From: sashiko-bot@kernel.org
To: "Jie Gan" <jie.gan@oss.qualcomm.com>
Cc: robh@kernel.org, devicetree@vger.kernel.org, conor+dt@kernel.org
Subject: Re: [PATCH] arm64: dts: qcom: shikra: Switch CPU ETMs to MMIO-based probing
Date: Tue, 22 Sep 2026 03:17:02 +0000 [thread overview]
Message-ID: <20260922031703.54C521F000FF@smtp.kernel.org> (raw)
In-Reply-To: <20260922-fix-etm-probe-issue-on-shikra-v1-1-56d25e9bbe17@oss.qualcomm.com>
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] arm64: dts: shikra: missing arm,coresight-loses-context-with-cpu property
--
commit aab8605634d60b3bebc7a736fcec36f07d87f859
Author: Jie Gan <jie.gan@oss.qualcomm.com>
arm64: dts: qcom: shikra: Switch CPU ETMs to MMIO-based probing
The etm0-etm3 nodes are declared with "arm,coresight-etm4x-sysreg"
but do not implement self-hosted system-register trace access on
this SoC. The CPU ETMs have a memory-mapped aperture, so switch each
node to the standard "arm,coresight-etm4x", "arm,primecell" compatible
with its MMIO reg range.
> diff --git a/arch/arm64/boot/dts/qcom/shikra.dtsi b/arch/arm64/boot/dts/qcom/shikra.dtsi
> index c1f06f692f664..62bacf749241f 100644
> --- a/arch/arm64/boot/dts/qcom/shikra.dtsi
> +++ b/arch/arm64/boot/dts/qcom/shikra.dtsi
[ ... ]
> @@ -3218,6 +3150,24 @@ cti@9020000 {
> label = "cti_apss_pe0";
> };
>
> + etm@9040000 {
> + compatible = "arm,coresight-etm4x", "arm,primecell";
[Severity: Medium]
Will this omission cause ETM tracing to silently stop functioning during CPU
deep idle?
By switching to MMIO without adding the arm,coresight-loses-context-with-cpu
property, the coresight driver will skip allocating the save state.
drivers/hwtracing/coresight/coresight-etm4x-core.c:etm4_add_coresight_dev() {
...
else if (pm_save_enable == PARAM_PM_SAVE_FIRMWARE)
pm_save = coresight_loses_context_with_cpu(dev);
...
}
Should the arm,coresight-loses-context-with-cpu property be added to these
new MMIO etm nodes?
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260922-fix-etm-probe-issue-on-shikra-v1-1-56d25e9bbe17@oss.qualcomm.com?part=1
next prev parent reply other threads:[~2026-09-22 3:17 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-22 3:09 [PATCH] arm64: dts: qcom: shikra: Switch CPU ETMs to MMIO-based probing Jie Gan
2026-09-22 3:17 ` sashiko-bot [this message]
2026-09-22 3:27 ` Jie Gan
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