Re: [PATCH net-next v2 1/2] dt-bindings: net: airoha: npu: Add EN7581-7996 support

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> > In the current codebase the NPU driver does not need to access the WiFi PCIe
> > slot (or any other external device) since the offloading (wired and wireless)
> > is fully managed by the NPU chip (hw + firmware binaries).
> 
> Are you saying the NPU itself enumerates the PCI busses and finds the
> WiFi device?  If it can do that, why not ask it which PCI device it is
> using?

nope, we do not need any PCI enumeration in the NPU driver at the moment
(please see below).

> 
> Or this the PCI slot to use somehow embedded within the firmware?

in the current implementation the NPU driver does not need any reference to
WiFi or Ethernet devices. The NPU exports offloading APIs to consumer devices
(e.g. WiFi or Ethernet devices). In particular,
1- during NPU module probe, the NPU driver configures NPU hw registers and
   loads the NPU firmware binaries.
2- NPU consumers (ethernet and/or wifi devices) get a reference to the NPU
   device via device-tree in order to consume NPU APIs for offloading.
3- netfilter flowtable offloads traffic to the selected ethernet and/or WiFi
   device that runs the NPU APIs accessible via the NPU reference obtained via
   dts.

The issue here is the NPU firmware binaries for EN7581, loaded by the NPU
driver during NPU probe and used for offloading, depend on the WiFi chipset
(e.g. MT7996 or MT7992) available on the EN7581 board (we have two different
NPU binaries for MT7996 offloading and for MT7992 offloading).

Regards,
Lorenzo

> 
> Or is it simply hard coded in the NPU silicon which slot to use?
> 
>    Andrew

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