[v3,2/2] ARM: SMP: Refactor Kconfig to be more maintainable

Making SMP depend on (huge list of MACH_ and ARCH_ configs) is
bothersome to maintain and likely to lead to merge conflicts.

This patch moves the knowledge of which platforms are SMP-capable
to the individual machines.  To enable this, a new HAVE_SMP config
option is introduced to allow machines to indicate that they have
such a cache controller independently of each other.

Signed-off-by: Dave Martin <dave.martin@linaro.org>
---
This is the first version of this patch.  There is no version prior to
v3.

 arch/arm/Kconfig               |   15 +++++++++++----
 arch/arm/mach-exynos/Kconfig   |    1 +
 arch/arm/mach-imx/Kconfig      |    1 +
 arch/arm/mach-msm/Kconfig      |    1 +
 arch/arm/mach-omap2/Kconfig    |    1 +
 arch/arm/mach-realview/Kconfig |    4 ++++
 arch/arm/mach-vexpress/Kconfig |    1 +
 7 files changed, 20 insertions(+), 4 deletions(-)

On Mon, Dec 12, 2011 at 11:47:06AM +0000, Dave Martin wrote:
> diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
> index 4234937..4aa7f7e 100644
> --- a/arch/arm/mach-imx/Kconfig
> +++ b/arch/arm/mach-imx/Kconfig
> @@ -611,6 +611,7 @@ config SOC_IMX6Q
>  	select ARM_GIC
>  	select CPU_V7
>  	select HAVE_ARM_SCU
> +	select HAVE_SMP
>  	select HAVE_IMX_GPC
>  	select HAVE_IMX_MMDC
>  	select HAVE_IMX_SRC

NAK.  I'll let you work out why.  It has something to do with ABCDEFGH...

On Mon, Dec 12, 2011 at 02:10:01PM +0000, Russell King - ARM Linux wrote:
> On Mon, Dec 12, 2011 at 11:47:06AM +0000, Dave Martin wrote:
> > diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
> > index 4234937..4aa7f7e 100644
> > --- a/arch/arm/mach-imx/Kconfig
> > +++ b/arch/arm/mach-imx/Kconfig
> > @@ -611,6 +611,7 @@ config SOC_IMX6Q
> >  	select ARM_GIC
> >  	select CPU_V7
> >  	select HAVE_ARM_SCU
> > +	select HAVE_SMP
> >  	select HAVE_IMX_GPC
> >  	select HAVE_IMX_MMDC
> >  	select HAVE_IMX_SRC
> 
> NAK.  I'll let you work out why.  It has something to do with ABCDEFGH...

Duh.  Sorry about that -- will fix and repost.


Do you have a preference about where to insert new items where the list
is not already in alphabetical order?

Currently, I've just tried not to make things worse than they already
are (except in this particular case...)

Cheers
---Dave

On Mon, Dec 12, 2011 at 03:04:05PM +0000, Dave Martin wrote:
> On Mon, Dec 12, 2011 at 02:10:01PM +0000, Russell King - ARM Linux wrote:
> > On Mon, Dec 12, 2011 at 11:47:06AM +0000, Dave Martin wrote:
> > > diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
> > > index 4234937..4aa7f7e 100644
> > > --- a/arch/arm/mach-imx/Kconfig
> > > +++ b/arch/arm/mach-imx/Kconfig
> > > @@ -611,6 +611,7 @@ config SOC_IMX6Q
> > >  	select ARM_GIC
> > >  	select CPU_V7
> > >  	select HAVE_ARM_SCU
> > > +	select HAVE_SMP
> > >  	select HAVE_IMX_GPC
> > >  	select HAVE_IMX_MMDC
> > >  	select HAVE_IMX_SRC
> > 
> > NAK.  I'll let you work out why.  It has something to do with ABCDEFGH...
> 
> Duh.  Sorry about that -- will fix and repost.
> 
> 
> Do you have a preference about where to insert new items where the list
> is not already in alphabetical order?

What I've done in the past is roughly to ignore anything which isn't
alphabetical from the top, and place it within that subset.  I
simetimes change that (if there's a group of HAVE_xxx which is already
sorted, I add it within that sub-group.)

In other words, try to sensibly place it so the addition itself is
alphabetically between two other options which are already so sorted.

On Mon, Dec 12, 2011 at 03:59:12PM +0000, Russell King - ARM Linux wrote:
> On Mon, Dec 12, 2011 at 03:04:05PM +0000, Dave Martin wrote:

[...]

> > Duh.  Sorry about that -- will fix and repost.
> > 
> > 
> > Do you have a preference about where to insert new items where the list
> > is not already in alphabetical order?
> 
> What I've done in the past is roughly to ignore anything which isn't
> alphabetical from the top, and place it within that subset.  I
> simetimes change that (if there's a group of HAVE_xxx which is already
> sorted, I add it within that sub-group.)
> 
> In other words, try to sensibly place it so the addition itself is
> alphabetically between two other options which are already so sorted.

OK; I've attempted to do this where I can.

Where it's possible to chop a jumbled list somewhere in the middle such
that the added option sorts strictly after everything in the first
chunk and strictly before everything in the second chunk, I've done that,
so:

	A
	G
	F
+	I
	Z
	P
	W

...which I believe satisfies your criterion.

Where this is not possible, I ignore the smallest amount of items
possible at either end of the list such that the above works, so in:

	A
	G
	F
+	I
	Z
	P
	W
	H
	Z

... I ignore the final H and Z.  The only way to be in order with
respect to those would be to put I far away from its correct position,
which would be undesirable.

This stragety should mean that nothing ever needs to move across the
newly added item, unless the list is already significantly out of order
(in which case there's no perfect solution except for sorting the list).

Cheers
---Dave