1.. SPDX-License-Identifier: GPL-2.0 2 3============================== 4Trace Buffer Extension (TRBE). 5============================== 6 7 :Author: Anshuman Khandual <anshuman.khandual@arm.com> 8 :Date: November 2020 9 10Hardware Description 11-------------------- 12 13Trace Buffer Extension (TRBE) is a percpu hardware which captures in system 14memory, CPU traces generated from a corresponding percpu tracing unit. This 15gets plugged in as a coresight sink device because the corresponding trace 16generators (ETE), are plugged in as source device. 17 18The TRBE is not compliant to CoreSight architecture specifications, but is 19driven via the CoreSight driver framework to support the ETE (which is 20CoreSight compliant) integration. 21 22Sysfs files and directories 23--------------------------- 24 25The TRBE devices appear on the existing coresight bus alongside the other 26coresight devices:: 27 28 >$ ls /sys/bus/coresight/devices 29 trbe0 trbe1 trbe2 trbe3 30 31The ``trbe<N>`` named TRBEs are associated with a CPU.:: 32 33 >$ ls /sys/bus/coresight/devices/trbe0/ 34 align flag 35 36*Key file items are:-* 37 * ``align``: TRBE write pointer alignment 38 * ``flag``: TRBE updates memory with access and dirty flags 39