eth: mpnic: add a netdevice and basic Tx handling

Register the network interface and let it transmit skbs.

The typical TWQ descriptor sequence for an skb is: 1 primary metadata,
followed by 0 or more non-last address + length (A/L) descriptors,
terminated by an always present last A/L descriptor.

The device does not write a Tx completion unless it is requested in the
primary metadata desc. The xmit path sets this bit when the stack does
not report netdev_xmit_more(). This can create a problem if the last
packet in a burst is dropped by the driver. To deal with that case, the
driver latches the last metadata for which a completion was not
requested, and uses this to request a completion and flush queued
packets when one is dropped.

There is no link state yet, so carrier follows the administrative
state.

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Link: https://patch.msgid.link/20260924-linux-mpnic-v2-6-4badc9b58b9e@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

0 files changed, 0 insertions, 0 deletions