[PATCH] usb: gadget: dwc2_udc_otg: implement pullup()

[PATCH] usb: gadget: dwc2_udc_otg: implement pullup()

[Mattijs Korpershoek]

Pullup is used by the usb framework in order to do software-controlled
usb_gadget_connect() and usb_gadget_disconnect().

Implement pullup() for dwc2 using the SOFT_DISCONNECT bit in the dctl
register.

This is especially useful when a gadget disconnection is initiated but
no board_usb_cleanup() is called.

Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
---
On some boards using the dwc2 controller, like the Khadas VIM3L, whenever
usb_gadget_release() is called, the D+ and D- lines are in an unknown state.

Because of that, the host can't detect usb disconnection.

It was attempted to be be fixed with [1] but ended up doing the gadget disconnection
too early, creating issues on NXP-based boards which use uuu [2].

By implementing pullup() in the controller driver, we ensure that the disconnection will
only be done when the framework calls usb_gadget_disconnect().

[1] https://lore.kernel.org/all/20220728-reset-usb-controller-v2-1-ef7657ce78b1@baylibre.com/
[2] https://lore.kernel.org/all/20230107164807.3597020-1-dario.binacchi@amarulasolutions.com/
---
 drivers/usb/gadget/dwc2_udc_otg.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/usb/gadget/dwc2_udc_otg.c b/drivers/usb/gadget/dwc2_udc_otg.c
index 77988f78ab30..93ed9712d18a 100644
--- a/drivers/usb/gadget/dwc2_udc_otg.c
+++ b/drivers/usb/gadget/dwc2_udc_otg.c
@@ -236,6 +236,21 @@ static int udc_enable(struct dwc2_udc *dev)
 	return 0;
 }
 
+static int dwc2_gadget_pullup(struct usb_gadget *g, int is_on)
+{
+	unsigned int uTemp;
+
+	is_on = !!is_on;
+	uTemp = readl(&reg->dctl);
+	if (is_on)
+		uTemp = uTemp & ~SOFT_DISCONNECT;
+	else
+		uTemp |= SOFT_DISCONNECT;
+	writel(uTemp, &reg->dctl);
+
+	return 0;
+}
+
 #if !CONFIG_IS_ENABLED(DM_USB_GADGET)
 /*
   Register entry point for the peripheral controller driver.
@@ -805,6 +820,7 @@ static void dwc2_fifo_flush(struct usb_ep *_ep)
 }
 
 static const struct usb_gadget_ops dwc2_udc_ops = {
+	.pullup = dwc2_gadget_pullup,
 	/* current versions must always be self-powered */
 #if CONFIG_IS_ENABLED(DM_USB_GADGET)
 	.udc_start		= dwc2_gadget_start,

---
base-commit: 7b84c973b96775576dcff228d865e8570be26c82
change-id: 20230110-dwc2-pullup-5b0f5a073d6b

Best regards,
-- 
Mattijs Korpershoek <mkorpershoek@baylibre.com>

Re: [PATCH] usb: gadget: dwc2_udc_otg: implement pullup()

[Harald Seiler]

Hi,

On Tue, 2023-01-10 at 10:11 +0100, Mattijs Korpershoek wrote:
> Pullup is used by the usb framework in order to do software-controlled
> usb_gadget_connect() and usb_gadget_disconnect().
> 
> Implement pullup() for dwc2 using the SOFT_DISCONNECT bit in the dctl
> register.
> 
> This is especially useful when a gadget disconnection is initiated but
> no board_usb_cleanup() is called.
> 
> Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
> ---
> On some boards using the dwc2 controller, like the Khadas VIM3L, whenever
> usb_gadget_release() is called, the D+ and D- lines are in an unknown state.
> 
> Because of that, the host can't detect usb disconnection.
> 
> It was attempted to be be fixed with [1] but ended up doing the gadget disconnection
> too early, creating issues on NXP-based boards which use uuu [2].
> 
> By implementing pullup() in the controller driver, we ensure that the disconnection will
> only be done when the framework calls usb_gadget_disconnect().
> 
> [1] https://lore.kernel.org/all/20220728-reset-usb-controller-v2-1-ef7657ce78b1@baylibre.com/
> [2] https://lore.kernel.org/all/20230107164807.3597020-1-dario.binacchi@amarulasolutions.com/
> ---
>  drivers/usb/gadget/dwc2_udc_otg.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/usb/gadget/dwc2_udc_otg.c b/drivers/usb/gadget/dwc2_udc_otg.c
> index 77988f78ab30..93ed9712d18a 100644
> --- a/drivers/usb/gadget/dwc2_udc_otg.c
> +++ b/drivers/usb/gadget/dwc2_udc_otg.c
> @@ -236,6 +236,21 @@ static int udc_enable(struct dwc2_udc *dev)
>  	return 0;
>  }
>  
> +static int dwc2_gadget_pullup(struct usb_gadget *g, int is_on)
> +{
> +	unsigned int uTemp;

