Re: [GIT PULL] Renesas ARM-based SoC defconfig for v3.8

[Simon Horman <horms@verge.net.au>]

On Mon, Oct 22, 2012 at 09:33:51AM +0900, Simon Horman wrote:
> On Fri, Oct 19, 2012 at 08:18:50AM +0000, Arnd Bergmann wrote:
> > On Friday 19 October 2012, Simon Horman wrote:
> > > On Thu, Oct 18, 2012 at 05:13:10PM +0900, Simon Horman wrote:
> > > I have made a limited amount of progress on this trying to create a
> > > defconfig that will work on both the Marzen and Armadillo 800 EVA boards.
> > > 
> > > * Serial console appears to work, although for the Marzen at
> > >   least enabling earlyprintk seems to require the bootloader to specify
> > >   e.g.  console=ttySC2,115200 earlyprintk
> > > 
> > >   This is done by fully specifying bootargs in U-Boot.
> > >   The boodloaders on the Marzen board has an ampty bootargs by default.
> > >
> > >   I guess I can live without earlyprink by default,
> > >   though it does seem to be a regression in the user experience.
> > 
> > Right. So who is using the defconfig for these boards? Usually most
> > people using it actually have their own configuration files that are
> > tuned for their needs, and you often also need to change the command
> > line in order to configure the root partition etc.
> 
> I imagine they are primarily used by developers, like myself, but
> to be honest I am unsure. Ideally I would like the defconfig to be as
> useful as possible out of the box. But I agree that most users probably
> end up making some customisations, e.g. to the location of the rootfs.
> 
> > > * A more significant problem seems to be the use of CONFIG_MEMORY_START
> > >   to define PLAT_PHYS_OFFSET in arch/arm/mach-shmobile/include/mach/memory.h
> > > 
> > >   I'm not sure that I see an easy way to get around this one.
> > 
> > ARM_PATCH_PHYS_VIRT should take care of this, have you tried it?

I believe that this leaves mach-shmobile with three areas
where CONFIG_MEMORY_START/PLAT_PHYS_OFFSET is used.

* arch/arm/mach-shmobile/headsmp.S

  This uses PLAT_PHYS_OFFSET.

  I believe this can be replaced with a run-time calculation. Though I
  haven't thought about the details yet.

* arch/arm/boot/compressed/head-shmobile.S

  This makes use of CONFIG_MEMORY_START.

  This is only used if CONFIG_ZBOOT_ROM is set.

  I'm unsure if this can be replaced with a run-time calculation or not.
  But regardless it is only used if CONFIG_ZBOOT_ROM is set, which is not
  the default at this time.


* arch/arm/mach-shmobile/Makefile.boot

 This makes use of CONFIG_MEMORY_START to set zreladdr.

 I believe that the solution to this is to make use of CONFIG_AUTO_ZRELADDR.
 However, it is not yet clear to me how that can be used in conjunction
 with a uImage.  As I understand it the boot loader on many of our boards,
 including the Marzen board which is my first target for this work, boot
 uImage imagess.