0001 .. SPDX-License-Identifier: GPL-2.0
0002
0003 ==============================
0004 Trace Buffer Extension (TRBE).
0005 ==============================
0006
0007 :Author: Anshuman Khandual <anshuman.khandual@arm.com>
0008 :Date: November 2020
0009
0010 Hardware Description
0011 --------------------
0012
0013 Trace Buffer Extension (TRBE) is a percpu hardware which captures in system
0014 memory, CPU traces generated from a corresponding percpu tracing unit. This
0015 gets plugged in as a coresight sink device because the corresponding trace
0016 generators (ETE), are plugged in as source device.
0017
0018 The TRBE is not compliant to CoreSight architecture specifications, but is
0019 driven via the CoreSight driver framework to support the ETE (which is
0020 CoreSight compliant) integration.
0021
0022 Sysfs files and directories
0023 ---------------------------
0024
0025 The TRBE devices appear on the existing coresight bus alongside the other
0026 coresight devices::
0027
0028 >$ ls /sys/bus/coresight/devices
0029 trbe0 trbe1 trbe2 trbe3
0030
0031 The ``trbe<N>`` named TRBEs are associated with a CPU.::
0032
0033 >$ ls /sys/bus/coresight/devices/trbe0/
0034 align flag
0035
0036 *Key file items are:-*
0037 * ``align``: TRBE write pointer alignment
0038 * ``flag``: TRBE updates memory with access and dirty flags
