[PATCH v2] usb: dwc2: drd: fix soft connect when gadget is unconfigured

[PATCH v2] usb: dwc2: drd: fix soft connect when gadget is unconfigured

[Fabrice Gasnier]

When the gadget driver hasn't been (yet) configured, and the cable is
connected to a HOST, the SFTDISCON gets cleared unconditionally, so the
HOST tries to enumerate it.
At the host side, this can result in a stuck USB port or worse. When
getting lucky, some dmesg can be observed at the host side:
 new high-speed USB device number ...
 device descriptor read/64, error -110

Fix it in drd, by checking the enabled flag before calling
dwc2_hsotg_core_connect(). It will be called later, once configured,
by the normal flow:
- udc_bind_to_driver
 - usb_gadget_connect
   - dwc2_hsotg_pullup
     - dwc2_hsotg_core_connect

Fixes: 17f934024e84 ("usb: dwc2: override PHY input signals with usb role switch support")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
---
Changes in v2:
- Fix build error: 'struct dwc2_hsotg' has no member named 'enabled';
  as reported by the kernel test robot.
  https://lore.kernel.org/all/202202112236.AwoOTtHO-lkp@intel.com/
  Add dwc2_is_device_enabled() macro to handle this.
---
 drivers/usb/dwc2/core.h | 2 ++
 drivers/usb/dwc2/drd.c  | 6 ++++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 8a63da3..8a7751b 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -1418,6 +1418,7 @@ void dwc2_hsotg_core_connect(struct dwc2_hsotg *hsotg);
 void dwc2_hsotg_disconnect(struct dwc2_hsotg *dwc2);
 int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg, int testmode);
 #define dwc2_is_device_connected(hsotg) (hsotg->connected)
+#define dwc2_is_device_enabled(hsotg) ((hsotg)->enabled)
 int dwc2_backup_device_registers(struct dwc2_hsotg *hsotg);
 int dwc2_restore_device_registers(struct dwc2_hsotg *hsotg, int remote_wakeup);
 int dwc2_gadget_enter_hibernation(struct dwc2_hsotg *hsotg);
@@ -1454,6 +1455,7 @@ static inline int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg,
 					   int testmode)
 { return 0; }
 #define dwc2_is_device_connected(hsotg) (0)
+#define dwc2_is_device_enabled(hsotg) (0)
 static inline int dwc2_backup_device_registers(struct dwc2_hsotg *hsotg)
 { return 0; }
 static inline int dwc2_restore_device_registers(struct dwc2_hsotg *hsotg,
diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
index 1b39c47..d8d6493 100644
--- a/drivers/usb/dwc2/drd.c
+++ b/drivers/usb/dwc2/drd.c
@@ -130,8 +130,10 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
 		already = dwc2_ovr_avalid(hsotg, true);
 	} else if (role == USB_ROLE_DEVICE) {
 		already = dwc2_ovr_bvalid(hsotg, true);
-		/* This clear DCTL.SFTDISCON bit */
-		dwc2_hsotg_core_connect(hsotg);
+		if (dwc2_is_device_enabled(hsotg)) {
+			/* This clear DCTL.SFTDISCON bit */
+			dwc2_hsotg_core_connect(hsotg);
+		}
 	} else {
 		if (dwc2_is_device_mode(hsotg)) {
 			if (!dwc2_ovr_bvalid(hsotg, false))
-- 
2.7.4

Re: [PATCH v2] usb: dwc2: drd: fix soft connect when gadget is unconfigured

[Greg KH]

On Tue, Feb 15, 2022 at 12:04:19PM +0100, Fabrice Gasnier wrote:
> When the gadget driver hasn't been (yet) configured, and the cable is
> connected to a HOST, the SFTDISCON gets cleared unconditionally, so the
> HOST tries to enumerate it.
> At the host side, this can result in a stuck USB port or worse. When
> getting lucky, some dmesg can be observed at the host side:
>  new high-speed USB device number ...
>  device descriptor read/64, error -110
> 
> Fix it in drd, by checking the enabled flag before calling
> dwc2_hsotg_core_connect(). It will be called later, once configured,
> by the normal flow:
> - udc_bind_to_driver
>  - usb_gadget_connect
>    - dwc2_hsotg_pullup
>      - dwc2_hsotg_core_connect
> 
> Fixes: 17f934024e84 ("usb: dwc2: override PHY input signals with usb role switch support")
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> ---
> Changes in v2:
> - Fix build error: 'struct dwc2_hsotg' has no member named 'enabled';
>   as reported by the kernel test robot.
>   https://lore.kernel.org/all/202202112236.AwoOTtHO-lkp@intel.com/
>   Add dwc2_is_device_enabled() macro to handle this.
> ---
>  drivers/usb/dwc2/core.h | 2 ++
>  drivers/usb/dwc2/drd.c  | 6 ++++--
>  2 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
> index 8a63da3..8a7751b 100644
> --- a/drivers/usb/dwc2/core.h
> +++ b/drivers/usb/dwc2/core.h
> @@ -1418,6 +1418,7 @@ void dwc2_hsotg_core_connect(struct dwc2_hsotg *hsotg);
>  void dwc2_hsotg_disconnect(struct dwc2_hsotg *dwc2);
>  int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg, int testmode);
>  #define dwc2_is_device_connected(hsotg) (hsotg->connected)
> +#define dwc2_is_device_enabled(hsotg) ((hsotg)->enabled)

Why the extra ()?  dwc2_is_device_connected does not have it, so this
one probably should not either, right?

