Re: [PATCH v2 3/3] Documentation: trace: Add documentation for Coresight Dummy Trace

[Hao Zhang]

Hi Suzuki,

On 3/24/2023 7:00 PM, Suzuki K Poulose wrote:
> On 24/03/2023 06:16, Hao Zhang wrote:
> > Add documentation for Coresight Dummy Trace under trace/coresight.
> >
> > Signed-off-by: Hao Zhang <quic_hazha@xxxxxxxxxxx>
> > ---
> >   .../trace/coresight/coresight-dummy.rst       | 58 +++++++++++++++++++
> >   1 file changed, 58 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..819cabab8623
> > --- /dev/null
> > +++ b/Documentation/trace/coresight/coresight-dummy.rst
> > @@ -0,0 +1,58 @@
> > +.. SPDX-License-Identifier: GPL-2.0
> > +
> > +=============================
> > +Coresight Dummy Trace Module
> > +=============================
> > +
> > +    :Author:   Hao Zhang <quic_hazha@xxxxxxxxxxx>
> > +    :Date:     March 2023
> > +
> > +Introduction
> > +---------------------------
> > +
> > +Coresight Dummy Trace Module is for the specific devices that HLOS don't
>
> Please do not use cryptic abbreviations, please use "kernel"
Sure, I will change it to "kernel".
> > +have permission to access or configure. 
>
> Such as Coresight sink EUD, some
> > +TPDMs etc. 
> Say "e.g., CoreSight TPDMs on Qualcomm platforms.:
>
> So there need driver to register dummy devices as Coresight
> > +devices.
>
> Add:
>
> "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.
I will take your advice in the next version of patch.
> I think the following content may not be needed as they are part
> of the standard source/sink type devices, nothing specific to
> dummy devices.
>
> --- vvvvv ---
> > +
> > +Sysfs files and directories
> > +---------------------------
> > +
> > +Root: ``/sys/bus/coresight/devices/dummy<N>``
> > +
> > +----
> > +
> > +:File:            ``enable_source`` (RW)
> > +:Notes:
> > +    - > 0 : enable the datasets of dummy source.
> > +
> > +    - = 0 : disable the datasets of dummy source.
> > +
> > +:Syntax:
> > +    ``echo 1 > enable_source``
> > +
> > +----
> > +
> > +:File:            ``enable_sink`` (RW)
> > +:Notes:
> > +    - > 0 : enable the datasets of dummy sink.
> > +
> > +    - = 0 : disable the datasets of dummy sink.
> > +
> > +:Syntax:
> > +    ``echo 1 > enable_sink``
> > +
> > +----
> > +
>
> --- You may remove the above ^^^ ----
I will remove the above notes in the next version of patch.

Thanks,
Hao

> > +Config details
> > +---------------------------
> > +
> > +There are two types of nodes, dummy sink and dummy source. The nodes
> > +should be observed at the coresight path
> > +"/sys/bus/coresight/devices".
> > +e.g.
> > +/sys/bus/coresight/devices # ls -l | grep dummy
> > +dummy0 -> ../../../devices/platform/soc@0/soc@0:dummy_source/dummy0
> > +dummy1 -> ../../../devices/platform/soc@0/soc@0:dummy_sink/dummy1
>
> Suzuki