[U-Boot] [PATCH] tegra2: move tegra2 SoC code to arch/arm/cpu/tegra2-common

[Allen Martin]

On Thu, Apr 19, 2012 at 11:27:05AM -0700, Simon Glass wrote:
> >
> > This is part of an upcoming patch set to move all armv4t code out of
> > tegra2 u-boot and put it into an SPL, but I wanted to get some early
> > feedback on this patch.  This moves most of the tegra2 SoC code from
> > arch/arm/cpu/armv7 to a new directory arch/arm/cpu/tegra2-common.
> > This code will be shared between the armv7 and armv4t builds of
> > tegra2.
> 
> I am not sure whether moving things up a level is OK. It makes some
> sense to me but is different from what other boards do.

Agreed I couldn't find any other examples, but AFAIK no other board is
trying to do what we do (sharing code between 2 different CPU
models).  The other options I contemplated were:

-Have the armv4t build reach up and over into armv7
-Move the code out to board/nvidia

Both of these seemed worse


> Secondly, you will at some point add Tegra 3 support I suppose. In
> that case much of this code will become common anyway. Should you do
> that split (tegra-common, tegra2-common) now or later?

I'd like to keep the tegra3 changes separate since that will involve
refactoring of much of this code.  For the SPL build it's mostly
hidden in the config and Makefiles.  

I thought about doing exactly what you said to reduce the amount of
code I needed to pull into the SPL build, but what I found was that
because the SPL needs to initialize some regulators, clocks, and
pinmux to bring up the A9 and UART it ends up needing much of the
tegra2 SoC code, so there's not a lot of opportunity to minize the
code set for the SPL build beyond the CONFIG options to disable
drivers that area already there.

-Allen
nvpublic