From: srikanth TS [mailto:srikantht.shivanand-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org]
Sent: Wednesday, February 26, 2014 1:53 PM
To: Sethi Varun-B16395
Cc: sungjinn.chung-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org; linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; Will Deacon; iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org; ts.srikanth-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org
Subject: RE: your mail

On Feb 25, 2014 8:28 PM, "Varun Sethi" <Varun.Sethi-KZfg59tc24xl57MIdRCFDg@public.gmane.org> wrote:
>
>
>
> > -----Original Message-----
> > From: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org [mailto:iommu-
> > bounces@lists.linux-foundation.org] On Behalf Of Will Deacon
> > Sent: Monday, February 24, 2014 10:59 PM
> > To: srikanth TS
> > Cc: iommu@lists.linux-foundation.org; sungjinn.chung-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org; linux-
> > kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; ts.srikanth-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org
> > Subject: Re: your mail
> >
> > 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.
> This could be done in add device notifier. I am working on similar(not PCI) hot plug device infrastructure for arm smmu driver. I will post an RFC patch by next week.
Can you please explain with little more detail. We just want to make sure your idea fits in for pci iov also.

[Sethi Varun-B16395] In the add device notifier we can allocate the streamID (and the corresponding smmu master), while allocating the iommu group for the PCI devices. All, the PCIe devices sharing the same iommu group would share the stream ID.  Currently, I am working on a add device framework for hot plug devices.

-Varun