Re: [PATCH v2 09/24] arm64: dts: qcom: sm8250: 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 conflicts with the qcom-pdc driver's hardcoded minimum size constraint, triggering a spurious boot warning and failing to actually reduce the mapped memory region.
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commit d119056e24f5f045fcb50e0c6e437fe3a3f6f22f
Author: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>

arm64: dts: qcom: sm8250: Reduce OS PDC DRV span to 0x10000

This commit reduces the register window size for the OS PDC DRV on the sm8250
platform from 0x30000 to 0x10000 bytes.

> diff --git a/arch/arm64/boot/dts/qcom/sm8250.dtsi b/arch/arm64/boot/dts/qcom/sm8250.dtsi
> index 7076720413ab2..23aa483e5c439 100644
> --- a/arch/arm64/boot/dts/qcom/sm8250.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sm8250.dtsi
> @@ -5053,7 +5053,7 @@ dispcc: clock-controller@af00000 {
>  
>  		pdc: interrupt-controller@b220000 {
>  			compatible = "qcom,sm8250-pdc", "qcom,pdc";
> -			reg = <0 0x0b220000 0 0x30000>, <0 0x17c000f0 0 0x60>;
> +			reg = <0 0x0b220000 0 0x10000>, <0 0x17c000f0 0 0x60>;

[Severity: Medium]
Will this change cause a spurious boot warning and fail to actually reduce the
mapped memory region?

Looking at the driver in drivers/irqchip/qcom-pdc.c, qcom_pdc_probe() enforces
a minimum register window size of 0x30000 bytes (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);
    ...
}

Since the driver evaluates res_size to 0x30000 and the new DT size is 0x10000,
it seems this will trigger the warning and still map 0x30000 bytes at runtime.

Does the qcom-pdc driver also need an update to handle this smaller size?

>  			qcom,pdc-ranges = <0 480 94>, <94 609 31>,
>  					  <125 63 1>, <126 716 12>;
>  			#interrupt-cells = <2>;

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Sashiko AI review · https://sashiko.dev/#/patchset/20260527094333.2311731-1-mukesh.ojha@oss.qualcomm.com?part=9