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 1E105C7EE43 for ; Wed, 7 Jun 2023 19:51:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232012AbjFGTvc (ORCPT ); Wed, 7 Jun 2023 15:51:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231238AbjFGTv3 (ORCPT ); Wed, 7 Jun 2023 15:51:29 -0400 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3CB421BEF; Wed, 7 Jun 2023 12:51:28 -0700 (PDT) Received: from pps.filterd (m0279866.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 357JJQBg029061; Wed, 7 Jun 2023 19:51:16 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=MyBe12xlukVDy21RV8mGvzxBCep4BCefuMYAHQJmVTA=; b=erT+YlfWAvAso0poGql0wbYfGzp55tNqeAswL0ZN3Sh1dmus7+is+zxWoxuMDjyAyrvM iDiPBrWObbvQjFs9PQMW/C6h9IyroAztxaMdxEbCA2nXSHMUHRl/A4kSdf6I72Cv9ljq upAnEKz1ZTXKISq8IJTDAuVqfhHRzVFxpMWrEpI8UIQqW4B5wHaF0HFjjj+zf+StVudl 4PY9HW+qP1kxwbdCbdAaVaAS/K7P9FtPkrXdlmjvqXIo/YI8ZRsVg0xFgIfK440Bt0ud wgppbM7o8pqC+WqLz5hq06HXdD/qbFAs0iSODV2z2twRoO1JSK+wGQWhnec0wRrR7oP3 KQ== Received: from nalasppmta03.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3r2a71au0f-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 07 Jun 2023 19:51:16 +0000 Received: from nalasex01a.na.qualcomm.com (nalasex01a.na.qualcomm.com [10.47.209.196]) by NALASPPMTA03.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 357JpD6D003593 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 7 Jun 2023 19:51:13 GMT Received: from [10.216.57.240] (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.42; Wed, 7 Jun 2023 12:51:06 -0700 Message-ID: <99cded6f-6a71-ffce-8479-c7c0726bfb8e@quicinc.com> Date: Thu, 8 Jun 2023 01:21:02 +0530 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.11.1 Subject: Re: [PATCH v8 6/9] usb: dwc3: qcom: Add multiport controller support for qcom wrapper Content-Language: en-US To: Johan Hovold CC: Bjorn Andersson , Thinh Nguyen , Greg Kroah-Hartman , Philipp Zabel , Andy Gross , Konrad Dybcio , Rob Herring , Krzysztof Kozlowski , Felipe Balbi , , , , , , , , , , References: <20230514054917.21318-1-quic_kriskura@quicinc.com> <20230514054917.21318-7-quic_kriskura@quicinc.com> <20230515222730.7snn2i33gkg6ctd2@ripper> <82553597-ce0e-48f4-44d4-9eeaaf4cb1c4@quicinc.com> From: Krishna Kurapati PSSNV In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01a.na.qualcomm.com (10.47.209.196) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: SMXrvb58mo55Ql3-t1vKI85-JROj7oCV X-Proofpoint-ORIG-GUID: SMXrvb58mo55Ql3-t1vKI85-JROj7oCV X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.573,FMLib:17.11.176.26 definitions=2023-06-07_10,2023-06-07_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 impostorscore=0 bulkscore=0 phishscore=0 spamscore=0 adultscore=0 priorityscore=1501 mlxlogscore=999 suspectscore=0 malwarescore=0 clxscore=1011 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2305260000 definitions=main-2306070172 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/7/2023 5:07 PM, Johan Hovold wrote: > Hi Krishna, > > and sorry about the delay in following up on this. As usual, there are > just way too many threads and this one in particular requires a bit of > thought. > Hi Johan, Thanks for taking the time out and reviewing the patches again. > On Sat, May 20, 2023 at 11:18:52PM +0530, Krishna Kurapati PSSNV wrote: >> On 5/17/2023 10:07 PM, Johan Hovold wrote: > >>> I don't think we should be adding more of these layering violations. A >>> parent device driver has no business messing with the driver data for a >>> child device which may or may not even have probed yet. >>> >>> I added a FIXME elsewhere in the driver about fixing up the current >>> instances that have already snuck in (which in some sense is even worse >>> by accessing driver data of a grandchild device). >>> >>> We really need to try sort this mess out and how to properly handle the >>> interactions between these layers (e.g. glue, dwc3 core and xhci). This >>> will likely involve adding callbacks from the child to the parent, for >>> example, when the child is suspending. > >> I agree with you, but in this case I believe there is no other way we >> can find the number of ports present. Unless its a dt property which >> parent driver can access the child's of node and get the details. Like >> done in v4 [1]. But it would be adding redundant data into DT as pointed >> out by Rob and Krzysztof and so we removed these properties. > > So there at least two issues with this series: > > 1. accessing xhci registers from the dwc3 core > 2. accessing driver data of a child device > > 1. The first part about accessing xhci registers goes against the clear > separation between glue, core and xhci that Felipe tried to maintain. > > I'm not entirely against doing this from the core driver before > registering the xhci platform device as the registers are unmapped > afterwards. But if this is to be allowed, then the implementation should > be shared with xhci rather than copied verbatim. > > The alternative that avoids this issue entirely could indeed be to > simply count the number of PHYs described in DT as Rob initially > suggested. Why would that not work? > The reason why I didn't want to read the Phy's from DT is explained in [1]. I felt it makes the code unreadable and its very tricky to read the phy's properly, so we decided we would initialize phy's for all ports and if a phy is missing in DT, the corresponding member in dwc->usbX_generic_phy[] would be NULL and any phy op on it would be a NOP. Also as per Krzysztof suggestion on [2], we can add a compatible to read number of phy's / ports present. This avoids accessing xhci members atleast in driver core. But the layering violations would still be present. > 2. The driver is already accessing driver data of the child device so > arguably your series is not really making things much worse than they > already are. > > I've just sent a couple of fixes to address some of the symptoms of > this layering violation here: > > https://lore.kernel.org/lkml/20230607100540.31045-1-johan+linaro@kernel.org/ > As you pointed out offline to me that using xhci event notifiers I mentioned on [3], if it is not acceptable to use them as notifications to check whether we are in host mode, I believe the only way would be to use the patches you pushed in. > Getting this fixed properly is going to take a bit of work, and > depending on how your multiport wake up implementation is going to look > like, adding support for multiport controllers may not make this much > harder to address. > > So perhaps we can indeed merge support for multiport and then get back > to cleaning this up. So, you are referring to use the patches you pushed today as a partial way to cleanup layering violations and merge multiport on top of it ? If so, I am fine with it. I can rebase my changes on top of them. [1]: https://lore.kernel.org/all/4eb26a54-148b-942f-01c6-64e66541de8b@quicinc.com/ [2]: https://lore.kernel.org/all/ca729f62-672e-d3de-4069-e2205c97e7d8@linaro.org/ [3]: https://lore.kernel.org/all/37fd026e-ecb1-3584-19f3-f8c1e5a9d20a@quicinc.com/ Regards, Krishna,