Hello Mao,

I have looked through this set and have a few general questions.

My understanding based on the information in the code is that the TPDM devices will always send data to the TPDA device, the TPDM is not capable of directly driving the ATB itself? The TPDA device will then packetize the inputs and output these to the ATB over the normal CoreSight architecture to a standard ETR / ETF for collection.

Looking at the TPDM driver - it is assigned a trace ID but never actually uses it in the hardware. My assumption here is that this is used purely to satisfy the requirement that the CoreSight core has that all sources have a unique trace id?

For the TPDA driver you assign an ATID as an attribute in device tree, and then program this into the devices control register.

The trace IDs in ETM / ETE / STM, are programmed into the hardware and these values drive the ATID value on the trace bus. So assigning an ATID value to the TPDA driver through device tree will lead to clashes with the assignment of trace IDs in the other driver software.

The topology here appears to me that you have multiple "data source" devices TPDM, supplying a TPDA - which is the real CoreSight "trace source" from the viewpoint of the trace bus and CoreSight infrastructure. To get this to work in the current CoreSight driver stack, you have assigned the TPDM as a source type, and the TPDA as a link to ensure that when a TPDM is started, all the components on the path to the sink are activated. This is fine.

If my assumptions above are all accurate I suggest the following improvements

For TPDA drop the device tree assignment of ATID and instead use the coresight_get_system_trace_id() function you introduce in the 2nd patch in this set.

For TPDM you have assigned a unique source sub-type CORESIGHT_DEV_SUBTYPE_SOURCE_SYS.- this could become CORESIGHT_DEV_SUBTYPE_SOURCE_DATA_ONLY. If the trace ID assigned to this device is only to satisfy the unique ID requirement and is not used elsewhere, then the sub type could become CORESIGHT_DEV_SUBTYPE_SOURCE_DATA_ONLY. We can agree that this sub type does not need a unique ID and acts as none ATB a source for another component, The core code can be altered to drop the requirement for this sub-type and trace ID can be dropped for this component.

You should be aware that we are in the process of re-designed how trace IDs are allocated. The current mechanism does not scale for large multi-core systems (currently broken for any system > 46 cores), and as you have discovered there is a need for additional allocation of IDs. Also the ETE / TRBE combination does not need a trace ID. A dynamic allocation system is being proposed.

Regards

Mike

On Wed, 9 Feb 2022 at 10:57, Mao Jinlong quic_jinlmao@quicinc.com wrote:

This series adds support for the trace performance monitoring and diagnostics hardware (TPDM and TPDA). It is composed of two major elements. a) Changes for original coresight framework to support for TPDM and TPDA. b) Add driver code for TPDM and TPDA.

Introduction of changes for original coresight framework Support TPDM as new coresight source. Since only STM and ETM are supported as coresight source originally. TPDM is a newly added coresight source. We need to change the original way of saving coresight path to support more types source for coresight driver. The following patch is to add support more coresight sources. Use IDR to maintain all the enabled sources' paths. coresight: Use bitmap to assign trace id to the sources

Introduction of TPDM and TPDA TPDM - The trace performance monitoring and diagnostics monitor or TPDM in short serves as data collection component for various dataset types specified in the QPMDA(Qualcomm performance monitoring and diagnostics architecture) spec. The primary use case of the TPDM is to collect data from different data sources and send it to a TPDA for packetization, timestamping and funneling. Coresight: Add coresight TPDM source driver dt-bindings: arm: Adds CoreSight TPDM hardware definitions coresight-tpdm: Add DSB dataset support coresight-tpdm: Add integration test support docs: sysfs: coresight: Add sysfs ABI documentation for TPDM

TPDA - The trace performance monitoring and diagnostics aggregator or TPDA in short serves as an arbitration and packetization engine for the performance monitoring and diagnostics network as specified in the QPMDA (Qualcomm performance monitoring and diagnostics architecture) specification. The primary use case of the TPDA is to provide packetization, funneling and timestamping of Monitor data as specified in the QPMDA specification. The following patch is to add driver for TPDA. Coresight: Add TPDA link driver dt-bindings: arm: Adds CoreSight TPDA hardware definitions

The last patch of this series is a device tree modification, which add the TPDM and TPDA configuration to device tree for validating. ARM: dts: msm: Add coresight components for SM8250

Once this series patches are applied properly, the tpdm and tpda nodes should be observed at the coresight path /sys/bus/coresight/devices e.g. /sys/bus/coresight/devices # ls -l | grep tpd tpda0 -> ../../../devices/platform/soc@0/6004000.tpda/tpda0 tpdm0 -> ../../../devices/platform/soc@0/6c08000.mm.tpdm/tpdm0

We can use the commands are similar to the below to validate TPDMs. Enable coresight sink first.

echo 1 > /sys/bus/coresight/devices/tmc_etf0/enable_sink echo 1 > /sys/bus/coresight/devices/tpdm0/enable_source echo 1 > /sys/bus/coresight/devices/tpdm0/integration_test echo 2 > /sys/bus/coresight/devices/tpdm0/integration_test The test data will be collected in the coresight sink which is enabled. If rwp register of the sink is keeping updating when do integration_test (by cat tmc_etf0/mgmt/rwp), it means there is data generated from TPDM to sink.

Changes from V2:

1. Use bitmap to assign the trace id. (Mathieu Poirier)

Mao Jinlong (10): Use IDR to maintain all the enabled sources' paths. coresight: Use bitmap to assign trace id to the sources Coresight: Add coresight TPDM source driver dt-bindings: arm: Adds CoreSight TPDM hardware definitions coresight-tpdm: Add DSB dataset support coresight-tpdm: Add integration test support docs: sysfs: coresight: Add sysfs ABI documentation for TPDM Coresight: Add TPDA link driver dt-bindings: arm: Adds CoreSight TPDA hardware definitions ARM: dts: msm: Add coresight components for SM8250

.../testing/sysfs-bus-coresight-devices-tpdm | 6 + .../bindings/arm/coresight-tpda.yaml | 129 ++++ .../bindings/arm/coresight-tpdm.yaml | 81 ++ .../devicetree/bindings/arm/coresight.txt | 7 + MAINTAINERS | 1 + .../arm64/boot/dts/qcom/sm8250-coresight.dtsi | 690 ++++++++++++++++++ arch/arm64/boot/dts/qcom/sm8250.dtsi | 2 + drivers/hwtracing/coresight/Kconfig | 33 + drivers/hwtracing/coresight/Makefile | 2 + drivers/hwtracing/coresight/coresight-core.c | 127 ++-- drivers/hwtracing/coresight/coresight-tpda.c | 193 +++++ drivers/hwtracing/coresight/coresight-tpda.h | 32 + drivers/hwtracing/coresight/coresight-tpdm.c | 270 +++++++ drivers/hwtracing/coresight/coresight-tpdm.h | 57 ++ include/linux/coresight-pmu.h | 11 + include/linux/coresight.h | 1 + 16 files changed, 1592 insertions(+), 50 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm create mode 100644 Documentation/devicetree/bindings/arm/coresight-tpda.yaml create mode 100644 Documentation/devicetree/bindings/arm/coresight-tpdm.yaml create mode 100644 arch/arm64/boot/dts/qcom/sm8250-coresight.dtsi create mode 100644 drivers/hwtracing/coresight/coresight-tpda.c create mode 100644 drivers/hwtracing/coresight/coresight-tpda.h create mode 100644 drivers/hwtracing/coresight/coresight-tpdm.c create mode 100644 drivers/hwtracing/coresight/coresight-tpdm.h

-- 2.17.1

-- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK