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