[PATCHv2 1/2] ARM: mx51: Implement code to allow mx51 to enter WFI

[david.jander@protonic.nl (David Jander)]

On Thu, 10 Mar 2011 14:37:15 +0100
"s.hauer at pengutronix.de" <s.hauer@pengutronix.de> wrote:

> Hi David,
> 
> On Tue, Mar 08, 2011 at 12:40:23PM +0100, David Jander wrote:
> > 
> > Hi Sascha,
> > 
> > On Mon, 7 Mar 2011 19:07:00 +0100
> > "s.hauer at pengutronix.de" <s.hauer@pengutronix.de> wrote:
> > >[...]
> > > > The current imx for-next tree is not booting on my Babbage board. Is
> > > > it okay for you with your HW. I'll have to debug the booting part
> > > > first.
> > > 
> > > Probably because other than kconfig states i.MX51 and i.MX53 cannot be
> > > compiled in one kernel. the for-next branch boots fine on my babbage.
> > 
> > Would you mind explaining (or pointing to an explanation) as to why this is
> > not supposed to work? Given the high level of compatibility between MX51
> > and MX53, I'd say there must be a very good reason not to enable a single
> > binary kernel for both. Or is this just temporary brokenness?
> 
> i.MX51 and i.MX53 have different phys_offsets. Look at
> arch/arm/mach-mx5/Makefile.boot:
> 
>    zreladdr-$(CONFIG_ARCH_MX50) := 0x70008000
> params_phys-$(CONFIG_ARCH_MX50) := 0x70000100
> initrd_phys-$(CONFIG_ARCH_MX50) := 0x70800000
>    zreladdr-$(CONFIG_ARCH_MX51) := 0x90008000
> params_phys-$(CONFIG_ARCH_MX51) := 0x90000100
> initrd_phys-$(CONFIG_ARCH_MX51) := 0x90800000
>    zreladdr-$(CONFIG_ARCH_MX53) := 0x70008000
> params_phys-$(CONFIG_ARCH_MX53) := 0x70000100
> initrd_phys-$(CONFIG_ARCH_MX53) := 0x70800000
> 
> Compiling a kernel for i.MX50 and i.MX53 will work, but compiling a
> kernel for i.MX51 and i.MX53 will and up with a kernel assuming SDRAM
> at 0x70000000 which will fail on a i.MX51. We need
> phys_to_virt/virt_to_phys runtime patching to get this right. This
> will be merged in the next merge window.

Ok, so it classifies as "temporary brokenness" ;-)
Thanks a lot for clarifying.

Best regards,

-- 
David Jander
Protonic Holland.