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Message-ID: <102a8c21-2b78-56ca-874a-194e878dff8f@quicinc.com>
Date:   Tue, 8 Nov 2022 13:54:38 +0800
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Subject: Re: [PATCH v14 0/9] Coresight: Add support for TPDM and TPDA
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To:     Suzuki K Poulose <suzuki.poulose@arm.com>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Konrad Dybcio <konradybcio@gmail.com>,
        Mike Leach <mike.leach@linaro.org>
CC:     Leo Yan <leo.yan@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        <coresight@lists.linaro.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>,
        Tingwei Zhang <quic_tingweiz@quicinc.com>,
        Yuanfang Zhang <quic_yuanfang@quicinc.com>,
        Tao Zhang <quic_taozha@quicinc.com>,
        Trilok Soni <quic_tsoni@quicinc.com>,
        Hao Zhang <quic_hazha@quicinc.com>,
        <linux-arm-msm@vger.kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>
References: <20221102091915.15281-1-quic_jinlmao@quicinc.com>
 <69a3cd4b-c4b0-b998-b4c1-70a928690972@arm.com>
From:   Jinlong Mao <quic_jinlmao@quicinc.com>
In-Reply-To: <69a3cd4b-c4b0-b998-b4c1-70a928690972@arm.com>
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On 11/8/2022 2:38 AM, Suzuki K Poulose wrote:
> On 02/11/2022 09:19, Mao Jinlong 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.
>>      coresight: core: Use IDR for non-cpu bound sources' paths.
>>
> ---8>---
>
>> 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
>>      ARM: dts: msm: Add tpdm mm/prng 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.
>>
>> There must be a tpda between tpdm and the sink. When there are some
>> other trace event hw components in the same HW block with tpdm, tpdm
>> and these hw components will connect to the coresight funnel. When
>> there is only tpdm trace hw in the HW block, tpdm will connect to
>> tpda directly.
>>         +---------------+                +-------------+
>>      |  tpdm@6c08000 |                |tpdm@684C000 |
>>      +-------|-------+                +------|------+
>>              |                               |
>>      +-------|-------+                       |
>>      | funnel@6c0b000|                       |
>>      +-------|-------+                       |
>>              |                               |
>>      +-------|-------+                       |
>>      |funnel@6c2d000 |                       |
>>      +-------|-------+                       |
>>              |                               |
>>              |    +---------------+          |
>>              +----- tpda@6004000  -----------+
>>                   +-------|-------+
>>                           |
>>                   +-------|-------+
>>                   |funnel@6005000 |
>>                   +---------------+
>>
>
> --8<--
>
> Please could you add the above to a Documentation file (Of course
> skip the description of patches).
Sure. I will add them to the Documentation file.
>
>
>> This patch series depends on patch series:
>> "[v5,00/14] coresight: Add new API to allocate trace source ID values"
>> https://patchwork.kernel.org/project/linux-arm-kernel/cover/20221101163103.17921-1-mike.leach@linaro.org/ 
>>
>
> So, is there a strict binding between a TPDM and a TPDA ?
> i.e., Multiple TPDMs could never end up reaching the sam
> TPDA ? I see that the TPDMs could be connected to funnels
> and thus other TPDMs could be connected to the same funnels
> and thus reach the same TPDA.
There is no strict binding between TPDM and TPDA.
TPDA can have multiple TPDMs connect to it.
But There must be only one TPDA in the path from the TPDM source to TMC 
sink.
TPDM can directly connect to TPDA's inport
or connect to funnel which will connect to TPDA's inport.
>
> Also, the trace-id is bound to TPDA and not TPDM. So, if
> we have multiple TPDMs, trace decoding is going to be
> impossible.
The TPDMs which are connected to same TPDA shares the same
trace-id. When TPDA does packetization, different port will have
unique channel number for decoding.
>
> Thanks
> Suzuki
>
>>
>> Mao Jinlong (9):
>>    coresight: core: Use IDR for non-cpu bound sources' paths.
>>    Coresight: Add coresight TPDM source driver
>>    dt-bindings: arm: Adds CoreSight TPDM hardware
>>    coresight-tpdm: Add DSB dataset support
>>    coresight-tpdm: Add integration test support
>>    Coresight: Add TPDA link driver
>>    dt-bindings: arm: Adds CoreSight TPDA hardware definitions
>>    arm64: dts: qcom: sm8250: Add coresight components
>>    arm64: dts: qcom: sm8250: Add tpdm mm/prng
>>
>>   .../testing/sysfs-bus-coresight-devices-tpdm  |  13 +
>>   .../bindings/arm/qcom,coresight-tpda.yaml     | 111 +++
>>   .../bindings/arm/qcom,coresight-tpdm.yaml     |  93 +++
>>   MAINTAINERS                                   |   1 +
>>   arch/arm64/boot/dts/qcom/sm8250.dtsi          | 671 ++++++++++++++++++
>>   drivers/hwtracing/coresight/Kconfig           |  23 +
>>   drivers/hwtracing/coresight/Makefile          |   2 +
>>   drivers/hwtracing/coresight/coresight-core.c  |  42 +-
>>   drivers/hwtracing/coresight/coresight-tpda.c  | 208 ++++++
>>   drivers/hwtracing/coresight/coresight-tpda.h  |  35 +
>>   drivers/hwtracing/coresight/coresight-tpdm.c  | 259 +++++++
>>   drivers/hwtracing/coresight/coresight-tpdm.h  |  62 ++
>>   include/linux/coresight.h                     |   1 +
>>   13 files changed, 1509 insertions(+), 12 deletions(-)
>>   create mode 100644 
>> Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>>   create mode 100644 
>> Documentation/devicetree/bindings/arm/qcom,coresight-tpda.yaml
>>   create mode 100644 
>> Documentation/devicetree/bindings/arm/qcom,coresight-tpdm.yaml
>>   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
>>
>