enic: add MBOX VF handlers for capability, register and link state

Implement VF-side mailbox message processing for SR-IOV V2
admin channel communication.

VF receive handlers:
  - VF_CAPABILITY_REPLY: store PF protocol version, signal
    completion
  - VF_REGISTER_REPLY: mark VF as registered, signal completion
  - VF_UNREGISTER_REPLY: mark VF as unregistered, signal
    completion
  - PF_LINK_STATE_NOTIF: update carrier state via
    netif_carrier_on/off, send ACK back to PF

VF initiation functions for the probe-time handshake:
  - enic_mbox_vf_capability_check: send capability request,
    wait for PF reply via completion
  - enic_mbox_vf_register: send register request, wait for
    PF confirmation via completion
  - enic_mbox_vf_unregister: send unregister request, wait
    for PF confirmation

The wait helper (enic_mbox_wait_reply) uses
wait_for_completion_timeout, signaled when the admin ISR and
CQ-poll/dispatch workqueue pipeline delivers the reply message.

mbox_expected_reply is written by the request thread and read by the
admin CQ poll/dispatch context that runs the receive handlers; annotate
those accesses with READ_ONCE()/WRITE_ONCE() under the
single-outstanding-reply invariant.

Signed-off-by: Satish Kharat <satishkh@cisco.com>
Link: https://patch.msgid.link/20260812-enic-sriov-v2-admin-channel-v2-v13-8-b3809e448aba@cisco.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions