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Diffstat (limited to 'Documentation/trace/coresight/coresight-tpda.rst')
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diff --git a/Documentation/trace/coresight/coresight-tpda.rst b/Documentation/trace/coresight/coresight-tpda.rst new file mode 100644 index 000000000000..a37f387ceaea --- /dev/null +++ b/Documentation/trace/coresight/coresight-tpda.rst @@ -0,0 +1,52 @@ +.. 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. |