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Message-ID: <47191600-260a-46aa-9af8-dff2b08dc2e8@arm.com> Date: Thu, 18 Dec 2025 09:32:12 +0000 From: Suzuki K Poulose <suzuki.poulose@....com> To: Yuanfang Zhang <yuanfang.zhang@....qualcomm.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>, Sudeep Holla <sudeep.holla@....com> 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, maulik.shah@....qualcomm.com, Jie Gan <jie.gan@....qualcomm.com> Subject: Re: [PATCH v2 00/12] coresight: Add CPU cluster funnel/replicator/tmc support Cc: Sudeep On 18/12/2025 08:09, Yuanfang Zhang wrote: > 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. Why ? AFAIU, we have ways to tie the power-domain to that of the cluster and that can auto-magically keep the cluster power ON as long as you want to use them. Suzuki > > 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,
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