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| author | Rajmohan Mani <rajmohan.mani@intel.com> | 2021-04-01 18:42:38 +0300 |
|---|---|---|
| committer | Mika Westerberg <mika.westerberg@linux.intel.com> | 2021-06-01 10:53:31 +0300 |
| commit | 3fb10ea4ce86d4d06622be894099c59872e92c57 (patch) | |
| tree | 9fbeb49811791a1a415272603300868a78a65102 /Documentation/ABI | |
| parent | 3406de7cc20f254010f2f17450a58541fb77ffea (diff) | |
| download | linux-3fb10ea4ce86d4d06622be894099c59872e92c57.tar.bz2 | |
thunderbolt: Add support for retimer NVM upgrade when there is no link
With help from platform firmware (ACPI) it is possible to power on
retimers even when there is no USB4 link (e.g nothing is connected to
the USB4 ports). This allows us to bring the USB4 sideband up so that we
can access retimers and upgrade their NVM firmware.
If the platform has support for this, we expose two additional
attributes under USB4 ports: offline and rescan. These can be used to
bring the port offline, rescan for the retimers and put the port online
again. The retimer NVM upgrade itself works the same way than with cable
connected.
Signed-off-by: Rajmohan Mani <rajmohan.mani@intel.com>
Co-developed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-thunderbolt | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-thunderbolt b/Documentation/ABI/testing/sysfs-bus-thunderbolt index 3537ba1ba892..f6743dc33aac 100644 --- a/Documentation/ABI/testing/sysfs-bus-thunderbolt +++ b/Documentation/ABI/testing/sysfs-bus-thunderbolt @@ -297,6 +297,32 @@ Contact: Mika Westerberg <mika.westerberg@linux.intel.com> Description: Returns the current link mode. Possible values are "usb4", "tbt" and "none". +What: /sys/bus/thunderbolt/devices/usb4_portX/offline +Date: Sep 2021 +KernelVersion: v5.14 +Contact: Rajmohan Mani <rajmohan.mani@intel.com> +Description: Writing 1 to this attribute puts the USB4 port into + offline mode. Only allowed when there is nothing + connected to the port (link attribute returns "none"). + Once the port is in offline mode it does not receive any + hotplug events. This is used to update NVM firmware of + on-board retimers. Writing 0 puts the port back to + online mode. + + This attribute is only visible if the platform supports + powering on retimers when there is no cable connected. + +What: /sys/bus/thunderbolt/devices/usb4_portX/rescan +Date: Sep 2021 +KernelVersion: v5.14 +Contact: Rajmohan Mani <rajmohan.mani@intel.com> +Description: When the USB4 port is in offline mode writing 1 to this + attribute forces rescan of the sideband for on-board + retimers. Each retimer appear under the USB4 port as if + the USB4 link was up. These retimers act in the same way + as if the cable was connected so upgrading their NVM + firmware can be done the usual way. + What: /sys/bus/thunderbolt/devices/<device>:<port>.<index>/device Date: Oct 2020 KernelVersion: v5.9 |