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

[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().

So if the plan is to remove the function rather than add new
implementations of it, then I've got this backwards. Please drop the
patch. If the NPU driver ever goes upstream I'll make it stop relying on
iommu_flush_iotlb_all() rather than bring this one back.

Thanks for taking a look, and for the pointers to those two commits.

Jiaxing