On Wednesday 04 June 2014 14:56:01 Will Deacon wrote: > On Wed, Jun 04, 2014 at 02:44:03PM +0100, Thierry Reding wrote: > > On Fri, May 30, 2014 at 09:54:37PM +0200, Arnd Bergmann wrote: > > > On Friday 30 May 2014 22:29:13 Hiroshi Doyu wrote: > > > > The disadvantage of this is that this limits the max number of streamIDs > > > > to support. If # of streamID is increased later more than 64, this > > > > format cannot cover any more. You have to predict the max # of streamIDs > > > > in advance if steamID is statically assigned. > > > > > > > > > > Well, the iommu specific binding could allow a variable #address-cells. > > > That way, you just need to know the number of stream IDs for that instance > > > of the iommu. > > > > That sounds fairly complicated to me. I don't see what that buys us over > > the clarity and simplicity that the above explicit notation gives us. Is > > it not more common for a device to have a single master rather than a > > whole bunch of them? > > I've never seen a device upstream of an ARM SMMU with a single stream-id; > they always seem to have a whole bunch of them. Calxeda's SATA controller > had 10 IDs, for example, and a PL330 DMA controller tends to have at least > 3. What are those good for? Would we just always use the first one? Arnd -- 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
