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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <e383c17d-12b8-b134-acc5-82f515714562@arm.com>
Date:   Fri, 24 Mar 2023 11:00:55 +0000
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     Hao Zhang <quic_hazha@...cinc.com>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Konrad Dybcio <konradybcio@...il.com>,
        Mike Leach <mike.leach@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Jonathan Corbet <corbet@....net>
Cc:     Leo Yan <leo.yan@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        Tingwei Zhang <quic_tingweiz@...cinc.com>,
        Jinlong Mao <quic_jinlmao@...cinc.com>,
        Yuanfang Zhang <quic_yuanfang@...cinc.com>,
        Tao Zhang <quic_taozha@...cinc.com>,
        Trilok Soni <quic_tsoni@...cinc.com>,
        linux-arm-msm@...r.kernel.org,
        Bjorn Andersson <andersson@...nel.org>,
        linux-doc@...r.kernel.org
Subject: Re: [PATCH v2 3/3] Documentation: trace: Add documentation for
 Coresight Dummy Trace

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@...cinc.com>
> ---
>   .../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@...cinc.com>
> +    :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"


> +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 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 ^^^ ----

> +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@...oc@0:dummy_source/dummy0
> +dummy1 -> ../../../devices/platform/soc@...oc@0:dummy_sink/dummy1

Suzuki