Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753414Ab0HBJmO (ORCPT ); Mon, 2 Aug 2010 05:42:14 -0400 Received: from tx2ehsobe003.messaging.microsoft.com ([65.55.88.13]:39691 "EHLO TX2EHSOBE005.bigfish.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752669Ab0HBJmM (ORCPT ); Mon, 2 Aug 2010 05:42:12 -0400 X-SpamScore: -29 X-BigFish: VS-29(zz1102K1432N98dN936eMzz1202hzz15d4Rz32i87h2a8h43h61h) X-Spam-TCS-SCL: 0:0 X-FB-DOMAIN-IP-MATCH: fail X-WSS-ID: 0L6IQXY-02-855-02 X-M-MSG: Date: Mon, 2 Aug 2010 11:45:04 +0200 From: "Roedel, Joerg" To: FUJITA Tomonori CC: "benh@kernel.crashing.org" , "arnd@arndb.de" , "stepanm@codeaurora.org" , "linux-arm-kernel@lists.infradead.org" , "linux-arm-msm@vger.kernel.org" , "dwalker@codeaurora.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 1/2] arm: msm: Add System MMU support. Message-ID: <20100802094504.GF29744@amd.com> References: <1280546124.1902.30.camel@pasglop> <20100802074812.GM24084@amd.com> <1280736182.1902.55.camel@pasglop> <20100802172941C.fujita.tomonori@lab.ntt.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20100802172941C.fujita.tomonori@lab.ntt.co.jp> Organization: Advanced Micro Devices =?iso-8859-1?Q?GmbH?= =?iso-8859-1?Q?=2C_Karl-Hammerschmidt-Str=2E_34=2C_85609_Dornach_bei_M=FC?= =?iso-8859-1?Q?nchen=2C_Gesch=E4ftsf=FChrer=3A_Thomas_M=2E_McCoy=2C_Giuli?= =?iso-8859-1?Q?ano_Meroni=2C_Andrew_Bowd=2C_Sitz=3A_Dornach=2C_Gemeinde_A?= =?iso-8859-1?Q?schheim=2C_Landkreis_M=FCnchen=2C_Registergericht_M=FCnche?= =?iso-8859-1?Q?n=2C?= HRB Nr. 43632 User-Agent: Mutt/1.5.20 (2009-06-14) X-Reverse-DNS: unknown Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2678 Lines: 63 On Mon, Aug 02, 2010 at 04:30:26AM -0400, FUJITA Tomonori wrote: > On Mon, 02 Aug 2010 18:03:02 +1000 > Benjamin Herrenschmidt wrote: > > > On Mon, 2010-08-02 at 09:48 +0200, Roedel, Joerg wrote: > > > > Hrm, indeed I just noticed that. Pretty gross... it should definitly > > > be > > > > renamed, is will caused endless confusion with unrelated iommu.h and > > > > iommu_* interfaces which represent something different. > > > > > > The first direction to go should be trying to unify all the different > > > iommu* interfaces into the iommu-api. The generic api will definitly > > > need to be extended for that, but since it is an in-kernel interface > > > thats no problem. > > > > Well, I suppose I'm the de-facto candidate to take care of the powerpc > > side then :-) > > We already agreed that what the iommu-api looks like? Well, we currently trying to figure out how to extend the IOMMU-API concepts to fit the omap-hardware in. Thats what I currently discuss with Stephan. It looks to me that we need to add the concept of device contexts to the IOMMU-API. We should also add IO-TLB management functions. The TLB management is currently handled completly in the backend driver. This needs to be changed and makes sense for AMD IOMMUs and Intel IOMMUs with QPI too. > ARM's iommu code (arch/plat-omap/include/plat/iommu.h) is a library to > simplify the IOMMU implementations. It could be useful for all the > iommu implementations. To me it looks like a very hardware specific library. But it should fit well in the domain/device concept the IOMMU-API provides (when we also add device-contexts to it) > The current iommu-api (include/linux/iommu.h) provides the common > interface for specific purposes (for KVM). The IOMMU-API is not limited to the purposes of KVM. There is currently development effort to use the IOMMU-API for UIO stuff. So the IOMMU-API is by no means KVM specific. > Another question is how the above can work with the DMA-API. This would work if we handle every device-context the platform provides as 'struct device'. But does that really need to work with the DMA-API? What is the driver use-case for that? Joerg -- Joerg Roedel - AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo, Andrew Bowd Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632 -- 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/