David R. Piegdon
2018-11-27 16:57:05 UTC
on our embedded systems we rely on systemd's persistent netdev names.
Those currently do not work for USB netdevs that are connected to a
platform USB bus.
In https://github.com/systemd/systemd/pull/7273 a systemd patch was
suggested that would allow exactly this, but it was (rightfully) said
that numbering of theses busses is not guaranteed. Internally we used
the patch for a while now, but exactly that has happened with one of our
platforms across different kernel revisions.
The following kernel patches allow suggesting a USB busnumber for each
USB platform bus via a DTS alias, as can be done similarly for many
In combination with above systemd patch, these changes allow use of
persistent netdev names also on platform USB busses.
NOTE: this patch might change ordering of busses on devices that use
platform-busses, if aliases for these busses have already been defined!
In the current master there are a few platforms that contain such
aliases, e.g. am33xx, dm814x or imx6qdl
David R. Piegdon (2):
usb core: dts: allow suggesting usb bus number for platform busses
dt-bindings: allow suggesting usb bus number for usb platform busses
Documentation/devicetree/bindings/usb/usb-hcd.txt | 9 +++++++
drivers/usb/core/hcd.c | 30 ++++++++++++++++++-----
2 files changed, 33 insertions(+), 6 deletions(-)