[U-Boot] [PATCH 1/3] ARmv7: Add a soc_init hook to start.S

[Tom Rini <trini@ti.com>]

On Thu, Jan 22, 2015 at 08:10:06PM +0100, Hans de Goede wrote:
> Hi,
> 
> On 22-01-15 17:20, Tom Rini wrote:
> >On Wed, Jan 21, 2015 at 09:03:25PM +0100, Hans de Goede wrote:
> >
> >>On some SoCs / ARMv7 CPU cores we need to do some setup before enabling the
> >>icache, etc. Add a soc_init hook with a weak default which just calls
> >>cpu_init_cp15.
> >>
> >>This way different implementations can be provided to do some extra work
> >>before or after cpu_init_cp15, or completely replacing cpu_init_cp15.
> >>
> >>Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> >>---
> >>  arch/arm/cpu/armv7/start.S | 18 +++++++++++++++++-
> >>  1 file changed, 17 insertions(+), 1 deletion(-)
> >>
> >>diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
> >>index fdc05b9..9882b20 100644
> >>--- a/arch/arm/cpu/armv7/start.S
> >>+++ b/arch/arm/cpu/armv7/start.S
> >>@@ -64,7 +64,7 @@ reset:
> >>
> >>  	/* the mask ROM code should have PLL and others stable */
> >>  #ifndef CONFIG_SKIP_LOWLEVEL_INIT
> >>-	bl	cpu_init_cp15
> >>+	bl	soc_init
> >>  	bl	cpu_init_crit
> >>  #endif
> >
> >I like the direction here.  And I want to make sure I get the sunxi
> >direction right here too (as I agree with the need / desire for boot0 +
> >U-Boot to be a valid combination).  I think we can take this a step
> >farther.  cpu_init_crit (on armv7) is basically a call to s_init().
> >
> >For am33xx (and I bet but need to do and test omap3+) we can, with
> >Simon's patch to let us move stack to DDR a tiny bit later, in the SPL
> >case make s_init empty, which just leaves us with (with your patch)
> >soc_init.  Is there some way we can put all of this together in a
> >function?
> 
> You mean essentially call s_init here and have s_init call cpu_init_cp15
> I guess we could do that, but it would require auditing all existing armv7
> users of s_init. This may require me to rethink how / when I do timer &
> gpio init etc. for u-boot.bin on sunxi, but that should not be a (big)
> problem.

Basically.  From my first pass audit of s_init, it's either empty
(Kona), sunxi, or omap/etc so I get to deal with it.  And the default
soc_init would just be the call to cpu_init_cp15 as you have it and we
drop the lowlevel_init hurdles.

-- 
Tom
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