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Merge branch 'Thunderbolt-networking'
Mika Westerberg says: ==================== Thunderbolt networking In addition of tunneling PCIe, Display Port and USB traffic, Thunderbolt allows connecting two hosts (domains) over a Thunderbolt cable. It is possible to tunnel arbitrary data packets over such connection using high-speed DMA rings available in the Thunderbolt host controller. In order to discover Thunderbolt services the other host supports, there is a software protocol running on top of the automatically configured control channel (ring 0). This protocol is called XDomain discovery protocol and it uses XDomain properties to describe the host (domain) and the services it supports. Once both sides have agreed what services are supported they can enable high-speed DMA rings to transfer data over the cable. This series adds support for the XDomain protocol so that we expose each remote connection as Thunderbolt XDomain device and each service as Thunderbolt service device. On top of that we create an API that allows writing drivers for these services and finally we provide an example Thunderbolt service driver that creates virtual ethernet inferface that allows tunneling networking packets over Thunderbolt cable. The API could be used for creating other future Thunderbolt services, such as tunneling SCSI over Thunderbolt, for example. The XDomain protocol and networking support is also available in macOS and Windows so this makes it possible to connect Linux to macOS and Windows as well. The patches are based on previous Thunderbolt networking patch series by Amir Levy and Michael Jamet, that can be found here: https://lwn.net/Articles/705998/ The main difference to that patch series is that we have the XDomain protocol running in the kernel now so there is no need for a separate userspace daemon. Note this does not affect the existing functionality, so security levels and NVM firmware upgrade continue to work as before (with the small exception that now sysfs also shows the XDomain connections and services in addition to normal Thunderbolt devices). It is also possible to connect up to 5 Thunderbolt devices and then another host, and the network driver works exactly the same. This is third version of the patch series. The previous versions can be be found here: v2: https://lkml.org/lkml/2017/9/25/225 v1: https://lwn.net/Articles/734019/ Changes from the v2: * Add comment regarding calculation of interrupt throttling value * Add UUIDs as strings in comments on top of each declaration * Add a patch removing __packed from existing ICM messages. They are all 32-bit aligned and should pack fine without the __packed. * Move adding MAINTAINERS entries to a separate patches * Added Michael and Yehezkel to be maintainers of the network driver * Remove __packed from the new ICM messages. They should pack fine as well without it. * Call register_netdev() after all other initialization is done in the network driver. * Use build_skb() instead of copying. We allocate order 1 page here to leave room for SKB shared info required by build_skb(). However, we do not leave room for full NET_SKB_PAD because the NHI hardware does not cope well if a frame crosses 4kB boundary. According comments in __build_skb() that should still be fine. * Added Reviewed-by tag from Andy. Changes from the v1: * Add include/linux/thunderbolt.h to MAINTAINERS * Correct Linux version and date of new sysfs entries in Documentation/ABI/testing/sysfs-bus-thunderbolt * Move network driver from drivers/thunderbolt/net.c to drivers/net/thunderbolt.c and update it to follow coding style in drivers/net/*. * Add MAINTAINERS entry for the network driver * Minor cleanups In case someone wants to try this out, the last patch adds documentation how the networking driver can be used. In short, if you connect Linux to a macOS or Windows, everything is done automatically (as those systems have the networking service enabled by default). For Linux to Linux connection one host needs to load the networking driver first (so that the other side can locate the networking service and load the corresponding driver). ==================== Signed-off-by:David S. Miller <davem@davemloft.net>