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 E2D29C7EE23 for ; Thu, 8 Jun 2023 09:42:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233994AbjFHJmM (ORCPT ); Thu, 8 Jun 2023 05:42:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44476 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234020AbjFHJmH (ORCPT ); Thu, 8 Jun 2023 05:42:07 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D3ECC213C; Thu, 8 Jun 2023 02:42:05 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 68D6964B73; Thu, 8 Jun 2023 09:42:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8720C433EF; Thu, 8 Jun 2023 09:42:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686217324; bh=m8N40M4lIXVobIW+tOavlfsHEn5dzitNcBam5qP1h2k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=U7yrqaFrL/wQWiYIteDiSB6N77X98ODTHEx2BFKkgYBsHSw3EZixZCnQnxSqJQUMG gRZ/oC/XTcdFTDrvEVoAefB51KMidW+pUdLgC6MmO9CbpH1NvMMFhN6SZaNSsFERvI Ytzu24a4mkPa05AyaDzgkjbzklIMAT6TYDO12TBrLNTN8cPUr2Vu9CD9h+cIxsM9dl PJtvBkIy9BRpnDpa68EQbJ/EW36hXDxhluEi7XeG+nZ/koLCHBXbtUA/vJbgkkH6pF dGzxdsTxqhon4S7wMYU9E8i8uRiJWY0gE7yJ3+eEUc2Dks/kxYSxFC9ET7jooTk4RJ 0wLe044d+cMJA== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1q7CA1-00049R-5m; Thu, 08 Jun 2023 11:42:29 +0200 Date: Thu, 8 Jun 2023 11:42:29 +0200 From: Johan Hovold To: Krishna Kurapati PSSNV Cc: Bjorn Andersson , Thinh Nguyen , Greg Kroah-Hartman , Philipp Zabel , Andy Gross , Konrad Dybcio , Rob Herring , Krzysztof Kozlowski , Felipe Balbi , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, quic_pkondeti@quicinc.com, quic_ppratap@quicinc.com, quic_wcheng@quicinc.com, quic_jackp@quicinc.com, quic_harshq@quicinc.com, ahalaney@redhat.com Subject: Re: [PATCH v8 6/9] usb: dwc3: qcom: Add multiport controller support for qcom wrapper Message-ID: 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> <99cded6f-6a71-ffce-8479-c7c0726bfb8e@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <99cded6f-6a71-ffce-8479-c7c0726bfb8e@quicinc.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 08, 2023 at 01:21:02AM +0530, Krishna Kurapati PSSNV wrote: > On 6/7/2023 5:07 PM, Johan Hovold wrote: > > 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. That doesn't sound too convincing. Can't you just iterate over the PHYs described in DT and determine the maximum port number used for HS and SS? > 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. Yes, but if the information is already available in DT it's better to use it rather than re-encode it in the driver. > > 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. I still think we'll end up using callbacks from the xhci/core into the glue driver, but dedicated ones rather than using usb_register_notify(). The fixes I posted can work as a stop-gap solution until then. > > 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. Right. A bit depending on how your wakeup implementation looks like, it seems we can merge multiport support and then address the layering issues which are already present in the driver. > [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/ Johan