Re: [PATCH v6 11/11] arm64: dts: qcom: monaco-arduino-monza: Add QCA2066 M.2 WiFi/BT support

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Invalid bus-range property for PCI-to-PCI bridge (pcie@1,0).
--

commit 44e277594358ae378b8bf12010e21f9f5a15795b
Author: Loic Poulain <loic.poulain@oss.qualcomm.com>

arm64: dts: qcom: monaco-arduino-monza: Add QCA2066 M.2 WiFi/BT support

This commit adds support for the QCA2066 WiFi/Bluetooth module on the
Arduino VENTUNO Q board. It introduces a wireless LGA connector node
and a downstream PCIe port node so the power sequencer can enable the
M.2 slot.

> diff --git a/arch/arm64/boot/dts/qcom/monaco-arduino-monza.dts b/arch/arm64/boot/dts/qcom/monaco-arduino-monza.dts
> index 299d0da15a150..afa6f0ecbf602 100644
> --- a/arch/arm64/boot/dts/qcom/monaco-arduino-monza.dts
> +++ b/arch/arm64/boot/dts/qcom/monaco-arduino-monza.dts

[ ... ]

> @@ -429,6 +463,22 @@ pcie@0,0 {
>  		ranges;
>  		reg = <0x010000 0x00 0x00 0x00 0x00>;
>  
> +		pcie@1,0 {
> +			#address-cells = <3>;
> +			#size-cells = <2>;
> +			device_type = "pci";
> +			compatible = "pciclass,0604";
> +			bus-range = <0x00 0xff>;

[Severity: Low]
Does this bus-range property create an invalid PCI topology loop?

The pcie@1,0 downstream port is configured as a PCI-to-PCI bridge. Based on
its reg property (0x020800), it sits on primary bus 2. However, the bus-range
property here defines a secondary bus of 0.

Because a downstream secondary bus must be strictly greater than its upstream
primary bus, having a secondary bus of 0 creates an impossible PCI
topological loop.

While Linux's PCI core currently ignores the bus-range property for downstream
P2P bridges and relies on dynamic enumeration instead (avoiding any runtime
impact), this still introduces a logically incorrect hardware description into
the device tree.

Should this property be omitted or updated to accurately reflect the
downstream bus topology?

> +			ranges;
> +			reg = <0x020800 0x00 0x00 0x00 0x00>;
> +
> +			port {
> +				pcie_ep: endpoint {
> +					remote-endpoint = <&lga_pcie_ep>;
> +				};
> +			};
> +		};

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260904-monza-wireless-v6-0-d8c5042b3efd@oss.qualcomm.com?part=11