Just some minor points about style...

I think the `u32` type should be used for 32-bit registers instead.
More explicit and no room for accidentally choosing the wrong size.

Also, U-Boot and Linux don't use hungarian notation for variable names,
just call it `tmp` or even better `dctl` to be explicit.

> +
> +	is_on = !!is_on;

This is superfluous, the if condition works either way.

> +	uTemp = readl(&reg->dctl);
> +	if (is_on)
> +		uTemp = uTemp & ~SOFT_DISCONNECT;
> +	else
> +		uTemp |= SOFT_DISCONNECT;
> +	writel(uTemp, &reg->dctl);
> +
> +	return 0;
> +}
> +
>  #if !CONFIG_IS_ENABLED(DM_USB_GADGET)
>  /*
>    Register entry point for the peripheral controller driver.
> @@ -805,6 +820,7 @@ static void dwc2_fifo_flush(struct usb_ep *_ep)
>  }
>  
>  static const struct usb_gadget_ops dwc2_udc_ops = {
> +	.pullup = dwc2_gadget_pullup,
>  	/* current versions must always be self-powered */
>  #if CONFIG_IS_ENABLED(DM_USB_GADGET)
>  	.udc_start		= dwc2_gadget_start,
> 
> ---
> base-commit: 7b84c973b96775576dcff228d865e8570be26c82
> change-id: 20230110-dwc2-pullup-5b0f5a073d6b
> 
> Best regards,

Regards,

Harald

Re: [PATCH] usb: gadget: dwc2_udc_otg: implement pullup()

[Marek Vasut]

On 1/10/23 14:30, Harald Seiler wrote:
> Hi,
> 
> On Tue, 2023-01-10 at 10:11 +0100, Mattijs Korpershoek wrote:
>> Pullup is used by the usb framework in order to do software-controlled
>> usb_gadget_connect() and usb_gadget_disconnect().
>>
>> Implement pullup() for dwc2 using the SOFT_DISCONNECT bit in the dctl
>> register.
>>
>> This is especially useful when a gadget disconnection is initiated but
>> no board_usb_cleanup() is called.
>>
>> Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
>> ---
>> On some boards using the dwc2 controller, like the Khadas VIM3L, whenever
>> usb_gadget_release() is called, the D+ and D- lines are in an unknown state.
>>
>> Because of that, the host can't detect usb disconnection.
>>
>> It was attempted to be be fixed with [1] but ended up doing the gadget disconnection
>> too early, creating issues on NXP-based boards which use uuu [2].
>>
>> By implementing pullup() in the controller driver, we ensure that the disconnection will
>> only be done when the framework calls usb_gadget_disconnect().
>>
>> [1] https://lore.kernel.org/all/20220728-reset-usb-controller-v2-1-ef7657ce78b1@baylibre.com/
>> [2] https://lore.kernel.org/all/20230107164807.3597020-1-dario.binacchi@amarulasolutions.com/
>> ---
>>   drivers/usb/gadget/dwc2_udc_otg.c | 16 ++++++++++++++++
>>   1 file changed, 16 insertions(+)
>>
>> diff --git a/drivers/usb/gadget/dwc2_udc_otg.c b/drivers/usb/gadget/dwc2_udc_otg.c
>> index 77988f78ab30..93ed9712d18a 100644
>> --- a/drivers/usb/gadget/dwc2_udc_otg.c
>> +++ b/drivers/usb/gadget/dwc2_udc_otg.c
>> @@ -236,6 +236,21 @@ static int udc_enable(struct dwc2_udc *dev)
>>   	return 0;
>>   }
>>   
>> +static int dwc2_gadget_pullup(struct usb_gadget *g, int is_on)
>> +{
>> +	unsigned int uTemp;
> 
> Just some minor points about style...
> 
> I think the `u32` type should be used for 32-bit registers instead.
> More explicit and no room for accidentally choosing the wrong size.
> 
> Also, U-Boot and Linux don't use hungarian notation for variable names,
> just call it `tmp` or even better `dctl` to be explicit.
> 
>> +
>> +	is_on = !!is_on;
> 
> This is superfluous, the if condition works either way.

