Re: [PATCH v14 0/9] Coresight: Add support for TPDM and TPDA

[Suzuki K Poulose <suzuki.poulose@arm.com>]

On 08/11/2022 05:54, Jinlong Mao wrote:
> 
> 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, please update the above in the TPDA code in a comment
and also in the recommended document above.

Thanks
Suzuki
>> 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
>>>
>>