > When the device is in a low power state, access to the following
> > > > registers takes a long time:
> > > > - EP_CFG
> > > > - EP_TRADDR
> > > > - EP_CMD
> > > > - EP_SEL
> > > > - EP_STS
> > > > - USB_CONF

[...]

> > > > @@ -2997,6 +2997,20 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
> > > >  	/* limit speed if necessary */
> > > >  	max_speed = min(driver->max_speed, gadget->max_speed);
> > > >  
> > > > +	/*  keep Fast Access bit */
> > > > +	writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);
> > > > +	reg = readl(&priv_dev->regs->usb_pwr);
> > > > +	if (!(reg & PUSB_PWR_FST_REG_ACCESS_STAT)) {
> > > > +		ret = readl_poll_timeout_atomic(&priv_dev->regs->usb_pwr, reg,
> > > > +						(reg & PUSB_PWR_FST_REG_ACCESS_STAT),
> > > > +						10, 1000);
> > > > +		if (ret) {
> > > > +			dev_err(priv_dev->dev, "Failed to enable fast access\n");
> > > > +			spin_unlock_irqrestore(&priv_dev->lock, flags);
> > > > +			return ret;
> > > > +		}
> > > > +	}
> > > > +
> > > >  	switch (max_speed) {
> > > >  	case USB_SPEED_FULL:
> > > >  		writel(USB_CONF_SFORCE_FS, &priv_dev->regs->usb_conf);
> > > 
> > > Hi Siddharth,
> > > 
> > > Would you please keep this change at cdns3_gadget_config in case the
> > > controller is power lost during the system suspend?
> > 
> > I did think of that initially, but the problem with doing so is that we
> > are already accessing USB_CONF above in the "switch(max_speed)" section.
> > The PUSB_PWR_FST_REG_ACCESS bit needs to be set before accessing any of:
> > - EP_CFG
> > - EP_TRADDR
> > - EP_CMD
> > - EP_SEL
> > - EP_STS
> > - USB_CONF
> > 
> > Please let me know if you have an alternate suggestion to address the
> > above.
> > 
> 
> How about move cdns3_gadget_config at the beginning of function
> cdns3_gadget_udc_start, and add your changes at cdns3_gadget_config?

Yes, I could do that, but I will still move the following section within
cdns3_gadget_config() function to the top of that function:

	/*  keep Fast Access bit */
	writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);

Additionally, I will update cdns3_gadget_config() to return an error
code if Fast Access bit cannot be set. The diff corresponding to this is:
--------------------------------------------------------------------------------------------
diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
index fd1beb10bba7..67d8b0805ba0 100644
--- a/drivers/usb/cdns3/cdns3-gadget.c
+++ b/drivers/usb/cdns3/cdns3-gadget.c
@@ -2935,10 +2935,24 @@ static int cdns3_gadget_pullup(struct usb_gadget *gadget, int is_on)
 	return 0;
 }
 
-static void cdns3_gadget_config(struct cdns3_device *priv_dev)
+static int cdns3_gadget_config(struct cdns3_device *priv_dev)
 {
 	struct cdns3_usb_regs __iomem *regs = priv_dev->regs;
 	u32 reg;
+	int ret;
+
+	/*  keep Fast Access bit */
+	writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);
+	reg = readl(&priv_dev->regs->usb_pwr);
+	if (!(reg & PUSB_PWR_FST_REG_ACCESS_STAT)) {
+		ret = readl_poll_timeout_atomic(&priv_dev->regs->usb_pwr, reg,
+						(reg & PUSB_PWR_FST_REG_ACCESS_STAT),
+						10, 1000);
+		if (ret) {
+			dev_err(priv_dev->dev, "enabling fast access timed out\n");
+			return ret;
+		}
+	}
 
 	cdns3_ep0_config(priv_dev);
 
@@ -2971,10 +2985,10 @@ static void cdns3_gadget_config(struct cdns3_device *priv_dev)
 	/* enable generic interrupt*/
 	writel(USB_IEN_INIT, &regs->usb_ien);
 	writel(USB_CONF_CLK2OFFDS | USB_CONF_L1DS, &regs->usb_conf);
-	/*  keep Fast Access bit */
-	writel(PUSB_PWR_FST_REG_ACCESS, &priv_dev->regs->usb_pwr);
 
 	cdns3_configure_dmult(priv_dev, NULL);
+
+	return 0;
 }
 
 /**
@@ -2990,10 +3004,15 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
 	struct cdns3_device *priv_dev = gadget_to_cdns3_device(gadget);
 	unsigned long flags;
 	enum usb_device_speed max_speed = driver->max_speed;
+	int ret;
 
 	spin_lock_irqsave(&priv_dev->lock, flags);
 	priv_dev->gadget_driver = driver;
 
+	ret = cdns3_gadget_config(priv_dev);
+	if (ret)
+		return ret;
+
 	/* limit speed if necessary */
 	max_speed = min(driver->max_speed, gadget->max_speed);
 
@@ -3018,7 +3037,6 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
 		break;
 	}
 
-	cdns3_gadget_config(priv_dev);
 	spin_unlock_irqrestore(&priv_dev->lock, flags);
 	return 0;
 }
@@ -3471,11 +3489,15 @@ __must_hold(&cdns->lock)
 static int cdns3_gadget_resume(struct cdns *cdns, bool hibernated)
 {
 	struct cdns3_device *priv_dev = cdns->gadget_dev;
+	int ret;
 
 	if (!priv_dev->gadget_driver)
 		return 0;
 
-	cdns3_gadget_config(priv_dev);
+	ret = cdns3_gadget_config(priv_dev);
+	if (ret)
+		return ret;
+
 	if (hibernated)
 		writel(USB_CONF_DEVEN, &priv_dev->regs->usb_conf);
--------------------------------------------------------------------------------------------

Regards,
Siddharth.