imx8mm USB Mass Storage fails through a HUB

[Marcel Ziswiler]

Hi Tim

On Thu, 2023-02-09 at 11:58 -0800, Tim Harvey wrote:
> Greetings,
> 
> I'm finding that USB Mass Storage devices appear to fail detection on
> imx8mm when hanging off a USB hub whereas other devices such as USB
> ethernet work fine.
> 
> u-boot=> usb start && usb tree
> starting USB...
> Bus usb at 32e40000: Bus usb at 32e50000: USB EHCI 1.00
> scanning bus usb at 32e40000 for devices... 1 USB Device(s) found
> scanning bus usb at 32e50000 for devices... cannot reset port 3!?
> 3 USB Device(s) found
>        scanning usb for storage devices... 0 Storage Device(s) found
> USB device tree:
>   1  Hub (480 Mb/s, 0mA)
>      u-boot EHCI Host Controller
> 
>   1  Hub (480 Mb/s, 0mA)
>   |  u-boot EHCI Host Controller
>   |
>   +-2  Hub (480 Mb/s, 0mA)
>     |  Microchip Tech USB2744
>     |
>     +-3  Vendor specific (480 Mb/s, 0mA)
>          Microchip Tech Hub Controller
> 
> Depending on the board and port sometimes I see the 'cannot reset
> port' issue calling out the port of the hub and sometimes I see a
> 'EHCI timed out on TD - token=0x80008c80 unable to get device
> descriptor (error=-1)' error.
> 
> I have several imx8m{m,n,p}-venice boards with onboard hubs I noticed
> this with but you can re-create this on an imx8mm-evk if you attach a
> HUB with a USB Mass Storage Device to the front-panel USB Type-C
> connector after manually enabling VBUS (due to the lack of a PTN5110
> driver that would handle source/sink detection on that port):
> i2c dev 1 && i2c mw 0x50 0x23 0x77 1 # COMMAND: SRC_VBUS_HIGH
> usb start && usb tree
> 
> So far I've tried without success:
> - setenv usb_pgood_delay 5000
> - CONFIG_USB_ONBOARD_HUB=y
> 
> Any ideas on this?

Strange, I do not recall any such generic issue on our Verdin iMX8M Mini. This is with today's latest master
built for verdin-imx8mm:

Verdin iMX8MM # usb start && usb tree
starting USB...
Bus usb at 32e40000: Bus usb at 32e50000: USB EHCI 1.00
scanning bus usb at 32e40000 for devices... 1 USB Device(s) found
scanning bus usb at 32e50000 for devices... 5 USB Device(s) found
       scanning usb for storage devices... 1 Storage Device(s) found
USB device tree:
  1  Hub (480 Mb/s, 0mA)
     u-boot EHCI Host Controller 
   
  1  Hub (480 Mb/s, 0mA)
  |  u-boot EHCI Host Controller 
  |
  +-2  Hub (480 Mb/s, 0mA)
    |  Microchip Tech USB2744 
    |
    +-3  Vendor specific (480 Mb/s, 0mA)
    |    Microchip Tech Hub Controller 
    |  
    +-4  Human Interface (12 Mb/s, 98mA)
    |    Logitech USB Receiver 
    |  
    +-5  Mass Storage (480 Mb/s, 100mA)
         General  UDisk            ?

The second USB port has a on-carrier USB hub both on Dahlia as well as the Verdin Development board.

Sorry, that I do not have any good suggestion other than maybe comparing with our configuration/design.

> Best Regards,
> 
> Tim

Cheers

Marcel