From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0D27C77B60 for ; Tue, 28 Mar 2023 11:32:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230245AbjC1LcR (ORCPT ); Tue, 28 Mar 2023 07:32:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51252 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230390AbjC1LcL (ORCPT ); Tue, 28 Mar 2023 07:32:11 -0400 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 274E76E95; Tue, 28 Mar 2023 04:32:08 -0700 (PDT) Received: from pps.filterd (m0279863.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 32S9Aml8006772; Tue, 28 Mar 2023 11:31:33 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=qcppdkim1; bh=YXxP603e7d+v2V5F9PPJdor+5u8/ybIrmFKC4tCss1A=; b=Cfvc0d9AWEFplazy/EGXts/jotQQRQHOKlxyh7VdRyCRXnCKVy9vLPpGnntvrmYr7WdT +Ye2Qb0Lzcr3/iCTGMFjQs69ARfPscOGbmorhEt4qOmGChhEaeiLDb0/bpCI9nnW37Ou MjwVvK4+kY4H8f5rJZVF/Y3I/Y0oaiefDskQ+speTYWx1F57AlQ0rDVePyzfPL6EZyTE x0GwAey1WIkidJMqShf4pZq12CYBZao+MY05H3DfuMYnBm2bUfK10krf9oQkxwmkrhSc uDfTjUk4PZ33GZej7ZWL+wZZRZgg+vjfjFxAw5zRYhwJ157vX+kW3GAXsj2M6M/cF/Iq dg== Received: from nalasppmta05.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3pkbmytu8c-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 28 Mar 2023 11:31:32 +0000 Received: from nalasex01c.na.qualcomm.com (nalasex01c.na.qualcomm.com [10.47.97.35]) by NALASPPMTA05.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 32SBVW3I022397 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 28 Mar 2023 11:31:32 GMT Received: from [10.239.133.211] (10.80.80.8) by nalasex01c.na.qualcomm.com (10.47.97.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.41; Tue, 28 Mar 2023 04:31:26 -0700 Message-ID: Date: Tue, 28 Mar 2023 19:31:24 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [PATCH v3 02/11] coresight-tpda: Add DSB dataset support Content-Language: en-US To: Suzuki K Poulose , Mathieu Poirier , Alexander Shishkin , Konrad Dybcio , Mike Leach , Rob Herring , Krzysztof Kozlowski , James Clark CC: Jinlong Mao , Leo Yan , "Greg Kroah-Hartman" , , , , , Tingwei Zhang , Yuanfang Zhang , Trilok Soni , Hao Zhang , , Bjorn Andersson References: <1679551448-19160-1-git-send-email-quic_taozha@quicinc.com> <1679551448-19160-3-git-send-email-quic_taozha@quicinc.com> <51ad3cb3-bd83-51c9-52bc-f700cd17103c@quicinc.com> <48f31b84-573f-fe1d-bcd7-e55ec7f47831@arm.com> <595568c3-d2bc-e37e-83b3-2adfd3fa4193@quicinc.com> <6f8b087d-77a7-512e-6504-e4841447eda9@arm.com> From: Tao Zhang In-Reply-To: <6f8b087d-77a7-512e-6504-e4841447eda9@arm.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01c.na.qualcomm.com (10.47.97.35) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: -M1KzI9i-s6qqu8CNSKmGEA0GAsEXQBv X-Proofpoint-GUID: -M1KzI9i-s6qqu8CNSKmGEA0GAsEXQBv X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-03-24_11,2023-03-28_01,2023-02-09_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 spamscore=0 adultscore=0 bulkscore=0 mlxlogscore=999 mlxscore=0 suspectscore=0 phishscore=0 malwarescore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2303200000 definitions=main-2303280094 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Suzuki, On 3/27/2023 5:43 PM, Suzuki K Poulose wrote: > On 27/03/2023 04:31, Tao Zhang wrote: >> >> On 3/26/2023 3:31 AM, Suzuki K Poulose wrote: >>> On 24/03/2023 14:58, Tao Zhang wrote: >>>> Hi Suzuki, >>>> >>>> 在 3/23/2023 7:51 PM, Suzuki K Poulose 写道: >>>>> On 23/03/2023 06:03, Tao Zhang wrote: >>>>>> Read the DSB element size from the device tree. Set the register >>>>>> bit that controls the DSB element size of the corresponding port. >>>>>> >>>>>> Signed-off-by: Tao Zhang >>>>>> --- >>>>>>   drivers/hwtracing/coresight/coresight-tpda.c | 58 >>>>>> ++++++++++++++++++++++++++++ >>>>>>   drivers/hwtracing/coresight/coresight-tpda.h |  4 ++ >>>>>>   2 files changed, 62 insertions(+) >>>>>> >>>>>> diff --git a/drivers/hwtracing/coresight/coresight-tpda.c >>>>>> b/drivers/hwtracing/coresight/coresight-tpda.c >>>>>> index f712e11..8dcfc4a 100644 >>>>>> --- a/drivers/hwtracing/coresight/coresight-tpda.c >>>>>> +++ b/drivers/hwtracing/coresight/coresight-tpda.c >>>>>> @@ -21,6 +21,47 @@ >>>>>>     DEFINE_CORESIGHT_DEVLIST(tpda_devs, "tpda"); >>>>>>   +/* Search and read element data size from the TPDM node in >>>>>> + * the devicetree. Each input port of TPDA is connected to >>>>>> + * a TPDM. Different TPDM supports different