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

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Message-ID: <fa7bd706-c8ca-d7d8-eef9-05b908625741@quicinc.com>
Date:   Tue, 28 Mar 2023 16:07:04 +0800
From:   Hao Zhang <quic_hazha@...cinc.com>
To:     Bagas Sanjaya <bagasdotme@...il.com>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        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

Hi Bagas,

On 3/27/2023 5:06 PM, Bagas Sanjaya wrote:
> On Fri, Mar 24, 2023 at 02:16:08PM +0800, Hao Zhang wrote:
>> +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``
> 
> Is enable_{source,sink} integer-valued or bit (0/1)? In other words, is
> it OK to `echo 2` to both sysfs files?

It should be the integer value, that is OK to "echo 2" to the sysfs files.

>> +
>> +----
>> +
>> +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".
> 
> For consistency, inline this sysfs also (thus
> ``/sys/bus/coresight/devices``.
> 
>> +e.g.
> e.g.:: (make the shell snippet below code block)

I will correct it in the next version of patch.

>> +/sys/bus/coresight/devices # ls -l | grep dummy
> IMO I prefer `PS1=\$` (that is, omit the directory). Alternatively,
> you can write `ls -l /sys/bus/coresight/devices | grep dummy` (specify
> the directory to `ls`).
> 
> Thanks.
> 

Thanks for your comments, I will take your advice in the next version of 
patch.

Thanks,
Hao