MLX driver for host-to-ARM communication

[Tariq Toukan <tariqt@nvidia.com>]

Hi,

I plan to submit a patch series introducing a new minimalist MLX 
host-to-ARM communication driver.

Could you confirm whether this series can be submitted in parallel with 
our regular mlx5 feature patches without conflicting with the 15-patch 
limit?

It is to be placed in its own new directory:
drivers/net/ethernet/mellanox/mlx5/nodnic/

Find more details below [1].

Regards,
Tariq


[1]
net/mlx5: Introduce mlx5_nodnic driver for BF4 management PF

BlueField-4 no longer includes the RSHIM hardware that previous
BlueField generations relied on for host-to-ARM communication. In its
place, the firmware exposes two dedicated management PFs — one facing
the host side and one facing the ARM side — and configures steering
rules to loop traffic between them, enabling host-to-ARM communication
through standard networking interfaces.

Add mlx5_nodnic, a lightweight driver for these management PFs.
NODNIC (No DRAM NIC) is a lightweight interface intended to allow
simple packet transmission for minimalistic drivers with a low memory
footprint. The driver communicates with the firmware through PCI
Vendor Specific Capability (VSC) — reads and writes over PCI config
space, unlike mlx5_core which uses a DMA-based command interface.

Each management PF exposes a single SQ and a single RQ that share
one CQ. The interface configures two MSI-Xs: the data MSI-X fires
on CQEs, driving both TX and RX completions; the event MSI-X notifies
on port state changes, where the firmware brings the port up once both
the host and ARM sides have gone up.