Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751028Ab0G2EQI (ORCPT ); Thu, 29 Jul 2010 00:16:08 -0400 Received: from sh.osrg.net ([192.16.179.4]:40053 "EHLO sh.osrg.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750735Ab0G2EQE (ORCPT ); Thu, 29 Jul 2010 00:16:04 -0400 Date: Thu, 29 Jul 2010 13:15:37 +0900 To: linux@arm.linux.org.uk Cc: arnd@arndb.de, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, dwalker@codeaurora.org, stepanm@codeaurora.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] arm: msm: Add System MMU support. From: FUJITA Tomonori In-Reply-To: <20100728212156.GA6729@n2100.arm.linux.org.uk> References: <201007281950.20847.arnd@arndb.de> <20100728212156.GA6729@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: <20100729131500Q.fujita.tomonori@lab.ntt.co.jp> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-3.0 (sh.osrg.net [192.16.179.4]); Thu, 29 Jul 2010 13:15:39 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1499 Lines: 29 On Wed, 28 Jul 2010 22:21:56 +0100 Russell King - ARM Linux wrote: > On Wed, Jul 28, 2010 at 07:50:20PM +0200, Arnd Bergmann wrote: > > The DMA API is extremely flexible, it works just fine with all the > > IOMMUs that I've seen so far. Please take a look at > > include/asm-generic/dma-mapping-common.h and its users to see how > > to use multiple IOMMUs depending on the device. > > We don't yet use those DMA API interface extensions because we haven't > had the need. If someone who has the need wants to put the effort in > though... > > One of the problems with it though is the abstraction of the sync* > operations is the wrong way around for stuff like dmabounce - we want > to be passed the base address of the buffer (so we can look this up), > plus offset and length. We don't want to know just the region which > is affected. We can't pass the base address because the DMA API callers don't pass the base address for dma_sync_single_for_{device|cpu}. dma_sync_single_range_for_* requires the base address but they are obsolete. So you need to fix dmabounce. Actually, I send you a patch to fix dmabounce long ago (looks like not applied yet): http://kerneltrap.org/mailarchive/linux-netdev/2010/4/5/6274046 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/