From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 739FD1A5B97; Sat, 1 Mar 2025 11:10:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740827441; cv=none; b=nJ0DAY7Z/b6WE/q8k7mPvc9MWPy/HMJ8M7dfF8/qJrVk61Q5hTQG9F5/fa7eZaho9HY8Cm17MJyKnu5jOnOTGuISuPbTVrYYikPplufwJsw80eEwOt8TJrLIseVUw3984xTEsdK+Tu1FvWRVcDXF2SWcjNnSyfRVom9+/T0/qkQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740827441; c=relaxed/simple; bh=nNqG0GMewRObnyRAAVI9p6JFUYawaXI8WiP+ukd2A5o=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=EwQutLlUhC5d/bIRepbzwDQYS+4msRVN867eRnRlViBd+OY9aQPmzqR2VSzWatfPnFC12zbhhl6UbREKZWEGndqOcV03jvtHFuLvMDJF8GA9ucjEUq2sNZPsshLXe2qHZ61++XYt3xKWpF6aaXADog1LOtlJ90K82fwhGvj4qL0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RqcJd/cY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RqcJd/cY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C2E79C4CEDD; Sat, 1 Mar 2025 11:10:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740827439; bh=nNqG0GMewRObnyRAAVI9p6JFUYawaXI8WiP+ukd2A5o=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=RqcJd/cYGKltRT9h6KNka1heUSDbeIOA2o7SOUY8yXx1mXGc/buNEIQrzp8usT0R5 oIIAoVNh0/DFsFRbxtgmVt5jIleViLUgMrXRnxLJeOPdu0Fhv6ZiVvg6T7/6vJBl6D QxEbxiEZeQC53aFcFH2ROVff6XP2uhKcZDO8GUBU/ndaT3+ZdKFvuOGWcf/+NkyIIM yOr4n7pLdKhjqdyyCBiHm4Pwpm650y90r0D/I6bYgRHAWjMSE7fV7tOKEP39Rb2RnM WyhQnNBNMTsQdpIlcwxbUoMhjZzG440kCGXu7d/ZX6w82326HJnqQ9NbHvq+EG7t9k ZI7SN1pmRobeA== 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 1toKjt-009LKs-1e; Sat, 01 Mar 2025 11:10:37 +0000 Date: Sat, 01 Mar 2025 11:10:35 +0000 Message-ID: <86plj1ovkk.wl-maz@kernel.org> From: Marc Zyngier To: Frank Li Cc: Kishon Vijay Abraham I , "Rafael J. Wysocki" , Thomas Gleixner , Anup Patel , Greg Kroah-Hartman , Danilo Krummrich , Manivannan Sadhasivam , Krzysztof =?UTF-8?B?V2lsY3p5xYRza2k=?= , Bjorn Helgaas , Arnd Bergmann , Shuah Khan , Richard Zhu , Lucas Stach , Lorenzo Pieralisi , Rob Herring , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , Krzysztof Kozlowski , Conor Dooley , Niklas Cassel , dlemoal@kernel.org, jdmason@kudzu.us, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, linux-kselftest@vger.kernel.org, imx@lists.linux.dev, devicetree@vger.kernel.org Subject: Re: [PATCH v15 02/15] irqdomain: Add IRQ_DOMAIN_FLAG_MSI_IMMUTABLE and irq_domain_is_msi_immutable() In-Reply-To: <20250211-ep-msi-v15-2-bcacc1f2b1a9@nxp.com> References: <20250211-ep-msi-v15-0-bcacc1f2b1a9@nxp.com> <20250211-ep-msi-v15-2-bcacc1f2b1a9@nxp.com> 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/29.4 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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: Frank.Li@nxp.com, kishon@kernel.org, rafael@kernel.org, tglx@linutronix.de, apatel@ventanamicro.com, gregkh@linuxfoundation.org, dakr@kernel.org, manivannan.sadhasivam@linaro.org, kw@linux.com, bhelgaas@google.com, arnd@arndb.de, shuah@kernel.org, hongxing.zhu@nxp.com, l.stach@pengutronix.de, lpieralisi@kernel.org, robh@kernel.org, shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com, krzk+dt@kernel.org, conor+dt@kernel.org, cassel@kernel.org, dlemoal@kernel.org, jdmason@kudzu.us, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, linux-kselftest@vger.kernel.org, imx@lists.linux.dev, devicetree@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Tue, 11 Feb 2025 19:21:55 +0000, Frank Li wrote: > > Add the flag IRQ_DOMAIN_FLAG_MSI_IMMUTABLE and the API function > irq_domain_is_msi_immutable() to check if the MSI controller retains an > immutable address/data pair during irq_set_affinity(). > > Ensure compatibility with MSI users like PCIe Endpoint Doorbell, which > require the address/data pair to remain unchanged after setup. Use this > function to verify if the MSI controller is immutable. Why is that a requirement? Why should a driver even care? M. -- Without deviation from the norm, progress is not possible.