xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

thunderbolt: Add support for XDomain discovery protocol

Browse Source 
When two hosts are connected over a Thunderbolt cable, there is a
protocol they can use to communicate capabilities supported by the host.
The discovery protocol uses automatically configured control channel
(ring 0) and is build on top of request/response transactions using
special XDomain primitives provided by the Thunderbolt base protocol.

The capabilities consists of a root directory block of basic properties
used for identification of the host, and then there can be zero or more
directories each describing a Thunderbolt service and its capabilities.

Once both sides have discovered what is supported the two hosts can
setup high-speed DMA paths and transfer data to the other side using
whatever protocol was agreed based on the properties. The software
protocol used to communicate which DMA paths to enable is service
specific.

This patch adds support for the XDomain discovery protocol to the
Thunderbolt bus. We model each remote host connection as a Linux XDomain
device. For each Thunderbolt service found supported on the XDomain
device, we create Linux Thunderbolt service device which Thunderbolt
service drivers can then bind to based on the protocol identification
information retrieved from the property directory describing the
service.

This code is based on the work done by Amir Levy and Michael Jamet.

Signed-off-by: Michael Jamet <michael.jamet@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Mika Westerberg
2017-10-02 13:38:34 +03:00
committed by David S. Miller
parent e69b71f845
commit d1ff70241a
15 changed files with 2507 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

48
Documentation/ABI/testing/sysfs-bus-thunderbolt
View File

@@ -110,3 +110,51 @@ Description: When new NVM image is written to the non-active NVM
is directly the status value from the DMA configuration
based mailbox before the device is power cycled. Writing
0 here clears the status.
What: /sys/bus/thunderbolt/devices/<xdomain>.<service>/key
Date: Jan 2018
KernelVersion: 4.15
Contact: thunderbolt-software@lists.01.org
Description: This contains name of the property directory the XDomain
service exposes. This entry describes the protocol in
question. Following directories are already reserved by
the Apple XDomain specification:
network: IP/ethernet over Thunderbolt
targetdm: Target disk mode protocol over Thunderbolt
extdisp: External display mode protocol over Thunderbolt
What: /sys/bus/thunderbolt/devices/<xdomain>.<service>/modalias
Date: Jan 2018
KernelVersion: 4.15
Contact: thunderbolt-software@lists.01.org
Description: Stores the same MODALIAS value emitted by uevent for
the XDomain service. Format: tbtsvc:kSpNvNrN
What: /sys/bus/thunderbolt/devices/<xdomain>.<service>/prtcid
Date: Jan 2018
KernelVersion: 4.15
Contact: thunderbolt-software@lists.01.org
Description: This contains XDomain protocol identifier the XDomain
service supports.
What: /sys/bus/thunderbolt/devices/<xdomain>.<service>/prtcvers
Date: Jan 2018
KernelVersion: 4.15
Contact: thunderbolt-software@lists.01.org
Description: This contains XDomain protocol version the XDomain
service supports.
What: /sys/bus/thunderbolt/devices/<xdomain>.<service>/prtcrevs
Date: Jan 2018
KernelVersion: 4.15
Contact: thunderbolt-software@lists.01.org
Description: This contains XDomain software version the XDomain
service supports.
What: /sys/bus/thunderbolt/devices/<xdomain>.<service>/prtcstns
Date: Jan 2018
KernelVersion: 4.15
Contact: thunderbolt-software@lists.01.org
Description: This contains XDomain service specific settings as
bitmask. Format: %x