thanks,

greg k-h

Re: [PATCH v2] usb: dwc2: drd: fix soft connect when gadget is unconfigured

[Fabrice Gasnier]

On 2/15/22 3:04 PM, Greg KH wrote:
> On Tue, Feb 15, 2022 at 12:04:19PM +0100, Fabrice Gasnier wrote:
>> When the gadget driver hasn't been (yet) configured, and the cable is
>> connected to a HOST, the SFTDISCON gets cleared unconditionally, so the
>> HOST tries to enumerate it.
>> At the host side, this can result in a stuck USB port or worse. When
>> getting lucky, some dmesg can be observed at the host side:
>>  new high-speed USB device number ...
>>  device descriptor read/64, error -110
>>
>> Fix it in drd, by checking the enabled flag before calling
>> dwc2_hsotg_core_connect(). It will be called later, once configured,
>> by the normal flow:
>> - udc_bind_to_driver
>>  - usb_gadget_connect
>>    - dwc2_hsotg_pullup
>>      - dwc2_hsotg_core_connect
>>
>> Fixes: 17f934024e84 ("usb: dwc2: override PHY input signals with usb role switch support")
>> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
>> ---
>> Changes in v2:
>> - Fix build error: 'struct dwc2_hsotg' has no member named 'enabled';
>>   as reported by the kernel test robot.
>>   https://lore.kernel.org/all/202202112236.AwoOTtHO-lkp@intel.com/
>>   Add dwc2_is_device_enabled() macro to handle this.
>> ---
>>  drivers/usb/dwc2/core.h | 2 ++
>>  drivers/usb/dwc2/drd.c  | 6 ++++--
>>  2 files changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
>> index 8a63da3..8a7751b 100644
>> --- a/drivers/usb/dwc2/core.h
>> +++ b/drivers/usb/dwc2/core.h
>> @@ -1418,6 +1418,7 @@ void dwc2_hsotg_core_connect(struct dwc2_hsotg *hsotg);
>>  void dwc2_hsotg_disconnect(struct dwc2_hsotg *dwc2);
>>  int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg, int testmode);
>>  #define dwc2_is_device_connected(hsotg) (hsotg->connected)
>> +#define dwc2_is_device_enabled(hsotg) ((hsotg)->enabled)
> 
> Why the extra ()?  dwc2_is_device_connected does not have it, so this
> one probably should not either, right?

Hi Greg,

I was wondering the same, checkpatch complains without it:

CHECK: Macro argument 'hsotg' may be better as '(hsotg)' to avoid
precedence issues

I can remove the extra () in a v3 if you wish ?

Thanks for reviewing,
Best Regards,
Fabrice

> 
> thanks,
> 
> greg k-h
> 

Re: [PATCH v2] usb: dwc2: drd: fix soft connect when gadget is unconfigured

[Greg KH]

On Tue, Feb 15, 2022 at 04:42:46PM +0100, Fabrice Gasnier wrote:
> On 2/15/22 3:04 PM, Greg KH wrote:
> > On Tue, Feb 15, 2022 at 12:04:19PM +0100, Fabrice Gasnier wrote:
> >> When the gadget driver hasn't been (yet) configured, and the cable is
> >> connected to a HOST, the SFTDISCON gets cleared unconditionally, so the
> >> HOST tries to enumerate it.
> >> At the host side, this can result in a stuck USB port or worse. When
> >> getting lucky, some dmesg can be observed at the host side:
> >>  new high-speed USB device number ...
> >>  device descriptor read/64, error -110
> >>
> >> Fix it in drd, by checking the enabled flag before calling
> >> dwc2_hsotg_core_connect(). It will be called later, once configured,
> >> by the normal flow:
> >> - udc_bind_to_driver
> >>  - usb_gadget_connect
> >>    - dwc2_hsotg_pullup
> >>      - dwc2_hsotg_core_connect
> >>
> >> Fixes: 17f934024e84 ("usb: dwc2: override PHY input signals with usb role switch support")
> >> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> >> ---
> >> Changes in v2:
> >> - Fix build error: 'struct dwc2_hsotg' has no member named 'enabled';
> >>   as reported by the kernel test robot.
> >>   https://lore.kernel.org/all/202202112236.AwoOTtHO-lkp@intel.com/
> >>   Add dwc2_is_device_enabled() macro to handle this.
> >> ---
> >>  drivers/usb/dwc2/core.h | 2 ++
> >>  drivers/usb/dwc2/drd.c  | 6 ++++--
> >>  2 files changed, 6 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
> >> index 8a63da3..8a7751b 100644
> >> --- a/drivers/usb/dwc2/core.h
> >> +++ b/drivers/usb/dwc2/core.h
> >> @@ -1418,6 +1418,7 @@ void dwc2_hsotg_core_connect(struct dwc2_hsotg *hsotg);
> >>  void dwc2_hsotg_disconnect(struct dwc2_hsotg *dwc2);
> >>  int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg, int testmode);
> >>  #define dwc2_is_device_connected(hsotg) (hsotg->connected)
> >> +#define dwc2_is_device_enabled(hsotg) ((hsotg)->enabled)
> > 
> > Why the extra ()?  dwc2_is_device_connected does not have it, so this
> > one probably should not either, right?
> 
> Hi Greg,
> 
> I was wondering the same, checkpatch complains without it:
> 
> CHECK: Macro argument 'hsotg' may be better as '(hsotg)' to avoid
> precedence issues

checkpatch is wrong here, this is a structure pointer, not anything you
could ever use that could be evaluated any other way.

> I can remove the extra () in a v3 if you wish ?

Please do.

thanks,

greg k-h