coresight-trbe.rst 1.2 KB

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