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| author | Anshuman Khandual <anshuman.khandual@arm.com> | 2021-04-05 18:43:06 +0200 |
|---|---|---|
| committer | Mathieu Poirier <mathieu.poirier@linaro.org> | 2021-04-07 00:05:38 +0200 |
| commit | 4af432186122bb274b76e7ac549073122c41d2fb (patch) | |
| tree | d3848105036be3da56d8ab8b01f079d22fac68f9 /Documentation/trace | |
| parent | Documentation: coresight: trbe: Sysfs ABI description (diff) | |
| download | linux-4af432186122bb274b76e7ac549073122c41d2fb.tar.xz linux-4af432186122bb274b76e7ac549073122c41d2fb.zip | |
Documentation: trace: Add documentation for TRBE
Add documentation for the TRBE under trace/coresight.
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
[ Split from the TRBE driver patch ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210405164307.1720226-20-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Diffstat (limited to 'Documentation/trace')
| -rw-r--r-- | Documentation/trace/coresight/coresight-trbe.rst | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/Documentation/trace/coresight/coresight-trbe.rst b/Documentation/trace/coresight/coresight-trbe.rst new file mode 100644 index 000000000000..b9928ef148da --- /dev/null +++ b/Documentation/trace/coresight/coresight-trbe.rst @@ -0,0 +1,38 @@ +.. 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 |