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 X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8D55FC43387 for ; Thu, 10 Jan 2019 16:34:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C6C3214DA for ; Thu, 10 Jan 2019 16:34:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linaro.org header.i=@linaro.org header.b="QAhfecLQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728087AbfAJQeu (ORCPT ); Thu, 10 Jan 2019 11:34:50 -0500 Received: from mail-wm1-f67.google.com ([209.85.128.67]:37933 "EHLO mail-wm1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727771AbfAJQet (ORCPT ); Thu, 10 Jan 2019 11:34:49 -0500 Received: by mail-wm1-f67.google.com with SMTP id m22so12759337wml.3 for ; Thu, 10 Jan 2019 08:34:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:openpgp:autocrypt:message-id:date :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=w32hLnAw5bLjWDJ9T8+qGhKha4sKnjjXz6R6e6acIX4=; b=QAhfecLQFQMuw408R6wdu7wFUxU09DyOPUJ9LVygjs2aadQbCPUJHyNDHX+KKOniap dMAArhSzvv1eeKNynMDzAPBUZiLs1sYaiRrw50xK0bHlq9avMpnlCme043QMKGix8WZS dz+nn/ms7ee+iuW3ZeKx5rCJBHTMciOjrIAPE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:openpgp:autocrypt :message-id:date:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=w32hLnAw5bLjWDJ9T8+qGhKha4sKnjjXz6R6e6acIX4=; b=iQG6+30/PE4gPYWJbL7//rwv6kBjn82v5CV+Hz0bjh7+HfPYIO/aB9eSrppl/0K5W2 izXlTLtME46Ypyjh/QJ0TqpM+NHtYKjUdKsQ5aRk7/1GC1E0xkIAm640jZy6qePPBDcS It0OUqPGtLaiiKDbBtJHmuo/ck7T5pIhKVTTE0kxfrHmoqFG3chc7OCGBtZN8jxPJR+1 AUyPYAv40/EE+vsynBY//JJgckeOMoGWo48NSra8+fwgdmFgOYyNn/oyhAjA69+LQl+E KfB2VTf2T+LfmnOVwWayTCqi8M/3Z8b1QsWau0p5rt5NsQ5hNWrSSJguEPjYpyOFii9G Ic6w== X-Gm-Message-State: AJcUukfQCXfFimvzh/cRUYcRAvlWWb+NcQ6bCUT72XqACg3TOHDpd3YY 9sZgFpxmZ4KL/P3iuIi0mtxbyg== X-Google-Smtp-Source: ALg8bN5aj5as7M96AsGERTcrl249DmAuGIutaCvQjhYPW0GTTPFG1sBE2A4JwnObhzRGytXMT7GSfw== X-Received: by 2002:a1c:990c:: with SMTP id b12mr10982437wme.106.1547138087097; Thu, 10 Jan 2019 08:34:47 -0800 (PST) Received: from [10.44.66.8] ([212.45.67.2]) by smtp.googlemail.com with ESMTPSA id m4sm5658204wmi.3.2019.01.10.08.34.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 10 Jan 2019 08:34:46 -0800 (PST) Subject: Re: [PATCH v10 0/8] Introduce on-chip interconnect API To: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" , Arnd Bergmann , Olof Johansson , evgreen@chromium.org, Linux PM , "Rafael J. Wysocki" , Rob Herring , Michael Turquette , Kevin Hilman , Vincent Guittot , Saravana Kannan , bjorn.andersson@linaro.org, Amit Kucheria , seansw@qti.qualcomm.com, daidavid1@codeaurora.org, Mark Rutland , Lorenzo Pieralisi , abailon@baylibre.com, maxime.ripard@bootlin.com, Thierry Reding , ksitaraman@nvidia.com, sanjayc@nvidia.com, "devicetree@vger.kernel.org" , Linux Kernel Mailing List , Linux ARM , linux-arm-msm , linux-tegra@vger.kernel.org, Doug Anderson , Andy Gross References: <20181127180349.29997-1-georgi.djakov@linaro.org> <20181206145547.GA7884@kroah.com> <6923d6ed-e357-b083-1830-8396d788efe5@linaro.org> <9a3aae02-c7e0-97e3-2330-af4fccee6c14@linaro.org> <20181211065808.GB5161@kroah.com> <199be960-032a-d72d-4293-820e23a15b7a@linaro.org> <20190110162906.GA19693@kroah.com> From: Georgi Djakov Openpgp: preference=signencrypt Autocrypt: