Re: [PATCH 1/5] arm64: dts: qcom: qcs6490-rb3gen2: use pci for device nodes

[Alex Elder <elder@riscstar.com>]

On 9/1/26 12:39 PM, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] Conceptual Flaw / False Premise: Renaming the node does not prevent it from being treated as a PCI bus because `device_type = "pci"` is still present.
> --
> 
> commit 3cd795cb2f33ffae376d5bceb9ba0da490602d05
> Author: Alex Elder <elder@riscstar.com>
> 
> arm64: dts: qcom: qcs6490-rb3gen2: use pci for device nodes
> 
> This commit renames devicetree nodes from pcie@ to pci@ with the intent of
> stopping the embedded PCIe endpoints from being treated as PCI buses by the
> devicetree parsing code.
> 
>> diff --git a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
>> index a13315bf0fb07..99a985a177a61 100644
>> --- a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
>> +++ b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
>> @@ -954,7 +954,7 @@ 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>;
>>   				device_type = "pci";
> 
> [Severity: Medium]
> Does this node rename actually prevent the devicetree parsing code from
> treating it as a PCI bus?

This patch (series) is being done separate from another pre-existing
series that addresses that particular issue.  I suppose once that
is merged I can re-issue this one.

   https://lore.kernel.org/lkml/20260901013654.1343537-1-elder@riscstar.com/

It looks like I might get a similar comment from Sashiko on other
patches in this series... I won't respond to any others unless what
is noted differs from what I've explained here.

					-Alex

> The commit message indicates that renaming the node away from pcie@ will stop
> of_node_is_pcie() from matching it. However, because this node explicitly
> specifies device_type = "pci", of_bus_pci_match() in drivers/of/address.c
> will still return true immediately.
> 
> When evaluating buses, of_bus_pci_match() checks:
> 
>      of_node_is_type(np, "pci") || of_node_is_pcie(np)
> 
> Since the device type is explicitly "pci", the match succeeds before
> of_node_is_pcie() is evaluated. Should device_type = "pci" also be removed to
> actually prevent this endpoint from being treated as a PCI bridge?
> 
> [ ... ]
>