clrsetbits_le32() would turn the above into a oneliner.

Re: [PATCH] usb: gadget: dwc2_udc_otg: implement pullup()

[Mattijs Korpershoek]

Hi Harald,

Thank you for your review.

On Tue, Jan 10, 2023 at 14:30, Harald Seiler <hws@denx.de> wrote:

> Hi,
>
> On Tue, 2023-01-10 at 10:11 +0100, Mattijs Korpershoek wrote:
>> Pullup is used by the usb framework in order to do software-controlled
>> usb_gadget_connect() and usb_gadget_disconnect().
>> 
>> Implement pullup() for dwc2 using the SOFT_DISCONNECT bit in the dctl
>> register.
>> 
>> This is especially useful when a gadget disconnection is initiated but
>> no board_usb_cleanup() is called.
>> 
>> Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
>> ---
>> On some boards using the dwc2 controller, like the Khadas VIM3L, whenever
>> usb_gadget_release() is called, the D+ and D- lines are in an unknown state.
>> 
>> Because of that, the host can't detect usb disconnection.
>> 
>> It was attempted to be be fixed with [1] but ended up doing the gadget disconnection
>> too early, creating issues on NXP-based boards which use uuu [2].
>> 
>> By implementing pullup() in the controller driver, we ensure that the disconnection will
>> only be done when the framework calls usb_gadget_disconnect().
>> 
>> [1] https://lore.kernel.org/all/20220728-reset-usb-controller-v2-1-ef7657ce78b1@baylibre.com/
>> [2] https://lore.kernel.org/all/20230107164807.3597020-1-dario.binacchi@amarulasolutions.com/
>> ---
>>  drivers/usb/gadget/dwc2_udc_otg.c | 16 ++++++++++++++++
>>  1 file changed, 16 insertions(+)
>> 
>> diff --git a/drivers/usb/gadget/dwc2_udc_otg.c b/drivers/usb/gadget/dwc2_udc_otg.c
>> index 77988f78ab30..93ed9712d18a 100644
>> --- a/drivers/usb/gadget/dwc2_udc_otg.c
>> +++ b/drivers/usb/gadget/dwc2_udc_otg.c
>> @@ -236,6 +236,21 @@ static int udc_enable(struct dwc2_udc *dev)
>>  	return 0;
>>  }
>>  
>> +static int dwc2_gadget_pullup(struct usb_gadget *g, int is_on)
>> +{
>> +	unsigned int uTemp;
>
> Just some minor points about style...
>
> I think the `u32` type should be used for 32-bit registers instead.
> More explicit and no room for accidentally choosing the wrong size.
>
> Also, U-Boot and Linux don't use hungarian notation for variable names,
> just call it `tmp` or even better `dctl` to be explicit.

I agree with this. I actually picked up some of the code from
reconfig_usbd() where hungarian nototation is used. That's also where
the unsigned int comes from.

Sorry I did not convert it to some more Linux/U-Boot oriented style
before submitting.

>
>> +
>> +	is_on = !!is_on;
>
> This is superfluous, the if condition works either way.

Ack.

The maintainer (Marek) already picked this up in his usb tree:
https://lore.kernel.org/all/1f2c5d74-faae-42f8-5d4d-dfc08cb093aa@denx.de/

Should I send a clean-up/follow-up patch for this?


