The system on chip (SoC) consists of main APSS(Applications processor subsytem) and additional processors like modem, lpass. There is coresight-etm driver for etm trace of APSS. Coresight remote etm driver is for enabling and disabling the etm trace of remote processors. It uses QMI interface to communicate with remote processors' software and uses coresight framework to configure the connection from remote etm source to TMC sinks.
Example to capture the remote etm trace:
Enable source: echo 1 > /sys/bus/coresight/devices/tmc_etf0/enable_sink echo 1 > /sys/bus/coresight/devices/remote_etm0/enable_source
Capture the trace: cat /dev/tmc_etf0 > /data/remote_etm.bin
Disable source: echo 0 > /sys/bus/coresight/devices/remote_etm0/enable_source
Changes since V5: 1. Fix the warning and error when compile. 2. Add traceid for remote etm. 3. Change qcom,qmi-id tp qcom,qmi-instance-id.
Changes since V4: 1. Add coresight QMI driver 2. Add coresight qmi node and qcom,qmi-id of modem-etm in msm8996 dtsi V5: https://lwn.net/ml/all/20250424115854.2328190-1-quic_jinlmao@quicinc.com/
Changes since V3: 1. Use different compatible for different remote etms in dt. 2. Get qmi instance id from the match table data in driver.
Change since V2: 1. Change qcom,inst-id to qcom,qmi-id 2. Fix the error in code for type of remote_etm_remove 3. Depend on QMI helper in Kconfig
Changes since V1: 1. Remove unused content 2. Use CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS as remote etm source type. 3. Use enabled instead of enable in driver data. 4. Validate instance id value where it's read from the DT.
Mao Jinlong (5): dt-bindings: arm: Add CoreSight QMI component description coresight: Add coresight QMI driver dt-bindings: arm: Add qcom,qmi-id for remote etm coresight: Add remote etm support arm64: dts: qcom: msm8996: Add coresight qmi node
.../bindings/arm/qcom,coresight-qmi.yaml | 65 +++++ .../arm/qcom,coresight-remote-etm.yaml | 9 + arch/arm64/boot/dts/qcom/msm8996.dtsi | 11 + drivers/hwtracing/coresight/Kconfig | 23 ++ drivers/hwtracing/coresight/Makefile | 2 + drivers/hwtracing/coresight/coresight-qmi.c | 198 +++++++++++++ drivers/hwtracing/coresight/coresight-qmi.h | 101 +++++++ .../coresight/coresight-remote-etm.c | 262 ++++++++++++++++++ 8 files changed, 671 insertions(+) create mode 100644 Documentation/devicetree/bindings/arm/qcom,coresight-qmi.yaml create mode 100644 drivers/hwtracing/coresight/coresight-qmi.c create mode 100644 drivers/hwtracing/coresight/coresight-qmi.h create mode 100644 drivers/hwtracing/coresight/coresight-remote-etm.c