addr=georgi.djakov@linaro.org; prefer-encrypt=mutual; keydata= mQINBFjTuRcBEACyAOVzghvyN19Sa/Nit4LPBWkICi5W20p6bwiZvdjhtuh50H5q4ktyxJtp 1+s8dMSa/j58hAWhrc2SNL3fttOCo+MM1bQWwe8uMBQJP4swgXf5ZUYkSssQlXxGKqBSbWLB uFHOOBTzaQBaNgsdXo+mQ1h8UCgM0zQOmbs2ort8aHnH2i65oLs5/Xgv/Qivde/FcFtvEFaL 0TZ7odM67u+M32VetH5nBVPESmnEDjRBPw/DOPhFBPXtal53ZFiiRr6Bm1qKVu3dOEYXHHDt nF13gB+vBZ6x5pjl02NUEucSHQiuCc2Aaavo6xnuBc3lnd4z/xk6GLBqFP3P/eJ56eJv4d0B 0LLgQ7c1T3fU4/5NDRRCnyk6HJ5+HSxD4KVuluj0jnXW4CKzFkKaTxOp7jE6ZD/9Sh74DM8v etN8uwDjtYsM07I3Szlh/I+iThxe/4zVtUQsvgXjwuoOOBWWc4m4KKg+W4zm8bSCqrd1DUgL f67WiEZgvN7tPXEzi84zT1PiUOM98dOnmREIamSpKOKFereIrKX2IcnZn8jyycE12zMkk+Sc ASMfXhfywB0tXRNmzsywdxQFcJ6jblPNxscnGMh2VlY2rezmqJdcK4G4Lprkc0jOHotV/6oJ mj9h95Ouvbq5TDHx+ERn8uytPygDBR67kNHs18LkvrEex/Z1cQARAQABtChHZW9yZ2kgRGph a292IDxnZW9yZ2kuZGpha292QGxpbmFyby5vcmc+iQI+BBMBAgAoBQJY07kXAhsDBQkHhM4A BgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRCyi/eZcnWWUuvsD/4miikUeAO6fU2Xy3fT l7RUCeb2Uuh1/nxYoE1vtXcow6SyAvIVTD32kHXucJJfYy2zFzptWpvD6Sa0Sc58qe4iLY4j M54ugOYK7XeRKkQHFqqR2T3g/toVG1BOLS2atooXEU+8OFbpLkBXbIdItqJ1M1SEw8YgKmmr JlLAaKMq3hMb5bDQx9erq7PqEKOB/Va0nNu17IL58q+Q5Om7S1x54Oj6LiG/9kNOxQTklOQZ t61oW1Ewjbl325fW0/Lk0QzmfLCrmGXXiedFEMRLCJbVImXVKdIt/Ubk6SAAUrA5dFVNBzm2 L8r+HxJcfDeEpdOZJzuwRyFnH96u1Xz+7X2V26zMU6Wl2+lhvr2Tj7spxjppR+nuFiybQq7k MIwyEF0mb75RLhW33sdGStCZ/nBsXIGAUS7OBj+a5fm47vQKv6ekg60oRTHWysFSJm1mlRyq exhI6GwUo5GM/vE36rIPSJFRRgkt6nynoba/1c4VXxfhok2rkP0x3CApJ5RimbvITTnINY0o CU6f1ng1I0A1UTi2YcLjFq/gmCdOHExT4huywfu1DDf0p1xDyPA1FJaii/gJ32bBP3zK53hM dj5S7miqN7F6ZpvGSGXgahQzkGyYpBR5pda0m0k8drV2IQn+0W8Qwh4XZ6/YdfI81+xyFlXc CJjljqsMCJW6PdgEH7kCDQRY07kXARAAvupGd4Jdd8zRRiF+jMpv6ZGz8L55Di1fl1YRth6m lIxYTLwGf0/p0oDLIRldKswena3fbWh5bbTMkJmRiOQ/hffhPSNSyyh+WQeLY2kzl6geiHxD zbw37e2hd3rWAEfVFEXOLnmenaUeJFyhA3Wd8OLdRMuoV+RaLhNfeHctiEn1YGy2gLCq4VNb 4Wj5hEzABGO7+LZ14hdw3hJIEGKtQC65Jh/vTayGD+qdwedhINnIqslk9tCQ33a+jPrCjXLW X29rcgqigzsLHH7iVHWA9R5Aq7pCy5hSFsl4NBn1uV6UHlyOBUuiHBDVwTIAUnZ4S8EQiwgv WQxEkXEWLM850V+G6R593yZndTr3yydPgYv0xEDACd6GcNLR/x8mawmHKzNmnRJoOh6Rkfw2 fSiVGesGo83+iYq0NZASrXHAjWgtZXO1YwjW9gCQ2jYu9RGuQM8zIPY1VDpQ6wJtjO/KaOLm NehSR2R6tgBJK7XD9it79LdbPKDKoFSqxaAvXwWgXBj0Oz+Y0BqfClnAbxx3kYlSwfPHDFYc R/ppSgnbR5j0Rjz/N6Lua3S42MDhQGoTlVkgAi1btbdV3qpFE6jglJsJUDlqnEnwf03EgjdJ 6KEh0z57lyVcy5F/EUKfTAMZweBnkPo+BF2LBYn3Qd+CS6haZAWaG7vzVJu4W/mPQzsAEQEA AYkCJQQYAQIADwUCWNO5FwIbDAUJB4TOAAAKCRCyi/eZcnWWUhlHD/0VE/2x6lKh2FGP+QHH UTKmiiwtMurYKJsSJlQx0T+j/1f+zYkY3MDX+gXa0d0xb4eFv8WNlEjkcpSPFr+pQ7CiAI33 99kAVMQEip/MwoTYvM9NXSMTpyRJ/asnLeqa0WU6l6Z9mQ41lLzPFBAJ21/ddT4xeBDv0dxM GqaH2C6bSnJkhSfSja9OxBe+F6LIAZgCFzlogbmSWmUdLBg+sh3K6aiBDAdZPUMvGHzHK3fj gHK4GqGCFK76bFrHQYgiBOrcR4GDklj4Gk9osIfdXIAkBvRGw8zg1zzUYwMYk+A6v40gBn00 OOB13qJe9zyKpReWMAhg7BYPBKIm/qSr82aIQc4+FlDX2Ot6T/4tGUDr9MAHaBKFtVyIqXBO xOf0vQEokkUGRKWBE0uA3zFVRfLiT6NUjDQ0vdphTnsdA7h01MliZLQ2lLL2Mt5lsqU+6sup Tfql1omgEpjnFsPsyFebzcKGbdEr6vySGa3Cof+miX06hQXKe99a5+eHNhtZJcMAIO89wZmj 7ayYJIXFqjl/X0KBcCbiAl4vbdBw1bqFnO4zd1lMXKVoa29UHqby4MPbQhjWNVv9kqp8A39+ E9xw890l1xdERkjVKX6IEJu2hf7X3MMl9tOjBK6MvdOUxvh1bNNmXh7OlBL1MpJYY/ydIm3B KEmKjLDvB0pePJkdTw== Message-ID: <69f004fa-2705-5cf4-3812-8e7b68a16400@linaro.org> Date: Thu, 10 Jan 2019 18:34:41 +0200 MIME-Version: 1.0 In-Reply-To: <20190110162906.GA19693@kroah.