>
>> +	uTemp = readl(&reg->dctl);
>> +	if (is_on)
>> +		uTemp = uTemp & ~SOFT_DISCONNECT;
>> +	else
>> +		uTemp |= SOFT_DISCONNECT;
>> +	writel(uTemp, &reg->dctl);
>> +
>> +	return 0;
>> +}
>> +
>>  #if !CONFIG_IS_ENABLED(DM_USB_GADGET)
>>  /*
>>    Register entry point for the peripheral controller driver.
>> @@ -805,6 +820,7 @@ static void dwc2_fifo_flush(struct usb_ep *_ep)
>>  }
>>  
>>  static const struct usb_gadget_ops dwc2_udc_ops = {
>> +	.pullup = dwc2_gadget_pullup,
>>  	/* current versions must always be self-powered */
>>  #if CONFIG_IS_ENABLED(DM_USB_GADGET)
>>  	.udc_start		= dwc2_gadget_start,
>> 
>> ---
>> base-commit: 7b84c973b96775576dcff228d865e8570be26c82
>> change-id: 20230110-dwc2-pullup-5b0f5a073d6b
>> 
>> Best regards,
>
> Regards,
>
> Harald

Re: [PATCH] usb: gadget: dwc2_udc_otg: implement pullup()

[Marek Vasut]

On 1/10/23 14:39, Mattijs Korpershoek wrote:
> Hi Harald,
> 
> Thank you for your review.
> 
> On Tue, Jan 10, 2023 at 14:30, Harald Seiler <hws@denx.de> wrote:
> 
>> Hi,
>>
>> On Tue, 2023-01-10 at 10:11 +0100, Mattijs Korpershoek wrote:
>>> Pullup is used by the usb framework in order to do software-controlled
>>> usb_gadget_connect() and usb_gadget_disconnect().
>>>
>>> Implement pullup() for dwc2 using the SOFT_DISCONNECT bit in the dctl
>>> register.
>>>
>>> This is especially useful when a gadget disconnection is initiated but
>>> no board_usb_cleanup() is called.
>>>
>>> Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
>>> ---
>>> On some boards using the dwc2 controller, like the Khadas VIM3L, whenever
>>> usb_gadget_release() is called, the D+ and D- lines are in an unknown state.
>>>
>>> Because of that, the host can't detect usb disconnection.
>>>
>>> It was attempted to be be fixed with [1] but ended up doing the gadget disconnection
>>> too early, creating issues on NXP-based boards which use uuu [2].
>>>
>>> By implementing pullup() in the controller driver, we ensure that the disconnection will
>>> only be done when the framework calls usb_gadget_disconnect().
>>>
>>> [1] https://lore.kernel.org/all/20220728-reset-usb-controller-v2-1-ef7657ce78b1@baylibre.com/
>>> [2] https://lore.kernel.org/all/20230107164807.3597020-1-dario.binacchi@amarulasolutions.com/
>>> ---
>>>   drivers/usb/gadget/dwc2_udc_otg.c | 16 ++++++++++++++++
>>>   1 file changed, 16 insertions(+)
>>>
>>> diff --git a/drivers/usb/gadget/dwc2_udc_otg.c b/drivers/usb/gadget/dwc2_udc_otg.c
>>> index 77988f78ab30..93ed9712d18a 100644
>>> --- a/drivers/usb/gadget/dwc2_udc_otg.c
>>> +++ b/drivers/usb/gadget/dwc2_udc_otg.c
>>> @@ -236,6 +236,21 @@ static int udc_enable(struct dwc2_udc *dev)
>>>   	return 0;
>>>   }
>>>   
>>> +static int dwc2_gadget_pullup(struct usb_gadget *g, int is_on)
>>> +{
>>> +	unsigned int uTemp;
>>
>> Just some minor points about style...
>>
>> I think the `u32` type should be used for 32-bit registers instead.
>> More explicit and no room for accidentally choosing the wrong size.
>>
>> Also, U-Boot and Linux don't use hungarian notation for variable names,
>> just call it `tmp` or even better `dctl` to be explicit.
> 
> I agree with this. I actually picked up some of the code from
> reconfig_usbd() where hungarian nototation is used. That's also where
> the unsigned int comes from.
> 
> Sorry I did not convert it to some more Linux/U-Boot oriented style
> before submitting.
> 
>>
>>> +
>>> +	is_on = !!is_on;
>>
>> This is superfluous, the if condition works either way.
> 
> Ack.
> 
> The maintainer (Marek) already picked this up in his usb tree:
> https://lore.kernel.org/all/1f2c5d74-faae-42f8-5d4d-dfc08cb093aa@denx.de/
> 
> Should I send a clean-up/follow-up patch for this?

