[PATCH 4/8] of/base.c: export property access/modification functions

[Stephen Neuendorffer]

> -----Original Message-----
> From: glikely at secretlab.ca [mailto:glikely at secretlab.ca] On Behalf Of Grant Likely
> Sent: Friday, July 16, 2010 2:44 PM
> To: Stephen Neuendorffer
> Cc: devicetree-discuss at lists.ozlabs.org
> Subject: Re: [PATCH 4/8] of/base.c: export property access/modification functions
> 
> On Fri, Jul 16, 2010 at 2:07 PM, Stephen Neuendorffer
> <stephen.neuendorffer at xilinx.com> wrote:
> >
> >
> >> -----Original Message-----
> >> From: glikely at secretlab.ca [mailto:glikely at secretlab.ca] On Behalf Of Grant Likely
> >> Sent: Friday, July 16, 2010 11:57 AM
> >> To: Stephen Neuendorffer
> >> Cc: devicetree-discuss at lists.ozlabs.org
> >> Subject: Re: [PATCH 4/8] of/base.c: export property access/modification functions
> >>
> >> On Fri, Jul 16, 2010 at 12:38 PM, Stephen Neuendorffer
> >> <stephen.neuendorffer at xilinx.com> wrote:
> >> >
> >> >
> >> >> -----Original Message-----
> >> >> From: glikely at secretlab.ca [mailto:glikely at secretlab.ca] On Behalf Of
> >> > Grant Likely
> >> >> Sent: Friday, July 16, 2010 11:34 AM
> >> >> To: Stephen Neuendorffer
> >> >> Cc: devicetree-discuss at lists.ozlabs.org
> >> >> Subject: Re: [PATCH 4/8] of/base.c: export property
> >> > access/modification functions
> >> >>
> >> >> On Fri, Jul 16, 2010 at 12:13 PM, Stephen Neuendorffer
> >> >> <stephen.neuendorffer at xilinx.com> wrote:
> >> >> > These functions can be usefully used by device drivers.
> >> >>
> >> >> I'd like a little more description of the intended use case.  What are
> >> >> the circumstances where a driver needs to modify the data (this
> >> >> information should be part of the patch description)?
> >> >
> >> > The PCIPR driver code needs to stuff the ranges property using these
> >> > calls...
> >>
> >> I'd rather change the translation code to give you an intermediary
> >> value (an offset from a bar), and then use non-OF code to translate
> >> that into a physical address.
> >
> > I don't see how that will work, since there is no callback from the device-tree
> > code behind platform_get_resource/of_address_to_resource back into the pcipr driver to
> > do the last translation bit.  I considered having a new 'bus_type' registered in the
> > address translation code that would take care of it, but it seemed to still require
> > the information from somewhere and it wasn't clear where to get it.
> 
> You get the information from the PCI device instance.  We can change
> the bus_type infrastructure to allow instance specific data if need
> be.
> 
> Alternately, the translation could be done at device registration
> time.  With the changes being made to the of code, of_devices are
> going away, and being replaced with normal platform_devices which have
> a resource structure.  We could do the translation at device
> registration time so that drivers only need to look at the resource
> structure.  This will require some changes to the current
> of_platform_drivers, but in the long run I think it is the right thing
> to do.

OK, perhaps I'm being a little dense, but I don't see how to proceed here.
Can you make this more concrete?

Steve


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