[PATCH v8 3/9] pci: Introduce pci_register_io_range() helper function.

Liviu Dudau Liviu.Dudau at arm.com
Wed Jul 9 01:59:11 PDT 2014


On Tue, Jul 08, 2014 at 03:14:17PM +0100, Arnd Bergmann wrote:
> On Tuesday 08 July 2014, Liviu Dudau wrote:
> > > Here's what these look like in /proc/iomem and /proc/ioports (note that
> > > there are two resource structs for each memory-mapped IO port space: one
> > > IORESOURCE_MEM for the memory-mapped area (used only by the host bridge
> > > driver), and one IORESOURCE_IO for the I/O port space (this becomes the
> > > parent of a region used by a regular device driver):
> > > 
> > >   /proc/iomem:
> > >     PCI Bus 0000:00 I/O Ports 00000000-00000fff
> > >     PCI Bus 0001:00 I/O Ports 01000000-01000fff
> > > 
> > >   /proc/ioports:
> > >     00000000-00000fff : PCI Bus 0000:00
> > >     01000000-01000fff : PCI Bus 0001:00
> > 
> > OK, I have a question that might be ovbious to you but I have missed the answer
> > so far: how does the IORESOURCE_MEM area gets created? Is it the host bridge
> > driver's job to do it? Is it something that the framework should do when it
> > notices that the IORESOURCE_IO is memory mapped?
> 
> The host bridge driver should either register the IORESOURCE_MEM resource
> itself from its probe or setup function, or it should get registered behind
> the covers in drivers using of_create_pci_host_bridge().
> 
> Your new pci_host_bridge_of_get_ranges already loops over all the 
> resources, so it would be a good place to put that.

OK, so it is not something that I've missed, just something that x86-64 does and
my version doesn't yet.

Thanks for confirming that.

Liviu

> 
> 	Arnd
> 

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