From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH] documentation: iommu: add description of ARM System MMU binding Date: Mon, 13 May 2013 11:04:11 +0100 Message-ID: <20130513100411.GD29814@mudshark.cambridge.arm.com> References: <5162F87A.7070409@codeaurora.org> <20130410173732.GQ26992@mudshark.cambridge.arm.com> <5169C7D1.8070300@codeaurora.org> <20130415131341.GG9827@mudshark.cambridge.arm.com> <516D9602.2010404@codeaurora.org> <20130418190131.GA12344@mudshark.cambridge.arm.com> <5177113D.7060300@codeaurora.org> <20130424095501.GC21850@mudshark.cambridge.arm.com> <5189635A.8090504@codeaurora.org> <20130513090724.GA10369@alberich> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20130513090724.GA10369@alberich> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Andreas Herrmann Cc: Olav Haugan , "linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org" , "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: devicetree@vger.kernel.org On Mon, May 13, 2013 at 10:07:24AM +0100, Andreas Herrmann wrote: > On Tue, May 07, 2013 at 04:26:02PM -0400, Olav Haugan wrote: > > I think you misunderstood me. I am talking about having for example 1 > > master with two (2) context banks so that StreamID "1" goes to CB0 and > > StreamID "2" goes to CB1. This means that the master device is attached > > to two different domains. How do I model this with the the device tree > > bindings? > > Hi Olav, > > I think with the proposed device tree binding you can't model this. > > Do we have such use cases already? Or what future use cases would > require this? > > I can imagine of multiple contexts per device for stuff similar to > what PASID in PCI Express are used for. > > But in such a case you probably want to have some configurable bits in > the StreamID (that should be set by an SMMU driver). And the DT > binding should contain the number of contexts that a master device can > support. See my reply to your other thread, but I don't think this should be solved in the SMMU driver. I really think that the device/domain configuration should be driven by the master device drivers, rather than the device-tree. Will