[PATCH v2] arm64: pci: add support for pci_mmap_page_range

[arnd@arndb.de (Arnd Bergmann)]

On Friday 15 April 2016 14:09:53 Will Deacon wrote:
> On Thu, Apr 14, 2016 at 02:40:56AM +0530, Jerin Jacob wrote:
> > Certain X11 servers and user space network drivers frameworks
> > need PCI mmaped /sys/bus/pci/devices/B:D:F/resourceX file to
> > access PCI bar address space from user space.
> > 
> > Signed-off-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
> > ---
> > Changes in v2:
> >   - Rebased to 4.6.0-rc3.
> >   - Tested and verified the change on Thunderx and xgene1 arm64 platforms
> > 
> >  arch/arm64/include/asm/pci.h |  6 ++++++
> >  arch/arm64/kernel/pci.c      | 20 ++++++++++++++++++++
> >  2 files changed, 26 insertions(+)
> > 
> > diff --git a/arch/arm64/include/asm/pci.h b/arch/arm64/include/asm/pci.h
> > index b9a7ba9..9d7e460 100644
> > --- a/arch/arm64/include/asm/pci.h
> > +++ b/arch/arm64/include/asm/pci.h
> > @@ -37,5 +37,11 @@ static inline int pci_proc_domain(struct pci_bus *bus)
> >  }
> >  #endif  /* CONFIG_PCI */
> >  
> > +#define HAVE_PCI_MMAP
> 
> By defining this symbol, we also get lumbered with the legacy /proc
> interface, which I'd be keen to avoid exposing until we have people
> explicitly asking for it.
> 
> Any chance you could expose only the /sysfs interface on arm64?
> 

Do we have an idea how much user space code is affected by this?
Maybe it can instead be changed to use VFIO, which is basically
the current way to do this.

	Arnd