Hi.
On 17/01/2026 23:18, Andrew Lunn wrote:

quoted

Airoha folks reported the NPU hw can't provide the PCIe Vendor/Device ID info
of the connected WiFi chip.
I guess we have the following options here:
- Rely on the firmware-name property as proposed in v1
- Access the PCIe bus from the NPU driver during probe in order to enumerate
   the PCIe devices and verify WiFi chip PCIe Vendor/Device ID
- During mt76 probe trigger the NPU fw reload if required. This approach would
   require adding a new callback in airoha_npu ops struct (please note I have
   not tested this approach and I not sure this is really doable).

What i'm wondering about is if the PCIe slots are hard coded in the
firmware.  If somebody builds a board using different slots, they
would then have different firmware?

You have to follow the reference design to get Airoha support. My guess 
is that everyone is following the reference designs thus there will only 
ever be one pcie configuration for each SoC to (Mediatek) Wifi-card pairing.

  Or if they used the same slots,
but swapped around the Ethernet and the WiFi, would it need different
firmware?

NPU acceleration should be able to freely route packets to any port 
connected to the PSE. On the following link you can see an illustration 
of my current understanding of the AN7581 SoC: 
https://github.com/merbanan/air_tools

So is the firmware name a property of the board?

If the PCIe slots are actually hard coded in the NPU silicon, cannot
be changed, then we might have a different solution, the firmware name
might be placed into a .dtsi file, or even hard coded in the driver?

quoted

What do you think? Which one do you prefer?

I prefer to try to extract more information for the Airoha folks. What
actually defines the firmware? Does the slots used matter? Does it
matter what device goes in what slots? Is it all hard coded in
silicon? Is there only one true hardware design and if you do anything
else your board design is FUBAR, never to be supported?

      Andrew

The NPU is a Risc-V cpu cluster. As such it should theoretically be 
possible to support any kind of configuration but if there only ever is 
one reference design my guess is that is the only officially supported one.

MvH

Benjamin Larsson