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 9374FC04AA5 for ; Thu, 25 Aug 2022 10:37:50 +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:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=cL3HN/WlHxvi4OlZOP4awMWatHIyBfAWWRclg0kZPao=; b=I2jyGrAhlBWpwR q2DlOwhPrDA93Ruy59k8HeP17Zqvk6SVeKXFBZcer3FV/lMxY9h/tVQIC/im5AnbbRyKUHJOkM1lk /mQXshSQ7yjpXu3zjN3guEs+JB4/TbNi41baX29ZRXuOhCXiF5fXT5KnYHtrfjLCBdeLF3lWoUyc6 hqa7qJxwXwJ11WtLQRt76A5Y3Pv1FSGMoRLTY8YJlTpNGJLXdO7C33m34YyJzcAK+kyXqYyRdoJVx LxdvfaMKJgU9XTlBJnMPUMGyg0PPQr7FdrYiYzS0Idr9pJBuuyluZnHOxEoArI+31o2yRjOEZa6Wl CpWMYIbPlMVozxE3fz/Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oRAED-00BxVw-PH; Thu, 25 Aug 2022 10:36:50 +0000 Received: from pandora.armlinux.org.uk ([2001:4d48:ad52:32c8:5054:ff:fe00:142]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oRADl-00Bw1e-UD for linux-arm-kernel@lists.infradead.org; Thu, 25 Aug 2022 10:36:23 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=OrUQl1w8kI5QhSNqJvaa54vHHJ53i9OB8US51/YU1L8=; b=dOMzffQRsvnWHPkw7/v6LcBrWi Fs4kPn1BDYoqaCHOUup+EWXTomIN/ugf3YEy/b0tqx3vcq/It9CcoUIQFwwERPNzK+Nx6qXkM0lyu fdpsA8KxVNtaoKAk+S8cAnyphTWFVwg/bxqQznLXnHpxstaszQSDx2XC8nLEqj3TxJIrZAkyy5h/2 JEH37D5VEthzUvRi0N/4KjHf4eSY6JxC4PZbnH06ghUBqQt9O3MHwO7tCYEjZ1VrM5z88L2Zc/l4e nGn/1OQc/X0dmhCfuELn0POm00309P1A6lE98689hrrlmdZGoJI9hwzwL/6Se15iREJbw0juaNZXC 2QSyV31g==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:33926) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1oRABi-00053G-BZ; Thu, 25 Aug 2022 11:34:14 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1oRABg-00051w-Ve; Thu, 25 Aug 2022 11:34:12 +0100 Date: Thu, 25 Aug 2022 11:34:12 +0100 From: "Russell King (Oracle)" To: Arnd Bergmann Cc: Christoph Hellwig , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Arnd Bergmann , Linus Walleij , Marc Zyngier Subject: Re: [PATCH 5/4] ARM: footbridge: remove custom DMA address handling Message-ID: References: <20220821055326.GA25950@lst.de> <20220825091752.3535657-1-arnd@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220825091752.3535657-1-arnd@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220825_033622_046684_F0A7A7BF X-CRM114-Status: GOOD ( 11.94 ) 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, Aug 25, 2022 at 11:17:52AM +0200, Arnd Bergmann wrote: > From: Arnd Bergmann > > Footbridge is the last Arm platform that has its own > __virt_to_bus()/__bus_to_virt()/phys_to_dma()/dma_to_phys() abstraction, > but this is just a simple offset now. > > For ISA DMA (floppy etc), the offset is actually zero, so the special > hack to subtract the bus offset can be removed from common code. No, the offset is definitely not zero for ISA devices. ISA devices have the same view of system memory as PCI devices, since ISA devices go through a southbridge and on to the PCI bus. So their view of the system is exactly the same as any other PCI device. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel