On Fri, 2021-01-29 at 18:21 -0800, Jakub Kicinski wrote:

On Wed, 27 Jan 2021 18:01:17 +0100 Loic Poulain wrote:

quoted

MBIM has initially been specified by USB-IF for transporting data
(IP)
between a modem and a host over USB. However some modern modems
also
support MBIM over PCIe (via MHI). In the same way as QMAP(rmnet),
it
allows to aggregate IP packets and to perform context multiplexing.

This change adds minimal MBIM support to MHI, allowing to support
MBIM
only modems. MBIM being based on USB NCM, it reuses some helpers
from
the USB stack, but the cdc-mbim driver is too USB coupled to be
reused.

At some point it would be interesting to move on a factorized
solution,
having a generic MBIM network lib or dedicated MBIM netlink virtual
interface support.

What would a kernel-side MBIM netlink interface do?  Just data-plane
stuff (like channel setup to create new netdevs), or are you thinking
about control-plane stuff like APN definition, radio scans, etc?

Dan

quoted

This code has been highly inspired from the mhi_mbim downstream
driver
(Carl Yin [off-list ref]).

Signed-off-by: Loic Poulain <redacted>

Does the existing MBIM over USB NCM also show up as a netdev?

Let's CC Dan and Bjorn on MBIM-related code, they may have opinions.