Re: [PATCH v6 0/5] Fix traceNoC probe issue on multiple QCOM platforms

[Jie Gan <jie.gan@oss.qualcomm.com>]

On 7/10/2026 10:38 AM, Jie Gan wrote:
> The CoreSight TNOC (Trace Network-On-Chip) binding so far only allowed the
> two-string AMBA form "qcom,coresight-tnoc", "arm,primecell". That form
> forces the device onto the AMBA bus, where the driver must read the
> peripheral ID from the device registers during probe. On several QCOM
> platforms this AMBA peripheral-ID probing fails, so the traceNoC device
> never probes and its trace path is unavailable.
> 
> This series drops the "arm,primecell" entry and turns "qcom,coresight-tnoc"
> into a standalone platform compatible. Without "arm,primecell" the device
> is created on the platform bus and probes through the platform driver by
> compatible string, bypassing the AMBA peripheral-ID read while remaining a
> fully functional Aggregator TNOC that allocates a system trace ID (ATID).
> 
> The series is organized as: binding first, then the driver support for the
> platform-bus compatible, followed by the per-platform DT fixes that switch
> the affected nodes over to it.
> 
> - Patch 1 (dt-bindings) drops "arm,primecell" and makes
> "qcom,coresight-tnoc" a single standalone compatible, and updates the
> example node accordingly.
> - Patch 2 (driver) adds "qcom,coresight-tnoc" to the platform driver's
> match table and renames the itnoc-specific names to generic tnoc names,
> since the platform driver now serves both the Interconnect and Aggregator
> TNOC. It also restricts the ATID-unsupported handling to
> "qcom,coresight-itnoc" only, so the Aggregator TNOC on the platform bus is
> no longer wrongly covered and correctly allocates a trace ID.
> - Patches 3-4 (kaanapali, sm8750) drop the "arm,primecell" entry on the
> traceNoC nodes and use the standalone "qcom,coresight-tnoc" compatible,
> fixing the probe failure on those platforms.
> - Patch 5 (glymur) switches the node from "qcom,coresight-itnoc" to
> "qcom,coresight-tnoc". This node is actually an Aggregator TNOC (its
> tn_ag_* endpoints show aggregation), so it should expose a system trace
> ID rather than being treated as an Interconnect TNOC.
> 

Gentle ping.


> Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
> ---
> Changes in v6:
> - update commit message for all commits to focus on describe the
>    hardware itself and the hardware issue we are facing on.
> - Link to v5: https://lore.kernel.org/r/20260707-fix-tracenoc-probe-issue-v5-0-bf733ed9ebd0@oss.qualcomm.com
> 
> Changes in v5:
> - Drop the separate "qcom,coresight-agtnoc" compatible. Instead drop the
>    "arm,primecell" entry and reuse the existing "qcom,coresight-tnoc" as a
>    standalone platform compatible.
> - Update the binding, driver match table, and per-platform DT nodes to the
>    standalone "qcom,coresight-tnoc" compatible accordingly.
> - Rewrite the commit messages to describe dropping "arm,primecell" and
>    binding on the platform bus.
> - Link to v4: https://lore.kernel.org/r/20260701-fix-tracenoc-probe-issue-v4-0-aefab449a470@oss.qualcomm.com
> 
> Changes in v4:
> - rewrite the commit message for the patch 3 - patch 5.
> - free the allocated ATID in remove path.
> - Link to v3: https://lore.kernel.org/r/20260630-fix-tracenoc-probe-issue-v3-0-7201e1841e94@oss.qualcomm.com
> 
> Changes in v3:
> - add standalone compatible for AG traceNoC device, allow it to be
>    probed with platform driver.
> - add fix patches for sm8750 and Glymur platforms
> - Link to v2: https://lore.kernel.org/r/20260624-fix-tracenoc-probe-issue-v2-0-786520f62f21@oss.qualcomm.com
> 
> Changes in v2:
> - address the ATID issue reported by Sashiko.
> - update binding to accept arm,primecell-periphid property.
> - Link to v1: https://lore.kernel.org/r/20260624-fix-tracenoc-probe-issue-v1-1-bcc785198fc5@oss.qualcomm.com
> 
> ---
> Jie Gan (5):
>        dt-bindings: arm: coresight-tnoc: Bind on platform bus instead of AMBA
>        coresight: tnoc: Bind Aggregator TNOC on the platform bus
>        arm64: dts: qcom: kaanapali: bind traceNoC on the platform bus
>        arm64: dts: qcom: sm8750: bind traceNoC on the platform bus
>        arm64: dts: qcom: glymur: use Aggregator TNOC compatible
> 
>   .../bindings/arm/qcom,coresight-tnoc.yaml          | 16 ++--------
>   arch/arm64/boot/dts/qcom/glymur.dtsi               |  6 ++--
>   arch/arm64/boot/dts/qcom/kaanapali.dtsi            |  2 +-
>   arch/arm64/boot/dts/qcom/sm8750.dtsi               |  2 +-
>   drivers/hwtracing/coresight/coresight-tnoc.c       | 37 ++++++++++++----------
>   5 files changed, 27 insertions(+), 36 deletions(-)
> ---
> base-commit: 4e5dfb7c84012007c3c7061126491bbc92d71bf1
> change-id: 20260624-fix-tracenoc-probe-issue-c6429da28df4
> 
> Best regards,