Re: [PATCH net-next v9 11/15] net: lan966x: add PCIe FDMA support

[Simon Horman]

On Mon, Sep 28, 2026 at 09:32:59PM +0200, Daniel Machon wrote:
> Add PCIe FDMA support for lan966x. The PCIe FDMA path uses contiguous
> DMA buffers mapped through the endpoint's ATU, with memcpy-based frame
> transfer instead of per-page DMA mappings.
> 
> With PCIe FDMA, throughput increases from ~33 Mbps (register-based I/O)
> to ~620 Mbps on an Intel x86 host with a lan966x PCIe card.
> 
> The RX path uses its own copy of lan966x_hw_offload() that reports back
> when skb_vlan_untag() frees the skb, so the caller can drop the frame
> instead of touching it.
> 
> XDP is not supported on this path yet, so do not advertise xdp_features
> and reject program attach for PCIe instances.
> 
> Tested-by: Herve Codina <herve.codina@xxxxxxxxxxx>
> Signed-off-by: Daniel Machon <daniel.machon@xxxxxxxxxxxxx>

Reviewed-by: Simon Horman <horms@xxxxxxxxxx>