From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757141Ab1KKLqe (ORCPT ); Fri, 11 Nov 2011 06:46:34 -0500 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:60377 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754631Ab1KKLqc (ORCPT ); Fri, 11 Nov 2011 06:46:32 -0500 Date: Fri, 11 Nov 2011 11:46:14 +0000 From: Catalin Marinas To: Russell King - ARM Linux Cc: "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v8 16/16] ARM: LPAE: Add the Kconfig entries Message-ID: <20111111114613.GF23243@arm.com> References: <1320682618-1182-1-git-send-email-catalin.marinas@arm.com> <1320682618-1182-17-git-send-email-catalin.marinas@arm.com> <20111110225737.GX12913@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111110225737.GX12913@n2100.arm.linux.org.uk> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 10, 2011 at 10:57:37PM +0000, Russell King - ARM Linux wrote: > On Mon, Nov 07, 2011 at 04:16:58PM +0000, Catalin Marinas wrote: > > +config ARCH_PHYS_ADDR_T_64BIT > > + def_bool ARM_LPAE > > + > > +config ARCH_DMA_ADDR_T_64BIT > > + def_bool ARM_LPAE > > + > > I still say this shouldn't depend on the host page table format. LPAE > itself has nothing to do with whether 64-bit DMA addresses are supported > by the system. So we could change this to: config ARCH_DMA_ADDR_T_64BIT depends on ARM_LPAE and let platforms select it. The x86 approach is to have another HIGHMEM64G config option for systems with more than 4GB of RAM and ARCH_DMA_ADDR_T_64BIT is selected automatically. But this comes under the assumption that there is a 1:1 mapping between phys and bus addresses. -- Catalin