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/10/19 18:29, Greg Kroah-Hartman wrote: > On Thu, Jan 10, 2019 at 04:19:14PM +0200, Georgi Djakov wrote: >> Hi Greg, >> >> On 12/17/18 13:17, Georgi Djakov wrote: >>> Hi Greg, >>> >>> On 12/11/18 08:58, Greg Kroah-Hartman wrote: >>>> On Mon, Dec 10, 2018 at 04:50:00PM +0200, Georgi Djakov wrote: >>>>> On 12/10/18 13:00, Rafael J. Wysocki wrote: >>>>>> On Mon, Dec 10, 2018 at 11:18 AM Georgi Djakov wrote: >>>>>>> >>>>>>> Hi Rafael, >>>>>>> >>>>>>> On 12/10/18 11:04, Rafael J. Wysocki wrote: >>>>>>>> On Thu, Dec 6, 2018 at 3:55 PM Greg KH wrote: >>>>>>>>> >>>>>>>>> On Wed, Dec 05, 2018 at 12:41:35PM -0800, Evan Green wrote: >>>>>>>>>> On Tue, Nov 27, 2018 at 10:03 AM Georgi Djakov wrote: >>>>>>>>>>> >>>>>>>>>>> Modern SoCs have multiple processors and various dedicated cores (video, gpu, >>>>>>>>>>> graphics, modem). These cores are talking to each other and can generate a >>>>>>>>>>> lot of data flowing through the on-chip interconnects. These interconnect >>>>>>>>>>> buses could form different topologies such as crossbar, point to point buses, >>>>>>>>>>> hierarchical buses or use the network-on-chip concept. >>>>>>>>>>> >>>>>>>>>>> These buses have been sized usually to handle use cases with high data >>>>>>>>>>> throughput but it is not necessary all the time and consume a lot of power. >>>>>>>>>>> Furthermore, the priority between masters can vary depending on the running >>>>>>>>>>> use case like video playback or CPU intensive tasks. >>>>>>>>>>> >>>>>>>>>>> Having an API to control the requirement of the system in terms of bandwidth >>>>>>>>>>> and QoS, so we can adapt the interconnect configuration to match those by >>>>>>>>>>> scaling the frequencies, setting link priority and tuning QoS parameters. >>>>>>>>>>> This configuration can be a static, one-time operation done at boot for some >>>>>>>>>>> platforms or a dynamic set of operations that happen at run-time. >>>>>>>>>>> >>>>>>>>>>> This patchset introduce a new API to get the requirement and configure the >>>>>>>>>>> interconnect buses across the entire chipset to fit with the current demand. >>>>>>>>>>> The API is NOT for changing the performance of the endpoint devices, but only >>>>>>>>>>> the interconnect path in between them. >>>>>>>>>> >>>>>>>>>> For what it's worth, we are ready to land this in Chrome OS. I think >>>>>>>>>> this series has been very well discussed and reviewed, hasn't changed >>>>>>>>>> much in the last few spins, and is in good enough shape to use as a >>>>>>>>>> base for future patches. Georgi's also done a great job reaching out >>>>>>>>>> to other SoC vendors, and there appears to be enough consensus that >>>>>>>>>> this framework will be usable by more than just Qualcomm. There are >>>>>>>>>> also several drivers out on the list trying to add patches to use this >>>>>>>>>> framework, with more to come, so it made sense (to us) to get this >>>>>>>>>> base framework nailed down. In my experiments this is an important >>>>>>>>>> piece of the overall power management story, especially on systems >>>>>>>>>> that are mostly idle. >>>>>>>>>> >>>>>>>>>> I'll continue to track changes to this series and we will ultimately >>>>>>>>>> reconcile with whatever happens upstream, but I thought it was worth >>>>>>>>>> sending this note to express our "thumbs