[PATCH v6 4/5] arm64: dts: qcom: sm8750: bind traceNoC on the platform bus
Konrad Dybcio
konrad.dybcio at oss.qualcomm.com
Fri Jul 10 02:49:59 PDT 2026
On 7/10/26 4:39 AM, Jie Gan wrote:
> The traceNoC node used the "qcom,coresight-tnoc", "arm,primecell"
> compatible, which places the device on the AMBA bus. To bind an AMBA
> device, the bus reads the peripheral and component ID registers (PID/CID)
> at the top of the device's register block and matches them against the
> primecell ID. The traceNoC exposes the CID registers, but the Component ID
> value returned by the hardware is 0x00000000 instead of a valid AMBA
> Component ID, so the match never succeeds, the AMBA probe fails, and the
> device is left stuck in deferred probe indefinitely.
>
> Drop the "arm,primecell" entry and use the standalone "qcom,coresight-tnoc"
> compatible, which binds via the platform driver by compatible string and
> does not rely on the component ID register at all. This lets the device
> probe on hardware that does not return a valid CID, while remaining an
> Aggregator TNOC that retains ATID functionality.
>
> Fixes: ebd1eb365cae ("arm64: qcom: dts: sm8750: add coresight nodes")
> Signed-off-by: Jie Gan <jie.gan at oss.qualcomm.com>
> ---
Reviewed-by: Konrad Dybcio <konrad.dybcio at oss.qualcomm.com>
Konrad
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