Message-Id: <20251218-cpu_cluster_component_pm-v2-0-2335a6ae62a0@oss.qualcomm.com>
Date: Thu, 18 Dec 2025 00:09:40 -0800
From: Yuanfang Zhang <yuanfang.zhang@....qualcomm.com>
To: Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach <mike.leach@...aro.org>,
        James Clark <james.clark@...aro.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Leo Yan <leo.yan@...ux.dev>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>
Cc: kernel@....qualcomm.com, coresight@...ts.linaro.org,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        Yuanfang Zhang <yuanfang.zhang@....qualcomm.com>,
        maulik.shah@....qualcomm.com, Jie Gan <jie.gan@....qualcomm.com>
Subject: [PATCH v2 00/12] coresight: Add CPU cluster funnel/replicator/tmc
 support

This patch series adds support for CoreSight components local to CPU clusters,
including funnel, replicator, and TMC, which reside within CPU cluster power
domains. These components require special handling due to power domain
constraints.

Unlike system-level CoreSight devices, these components share the CPU cluster's
power domain. When the cluster enters low-power mode (LPM), their registers
become inaccessible. Notably, `pm_runtime_get` alone cannot bring the cluster
out of LPM, making standard register access unreliable.

To address this, the series introduces:
- Identifying cluster-bound devices via a new `qcom,cpu-bound-components`
  device tree property.
- Implementing deferred probing: if associated CPUs are offline during
  probe, initialization is deferred until a CPU hotplug notifier detects
  the CPU coming online.
- Utilizing `smp_call_function_single()` to ensure register accesses
  (initialization, enablement, sysfs reads) are always executed on a
  powered CPU within the target cluster.
- Extending the CoreSight link `enable` callback to pass the `cs_mode`.
  This allows drivers to distinguish between SysFS and Perf modes and
  apply mode-specific logic.

Jie Gan (1):
  arm64: dts: qcom: hamoa: add Coresight nodes for APSS debug block

Yuanfang Zhang (11):
  dt-bindings: arm: coresight: Add 'qcom,cpu-bound-components' property
  coresight: Pass trace mode to link enable callback
  coresight-funnel: Support CPU cluster funnel initialization
  coresight-funnel: Defer probe when associated CPUs are offline
  coresight-replicator: Support CPU cluster replicator initialization
  coresight-replicator: Defer probe when associated CPUs are offline
  coresight-replicator: Update management interface for CPU-bound devices
  coresight-tmc: Support probe and initialization for CPU cluster TMCs
  coresight-tmc-etf: Refactor enable function for CPU cluster ETF support
  coresight-tmc: Update management interface for CPU-bound TMCs
  coresight-tmc: Defer probe when associated CPUs are offline

Verification:

This series has been verified on sm8750.

Test steps for delay probe:

1. limit the system to enable at most 6 CPU cores during boot.
2. echo 1 >/sys/bus/cpu/devices/cpu6/online.
3. check whether ETM6 and ETM7 have been probed.

Test steps for sysfs mode:

echo 1 >/sys/bus/coresight/devices/tmc_etf0/enable_sink
echo 1 >/sys/bus/coresight/devices/etm0/enable_source
echo 1 >/sys/bus/coresight/devices/etm6/enable_source
echo 0 >/sys/bus/coresight/devices/etm0/enable_source
echo 0 >/sys/bus/coresight/devicse/etm6/enable_source
echo 0 >/sys/bus/coresight/devices/tmc_etf0/enable_sink

echo 1 >/sys/bus/coresight/devices/tmc_etf1/enable_sink
echo 1 >/sys/bus/coresight/devcies/etm0/enable_source
cat /dev/tmc_etf1 >/tmp/etf1.bin
echo 0 >/sys/bus/coresight/devices/etm0/enable_source
echo 0 >/sys/bus/coresight/devices/tmc_etf1/enable_sink

echo 1 >/sys/bus/coresight/devices/tmc_etf2/enable_sink
echo 1 >/sys/bus/coresight/devices/etm6/enable_source
cat /dev/tmc_etf2 >/tmp/etf2.bin
echo 0 >/sys/bus/coresight/devices/etm6/enable_source
echo 0 >/sys/bus/coresight/devices/tmc_etf2/enable_sink

Test steps for sysfs node:

cat /sys/bus/coresight/devices/tmc_etf*/mgmt/*

cat /sys/bus/coresight/devices/funnel*/funnel_ctrl

cat /sys/bus/coresight/devices/replicator*/mgmt/*

Test steps for perf mode:

perf record -a -e cs_etm//k -- sleep 5

Signed-off-by: Yuanfang Zhang <yuanfang.zhang@....qualcomm.com>
---
Changes in v2:
- Use the qcom,cpu-bound-components device tree property to identify devices
  bound to a cluster.
- Refactor commit message.
- Introduce a supported_cpus field in the drvdata structure to record the CPUs
  that belong to the cluster where the local component resides.
- Link to v1: https://lore.kernel.org/r/20251027-cpu_cluster_component_pm-v1-0-31355ac588c2@oss.qualcomm.com

---
Jie Gan (1):
      arm64: dts: qcom: hamoa: Add CoreSight nodes for APSS debug block

Yuanfang Zhang (11):
      dt-bindings: arm: coresight: Add 'qcom,cpu-bound-components' property
      coresight-funnel: Support CPU cluster funnel initialization
      coresight-funnel: Defer probe when associated CPUs are offline
      coresight-replicator: Support CPU cluster replicator initialization
      coresight-replicator: Defer probe when associated CPUs are offline
      coresight-replicator: Update management interface for CPU-bound devices
      coresight-tmc: Support probe and initialization for CPU cluster TMCs
      coresight-tmc-etf: Refactor enable function for CPU cluster ETF support
      coresight-tmc: Update management interface for CPU-bound TMCs
      coresight-tmc: Defer probe when associated CPUs are offline
      coresight: Pass trace mode to link enable callback

 .../bindings/arm/arm,coresight-dynamic-funnel.yaml |   5 +
 .../arm/arm,coresight-dynamic-replicator.yaml      |   5 +
 .../devicetree/bindings/arm/arm,coresight-tmc.yaml |   5 +
 arch/arm64/boot/dts/qcom/hamoa.dtsi                | 926 +++++++++++++++++++++
 arch/arm64/boot/dts/qcom/purwa.dtsi                |  12 +
 drivers/hwtracing/coresight/coresight-core.c       |   7 +-
 drivers/hwtracing/coresight/coresight-funnel.c     | 258 +++++-
 drivers/hwtracing/coresight/coresight-replicator.c | 341 +++++++-
 drivers/hwtracing/coresight/coresight-tmc-core.c   | 387 +++++++--
 drivers/hwtracing/coresight/coresight-tmc-etf.c    | 106 ++-
 drivers/hwtracing/coresight/coresight-tmc.h        |  10 +
 drivers/hwtracing/coresight/coresight-tnoc.c       |   3 +-
 drivers/hwtracing/coresight/coresight-tpda.c       |   3 +-
 include/linux/coresight.h                          |   3 +-
 14 files changed, 1902 insertions(+), 169 deletions(-)
---
base-commit: 008d3547aae5bc86fac3eda317489169c3fda112
change-id: 20251016-cpu_cluster_component_pm-ce518f510433

Best regards,
-- 
Yuanfang Zhang <yuanfang.zhang@....qualcomm.com>

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