Re: [PATCH 5/5] arm64: dts: qcom: qcs6490-thundercomm-minipc-g1iot: use dev for device nodes

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The commit claims that renaming PCIe endpoint nodes from `pcie@` to `pci@` prevents them from being incorrectly treated as PCI buses by `of_bus_pci_match()`. However, this fix is logically flawed and entirely ineffective because the endpoint nodes still contain the `device_type = "pci"` property. `of_bus_pci_match()` checks `of_node_is_type(np, "pci")` before checking the node name via `of_node_is_pcie(np)`. Because the `device_type = "pci"` property is present on the nodes, the match short-circuits and evaluates to true unconditionally, bypassing the name check. As a result, the endpoints will still be treated as PCI buses, failing to restore the desired `default-flags` bus behavior.
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commit 1271b9698d89ac8a7e9afe5810c933ffba016f7f
Author: Alex Elder <elder@riscstar.com>

arm64: dts: qcom: qcs6490-thundercomm-minipc-g1iot: use dev for device nodes

This commit renames the PCIe endpoint nodes from "pcie@" to "pci@" in the
Thundercomm AI Mini PC G1 IoT devicetree. The goal is to prevent these
endpoints from being incorrectly treated as PCI buses by the parsing logic
in of_node_is_pcie().

> diff --git a/arch/arm64/boot/dts/qcom/qcs6490-thundercomm-minipc-g1iot.dts b/arch/arm64/boot/dts/qcom/qcs6490-thundercomm-minipc-g1iot.dts
> index 31bafa2cf51db..183ac59ca7d49 100644
> --- a/arch/arm64/boot/dts/qcom/qcs6490-thundercomm-minipc-g1iot.dts
> +++ b/arch/arm64/boot/dts/qcom/qcs6490-thundercomm-minipc-g1iot.dts
> @@ -790,7 +790,7 @@ 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: Medium]
Does this rename actually prevent the node from being treated as a PCI
bridge?

The commit message states that renaming the nodes to "pci@" stops them from
being treated as PCI bridges by bypassing of_node_is_pcie(). However, these
nodes still contain the property device_type = "pci" (visible just below
this diff context).

During devicetree address parsing, of_bus_pci_match() in
drivers/of/address.c checks the device type before it checks the node name:

drivers/of/address.c:of_bus_pci_match() {
	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 of_node_is_type(np, "pci") evaluates to true, the match short-circuits
and succeeds unconditionally, bypassing the of_node_is_pcie() check entirely.

Will these endpoints still be mistakenly treated as PCI buses despite the
name change?

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901172058.1512508-1-elder@riscstar.com?part=5