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 336EDC30653 for ; Tue, 25 Jun 2024 07:37:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: References:In-Reply-To:Subject:Cc:To:From:Message-ID:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=kprjt3x+vb1OZcl6liTuJsD4qj1RFjACz4jcrx0xQO8=; b=0Xj+XQKcbeNuus/w38vESBhEc9 9f3gxSLCieN8Q7a6fZh5WGvgX7ED/HbDSMM8iDglEvibf7lCDeQUM008ZIpoYhQ+6BpptUWk4kVLn Vi7gI4Ka3d3lJYzA/LKHNP0bJynMS62y4I0pNr+iYuRnWxoJxaKkfr+D80IS7GibzOAmiJk/mE99w RhibJlUdOQAFPcGs4tIXRsh3Pw648u4M4pFWBdtZlh13PAtOnO6Sj2HWm8m5nOfMMuNSyMaSQ8Vck YvY2+m7U/KtuMICzfbqLGJavG+eazAsFzNYBWaZrvDzmc9pHwsUk9VwMf2WOc58yoKSeuEO4pavQ2 KNC1Jqlg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sM0jw-00000001zI4-2Mhi; Tue, 25 Jun 2024 07:37:20 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sM0jp-00000001zFu-3uiE for linux-arm-kernel@lists.infradead.org; Tue, 25 Jun 2024 07:37:15 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 989B1611ED; Tue, 25 Jun 2024 07:37:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35C79C32789; Tue, 25 Jun 2024 07:37:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719301032; bh=GQZtXhAEg7WxvHsN/Xrc9fpa1acHEuQJQTIAFZ+PqC0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=qIqWOP8Mz4OTpTU6AINxjUUFnVqAa143m+m+ERwfP/SPXlVSTWNOvXO7cICeK+iFO BBexpH+vnbumu3dR/YLAi4qxtqEARjYyPbiEBtrdz4vrWYnIAYlKWrJUrczLNKYYxq 60/AbTm47++9XaDu82f1swvovvgEdr1lkPJK7IphSQNr3vGEvsmmuwYPIQoYs/bCM4 UpyDCykoJtZfEyVS4Puf6S3v72zdTAuOYA6Uov53flqirOp6OwjY1VpdYN06Y0sWBi WL8hR0DJ9oq6Wy5GpdZaDVArEhopVXrBvSvD8DGmgOAb/wSoP+SKD4tlZe7t24jf67 3GGXM//DpiJVQ== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1sM0jl-0074Fn-Jx; Tue, 25 Jun 2024 08:37:09 +0100 Date: Tue, 25 Jun 2024 08:37:09 +0100 Message-ID: <86y16tiica.wl-maz@kernel.org> From: Marc Zyngier To: Thomas Gleixner Cc: Shivamurthy Shastri , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, anna-maria@linutronix.de, shawnguo@kernel.org, s.hauer@pengutronix.de, festevam@gmail.com, bhelgaas@google.com, rdunlap@infradead.org, vidyas@nvidia.com, ilpo.jarvinen@linux.intel.com, apatel@ventanamicro.com, kevin.tian@intel.com, nipun.gupta@amd.com, den@valinux.co.jp, andrew@lunn.ch, gregory.clement@bootlin.com, sebastian.hesselbarth@gmail.com, gregkh@linuxfoundation.org, rafael@kernel.org, alex.williamson@redhat.com, will@kernel.org, lorenzo.pieralisi@arm.com, jgg@mellanox.com, ammarfaizi2@gnuweeb.org, robin.murphy@arm.com, lpieralisi@kernel.org, nm@ti.com, kristo@kernel.org, vkoul@kernel.org, okaya@kernel.org, agross@kernel.org, andersson@kernel.org, mark.rutland@arm.com, shameerali.kolothum.thodi@huawei.com, yuzenghui@huawei.com Subject: Re: [PATCH v3 14/24] genirq/gic-v3-mbi: Remove unused wired MSI mechanics In-Reply-To: <87ed8vu033.ffs@tglx> References: <20240614102403.13610-1-shivamurthy.shastri@linutronix.de> <20240614102403.13610-15-shivamurthy.shastri@linutronix.de> <86le36jf0q.wl-maz@kernel.org> <87plsfu3sz.ffs@tglx> <86h6drk9h1.wl-maz@kernel.org> <87h6dru0pb.ffs@tglx> <87ed8vu033.ffs@tglx> 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/29.2 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: tglx@linutronix.de, shivamurthy.shastri@linutronix.de, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, anna-maria@linutronix.de, shawnguo@kernel.org, s.hauer@pengutronix.de, festevam@gmail.com, bhelgaas@google.com, rdunlap@infradead.org, vidyas@nvidia.com, ilpo.jarvinen@linux.intel.com, apatel@ventanamicro.com, kevin.tian@intel.com, nipun.gupta@amd.com, den@valinux.co.jp, andrew@lunn.ch, gregory.clement@bootlin.com, sebastian.hesselbarth@gmail.com, gregkh@linuxfoundation.org, rafael@kernel.org, alex.williamson@redhat.com, will@kernel.org, lorenzo.pieralisi@arm.com, jgg@mellanox.com, ammarfaizi2@gnuweeb.org, robin.murphy@arm.com, lpieralisi@kernel.org, nm@ti.com, kristo@kernel.org, vkoul@kernel.org, okaya@kernel.org, agross@kernel.org, andersson@kernel.org, mark.rutland@arm.com, shameerali.kolothum.thodi@huawei.com, yuzenghui@huawei.com 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-20240625_003714_100752_E772CA10 X-CRM114-Status: GOOD ( 24.89 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, 17 Jun 2024 15:15:44 +0100, Thomas Gleixner wrote: > > On Mon, Jun 17 2024 at 16:02, Thomas Gleixner wrote: > > On Mon, Jun 17 2024 at 14:03, Marc Zyngier wrote: > >> Patch 9/24 rewrites the mbigen driver. Which has nothing to do with > >> what the gic-v3-mbi code does. They are different blocks, and the sole > >> machine that has the mbigen IP doesn't have any gic-v3-mbi support. > >> All they have in common are 3 random letters. > >> > >> What you are doing here is to kill any support for *devices* that need > >> to signal level-triggered MSIs in that driver, and nothing to do with > >> wire-MSI translation. > >> > >> So what replaces it? > > > > Hrm. I must have misread this mess. Let me stare some more. > > Ok. Found my old notes. > > AFAICT _all_ users of platform_device_msi_init_and_alloc_irqs(): > > ufs_qcom_config_esi() > smmu_pmu_setup_msi() > flexrm_mbox_probe() > arm_smmu_setup_msis() > hidma_request_msi() > mv_xor_v2_probe() > > just install their special MSI write callback. I don't see any of those > setting up LEVEL triggered MSIs. > > But then I'm might be missing something. If so can you point me please > to the usage instance which actually uses level signaled MSI? Good question. I'm pretty sure we had *something* at some point that used it, or that was planning on using it. I even vividly remember who was asking for this. But either that never really made it upstream, or they decided to move away from the kernel setting the MSI up and relied on firmware for that (which is fine as long as the device isn't behind an IOMMU). In the end, it begs the question of what we want to do with this feature. I don't think it is a big deal to keep it around, but maybe we should plan for it to be retired. That's independent of this series, IMO. Thanks, M. -- Without deviation from the norm, progress is not possible.