From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754273Ab1GIO7K (ORCPT ); Sat, 9 Jul 2011 10:59:10 -0400 Received: from caramon.arm.linux.org.uk ([78.32.30.218]:51163 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754055Ab1GIO7I (ORCPT ); Sat, 9 Jul 2011 10:59:08 -0400 Date: Sat, 9 Jul 2011 15:58:56 +0100 From: Russell King - ARM Linux To: Rob Herring Cc: nico@fluxnic.net, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 2/6] ARM: move ARCH_HAS_DMA_SET_COHERENT_MASK into memory.h Message-ID: <20110709145856.GM4812@n2100.arm.linux.org.uk> References: <1309366019-24379-1-git-send-email-robherring2@gmail.com> <1309366019-24379-3-git-send-email-robherring2@gmail.com> <4E1866A2.9040407@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E1866A2.9040407@gmail.com> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 09, 2011 at 09:33:06AM -0500, Rob Herring wrote: > I noticed this is going to have conflicts with your ARM_DMA_ZONE_SIZE > series. Can you add this into your series? This still presents another > issue to solve for single kernel binary, but hopefully the dma mapping > work will help. That's a different problem - its about limiting the maximum DMA mask which can be set, so that memory is sourced from the right place even for drivers which use 32-bit masks. It's needed to ensure that dma_set_coherent_mask() can be overridden. One solution to it would be to ensure that we always define ARCH_HAS_DMA_SET_COHERENT_MASK, and handle the differences internally, which is something I've been thinking about adding to my DMA bounce series of patches.