Re: [PATCH v5 2/5] arm64: dts: qcom: Add Kalambo SoC

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The bandwidth monitor PMU node for CPU cluster 0 (bwmon_cluster0) is not disabled or deleted, which can cause a boot crash when probed on Kalambo hardware that physically lacks this cluster.
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--- Patch [2]: [PATCH v5 2/5] arm64: dts: qcom: Add Kalambo SoC ---
commit 9554cda7ec4f38ae39a00604b42c25a1e924c0a8
Author: Gopikrishna Garmidi <gopikrishna.garmidi@oss.qualcomm.com>

arm64: dts: qcom: Add Kalambo SoC

This commit introduces support for the Qualcomm Kalambo SoC, which is
derived from Mahua. It removes CPU cluster 0 (cpu0-cpu5) and reassigns
the remaining cluster 1 CPUs as cluster 0, alongside adjusting SCMI
transport and PDC input mux pins.

[ ... ]
> diff --git a/arch/arm64/boot/dts/qcom/kalambo.dtsi b/arch/arm64/boot/dts/qcom/kalambo.dtsi
> new file mode 100644
> index 0000000000000..8e2077d9d0a8a
> --- /dev/null
> +++ b/arch/arm64/boot/dts/qcom/kalambo.dtsi
> @@ -0,0 +1,119 @@
> +// SPDX-License-Identifier: BSD-3-Clause
> +/*
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + */
> +
> +#include "mahua.dtsi"
> +
> +/delete-node/ &cluster0_pd;
> +/delete-node/ &cpu_map;
> +/delete-node/ &cpu0;
> +/delete-node/ &cpu1;
> +/delete-node/ &cpu2;
> +/delete-node/ &cpu3;
> +/delete-node/ &cpu4;
> +/delete-node/ &cpu5;
> +/delete-node/ &cpu_pd0;
> +/delete-node/ &cpu_pd1;
> +/delete-node/ &cpu_pd2;
> +/delete-node/ &cpu_pd3;
> +/delete-node/ &cpu_pd4;
> +/delete-node/ &cpu_pd5;
> +/delete-node/ &cpu_scp_lpri1;

[Severity: High]
Since CPU cluster 0 is removed, does this code also need to disable the
bwmon_cluster0 node to avoid a boot regression?

If the node is left with its implicit status="okay", the qcom,sdm845-bwmon
driver will unconditionally attempt to probe it during boot. Since the
Kalambo hardware physically lacks this cluster, accessing the unclocked
or removed registers can lead to a synchronous external abort (bus fault)
and a kernel panic.

Deleting the node directly with /delete-node/ might cause device tree
compiler errors because bwmon_cluster1 typically references the
&cpu_bwmon_opp_table nested inside bwmon_cluster0. Setting
status = "disabled" for &bwmon_cluster0 here instead would safely prevent
the probe.

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Sashiko AI review · https://sashiko.dev/#/patchset/20260801-b4-kalambo-crd-v5-0-22160abacf3d@oss.qualcomm.com?part=2