Re: [PATCH net-next v4 1/7] dt-bindings: net: airoha: npu: Add memory regions used for wlan offload

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> > On Thu, Jul 17, 2025 at 08:57:42AM +0200, Lorenzo Bianconi wrote:
> > > Document memory regions used by Airoha EN7581 NPU for wlan traffic
> > > offloading. The brand new added memory regions do not introduce any
> > > backward compatibility issues since they will be used just to offload
> > > traffic to/from the MT76 wireless NIC and the MT76 probing will not fail
> > > if these memory regions are not provide, it will just disable offloading
> > > via the NPU module.
> > 
> > That's not what I see entirely. I see the same problem I told you already.
> > of_reserved_mem_region_to_resource_byname returns error ->
> > airoha_npu_wlan_init_memory returns error -> your other patchset prints
> > big fat warning in mt7996_pci_probe().
> 
> Is it ok to use dev_info() instead dev_warn() or do you prefer to completely
> remove the log?
> 
> > 
> > So all correct DTS now gets a warning. Warning is a state of failure,
> > even if probe proceeds.
> > 
> > I don't understand why you can't make it fully optional, so also fully
> > backwards compatible.
> 
> I am completely fine to make it fully optional, but can you please explain
> what you mean here with 'optional'?
> 
> At the moment in mt76_npu_init() we first look for the "airoha,npu" property
> in mt76 node to load the NPU pointer running airoha_npu_get():
> 
> wifi@0,0 {
> 	compatible = "mediatek,mt76";
> 	...
> 	airoha,npu = <&npu>;
> 	...
> };

According to my understanding it is enough to get rid of the dev_warn() in the
MT76 series in order to avoid any backward compatibility issues. Am I wrong?
Moreover, we have the NPU phandle in the MT76 DTS node in order to check if the
reserved-memory properties are mandatory or not (if the MT76 node is configured
with the NPU phandle it is expected to have the reserved-memory properties properly
configured).
If my understanding is correct the NPU series does not require any change (the
only required change is in MT76 series). Since the current series is marked as
"Changes Requested' in patchwork, do I need to repost?

Regards,
Lorenzo

> 
> If this property is defined in the wifi node I guess it is fine to assume
> even the NPU memory regions are properly defined int the DTS.
> 
> Is it ok to use dev_info() instead of dev_warn() in mt7996_pci_probe() if
> the mt76_npu_init() returns an error (e.g. if the "airoha,npu" is not defined)
> or do you prefer to do something else to make this process optional?
> 
> Regards,
> Lorenzo
> 
> > 
> > Best regards,
> > Krzysztof
> > 



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