[PATCH v1 1/1] net: stmmac: dwmac-tegra: Read iommu stream id from device tree

[Andrew Lunn]

> I think there is some confusion here. I will try to summarize:
> - Ihe iommu is supported by the Tegra SOC.
> - The way the mgbe driver is written the iommu DT property is REQUIRED.

If it is required, please also include a patch to
nvidia,tegra234-mgbe.yaml and make iommus required.

> - "iommus" is a SOC DT property and is defined in tegra234.dtsi.
> - The mgbe device tree nodes in tegra234.dtsi DO have the iommus property.
> - There are no device tree changes required to to make this patch work.
> - This patch works fine with existing device trees.
> 
> I will add the fallback however in case there is changes made to the iommu
> subsystem in the future.

I would suggest you make iommus a required property and run the tests
over the existing .dts files.

I looked at the history of tegra234.dtsi. The ethernet nodes were
added in:

610cdf3186bc604961bf04851e300deefd318038
Author: Thierry Reding <treding at nvidia.com>
Date:   Thu Jul 7 09:48:15 2022 +0200

    arm64: tegra: Add MGBE nodes on Tegra234

and the iommus property is present. So the requires is safe.

Please expand the commit message. It is clear from all the questions
and backwards and forwards, it does not provide enough details.

I just have one open issue. The code has been like this for over 2
years. Why has it only now started crashing?

	Andrew