* Shilimkar, Santosh <santosh.shilimkar@ti.com> [090421 21:56]:
> > -----Original Message-----
> > From: Tony Lindgren [mailto:tony@atomide.com] 
> > Sent: Wednesday, April 22, 2009 12:10 AM
> > To: Shilimkar, Santosh
> > Cc: linux-omap@vger.kernel.org
> > Subject: Re: [PATCH 7/7][RFC] OMAP4: Enable basic build support.
> > 
> > * Santosh Shilimkar <santosh.shilimkar@ti.com> [090421 06:08]:
> > > This patch updates the Makefile and defconfig for OMAP4. 
> > Minimal set of
> > > drivers are enabled fot the kernel bootup.
> > > 
> > > Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
> > > ---
>  
> > > diff --git a/arch/arm/mach-omap2/Makefile 
> > b/arch/arm/mach-omap2/Makefile
> > > index c49d9bf..68d50a8 100644
> > > --- a/arch/arm/mach-omap2/Makefile
> > > +++ b/arch/arm/mach-omap2/Makefile
> > > @@ -3,9 +3,13 @@
> > >  #
> > >  
> > >  # Common support
> > > +ifeq ($(CONFIG_ARCH_OMAP4),y)
> > > +obj-y := id.o io.o control.o mux.o devices.o serial.o 
> > gpmc.o timer-gp.o
> > > +else
> > >  obj-y := irq.o id.o io.o sdrc.o control.o prcm.o clock.o mux.o \
> > >  		devices.o serial.o gpmc.o timer-gp.o powerdomain.o \
> > >  		clockdomain.o
> > > +endif
> > 
> > This ifeq else we don't want to do as it breaks things for multi-omap.
> 
> How do we handle this. For OMAP4, those files are not common and needed at this point of time. More so if we agree that OMAP4 won't support multi-omap, then this should be ok.

No way we're dropping multi-omap for a few ifdefs.

We need to have code where we can compile in all the selected things.
In this case we should be able to select any combination of CONFIG_ARCH_OMAP2,
CONFIG_ARCH_OMAP3, CONFIG_ARCH_OMAP4. And the code already gets optimized if
only one is selected.

The recent omap2 clock breakage with trivial clock patches is already a
good enough reason to support the multi-omap. So basically all the developers
should do their builds with the multi-omap selected.

Also the distros want multi-omap. Only the product specific kernels
should be built with only one option selected to optimize for speed and size.

> Some thing like this can be done but then Makefile will be completely rewamped. 
> 
> # Common support
> obj-y := id.o io.o control.o mux.o devices.o serial.o gpmc.o timer-gp.o
> 
> obj-$(CONFIG_ARCH_OMAP2) += display.o sdrc.o prcm.o clock.o powerdomain.o clockdomain.o
> obj-$(CONFIG_ARCH_OMAP3) += display.o sdrc.o prcm.o clock.o powerdomain.o clockdomain.o
> 
> Is this OK ?

How about the attached patch?

Tony