[PATCH v5 0/2] arm: dts: rockchip: rk3399: usb: ehci: Fix EHCI probe in rk3399 to access peripherals by USB 2.

[Christoph Fritz]

>    Changes:
> 
>    v5: fixes a bug that Christoph Fritz discovered, consisting in the
>        wrong eror code returned when enabling or disabling the clock
>        because property_enable() returns an error code in linux but
>        the modified register value in U-Boot. This caused the clk
>        disable to abort before freeing the clock and it apparently
>        left things bad enough to cause a hang or a reset.
> 

With your patches ontop of v2023.04-rc2, xhci works now fine on a
rk3399 board:

=> usb start
starting USB...
Bus usb at fe380000: USB EHCI 1.00
Bus usb at fe3c0000: USB EHCI 1.00
Bus usb at fe800000: Register 2000140 NbrPorts 2
Starting the controller
USB XHCI 1.10
Bus usb at fe900000: Register 2000140 NbrPorts 2
Starting the controller
USB XHCI 1.10
scanning bus usb at fe380000 for devices... 4 USB Device(s) found
scanning bus usb at fe3c0000 for devices... 1 USB Device(s) found
scanning bus usb at fe800000 for devices... 3 USB Device(s) found
scanning bus usb at fe900000 for devices... 1 USB Device(s) found
       scanning usb for storage devices... 0 Storage Device(s) found

Totally unrelated to your patches, stopping usb still crashes (with or
without your patch) but only when a USB-Ethernet-Dongle (+HUB) is
connected:

=> usb start
starting USB...
do_usb_start, 581
Bus usb at fe380000: USB EHCI 1.00
Bus usb at fe3c0000: USB EHCI 1.00
Bus usb at fe800000: Register 2000140 NbrPorts 2
Starting the controller
USB XHCI 1.10
Bus usb at fe900000: Register 2000140 NbrPorts 2
Starting the controller
USB XHCI 1.10
scanning bus usb at fe380000 for devices... 3 USB Device(s) found
scanning bus usb at fe3c0000 for devices... 1 USB Device(s) found
scanning bus usb at fe800000 for devices... 1 USB Device(s) found
scanning bus usb at fe900000 for devices... 1 USB Device(s) found
       scanning usb for storage devices... 0 Storage Device(s) found
=> usb tree
USB device tree:
  1  Hub (480 Mb/s, 0mA)
  |  u-boot EHCI Host Controller
  |
  +-2  Hub (480 Mb/s, 100mA)
    |   USB2.0 Hub
    |
    +-3  Human Interface (12 Mb/s, 400mA)
         ILITEK ILITEK-TP

  1  Hub (480 Mb/s, 0mA)
     u-boot EHCI Host Controller

  1  Hub (5 Gb/s, 0mA)
     U-Boot XHCI Host Controller

  1  Hub (5 Gb/s, 0mA)
     U-Boot XHCI Host Controller

=> usb stop
stopping USB..
=> usb start
starting USB...
Bus usb at fe380000: USB EHCI 1.00
Bus usb at fe3c0000: USB EHCI 1.00
Bus usb at fe800000: Register 2000140 NbrPorts 2
Starting the controller
USB XHCI 1.10
Bus usb at fe900000: Register 2000140 NbrPorts 2
Starting the controller
USB XHCI 1.10
scanning bus usb at fe380000 for devices... 4 USB Device(s) found
scanning bus usb at fe3c0000 for devices... 1 USB Device(s) found
scanning bus usb at fe800000 for devices... 3 USB Device(s) found
scanning bus usb at fe900000 for devices... 1 USB Device(s) found
       scanning usb for storage devices... 0 Storage Device(s) found
=> usb tree
USB device tree:
  1  Hub (480 Mb/s, 0mA)
  |  u-boot EHCI Host Controller
  |
  +-2  Hub (480 Mb/s, 100mA)
    |   USB2.0 Hub
    |
    +-3  Hub (480 Mb/s, 0mA)
    |    VIA Labs, Inc.          USB2.0 Hub
    |
    +-4  Human Interface (12 Mb/s, 400mA)
         ILITEK ILITEK-TP

  1  Hub (480 Mb/s, 0mA)
     u-boot EHCI Host Controller

  1  Hub (5 Gb/s, 0mA)
  |  U-Boot XHCI Host Controller
  |
  +-2  Hub (5 Gb/s, 0mA)
    |  VIA Labs, Inc.          USB3.0 Hub
    |
    +-3  Vendor specific (5 Gb/s, 36mA)
         Realtek USB 10/100/1000 LAN 00E04C68034E

  1  Hub (5 Gb/s, 0mA)
     U-Boot XHCI Host Controller

=> usb stop
stopping USB..
<hangs here forever>

I just quirked/masked the underlying issue by not doing usb_stop() at
all in drivers/usb/host/usb-uclass.c.