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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 42FF2C433F5 for ; Thu, 24 Mar 2022 17:23:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Subject:Cc:To:From:Message-ID:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=PiCqDgos+ufi7HtY2zXksbrjHoMZzwhTPX0xWRRIK1Q=; b=OkokHZ1H9Pkkja WHBJQGvukGxlW3dDimNHoSgHo0zYV9u/XKokqejT5lDFG9EDaGB2RppsGf430NWbHNiEgCmFfjE2X OMYpJkKaOPZ/qZzhk/6pLzk2Ljj7IXml9iyB/e0PtWCrjhWQ9jkCJnS7hyjl1MCmlGE1MT1XZXgXo vrhTP4yeBU45ul3g4SjP4KSwXNPaoD1GZbvYQkM0oon3d2KlSS1a5P0Jg2tD9RXK8D3vxHLFch+9B C5XKgrS+2Joq6VkbDElvy3H2HEwJPUqZ6TanKtRRMKO5HK3tz12llldoQua8VrUfmKZUUxtev4+BC g7ZiYfB3dKMM0bWhLDfQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nXR9r-00HLZQ-D8; Thu, 24 Mar 2022 17:21:59 +0000 Received: from ams.source.kernel.org ([2604:1380:4601:e00::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nXR9o-00HLYk-6p for linux-arm-kernel@lists.infradead.org; Thu, 24 Mar 2022 17:21:58 +0000 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 ams.source.kernel.org (Postfix) with ESMTPS id A8203B82331; Thu, 24 Mar 2022 17:21:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 607D5C340EC; Thu, 24 Mar 2022 17:21:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1648142513; bh=xLzfzYThBn01lrwpvVJEv2Gb/9OdefdCKN7vc1aeUEw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=bv1u1/1it7BaXwJku7/IYXiuVhgsiXBhQa4EgtACA5qnP77ziBSr3FZu1eJWeFEGs GjSaKFzuTC0XHywiUxlXa2LJEj/Sv3pWxlMSS9uXsLIKNG7cIvqB1DxZSgA8/tf1rg iujsDrtoqMBoPErwsB2IzuVfdIlNVHcVnQn1fTR2Rq9X9rCN4fk0lTTYKFAWcpknWr R1gwvpZMZgOiQ5hDiUVzcP9C64USoR9ACc4ro1CCeCT7yrwMYKiG+ti4t2vx/ZPuZH yVwzwE6KrGqVYN42yDBXYkPpZ1C4BU+9KNkIrr3Yh58o8ZVW99f/ofvA3rOECDmDaa mJ1BwG/AzO8fw== Received: from sofa.misterjones.org ([185.219.108.64] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nXR9j-00GlL9-5w; Thu, 24 Mar 2022 17:21:51 +0000 Date: Thu, 24 Mar 2022 17:21:50 +0000 Message-ID: <87lewz5kr5.wl-maz@kernel.org> From: Marc Zyngier To: Vladimir Oltean Cc: "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Rob Herring , Shawn Guo , Leo Li , Biwen Li , "Z.Q. Hou" , Kurt Kanzenbach , Rasmus Villemoes Subject: Re: [RFC PATCH devicetree 00/10] Do something about ls-extirq interrupt-map breakage In-Reply-To: <20220324171041.t5yoocinj6gizcc7@skbuf> References: <20211214013800.2703568-1-vladimir.oltean@nxp.com> <87ilvrk1r0.wl-maz@kernel.org> <20211214095853.4emzycaxkuqr4tun@skbuf> <87czlzjxmz.wl-maz@kernel.org> <20220324171041.t5yoocinj6gizcc7@skbuf> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: vladimir.oltean@nxp.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, robh+dt@kernel.org, shawnguo@kernel.org, leoyang.li@nxp.com, biwen.li@nxp.com, zhiqiang.hou@nxp.com, kurt@linutronix.de, linux@rasmusvillemoes.dk X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220324_102156_564768_C4C2221F X-CRM114-Status: GOOD ( 46.28 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, 24 Mar 2022 17:10:42 +0000, Vladimir Oltean wrote: > > Hello Marc, > > On Tue, Dec 14, 2021 at 10:20:36AM +0000, Marc Zyngier wrote: > > On Tue, 14 Dec 2021 09:58:54 +0000, > > Vladimir Oltean wrote: > > > > > > Hi Marc (with a c), > > > > > > I wish the firmware for these SoCs was smart enough to be compatible > > > with the bindings that are in the kernel and provide a blob that the > > > kernel could actually use. Some work has been started there and this is > > > work in progress. True, I don't know what other OF-based firmware some > > > other customers may use, but I trust it isn't a lot more advanced than > > > what U-Boot currently has :) > > > > > > Also, the machines may have been in the wild for years, but the > > > ls-extirq driver was added in November 2019. So not with the > > > introduction of the SoC device trees themselves. That isn't so long ago. > > > > > > As for compatibility between old kernel and new DT: I guess you'll hear > > > various opinions on this one. > > > https://www.spinics.net/lists/linux-mips/msg07778.html > > > > > > | > Are we okay with the new device tree blobs breaking the old kernel? > > > | > > > | From my point of view, newer device trees are not required to work on > > > | older kernel, this would impose an unreasonable limitation and the use > > > | case is very limited. > > > > My views are on the opposite side. DT is an ABI, full stop. If you > > change something, you *must* guarantee forward *and* backward > > compatibility. That's because: > > > > - you don't control how updatable the firmware is > > > > - people may need to revert to other versions of the kernel because > > the new one is broken > > > > - there are plenty of DT users beyond Linux, and we are not creating > > bindings for Linux only. > > > > You may disagree with this, but for the subsystems I maintain, this is > > the rule I intent to stick to. > > > > M. > > > > -- > > Without deviation from the norm, progress is not possible. > > I was just debugging an interesting issue with an old kernel not working > with a new DT blob, and after figuring out what the problem was (is), > I remembered this message and I'm curious what you have to say about it. > > I have this DT layout: > > ethernet-phy@1 { > reg = <0x1>; > interrupts-extended = <&extirq 2 IRQ_TYPE_LEVEL_LOW>; > }; > > extirq: interrupt-controller@1ac { > compatible = "fsl,ls1021a-extirq"; > > }; > > I booted the new DT blob (which has "interrupts-extended") on a kernel > where the ls-extirq driver did not exist. This had the result of > of_mdiobus_phy_device_register() -> of_irq_get() returning -EPROBE_DEFER > forever and ever. So the PHY driver in turn never probed, and Ethernet > was broken. So I had to delete the interrupts OF property to let the PHY > at least work in poll mode. > > What went wrong here in your opinion? I'm not sure what you expect me to say here. You have a device that references an interrupt. The DT seems sound (I don't get why you think "interrupt-extended" is a problem here, but hey...). If your kernel doesn't have a driver for the interrupt controller referenced here, what do you expect, other than things not working? M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel