39 lines
1.2 KiB
ReStructuredText
39 lines
1.2 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
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==============================
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Trace Buffer Extension (TRBE).
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==============================
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:Author: Anshuman Khandual <anshuman.khandual@arm.com>
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:Date: November 2020
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Hardware Description
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--------------------
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Trace Buffer Extension (TRBE) is a percpu hardware which captures in system
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memory, CPU traces generated from a corresponding percpu tracing unit. This
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gets plugged in as a coresight sink device because the corresponding trace
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generators (ETE), are plugged in as source device.
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The TRBE is not compliant to CoreSight architecture specifications, but is
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driven via the CoreSight driver framework to support the ETE (which is
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CoreSight compliant) integration.
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Sysfs files and directories
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---------------------------
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The TRBE devices appear on the existing coresight bus alongside the other
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coresight devices::
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>$ ls /sys/bus/coresight/devices
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trbe0 trbe1 trbe2 trbe3
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The ``trbe<N>`` named TRBEs are associated with a CPU.::
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>$ ls /sys/bus/coresight/devices/trbe0/
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align flag
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*Key file items are:-*
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* ``align``: TRBE write pointer alignment
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* ``flag``: TRBE updates memory with access and dirty flags
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