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 B690FCD4F52 for ; Fri, 22 Sep 2023 10:24:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233288AbjIVKYc (ORCPT ); Fri, 22 Sep 2023 06:24:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54266 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232616AbjIVKYb (ORCPT ); Fri, 22 Sep 2023 06:24:31 -0400 Received: from out2-smtp.messagingengine.com (out2-smtp.messagingengine.com [66.111.4.26]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DD7D094; Fri, 22 Sep 2023 03:24:25 -0700 (PDT) Received: from compute6.internal (compute6.nyi.internal [10.202.2.47]) by mailout.nyi.internal (Postfix) with ESMTP id B16D55C01FE; Fri, 22 Sep 2023 06:24:22 -0400 (EDT) Received: from imap51 ([10.202.2.101]) by compute6.internal (MEProxy); Fri, 22 Sep 2023 06:24:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arndb.de; h=cc :cc:content-type:content-type:date:date:from:from:in-reply-to :in-reply-to:message-id:mime-version:references:reply-to:sender :subject:subject:to:to; s=fm1; t=1695378262; x=1695464662; bh=A0 XJfKTmT4m+q8kCLVyRa+uLfx4AGYjYo6nvHEPffdA=; b=GTD+dHmCDg7zufMm6p oXcyZ+t63bJq7ylCADy4w931wBNORB8rG7UgSuVklWYaRFEuOu5aHNZPdmFLtMSB z08eD/Nn6jXWMniDEwxD6LzsXcUQY4xp/b361ExdTROSjpzbetbVHE6P9YdNyyTk FbqHNIjP2GQoOpdXqMlCic1dRIPLPsL8eMdwb9gzq9Zw/o1AtzkuzcCLyEBmv4vZ h62U+uKA0DR84cWYdYFyqck9MZx3RBdh4J/6tHOGcr8DWS8xO5HYizYl8A2od3AC N7ItA4WkWiLmcQ08OrP5ECW3BYkyKlTB3yWL0PvnpqGNd0Qw38ES8tZzGKWyV1Ys HnAA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:sender:subject :subject:to:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm2; t=1695378262; x=1695464662; bh=A0XJfKTmT4m+q 8kCLVyRa+uLfx4AGYjYo6nvHEPffdA=; b=XRMNJeYlK72hMxhN/3An8PUSvQ8Zs vbI4+6agWjVM0MapR6INJWexsglDbkRUw7pMOeIsBfBSF1u+I+kdSQvu6VXoH+54 Z/11Tc1BobX2Np+7T6CZYURaptzhz+rjsXYOkbASJLozDJx5cK15NSxhAmYM/AUZ 2e/5zWEHJJ0/0Dh/sZCMk+2887tX7mUlo91limrXLcG3vC8EvaPFrtrEGYowlpVv bJwczwlEqcyEZFYWJpM6WMohIUBeGFVTD3Nm0+YmHX/TYx7JUGeiE8thTOq/mSsD xVTDZaCp7sMtOHrzFQyaurf9kLy1W5x/zJs1rN0uiPf3yxciqCOhWPvZw== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedviedrudekkedgvdeiucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepofgfggfkjghffffhvfevufgtsehttdertderredtnecuhfhrohhmpedftehr nhguuceuvghrghhmrghnnhdfuceorghrnhgusegrrhhnuggsrdguvgeqnecuggftrfgrth htvghrnhepveefvdekgeejhfeggfejteeuieffhfevudeuudevtddukeejtedtteekveeg geehnecuffhomhgrihhnpehlihgsvghrrgdrtghhrghtnecuvehluhhsthgvrhfuihiivg eptdenucfrrghrrghmpehmrghilhhfrhhomheprghrnhgusegrrhhnuggsrdguvg X-ME-Proxy: Feedback-ID: i56a14606:Fastmail Received: by mailuser.nyi.internal (Postfix, from userid 501) id EF820B60089; Fri, 22 Sep 2023 06:24:20 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.9.0-alpha0-761-gece9e40c48-fm-20230913.001-gece9e40c MIME-Version: 1.0 Message-Id: <68ca306c-5ea2-437e-b7f1-68bad88557a0@app.fastmail.com> In-Reply-To: <20230913214944.59804-7-blarson@amd.com> References: <20230913214944.59804-1-blarson@amd.com> <20230913214944.59804-7-blarson@amd.com> Date: Fri, 22 Sep 2023 06:24:00 -0400 From: "Arnd Bergmann" To: "Brad Larson" , linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, "linux-mmc @ vger . kernel . org" , linux-spi@vger.kernel.org, "Adrian Hunter" , alcooperx@gmail.com, "Andy Shevchenko" , brendan.higgins@linux.dev, "Brian Norris" , "Catalin Marinas" , "Conor Dooley" , "David Gow" , gsomlo@gmail.com, "Greg Ungerer" , "Hal Feng" , "Hitomi Hasegawa" , =?UTF-8?Q?Jonathan_Neusch=C3=A4fer?