[PATCH v3 0/4] DWC3 link tunneling state reporting

[Konrad Dybcio]

Currently, retrieving the tunneled/native state of a running port is
only possible on Intel XHCI hosts. This series extends that to CIO-
capable DWC31 controllers (see [1]).

Note that this patchset only results in the correct udev->tunnel_mode
value being assigned. Creating the device links (which requires this
information) between the USB4 router and the USB3 controller does not
currently take place on DT-based platforms, but that will be amended
in a follow-up patchset.

Tested on a Qualcomm X1E80100 CRD board, with a (currently) out-of-tree
set of drivers.

[1] I'm not entirely sure about the DWC version range (particularly
    wrt DWC32 and newer), so I limited it to a reasonable subset. I'll
    happily amend that.

Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>
---
Changes in v3:
- Report USB_LINK_UNKNOWN instead of NATIVE if the DWC3 controller
  seems not to support USB4
- Cache the capability of reporting tunneling mode instead of checking
  it every single time
- Link to v2: https://patch.msgid.link/20260715-topic-dwc3_tunneling_state-v2-0-026487a08119@xxxxxxxxxxxxxxxx

Changes in v2:
- Add handling for XHCI v1.2's USB3 tunneling and PORTSC.TM for
  platforms that advertise it (!!! UNTESTED !!!, I have no access to
  HW that exposes this)
- Prefer the aforementioned cap over custom implementations
- Bail out of the DWC3-specific check if `usb4-host-interface` device
  property is absent - hence this now depends on:
  https://github.com/devicetree-org/dt-schema/pull/196

- Link to v1: https://patch.msgid.link/20260505-topic-dwc3_tunneling_state-v1-0-4aaa6c3c14cb@xxxxxxxxxxxxxxxx

---
Konrad Dybcio (4):
      usb: xhci: debugfs: Expose the USB3 tunneling ext_cap register value
      usb: xhci: Honor PORTSC.TM if valid
      usb: xhci: Allow custom op for usb_link_tunnel_mode reporting
      usb: dwc3: Notify XHCI core of tunneled status

 drivers/usb/dwc3/core.c          | 16 ++++++++++++++++
 drivers/usb/dwc3/core.h          | 18 ++++++++++++++++++
 drivers/usb/dwc3/host.c          | 12 ++++++++++++
 drivers/usb/host/xhci-debugfs.c  |  9 +++++++++
 drivers/usb/host/xhci-debugfs.h  |  2 ++
 drivers/usb/host/xhci-ext-caps.h |  4 ++++
 drivers/usb/host/xhci-hub.c      | 24 +++++++++++++++++++-----
 drivers/usb/host/xhci-plat.c     |  2 ++
 drivers/usb/host/xhci-plat.h     |  1 +
 drivers/usb/host/xhci-port.h     |  3 ++-
 drivers/usb/host/xhci.c          | 11 ++++++++++-
 drivers/usb/host/xhci.h          |  6 +++++-
 12 files changed, 100 insertions(+), 8 deletions(-)
---
base-commit: 89c07d98716a13454ec3fd9f97689e812cc71bd4
change-id: 20260504-topic-dwc3_tunneling_state-50588c0e1ae3

Best regards,
--  
Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>