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=-1.0 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 9A04EC04EB8 for ; Mon, 10 Dec 2018 10:18:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4B31220821 for ; Mon, 10 Dec 2018 10:18:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linaro.org header.i=@linaro.org header.b="QKLRXLD/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4B31220821 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726985AbeLJKS0 (ORCPT ); Mon, 10 Dec 2018 05:18:26 -0500 Received: from mail-wm1-f66.google.com ([209.85.128.66]:40342 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726923AbeLJKSY (ORCPT ); Mon, 10 Dec 2018 05:18:24 -0500 Received: by mail-wm1-f66.google.com with SMTP id q26so10529294wmf.5 for ; Mon, 10 Dec 2018 02:18:22 -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=e5cPfgHDBHHlkjbuTeNtqtIw6P84dpCVt6Hg5wYdwqA=; b=QKLRXLD/jdS3rGDLrtslRH4R3nAzGm5M/A2nq7vzlony70KclBc6cedyYWJFWAG1Ri k8Iwygku1dVgNGuoBK4wQX+26jx0cn7XQElLxbo1QXsNdgtB+t+rcXOU1wRt2srRg8RE vCAXBXYGcsWl4hXsNudJo+Ur3ZTm77J97qLFk= 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=e5cPfgHDBHHlkjbuTeNtqtIw6P84dpCVt6Hg5wYdwqA=; b=mzUlgPT/d5UlrTQGFb+GXDWogcRxcQDcpGgxWhy1Z2msrSFNNN0LFh7thhHW9Pp6xT aznVE1XN0fT3R+fWp+uqmZw5ojRHi0a6+EOQ1x2rlaoRfdKs8hf8DuqxuLSZdoP5HIRk WR6Oakk7gTjkAo3btzktW/zMoiG+cDJFSN2MupkpyZvo0YVk5hsIiqQEpG8UT7M7m6V3 SX0PKd/2aGJzrpucQyAIFh9sdi0wETgCqshaq0riNs3mtlHHlLpN2zFmIPy+RHKLR3kP jKd/GRPTQcT8Slw/OID0LkEbmdJJUrMnDpwkZ43ouAt0obf8WPCFGQCegGoFOWNlEvwy miQg== X-Gm-Message-State: AA+aEWZ83TplTFaL7jYal5BSj7ua4w8C1cFYxgR+jM/zmY8bwLngz4vW 0Q97mmo4Q3kLNLEn58nnmHdnWg== X-Google-Smtp-Source: AFSGD/WjbmefNG6dovYhgaq6NDUkxSluSfylpVTJX+jsr4BJiX5TiR92FF/5UyHC4hybqdjBKOteXw== X-Received: by 2002:a1c:e046:: with SMTP id x67mr9702713wmg.122.1544437101203; Mon, 10 Dec 2018 02:18:21 -0800 (PST) Received: from [10.44.66.8] ([212.45.67.2]) by smtp.googlemail.com with ESMTPSA id k135sm17922945wmd.42.2018.12.10.02.18.18 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 10 Dec 2018 02:18:20 -0800 (PST) Subject: Re: [PATCH v10 0/8] Introduce on-chip interconnect API To: "Rafael J. Wysocki" , Greg Kroah-Hartman Cc: 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, Arnd Bergmann , 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 References: <20181127180349.29997-1-georgi.djakov@linaro.org> <20181206145547.GA7884@kroah.com> From: Georgi Djakov Openpgp: preference=signencrypt Autocrypt: addr=georgi.djakov@linaro.org; prefer-encrypt=mutual; keydata= xsFNBFjTuRcBEACyAOVzghvyN19Sa/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/Z1cQARAQABzShHZW9yZ2kgRGph a292IDxnZW9yZ2kuZGpha292QGxpbmFyby5vcmc+wsF+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 CJjljqsMCJW6PdgEH87BTQRY07kXARAAvupGd4Jdd8zRRiF+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 AcLBZQQYAQIADwUCWNO5FwIbDAUJB4TOAAAKCRCyi/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: <6923d6ed-e357-b083-1830-8396d788efe5@linaro.org> Date: Mon, 10 Dec 2018 12:18:17 +0200 MIME-Version: 1.0 In-Reply-To: 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 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]. 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. Thanks, Georgi [1] https://lkml.org/lkml/2018/9/25/939 [2] https://lkml.org/lkml/2018/11/28/12