Re: [PATCH] iommu/rockchip: implement .flush_iotlb_all

[Heiko Stübner]

Hi,

Am Freitag, 10. Juli 2026, 13:15:08 Mitteleuropäische Sommerzeit schrieb Jiaxing Hu:
> On Fri, 10 Jul 2026, Will Deacon wrote:
> > So I think this is the wrong direction. We should try harder to remove
> > the function rather than add new implementations of it. I'm assuming
> > you're only adding it for some out-of-tree code that calls it?
> 
> Yes, that's right. The only caller is the out-of-tree RK3576 NPU
> (accel/rocket) bring-up I mentioned in the commit message. There's no
> in-tree rk_iommu user, since the in-tree consumers all invalidate through
> .unmap and none of them call iommu_flush_iotlb_all().

accel/rocket is in mainline, so I guess the interesting question is, why
are you expecting your changes to be (stay?) out of tree?

When you show your changes - even as a RFC - on the lists you might get
helpful comments - like the ones here for the iommu change.
That might also prevent you from going too far in a suboptimal direction
and thus could save time.

Additionally, you would show you're working on that, so that could
prevent someone else starting a duplicate of your work -  or at least
pool resources.

There are a bunch of people working on the RK3576 for different projects
so there is a pretty high chance of getting valuable feedback.
(like what happened with this patch ;-) )


Heiko