On Thu Aug 6, 2026 at 8:34 AM CEST, Jiaxing Hu wrote:
> The RK3576 NPU MMUs need more than aclk and iface. With only those two
> enabled the MMU accepts reads but silently drops register writes: a
> DTE_ADDR value written from the power domain, while the domain clocks
> are still on, reads back correctly, and the write rk_iommu_resume() does
> microseconds later does not land at all. The vendor DT names the CBUF
> clocks as that MMU's interface clocks and its driver keeps every NPU
> clock on for as long as the device is powered.
>
> The driver side of this is already upstream, commit 841363ebb508
> ("iommu/rockchip: Take all DT clocks"), which switched rk_iommu to
> devm_clk_bulk_get_all(). Widen the schema to match so those nodes can
> be described. minItems stays at 2, so every existing devicetree, which
> all carry exactly aclk and iface, is unaffected.I agree with all remarks Sashiko made wrt this patch: https://sashiko.dev/#/patchset/20260805063826.95682-1-gahing%40gahingwoo.com?part=3 Now every MMU with "rockchip,rk3568-iommu", "rockchip,rk3588-iommu" or "rockchip,rk3576-iommu" is allowed to have a minimum of 2 clocks, instead of having exactly 2 clocks. That does not sound desirable. Cheers, Diederik > > Signed-off-by: Jiaxing Hu <[email protected]> > --- > .../devicetree/bindings/iommu/rockchip,iommu.yaml | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/Documentation/devicetree/bindings/iommu/rockchip,iommu.yaml > b/Documentation/devicetree/bindings/iommu/rockchip,iommu.yaml > index 6ce41d11f..a3cedcaaa 100644 > --- a/Documentation/devicetree/bindings/iommu/rockchip,iommu.yaml > +++ b/Documentation/devicetree/bindings/iommu/rockchip,iommu.yaml > @@ -42,14 +42,22 @@ properties: > minItems: 1 > > clocks: > + minItems: 2 > items: > - description: Core clock > - description: Interface clock > + - description: Compute clock, RK3576 NPU MMUs only > + - description: Convolution buffer core clock, RK3576 NPU MMUs only > + - description: Convolution buffer interface clock, RK3576 NPU MMUs only > > clock-names: > + minItems: 2 > items: > - const: aclk > - const: iface > + - const: npu > + - const: aclk_cbuf > + - const: hclk_cbuf > > "#iommu-cells": > const: 0