types of dataset, >>>>>> + * and some may support more than one type of dataset. >>>>>> + * Parameter "inport" is used to pass in the input port number >>>>>> + * of TPDA, and it is set to 0 in the recursize call. >>>>>> + * Parameter "parent" is used to pass in the original call. >>>>>> + */ >>>>> >>>>> I am still not clear why we need to do this recursively ? >>>> >>>> Some TPDMs are not directly output connected to the TPDAs. So here I >>>> >>>> use a recursive method to check from the TPDA input port until I find >>>> >>>> the connected TPDM. >>>> >>>> Do you have a better suggestion besides a recursive method? >>>> >>>>> >>>>>> +static int tpda_set_element_size(struct tpda_drvdata *drvdata, >>>>>> +               struct coresight_device *csdev, int inport, bool >>>>>> parent) >>>>> >>>>> Please could we renamse csdev => tpda_dev >>>> >>>> Since this is a recursively called function, this Coresight device >>>> is not >>>> >>>> necessarily TPDA, it can be other Coresight device. >>>> >>>>> >>>>>> +{ >>>>>> +    static int nr_inport; >>>>>> +    int i; >>>>>> +    struct coresight_device *in_csdev; >>>>> >>>>> similarly tpdm_dev ? >>>> Same as above, this variable may not necessarily be a TPDM. >>>>> >>>>> Could we not add a check here to see if the dsb_esize[inport] is >>>>> already >>>>> set and then bail out, reading this over and over ? >>>>> >>>> I will update this in the next patch series. >>>>>> + >>>>>> +    if (inport > (TPDA_MAX_INPORTS - 1)) >>>>>> +        return -EINVAL; >>>>>> + >>>>>> +    if (parent) >>>>>> +        nr_inport = inport; >>>>>> + >>>>>> +    for (i = 0; i < csdev->pdata->nr_inconns; i++) { >>>>>> +        in_csdev = csdev->pdata->in_conns[i].remote_dev; >>>>> >>>>> Please note, the names of the structure field might change in the >>>>> next version of James' series >>>> Got it. I will keep an eye out for the James' patch series. >>>>> >>>>>> +        if (!in_csdev) >>>>>> +            break; >>>>>> + >>>>>> +        if (parent) >>>>>> +            if (csdev->pdata->in_conns[i].port != inport) >>>>>> +                continue; >>>>>> + >>>>>> +        if (in_csdev && strstr(dev_name(&in_csdev->dev), "tpdm")) { >>>>> >>>>> Isn't there a better way to distinguish a device to be TPDM ? May >>>>> be we >>>>> could even add a source_sub_type - SOURCE_TPDM instead of using >>>>> SOURCE_OTHERS ? Do you expect other sources to be connected to TPDA? >>>>> e.g., STMs ? >>>> >>>> I can add "SOURCE_TPDM" as a source_sub_type, but SOURCE_OTHERS needs >>>> >>>> to be kept since the other Coresight component we will upstream >>>> later may >>>> >>>> need it. >>>> >>>>> >>>>>> + of_property_read_u32(in_csdev->dev.parent->of_node, >>>>>> +                    "qcom,dsb-element-size", >>>>>> &drvdata->dsb_esize[nr_inport]); >>>>>> +            break; >>>>>> +        } >>>>>> +        tpda_set_element_size(drvdata, in_csdev, 0, false); >>>>> >>>>> What is the point of this ? Is this for covering the a TPDA >>>>> connected to >>>>> another TPDA ? >>>>> >>>>> e.g., { TPDM0, TPDM1 } -> TPDA0 -> TPDA1 ? >>>> >>>> A TPDM may not connect to the TPDA directly, for example, >>>> >>>> TPDM0 ->FUNNEL0->FUNNEL1->TPDA0 >>>> >>>> And many TPDMs can connect to one TPDA, one input port on TPDA only >>>> has >>>> >>>> one TPDM connected. Therefore, we use a recursive method to find >>>> the TPDM >>>> >>>> corresponding to the input port of TPDA. >>> >>> How do you find out decide what to choose, if there are multiple TPDMs >>> connected to FUNNEL0 or even FUNNEL1 ? >>> >>> e.g >>> >>> TPDM0->FUNNEL0->FUNNEL1->TPDA0 >>>                 / >>>           TPDM1 >> >> We can find out the corresponding TPDM by the input port number of TPDA. >> >> Each input port is connected to a TPDM. So we have an input port >> number in >> >> the input parameter of the recursive lookup function >> "tpda_set_element_size". > > I don't understand, how you would figure out, in the above situation. > i.e., FUNNEL1 is connected to TPDA0, but there are two TPDMs that could > be pumping the trace. They both arrive via FUNNEL1. So, how does that > solve your problem ? In our HW design, the input ports of TPDA and TPDM are one-one-one corresponding.  Only one TPDM can be found connected from one TPDA's input port. The path to a TPDA input port doesn't connect more than one TPDM. It's by HW design. Tao > > Suzuki > > >> >>> Suzuki >>> >>> >