linux-kernel - Re: [PATCH v1 3/3] coresight-tpda: Optimize the function of reading element size

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Message-ID: <c5d70219-0aea-4025-bee3-8d8446432742@quicinc.com>
Date: Thu, 11 Jul 2024 16:20:39 +0800
From: Tao Zhang <quic_taozha@...cinc.com>
To: Suzuki K Poulose <suzuki.poulose@....com>,
        Mathieu Poirier
	<mathieu.poirier@...aro.org>,
        Alexander Shishkin
	<alexander.shishkin@...ux.intel.com>,
        Mike Leach <mike.leach@...aro.org>, "Rob Herring" <robh+dt@...nel.org>,
        Krzysztof Kozlowski
	<krzysztof.kozlowski+dt@...aro.org>,
        James Clark <james.clark@....com>
CC: Jinlong Mao <quic_jinlmao@...cinc.com>, Leo Yan <leo.yan@...aro.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>,
        Song Chai <quic_songchai@...cinc.com>, <linux-arm-msm@...r.kernel.org>,
        Jie Gan <quic_jiegan@...cinc.com>
Subject: Re: [PATCH v1 3/3] coresight-tpda: Optimize the function of reading
 element size


On 7/8/2024 11:49 PM, Suzuki K Poulose wrote:
> On 05/07/2024 09:51, Tao Zhang wrote:
>> Since the new funnel device supports multi-port output scenarios,
>> there may be more than one TPDM connected to one TPDA. In this
>> way, when reading the element size of the TPDM, TPDA driver needs
>> to find the expected TPDM corresponding to the filter source.
>> When TPDA finds a TPDM or a filter source from a input connection,
>> it will read the Devicetree to get the expected TPDM's element
>> size.
>>
>> Signed-off-by: Tao Zhang <quic_taozha@...cinc.com>
>> ---
>>   drivers/hwtracing/coresight/coresight-tpda.c | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-tpda.c 
>> b/drivers/hwtracing/coresight/coresight-tpda.c
>> index 52b0201090fb..fc5a4e46cf5d 100644
>> --- a/drivers/hwtracing/coresight/coresight-tpda.c
>> +++ b/drivers/hwtracing/coresight/coresight-tpda.c
>> @@ -110,9 +110,12 @@ static int tpda_get_element_size(struct 
>> tpda_drvdata *drvdata,
>>               csdev->pdata->in_conns[i]->dest_port != inport)
>>               continue;
>>
>
>
>> -        if (coresight_device_is_tpdm(in)) {
>> +        if (coresight_device_is_tpdm(in)
>> +            || csdev->pdata->in_conns[i]->filter_src_dev) {
>
> How can we assume that the filter-source device is always TPDM ?
> It may be true for your test board, but driver must handle all
> possible cases. I would rather prefer:

Got it. I will update in the next patch series.


Best,

Tao

>
> diff --git a/drivers/hwtracing/coresight/coresight-tpda.c 
> b/drivers/hwtracing/coresight/coresight-tpda.c
> index bfca103f9f84..b1d6f1dd60e3 100644
> --- a/drivers/hwtracing/coresight/coresight-tpda.c
> +++ b/drivers/hwtracing/coresight/coresight-tpda.c
> @@ -110,6 +110,13 @@ static int tpda_get_element_size(struct 
> tpda_drvdata *drvdata,
>                     csdev->pdata->in_conns[i]->dest_port != inport)
>                         continue;
>
> +               /*
> +                * If this port is tied to a source device,
> +                * jump to that directly.
> +                */
> +               if (csdev->pdata->in_conns[i]->filter_src)
> +                       in = csdev->pdata->in_conns[i]->filter_src;
> +
>                 if (coresight_device_is_tpdm(in)) {
>                         if (drvdata->dsb_esize || drvdata->cmb_esize)
>                                 return -EEXIST;
>
>
> Suzuki
>