On Wed, Nov 13, 2013 at 05:53:36PM +0000, Stephen Warren wrote: > On 11/13/2013 10:31 AM, Will Deacon wrote: > > On Wed, Nov 13, 2013 at 04:06:10PM +0000, Hiroshi Doyu wrote: > >> This can be solved with introducing the fixed size of bitmap. The size > >> of bitmap can be fixed even per SoC. In tegra we used 64(2 cells) > >> which I expect at most. > > > > That really doesn't sound like a good idea where you have bridges (like a > > PCIe host controller) which could have a significant chunk of StreamID > > space. You'd also need to pad everything out with some dummy IDs for parsing > > purposes. Yuck! > > Can't you solve this by having the SMMU include a stream ID mapping > table. In the case of stream IDs having a large "address" space, then > just define the mapping table syntax to allow easy specification of > ranges using start/length, start/end, or value/mask pairs. Similar to > ranges or PCI's interrupt-map{,-mask}. That may work for windows, but the mapping from input stream IDs to output IDs can be arbitrary (I *really* hope people stick to windows for requester IDs though). Will -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html