Re: [PATCH v2 04/24] arm64: dts: qcom: sc7180: Reduce OS PDC DRV span to 0x10000

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Reducing the PDC `reg` size to 0x10000 in the device tree triggers a kernel boot warning in the `qcom-pdc` driver and fails to reduce the actually mapped memory region.
--

commit 81fc1fb188abb3ae08146cf2e02b2febea3e2f77
Author: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>

arm64: dts: qcom: sc7180: Reduce OS PDC DRV span to 0x10000

The OS PDC DRV register window on sc7180 spans 0x10000 bytes. Reduce
the size of the first reg entry from 0x30000 to 0x10000.

> diff --git a/arch/arm64/boot/dts/qcom/sc7180.dtsi b/arch/arm64/boot/dts/qcom/sc7180.dtsi
> index a4b17564469ee..3961948c7ee81 100644
> --- a/arch/arm64/boot/dts/qcom/sc7180.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sc7180.dtsi
> @@ -3507,7 +3507,7 @@ dispcc: clock-controller@af00000 {
>  
>  		pdc: interrupt-controller@b220000 {
>  			compatible = "qcom,sc7180-pdc", "qcom,pdc";
> -			reg = <0 0x0b220000 0 0x30000>;
> +			reg = <0 0x0b220000 0 0x10000>;

[Severity: Medium]
Will this change trigger a new boot warning?

The qcom-pdc driver enforces a minimum region size of 0x30000 via
QCOM_PDC_SIZE:

drivers/irqchip/qcom-pdc.c:qcom_pdc_probe() {
	...
	res_size = max_t(resource_size_t, resource_size(&res), QCOM_PDC_SIZE);
	if (res_size > resource_size(&res))
		pr_warn("%pOF: invalid reg size, please fix DT\n", node);
	...
}

Because QCOM_PDC_SIZE is 0x30000, setting the device tree reg size to 0x10000
will cause the driver to expand the size back to 0x30000 during mapping and
print the "invalid reg size" warning.

Are there corresponding driver updates planned to handle the reduced size?

>  			qcom,pdc-ranges = <0 480 94>, <94 609 31>, <125 63 1>;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260527094333.2311731-1-mukesh.ojha@oss.qualcomm.com?part=4