= , "Joel Stanley" , "Emil Renner Berthing" , "Krzysztof Kozlowski" , krzysztof.kozlowski+dt@linaro.org, "Lee Jones" , "Lee Jones" , "Mark Brown" , "Philipp Zabel" , "Randy Dunlap" , "Rob Herring" , "Samuel Holland" , "Serge Semin" , "Shuah Khan" , suravee.suthikulpanit@amd.com, "Tom Lendacky" , "Tony Huang" , "Ulf Hansson" , vaishnav.a@ti.com, "Walker Chen" , "Will Deacon" , "Yinbo Zhu" , devicetree@vger.kernel.org Subject: Re: [PATCH v16 6/6] soc: amd: Add support for AMD Pensando SoC Controller Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org On Wed, Sep 13, 2023, at 17:49, Brad Larson wrote: > The Pensando SoC controller is a SPI connected companion device > that is present in all Pensando SoC board designs. The essential > board management registers are accessed on chip select 0 with > board mgmt IO support accessed using additional chip selects. > > Signed-off-by: Brad Larson > --- > > v15 changes: > - Drop custom ioctl and use existing miscdevice interface. > - Delete unused definitions in amd-pensando-ctrl.h > - Makefile change to compile for ARCH_PENSANDO Hi Brad, I'm sorry I've been out of the loop for so long, and I hope we can find a way to manage your SoC support soon. My impression is that the normal support patches (1, 3, 4, and 5) are largely uncontroversial, while the SoC controller support seems like we are still not converging onto something that is ready to merge, so I would suggest you split the two parts and send the basic support for inclusion in linux-6.7 while we continue to discuss the soc controller driver. Please remove any references to the soc controller from the dts files and send that first series to:soc@kernel.org cc:linux-arm-kernel (and the other interested parties) so I can pick those up. Regarding the soc controller driver, let me try to give you my impression of where we are: - you have gone through 16 revisions already, which is way too much for a public review, we should have been able to find a solution earlier than that, and this is partly our fault on the reviewer side, and I'm sorry about that. - Andy's latest comments and a lot of the earlier reviews were focused on implementation details. While those comments are helpful suggestions for improving the code, they miss the larger point about the system design that I'm worried about and probably don't help you actually get it merged. - The main problem I still see is that this driver completely bypasses our normal kernel abstractions and instead creates a low-level passthrough interface for handling kernel functionality in userspace. This creates a liability both for the user ABI and the kernel implementation and prevents any - There is a chance that your design is in fact the best way to handle this particular hardware, but it is your job to write a convincing explanation of why this platform is different from all the others in the patch description. Your current one-paragraph text does not explain this at all. I would suggest you prioritize getting the other patches included for the moment, but we can keep discussion the API design for this driver either in this thread or on the #armlinux IRC channel (irc.libera.chat) in parallel if you like. In order to help you here, I would need either the documentation of the SPI software interface, or the source code for the userspace tool. Arnd