The maintainer already dropped it and waits for V2 :)

Re: [PATCH] usb: gadget: dwc2_udc_otg: implement pullup()

[Mattijs Korpershoek]

On Tue, Jan 10, 2023 at 14:45, Marek Vasut <marex@denx.de> wrote:

> On 1/10/23 14:39, Mattijs Korpershoek wrote:
>> Hi Harald,
>> 
>> Thank you for your review.
>> 
>> On Tue, Jan 10, 2023 at 14:30, Harald Seiler <hws@denx.de> wrote:
>> 
>>> Hi,
>>>
>>> On Tue, 2023-01-10 at 10:11 +0100, Mattijs Korpershoek wrote:
>>>> Pullup is used by the usb framework in order to do software-controlled
>>>> usb_gadget_connect() and usb_gadget_disconnect().
>>>>
>>>> Implement pullup() for dwc2 using the SOFT_DISCONNECT bit in the dctl
>>>> register.
>>>>
>>>> This is especially useful when a gadget disconnection is initiated but
>>>> no board_usb_cleanup() is called.
>>>>
>>>> Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
>>>> ---
>>>> On some boards using the dwc2 controller, like the Khadas VIM3L, whenever
>>>> usb_gadget_release() is called, the D+ and D- lines are in an unknown state.
>>>>
>>>> Because of that, the host can't detect usb disconnection.
>>>>
>>>> It was attempted to be be fixed with [1] but ended up doing the gadget disconnection
>>>> too early, creating issues on NXP-based boards which use uuu [2].
>>>>
>>>> By implementing pullup() in the controller driver, we ensure that the disconnection will
>>>> only be done when the framework calls usb_gadget_disconnect().
>>>>
>>>> [1] https://lore.kernel.org/all/20220728-reset-usb-controller-v2-1-ef7657ce78b1@baylibre.com/
>>>> [2] https://lore.kernel.org/all/20230107164807.3597020-1-dario.binacchi@amarulasolutions.com/
>>>> ---
>>>>   drivers/usb/gadget/dwc2_udc_otg.c | 16 ++++++++++++++++
>>>>   1 file changed, 16 insertions(+)
>>>>
>>>> diff --git a/drivers/usb/gadget/dwc2_udc_otg.c b/drivers/usb/gadget/dwc2_udc_otg.c
>>>> index 77988f78ab30..93ed9712d18a 100644
>>>> --- a/drivers/usb/gadget/dwc2_udc_otg.c
>>>> +++ b/drivers/usb/gadget/dwc2_udc_otg.c
>>>> @@ -236,6 +236,21 @@ static int udc_enable(struct dwc2_udc *dev)
>>>>   	return 0;
>>>>   }
>>>>   
>>>> +static int dwc2_gadget_pullup(struct usb_gadget *g, int is_on)
>>>> +{
>>>> +	unsigned int uTemp;
>>>
>>> Just some minor points about style...
>>>
>>> I think the `u32` type should be used for 32-bit registers instead.
>>> More explicit and no room for accidentally choosing the wrong size.
>>>
>>> Also, U-Boot and Linux don't use hungarian notation for variable names,
>>> just call it `tmp` or even better `dctl` to be explicit.
>> 
>> I agree with this. I actually picked up some of the code from
>> reconfig_usbd() where hungarian nototation is used. That's also where
>> the unsigned int comes from.
>> 
>> Sorry I did not convert it to some more Linux/U-Boot oriented style
>> before submitting.
>> 
>>>
>>>> +
>>>> +	is_on = !!is_on;
>>>
>>> This is superfluous, the if condition works either way.
>> 
>> Ack.
>> 
>> The maintainer (Marek) already picked this up in his usb tree:
>> https://lore.kernel.org/all/1f2c5d74-faae-42f8-5d4d-dfc08cb093aa@denx.de/
>> 
>> Should I send a clean-up/follow-up patch for this?
>
> The maintainer already dropped it and waits for V2 :)

Thank you, will send a V2 shortly.