Merge tag 'thunderbolt-for-v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt into usb-next

Mika writes:

thunderbolt: Changes for v5.12 merge window

This includes following Thunderbolt/USB4 changes for v5.12 merge
window:

  * Start lane initialization after sleep for Thunderbolt 3 compatible
    devices

  * Add support for de-authorizing PCIe tunnels (software based
    connection manager only)

  * Add support for new ACPI 6.4 USB4 _OSC

  * Allow disabling XDomain protocol

  * Add support for new SL5 security level

  * Clean up kernel-docs to pass W=1 builds

  * A couple of cleanups and minor fixes

All these have been in linux-next without reported issues.

* tag 'thunderbolt-for-v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt: (27 commits)
  thunderbolt: Add support for native USB4 _OSC
  ACPI: Add support for native USB4 control _OSC
  ACPI: Execute platform _OSC also with query bit clear
  thunderbolt: Allow disabling XDomain protocol
  thunderbolt: Add support for PCIe tunneling disabled (SL5)
  thunderbolt: dma_test: Drop unnecessary include
  thunderbolt: Add clarifying comments about USB4 terms router and adapter
  thunderbolt: switch: Fix kernel-doc descriptions of non-static functions
  thunderbolt: nhi: Fix kernel-doc descriptions of non-static functions
  thunderbolt: path: Fix kernel-doc descriptions of non-static functions
  thunderbolt: eeprom: Fix kernel-doc descriptions of non-static functions
  thunderbolt: ctl: Fix kernel-doc descriptions of non-static functions
  thunderbolt: switch: Fix function name in the header
  thunderbolt: tunnel: Fix misspelling of 'receive_path'
  thunderbolt: icm: Fix a couple of formatting issues
  thunderbolt: switch: Demote a bunch of non-conformant kernel-doc headers
  thunderbolt: tb: Kernel-doc function headers should document their parameters
  thunderbolt: nhi: Demote some non-conformant kernel-doc headers
  thunderbolt: xdomain: Fix 'tb_unregister_service_driver()'s 'drv' param
  thunderbolt: eeprom: Demote non-conformant kernel-doc headers to standard comment blocks
  ...

1 files changed, 23 insertions, 0 deletions

diff --git a/Documentation/admin-guide/thunderbolt.rst b/Documentation/admin-guide/thunderbolt.rst
index 613cb24c76c7..f18e881373c4 100644
--- a/Documentation/admin-guide/thunderbolt.rst
+++ b/Documentation/admin-guide/thunderbolt.rst
@@ -47,6 +47,9 @@ be DMA masters and thus read contents of the host memory without CPU and OS
 knowing about it. There are ways to prevent this by setting up an IOMMU but
 it is not always available for various reasons.
 
+Some USB4 systems have a BIOS setting to disable PCIe tunneling. This is
+treated as another security level (nopcie).
+
 The security levels are as follows:
 
   none
@@ -77,6 +80,10 @@ The security levels are as follows:
     Display Port in a dock. All PCIe links downstream of the dock are
     removed.
 
+  nopcie
+    PCIe tunneling is disabled/forbidden from the BIOS. Available in some
+    USB4 systems.
+
 The current security level can be read from
 ``/sys/bus/thunderbolt/devices/domainX/security`` where ``domainX`` is
 the Thunderbolt domain the host controller manages. There is typically
@@ -153,6 +160,22 @@ If the user still wants to connect the device they can either approve
 the device without a key or write a new key and write 1 to the
 ``authorized`` file to get the new key stored on the device NVM.
 
+De-authorizing devices
+----------------------
+It is possible to de-authorize devices by writing ``0`` to their
+``authorized`` attribute. This requires support from the connection
+manager implementation and can be checked by reading domain
+``deauthorization`` attribute. If it reads ``1`` then the feature is
+supported.
+
+When a device is de-authorized the PCIe tunnel from the parent device
+PCIe downstream (or root) port to the device PCIe upstream port is torn
+down. This is essentially the same thing as PCIe hot-remove and the PCIe
+toplogy in question will not be accessible anymore until the device is
+authorized again. If there is storage such as NVMe or similar involved,
+there is a risk for data loss if the filesystem on that storage is not
+properly shut down. You have been warned!
+
 DMA protection utilizing IOMMU
 ------------------------------
 Recent systems from 2018 and forward with Thunderbolt ports may natively