linux-kernel - Re: [PATCH v4 03/11] coresight-tpdm: Initialize DSB subunit configuration

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Message-ID: <320ee3b4-63ed-ec50-03c6-906803e34571@arm.com>
Date:   Thu, 25 May 2023 10:09:47 +0100
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     Tao Zhang <quic_taozha@...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>
Cc:     Jinlong Mao <quic_jinlmao@...cinc.com>,
        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>,
        Yuanfang Zhang <quic_yuanfang@...cinc.com>,
        Trilok Soni <quic_tsoni@...cinc.com>,
        Hao Zhang <quic_hazha@...cinc.com>,
        linux-arm-msm@...r.kernel.org, andersson@...nel.org
Subject: Re: [PATCH v4 03/11] coresight-tpdm: Initialize DSB subunit
 configuration

On 25/05/2023 09:12, Tao Zhang wrote:
> 
> On 5/23/2023 9:42 PM, Suzuki K Poulose wrote:
>> On 27/04/2023 10:00, Tao Zhang wrote:
>>> DSB is used for monitoring “events”. Events are something that
>>> occurs at some point in time. It could be a state decode, the
>>> act of writing/reading a particular address, a FIFO being empty,
>>> etc. This decoding of the event desired is done outside TPDM.
>>> DSB subunit need to be configured in enablement and disablement.
>>> A struct that specifics associated to dsb dataset is needed. It
>>> saves the configuration and parameters of the dsb datasets. This
>>> change is to add this struct and initialize the configuration of
>>> DSB subunit.
>>>
>>> Signed-off-by: Tao Zhang <quic_taozha@...cinc.com>

...

>>> + * dataset types. It covers Basic Counts(BC), Tenure Counts(TC),
>>> + * Continuous Multi-Bit(CMB), Multi-lane CMB(MCMB) and Discrete Single
>>> + * Bit(DSB). This function will initialize the configuration according
>>> + * to the dataset type supported by the TPDM.
>>> + */
>>>   static void __tpdm_enable(struct tpdm_drvdata *drvdata)
>>>   {
>>>       CS_UNLOCK(drvdata->base);
>>> @@ -110,15 +144,24 @@ static const struct coresight_ops tpdm_cs_ops = {
>>>       .source_ops    = &tpdm_source_ops,
>>>   };
>>>   -static void tpdm_init_default_data(struct tpdm_drvdata *drvdata)
>>> +static int tpdm_datasets_setup(struct tpdm_drvdata *drvdata)
>>>   {
>>>       u32 pidr;
>>>   -    CS_UNLOCK(drvdata->base);
>>>       /*  Get the datasets present on the TPDM. */
>>>       pidr = readl_relaxed(drvdata->base + CORESIGHT_PERIPHIDR0);
>>>       drvdata->datasets |= pidr & GENMASK(TPDM_DATASETS - 1, 0);
>>> -    CS_LOCK(drvdata->base);
>>
>> Why are we removing the CS_{UN,}LOCK here ?
> 
> CS_UNLOCK is used before writing data to Coresight registers. Here this 
> function
> 
> doesn't need to write data to any registers, so I remove the 
> CS_{UN,}LOCK here.

Please make this a separate patch to avoid confusing and keep it at the
beginning of the series.

Suzuki