Re: [PATCH net-next v2 2/7] net: airoha: npu: Add NPU wlan memory initialization commands

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> On 07/07/2025 09:24, Lorenzo Bianconi wrote:
> >> On Sat, Jul 05, 2025 at 11:09:46PM +0200, Lorenzo Bianconi wrote:
> >>> +
> >>>  struct airoha_npu *airoha_npu_get(struct device *dev, dma_addr_t *stats_addr)
> >>>  {
> >>>  	struct platform_device *pdev;
> >>> @@ -493,6 +573,7 @@ static int airoha_npu_probe(struct platform_device *pdev)
> >>>  	npu->ops.ppe_deinit = airoha_npu_ppe_deinit;
> >>>  	npu->ops.ppe_flush_sram_entries = airoha_npu_ppe_flush_sram_entries;
> >>>  	npu->ops.ppe_foe_commit_entry = airoha_npu_foe_commit_entry;
> >>> +	npu->ops.wlan_init_reserved_memory = airoha_npu_wlan_init_memory;
> >>
> >> I cannot find in your code single place calling this (later you add a
> >> wrapper... which is not called either).
> >>
> >> All this looks like dead code...
> > 
> > As pointed out in the commit log, these callbacks will be used by MT76 driver
> > to initialize the NPU reserved memory and registers during driver probe in
> > order to initialize the WiFi offloading. Since MT76 patches are going via
> > the wireless tree, I needed to add these callbacks first.
> 
> Cover letter does not link to your NPU patchset. You cannot add dead
> code to the kernel and now it is pure dead code. Post your user - in
> this or separate patchset.

I guess you mean the related MT76 patches are not linked in the cover-letter,
right? I have not posted them yet.

> 
> Your explanation of dependency is also confusing. If these are added to
> wireless tree (considering last experience how they rebase and cannot
> easily handle cross tree merges), how does it solve your problem? You
> will have it in one tree but not in the other, so still nothing...
> That's anyway separate problem, because main issue is you add code which
> we cannot even verify how it is being used.

My main point here is wireless tree can't acutally merge the MT76 patches
since, without the net-next ones (this series), it will not compile (so I
posted net-next patches as preliminary ones for MT76 changes).
Moreover, this is the same approach we used when we added WED support to
mtk_eth_soc driver and the related MT76 support.
However, I am fine to post the MT76 changes as RFC and just refer to it in
this series cover-letter. Agree? 

> 
> So far I see ABI break, but without user cannot judge. And that's the
> hard reason this cannot be accepted.

if you mean the dts changes, I will fix them in v3.

Regards,
Lorenzo

> 
> Best regards,
> Krzysztof

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