Re: [PATCH 2/5] arm64: dts: qcom: qcs6490-rb3gen2-industrial-mezzanine: use pci for device nodes

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] The patch claims to fix PCIe endpoints being incorrectly treated as PCI bridges by renaming them from `pcie@` back to `pci@`. However, this is a placebo fix that fails to resolve the issue because the nodes still retain the `device_type = "pci"` property.
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commit 8f05438af7136e29082530fe0089fb496985289a
Author: Alex Elder <elder@riscstar.com>

arm64: dts: qcom: qcs6490-rb3gen2-industrial-mezzanine: use pci for device nodes

This commit renames embedded PCIe endpoint nodes on the TC9564 SoCs from
pcie@ back to pci@ to prevent them from being incorrectly treated as PCI
bridges. The commit message states that the previous name pcie@ caused
of_node_is_pcie() to match them as bridge nodes.

> diff --git a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2-industrial-mezzanine.dtso b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2-industrial-mezzanine.dtso
> index 46bb52c667a4d..14c64439ae1e6 100644
> --- a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2-industrial-mezzanine.dtso
> +++ b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2-industrial-mezzanine.dtso
[ ... ]
> @@ -130,7 +130,7 @@ pcie@3,0 {
>  			ranges;
>  			bus-range = <0x5 0xff>;
>  
> -			pcie@0,0 {
> +			pci@0,0 {
>  				reg = <0x50000 0x0 0x0 0x0 0x0>;
>  				#address-cells = <3>;
>  				#size-cells = <2>;

[Severity: High]
This is a pre-existing issue, but does this rename actually resolve the
problem of endpoints being treated as PCI bridges?

Looking at drivers/of/address.c, the devicetree match logic in
of_bus_pci_match() is evaluated as:

    return of_node_is_type(np, "pci") || of_node_is_type(np, "pciex") ||
           of_node_is_type(np, "vci") || of_node_is_type(np, "ht") ||
           of_node_is_pcie(np);

Since the endpoint node retains the device_type = "pci" property just below
these cells, of_node_is_type(np, "pci") evaluates to true. This short-circuits
the condition before the of_node_is_pcie(np) name check is ever reached.

Because of this property, will the nodes continue to be matched as PCI buses
even with the name changed to pci@0,0, making this a placebo fix?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901172058.1512508-1-elder@riscstar.com?part=2