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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 32ED1C28D13 for ; Thu, 25 Aug 2022 10:34:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240983AbiHYKec (ORCPT ); Thu, 25 Aug 2022 06:34:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41498 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240893AbiHYKeV (ORCPT ); Thu, 25 Aug 2022 06:34:21 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E8E70A5C50 for ; Thu, 25 Aug 2022 03:34:17 -0700 (PDT) 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-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220825091752.3535657-1-arnd@kernel.org> Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.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!