Elkhart Lake/x6000E USB device mode

[patstew]

Can you dynamically switch an atom x6000E into USB device (XDCI) mode? For the Apollo Lake ones there's a documented "DEVICE MODE CONTROL REG 0 (DUAL_ROLE_CFG_REG0)" register with the relevant controls in, which is supported by Linux, but for the Elkhart Lake ones there doesn't seem to be any equivalent in the datasheet.

We're also having trouble getting the device mode to work at superspeed. We can get it into device mode by forcing the relevant high speed port to device mode in the BIOS, but forcing the superspeed ports, with or without the high speed port forced, doesn't seem to actually work at superspeed in Linux.

[Diego_INTEL]

Hello @patstew,

Thank you for contacting Intel Embedded Community.

In Apollo Lake there is 1x USB Dual Role.

In Elkhart Lake we have: USB3.x ->Ports 4 (2x dedicated port[1x Dual Role], 2x multiplexed with PCIe* 3.0)

There are 4 ports that supports USB 3.x plus the USB 2.0 ports.

You may check the document #601458 - EDS Vol 1 - Section 11 and document #614109 - EDS Vol 2 - Sections 17-18.

Best regards,

@Diego_INTEL 

[patstew]

Thanks. Unfortunately I'm not currently able to access those documents, as far as I know they're only available for 'Developer Zone Premier' and last time I tried to sign up to that I was unable to. I've tried again.

As far as I can see from the documentation I do have access to the USB 3 should be "Dual Role Configurable on any one port" - but how do I configure which one it is? For USB 2.0 configuring exactly one port as device mode in the BIOS seemed to work, but the same trick isn't working for USB 3.0.

[Diego_INTEL]

Hello @patstew,

For USB 3.0 it requires some specific changes.

Document #632931 -  Enable USB OTG Device Mode by USB Type-C Architecture on COM Express/Qseven /SMARC Design, may be of help too, but yes, you will need a Premier account, my apologies for the inconvenience.

Best regards,

@Diego_INTEL