Add documentation for Coresight Dummy Trace under trace/coresight.

Signed-off-by: Hao Zhang <quic_hazha@quicinc.com>
---
 .../trace/coresight/coresight-dummy.rst       | 34 +++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 Documentation/trace/coresight/coresight-dummy.rst

diff --git a/Documentation/trace/coresight/coresight-dummy.rst b/Documentation/trace/coresight/coresight-dummy.rst
new file mode 100644
index 000000000000..d0f73253f694
--- /dev/null
+++ b/Documentation/trace/coresight/coresight-dummy.rst
@@ -0,0 +1,34 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=============================
+Coresight Dummy Trace Module
+=============================
+
+    :Author:   Hao Zhang <quic_hazha@quicinc.com>
+    :Date:     April 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.
+
+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
-- 
2.17.1

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

Hi Bagas,

On 5/10/2023 12:29 PM, Bagas Sanjaya wrote:
> 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.
> 

Thanks for your review and comments, will update it in the next patch 
series.

Thanks,
Hao