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[v5,3/3] Documentation: trace: Add documentation for Coresight Dummy Trace

Message ID 20230526100753.34581-4-quic_hazha@quicinc.com
State Accepted
Commit 3b79104f80036231a40ba5d15c3e329985029a0f
Headers show
Series Add support to configure Coresight Dummy subunit | expand

Commit Message

Hao Zhang May 26, 2023, 10:07 a.m. UTC
Add documentation for Coresight Dummy Trace under trace/coresight.

Signed-off-by: Hao Zhang <quic_hazha@quicinc.com>
 .../trace/coresight/coresight-dummy.rst       | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 Documentation/trace/coresight/coresight-dummy.rst
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diff --git a/Documentation/trace/coresight/coresight-dummy.rst b/Documentation/trace/coresight/coresight-dummy.rst
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+.. SPDX-License-Identifier: GPL-2.0
+Coresight Dummy Trace Module
+    :Author:   Hao Zhang <quic_hazha@quicinc.com>
+    :Date:     May 2023
+The Coresight dummy trace module is for the specific devices that kernel don't
+have permission to access or configure, e.g., CoreSight TPDMs on Qualcomm
+platforms. For these devices, a dummy driver is needed to register them as
+Coresight devices. The module may also be used to define components that may
+not have any programming interfaces (e.g, static links), so that paths can be
+created in the driver. It provides Coresight API for operations on dummy
+devices, such as enabling and disabling them. It also provides the Coresight
+dummy sink/source paths for debugging.
+Config details
+There are two types of nodes, dummy sink and dummy source. These nodes
+are available at ``/sys/bus/coresight/devices``.
+Example output::
+    $ ls -l /sys/bus/coresight/devices | grep dummy
+    dummy_sink0 -> ../../../devices/platform/soc@0/soc@0:sink/dummy_sink0
+    dummy_source0 -> ../../../devices/platform/soc@0/soc@0:source/dummy_source0