From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: your mail Date: Mon, 24 Feb 2014 17:28:50 +0000 Message-ID: <20140224172850.GG2553@mudshark.cambridge.arm.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: 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: srikanth TS Cc: "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" , "sungjinn.chung-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "ts.srikanth-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org" List-Id: iommu@lists.linux-foundation.org On Mon, Feb 24, 2014 at 03:12:21PM +0000, srikanth TS wrote: > Hi Will Deacon, Hello, > Currently SMMU driver expecting all stream ID used by respective master > should be defined in the DT. > > We want to know how to handle in the case of virtual functions dynamically > created and destroyed. > > Is PCI driver responsible for creating stream ID respective BDand > requesting SMMU to add to the mapping table[stream Id to context mapping > table]? > > Or is there any right way of doing it? Correct, the driver currently doesn't support dynamic mappings (mainly because I didn't want to try and invent something that I couldn't test). There are a couple of ways to solve this: (1) Add a way for a PCI RC to dynamically allocate StreamIDs on an SMMU within a fixed range. That would probably need some code in the bus layer, so that a bus notifier can kick and call back to the relevant SMMU. (2) Describe the RID -> SID mapping in the device-tree. We probably want to avoid an enormous table, so this would only work for simple `SID = RID + offset' or 'SID = RID & mask' cases. How do your IDs map to each other? Will