linux-kernel - Re: [PATCH v6 2/2] coresight: add coresight Trace Network On Chip driver

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Message-ID: <40599afc-4342-467c-87d8-3f53cbcfd242@quicinc.com>
Date: Fri, 23 May 2025 16:08:58 +0800
From: Yuanfang Zhang <quic_yuanfang@...cinc.com>
To: Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach
	<mike.leach@...aro.org>,
        James Clark <james.clark@...aro.org>, Rob Herring
	<robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
	<conor+dt@...nel.org>,
        Alexander Shishkin
	<alexander.shishkin@...ux.intel.com>
CC: <kernel@....qualcomm.com>, <linux-arm-msm@...r.kernel.org>,
        <coresight@...ts.linaro.org>, <linux-arm-kernel@...ts.infradead.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6 2/2] coresight: add coresight Trace Network On Chip
 driver



On 5/22/2025 9:13 PM, Suzuki K Poulose wrote:
> On 22/05/2025 09:07, Yuanfang Zhang wrote:
>> Add a driver to support Coresight device Trace Network On Chip (TNOC),
>> which is an integration hierarchy integrating functionalities of TPDA
>> and funnels. It aggregates the trace and transports to coresight trace
>> bus.
>>
>> Compared to current configuration, it has the following advantages:
>> 1. Reduce wires between subsystems.
>> 2. Continue cleaning the infrastructure.
>> 3. Reduce Data overhead by transporting raw data from source to target.
>>
>>    +------------------------+                +-------------------------+
>>    | Video Subsystem        |                |Video Subsystem          |
>>    |       +-------------+  |                |       +------------+    |
>>    |       | Video TPDM  |  |                |       | Video TPDM |    |
>>    |       +-------------+  |                |       +------------+    |
>>    |            |           |                |              |          |
>>    |            v           |                |              v          |
>>    |   +---------------+    |                |        +-----------+    |
>>    |   | Video funnel  |    |                |        |Video TNOC |    |
>>    |   +---------------+    |                |        +-----------+    |
>>    +------------|-----------+                +------------|------------+
>>                 |                                         |
>>                 v-----+                                   |
>> +--------------------|---------+                         |
>> |  Multimedia        v         |                         |
>> |  Subsystem   +--------+      |                         |
>> |              |  TPDA  |      |                         v
>> |              +----|---+      |              +---------------------+
>> |                   |          |              |   Aggregator  TNOC  |
>> |                   |          |              +----------|----------+
>> |                   +--        |                         |
>> |                     |        |                         |
>> |                     |        |                         |
>> |              +------v-----+  |                         |
>> |              |  Funnel    |  |                         |
>> |              +------------+  |                         |
>> +----------------|-------------+                         |
>>                   |                                       |
>>                   v                                       v
>>        +--------------------+                    +------------------+
>>        |   Coresight Sink   |                    |  Coresight Sink  |
>>        +--------------------+                    +------------------+
>>
>>         Current Configuration                            TNOC
>>
>> Signed-off-by: Yuanfang Zhang <quic_yuanfang@...cinc.com>
> 
> 
>> +
>> +static int trace_noc_init_default_data(struct trace_noc_drvdata *drvdata)
>> +{
>> +    int atid;
>> +
>> +    atid = coresight_trace_id_get_system_id();
>> +    if (atid < 0)
>> +        return atid;
>> +
>> +    drvdata->atid = atid;
> 
> Do you need to expose this via sysfs ? Otherwise, how can you map
> a trace to a TNOC at decoding ?

yes, need to expose the atid via sysfs, but it better to expose it on source driver which connect with
this TNOC. so dont expose it on this driver.

> 
> Suzuki