[PATCH 1/2] ARM: calculate VMALLOC_END by probing in mdesc->map_io()

Russell King - ARM Linux linux at arm.linux.org.uk
Sun Jan 23 09:34:08 EST 2011

On Sun, Jan 23, 2011 at 09:21:19AM -0500, Nicolas Pitre wrote:
> On Sun, 23 Jan 2011, Eric Miao wrote:
> > > I'd instead suggest adding vmalloc_end to the machine description
> > > record.
> > >
> > 
> > And since all boards sharing a same machine_class is going to use
> > the same value, I'd rather we first introduce struct machine_class
> > like in the patch I posted months ago?
> Another way to look at it is to move vmalloc_end and the like into each 
> machine record now, and look at the machine class changes afterwards 
> with a better view of all that might be consolidated at that point.

The machine class stuff is only worthwhile if it results in a net
reduction in complexity.  I don't remember whether the previous set
of patches for this showed any platforms being converted - searching
the list archives seems to suggest not.

While the simpler platforms seem to have (eg) their .map_io in a class
pointing at the same function, more complex platforms tend to have it
pointing at board-level functions.  Same goes for the .init_irq

I don't think there's a clear-cut case where this approach will result
in a net reduction of complexity.  I suspect it might actually end up
making things more complicated.

What I'm basically saying is that I'd like to see the effect of having
existing board stuff converted over to show whether this is worthwhile
or not.

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