up" towards this framework. >>>>>>>>> >>>>>>>>> Looks like a v11 will be forthcoming, so I'll wait for that one to apply >>>>>>>>> it to the tree if all looks good. >>>>>>>> >>>>>>>> I'm honestly not sure if it is ready yet. >>>>>>>> >>>>>>>> New versions are coming on and on, which may make such an impression, >>>>>>>> but we had some discussion on it at the LPC and some serious questions >>>>>>>> were asked during it, for instance regarding the DT binding introduced >>>>>>>> here. I'm not sure how this particular issue has been addressed here, >>>>>>>> for example. >>>>>>> >>>>>>> There have been no changes in bindings since v4 (other than squashing >>>>>>> consumer and provider bindings into a single patch and fixing typos). >>>>>>> >>>>>>> The last DT comment was on v9 [1] where Rob wanted confirmation from >>>>>>> other SoC vendors that this works for them too. And now we have that >>>>>>> confirmation and there are patches posted on the list [2]. >>>>>> >>>>>> OK >>>>>> >>>>>>> The second thing (also discussed at LPC) was about possible cases where >>>>>>> some consumer drivers can't calculate how much bandwidth they actually >>>>>>> need and how to address that. The proposal was to extend the OPP >>>>>>> bindings with one more property, but this is not part of this patchset. >>>>>>> It is a future step that needs more discussion on the mailing list. If a >>>>>>> driver really needs some bandwidth data now, it should be put into the >>>>>>> driver and not in DT. After we have enough consumers, we can discuss >>>>>>> again if it makes sense to extract something into DT or not. >>>>>> >>>>>> That's fine by me. >>>>>> >>>>>> Admittedly, I have some reservations regarding the extent to which >>>>>> this approach will turn out to be useful in practice, but I guess as >>>>>> long as there is enough traction, the best way to find out it to try >>>>>> and see. :-) >>>>>> >>>>>> From now on I will assume that this series is going to be applied by Greg. >>>>> >>>>> That was the initial idea, but the problem is that there is a recent >>>>> change in the cmd_db API (needed by the sdm845 provider driver), which >>>>> is going through arm-soc/qcom/drivers. So either Greg pulls also the >>>>> qcom-drivers-for-4.21 tag from Andy or the whole series goes via Olof >>>>> and Arnd. Maybe there are other options. I don't have any preference and >>>>> don't want to put extra burden on any maintainers, so i am ok with what >>>>> they prefer. >>>> >>>> Let me take the time later this week to review the code, which I haven't >>>> done in a while... >>>> >>> >>> When you get a chance to review, please keep in mind that the latest >>> version is v12 (from 08.Dec). The same is also available in linux-next >>> with no reported issues. >> >> The dependencies for this patchset have been already merged in v5.0-rc1, >> so i was wondering if this can still go into -rc2? Various patches that >> use this API are already posted and having it sooner will make dealing >> with dependencies and merge paths a bit easier during the next merge >> window. Or i can just rebase and resend everything targeting v5.1. > > We can't add new features after -rc1, sorry. > > Please rebase and resend to target 5.1 Ok, i was expecting that. Thanks for confirming! BR, Georgi