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 B17D7EB8FAD for ; Wed, 6 Sep 2023 09:52:31 +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-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:Message-ID:References:In-Reply-To:Subject:Cc:To:From :Date:MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=+JUmH9cfdmGOAnuk5OldaQjqFDS5qhQCZIJ8kENDSRg=; b=z85bYMSkd7v+z39TIkqIlRhuA1 K30/GSxwWim+ny4Fifk3aiMEvzYlZ/RifSAn8NxZomfEtQgMMgcEo1Yp3x7eOYk3Wdw07fXsSH90y kxIAVl7YieZcJCApIF8AI1I92vrucWpKzHJL+wCbcuplULMZiInKdJLeNukDjxNxBIYe/grgaK0F2 wL/iq9NARKEchFejqQdsG/3O+WdkPFLp9Ix1cFwnzabnyRSshH9SaFtU7CKUpI09pJrU4vXzNplBz lcNHurOBXZqCpe5IKZzSG91M68tFmk3xux/7d+mRFv7ZhxWTm95f8Iy1XNYTWevbVTkkU54TPKj4r yBsWRCgQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qdpCj-0080y7-1i; Wed, 06 Sep 2023 09:52:09 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qdpCf-0080wc-18 for linux-arm-kernel@lists.infradead.org; Wed, 06 Sep 2023 09:52:07 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6B68F60FA4; Wed, 6 Sep 2023 09:52:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C91CEC433C7; Wed, 6 Sep 2023 09:52:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1693993923; bh=mmp8U7p0dsAb7N7ZOUIzbHp3mn89D9lJHI7IHcFjwRo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=fTuiTzK78yx9q/vHwz/EqLAO9mj/Zi2bgCReid1F9tXrrAW+oFQX7uwbKbZeXG8e8 edCZTS8PfSjdDiNcOxPPCm+lo+fSwTqFRFlS71EOBr2YUZLfIw2Lq6ZXdVqxOPIRkV XOUEDtYBdxXkKpvBU/oH9cKEB9ki0XCqRRdAQT6uvrkq8ae7XKpM/Or1kEy72wjeDD XXmTRfTbdu6FWQMPV+k2eJDHwQ0v4n2zzXxAPmVxFVlH1dkUxit57eht6G8NEU3xEg 8z/YaxBmRarOMcRLWhWN1FGN02pSyttK+8BF0IfotpB43Szu5qtNlyD2udfi9fiu1R WQx23mXUpZH0Q== Received: from disco-boy.misterjones.org ([217.182.43.188] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1qdpCb-00ApB2-9E; Wed, 06 Sep 2023 10:52:01 +0100 MIME-Version: 1.0 Date: Wed, 06 Sep 2023 10:52:01 +0100 From: Marc Zyngier To: Lorenzo Pieralisi Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, Mark Rutland , Robin Murphy , Rob Herring , Fang Xiang Subject: Re: [PATCH v2 0/2] irqchip/gic-v3: Enable non-coherent GIC designs probing In-Reply-To: <20230906094139.16032-1-lpieralisi@kernel.org> References: <20230905104721.52199-1-lpieralisi@kernel.org> <20230906094139.16032-1-lpieralisi@kernel.org> User-Agent: Roundcube Webmail/1.4.13 Message-ID: <6f94c6d38f00031bf7c59e0cb8baf04c@kernel.org> X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 217.182.43.188 X-SA-Exim-Rcpt-To: lpieralisi@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, mark.rutland@arm.com, robin.murphy@arm.com, robh+dt@kernel.org, fangxiang3@xiaomi.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-20230906_025205_497055_540A6012 X-CRM114-Status: GOOD ( 20.10 ) 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-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2023-09-06 10:41, Lorenzo Pieralisi wrote: > This series is v2 of a previous version[1]. > > v1 -> v2: > - Updated DT bindings as per feedback > - Updated patch[2] to use GIC quirks infrastructure > > [1] > https://lore.kernel.org/all/20230905104721.52199-1-lpieralisi@kernel.org > > Original cover letter > --- > The GICv3 architecture specifications provide a means for the > system programmer to set the shareability and cacheability > attributes the GIC components (redistributors and ITSes) use > to drive memory transactions. > > Albeit the architecture give control over shareability/cacheability > memory transactions attributes (and barriers), it is allowed to > connect the GIC interconnect ports to non-coherent memory ports > on the interconnect, basically tying off shareability/cacheability > "wires" and de-facto making the redistributors and ITSes non-coherent > memory observers. > > This series aims at starting a discussion over a possible solution > to this problem, by adding to the GIC device tree bindings the > standard dma-noncoherent property. The GIC driver uses the property > to force the redistributors and ITSes shareability attributes to > non-shareable, which consequently forces the driver to use CMOs > on GIC memory tables. > > On ARM DT DMA is default non-coherent, so the GIC driver can't rely > on the generic DT dma-coherent/non-coherent property management layer > (of_dma_is_coherent()) which would default all GIC designs in the field > as non-coherent; it has to rely on ad-hoc dma-noncoherent property > handling. > > When a consistent approach is agreed upon for DT an equivalent binding > will > be put forward for ACPI based systems. What is the plan for this last point? I'd like to see at least a proposal before taking this series in. M. -- Jazz is not dead. It just smells funny... _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel