Re: [PATCH v2 15/24] arm64: dts: qcom: x1e80100: 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 `reg` size in the Device Tree without updating the `qcom-pdc` driver causes a boot warning and fails to actually reduce the mapped memory region.
--

commit 905355b7e18725670918048d9deb9a052ae4824e
Author: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>

arm64: dts: qcom: x1e80100: Reduce OS PDC DRV span to 0x10000

This commit reduces the OS PDC DRV register window on x1e80100 from
0x30000 to 0x10000 bytes.

> diff --git a/arch/arm64/boot/dts/qcom/hamoa.dtsi b/arch/arm64/boot/dts/qcom/hamoa.dtsi
> index 051dee0764167..5056d1f7a6d31 100644
> --- a/arch/arm64/boot/dts/qcom/hamoa.dtsi
> +++ b/arch/arm64/boot/dts/qcom/hamoa.dtsi
> @@ -6100,7 +6100,7 @@ dispcc: clock-controller@af00000 {
>  
>  		pdc: interrupt-controller@b220000 {
>  			compatible = "qcom,x1e80100-pdc", "qcom,pdc";
> -			reg = <0 0x0b220000 0 0x30000>, <0 0x174000f0 0 0x64>;
> +			reg = <0 0x0b220000 0 0x10000>, <0 0x174000f0 0 0x64>;

[Severity: Medium]
Will this change trigger a boot warning and still map 0x30000 bytes?

Looking at the qcom-pdc driver (drivers/irqchip/qcom-pdc.c), it appears to
hardcode a minimum size:

#define QCOM_PDC_SIZE 0x30000

And in qcom_pdc_probe(), it checks the size against this minimum:

    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", np);

If this device tree patch is applied without a corresponding driver change to
relax the 0x30000 requirement, it looks like it will unconditionally warn
during boot and force the mapped size back to 0x30000 anyway.

>  
>  			qcom,pdc-ranges = <0 480 42>, <42 251 5>,
>  					  <47 522 52>, <99 609 32>,

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260527094333.2311731-1-mukesh.ojha@oss.qualcomm.com?part=15