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- .. SPDX-License-Identifier: GPL-2.0
- =================================================================
- The trace performance monitoring and diagnostics aggregator(TPDA)
- =================================================================
- :Author: Jinlong Mao <quic_jinlmao@quicinc.com>
- :Date: January 2023
- Hardware Description
- --------------------
- 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 specification.
- The primary use case of the TPDA is to provide packetization, funneling
- and timestamping of Monitor data.
- Sysfs files and directories
- ---------------------------
- Root: ``/sys/bus/coresight/devices/tpda<N>``
- Config details
- ---------------------------
- 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. The port of tpda which is connected to
- the tpdm will be enabled after commands below.
- 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.
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