Hi Andreas, On 5/13/2013 2:07 AM, Andreas Herrmann wrote: > On Tue, May 07, 2013 at 04:26:02PM -0400, Olav Haugan wrote: >> >>>>> If a master needs to be in two address spaces at once, then it will need to >>>>> attach it's StreamIDs to different domains. You can't place a single >>>>> StreamID in two address spaces (this is an architectural constraint). >>>> >>>> Yes, you would have a separate domain. I am just wondering how I would >>>> model this in DT using the bindings that you are proposing? How does it >>>> work? The bindings specify bus masters to StreamIDs. So if I call attach >>>> with the master device you will allocate a context bank and program the >>>> StreamIDs as specified in the DT. So now if I want to have another >>>> context bank associated with the same master device what do I do? I call >>>> into attach with a new domain but with the same master device but the >>>> master device is already attached to a context/domain. >>> >>> Why would you want to place a StreamID into two domains? That doesn't make >>> any sense and isn't even supported by the architecture (things like >>> conflicting SMR entries may not even be reported). >> >> 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. > Sorry for the late reply. The only real use case at this time for a master having more than 1 CB is for content protection I believe. I understand that this driver does not currently support content protection or anything related to security. Thanks, Olav Haugan -- The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
