Re: [PATCH v3 3/3] Documentation: trace: Add documentation for Coresight Dummy Trace

From: Bagas Sanjaya
Date: Wed May 10 2023 - 00:30:00 EST


On Sat, Apr 22, 2023 at 03:37:14PM +0800, Hao Zhang wrote:
> +Introduction
> +---------------------------
> +
> +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. So there need driver to register dummy devices
> +as Coresight devices. It may also be used to define components that
> +may not have any programming interfaces (e.g, static links), so that
> +paths can be established in the driver. Provide Coresight API for
> +dummy device operations, such as enabling and disabling dummy devices.
> +Build the Coresight path for dummy sink or dummy source for debugging.
> +
> +Config details
> +---------------------------
> +
> +There are two types of nodes, dummy sink and dummy source. The nodes
> +should be observed at the below coresight path::
> +
> + ``/sys/bus/coresight/devices``.
> +
> +e.g.::
> +
> + / $ ls -l /sys/bus/coresight/devices | grep dummy
> + dummy0 -> ../../../devices/platform/soc@0/soc@0:dummy_source/dummy0
> + dummy1 -> ../../../devices/platform/soc@0/soc@0:dummy_sink/dummy1

The wording confuses me, so I have to make the improv:

---- >8 ----
diff --git a/Documentation/trace/coresight/coresight-dummy.rst b/Documentation/trace/coresight/coresight-dummy.rst
index 7cb59f080c8892..f0a92669288b0c 100644
--- a/Documentation/trace/coresight/coresight-dummy.rst
+++ b/Documentation/trace/coresight/coresight-dummy.rst
@@ -8,27 +8,25 @@ Coresight Dummy Trace Module
:Date: May 2023

Introduction
----------------------------
+------------

-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. So there need driver to register dummy devices
-as Coresight devices. It may also be used to define components that
-may not have any programming interfaces (e.g, static links), so that
-paths can be established in the driver. Provide Coresight API for
-dummy device operations, such as enabling and disabling dummy devices.
-Build the Coresight path for dummy sink or dummy source for debugging.
+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. The nodes
-should be observed at the below coresight path::
+There are two types of nodes, dummy sink and dummy source. These nodes
+are available at ``/sys/bus/coresight/devices``.

- ``/sys/bus/coresight/devices``.
+Example output::

-e.g.::
-
- / $ ls -l /sys/bus/coresight/devices | grep dummy
+ $ 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

Thanks.

--
An old man doll... just what I always wanted! - Clara

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