[PATCH] usb: gadget: ether: Handle gadget driver registration in start and stop

[Mattijs Korpershoek]

Hi Zixun,

On mer., août 07, 2024 at 08:38, Mattijs Korpershoek <mkorpershoek at baylibre.com> wrote:

> Hi,
>
> On Fri, 26 Jul 2024 10:31:00 +0200, Zixun LI wrote:
>> Revert part of 718f1d41 to move
>>  usb_gadget_register_driver()/usb_gadget_unregister_driver()
>> back to usb_eth_start()/usb_eth_stop().
>> 
>> usb_gadget_register_driver() will initialize the USB controller which
>> enters ready to connect state with pull-up resistor enabled.
>> 
>> [...]
>
> Thanks, Applied to https://source.denx.de/u-boot/custodians/u-boot-dfu (u-boot-dfu)
>
> [1/1] usb: gadget: ether: Handle gadget driver registration in start and stop
>       https://source.denx.de/u-boot/custodians/u-boot-dfu/-/commit/d94c0ee1de89e2fbd3cc5bea6351dbaa9462c84f
>
> --
> Mattijs

There has been some ongoing discussion on IRC about this patch:
https://libera.irclog.whitequark.org/u-boot/2024-08-20

Marek, who has quite some knowledge about the USB stack in U-Boot (more
than myself) suggested that using usb_ether_init() should not be used
anymore.

Instead, to enable usb ethernet, we should manually bind the UDC driver
to the usb_ether gadget.

For example, on Khadas VIM3 board, this can be done with:

=> bind /soc/usb at ffe09000/usb at ff400000 usb_ether

Use "dm tree" to find the node path for your UDC.

Then, I can enable Ethernet Gadget with:

=> setenv ethact usb_ether

And only when using it, I will see enumerations:

=> dhcp

[437548.488938] usb 1-1: New USB device found, idVendor=1b8e, idProduct=fada, bcdDevice=7e.8a
[437548.488950] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[437548.488957] usb 1-1: Product: RNDIS/Ethernet Gadget
[437548.488963] usb 1-1: Manufacturer: U-Boot
[437548.634417] usbcore: registered new interface driver cdc_ether
[437548.640519] rndis_host 1-1:2.0 usb0: register 'rndis_host' at usb-0000:00:14.0-1, RNDIS device, de:ad:be:ef:00:00
[437548.640588] usbcore: registered new interface driver rndis_host
[437548.694343] rndis_host 1-1:2.0 enp0s20f0u1c2: renamed from usb0

So, with this method, I can't reproduce the problem that this patch was
initially try to solve.

Could you please try using the bind method instead of the (deprecated)
usb_ether_init() ?