[U-Boot] [PATCH v2 03/23] armv8: add lowlevel_init.S

Tom Rini trini at konsulko.com
Tue Dec 6 13:18:18 CET 2016


On Tue, Dec 06, 2016 at 08:04:24AM +0000, André Przywara wrote:
> On 05/12/16 21:56, Tom Rini wrote:
> > On Mon, Dec 05, 2016 at 01:52:10AM +0000, Andre Przywara wrote:
> > 
> >> For boards that call s_init() when the SPL runs, we are expected to
> >> setup an early stack before calling this C function.
> >> Implement the proper AArch64 version of this based on the ARMv7 code.
> >> This allows sunxi boards to setup the basic peripherals even on with a
> >> 64-bit SPL.
> >>
> >> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
> > 
> > This is going to override lowlevel_init from arch/arm/cpu/armv8/start.S
> > and is that really desired?  Thanks!
> 
> Not sure if it is desired, but it's needed. The weak function in start.S
> just initialises the GIC (if configured), that looks like a NOP for
> sunxi to me (we do this already much better in ARM Trusted Firmware).
> For 32-bit sunxi we call s_init() through lowlevel_init(), which is what
> I copy here for armv8.
> Now there is this comment which discourages doing so and Alex already
> complained about it as well, so I might take a look at how we would skip
> this step. I was a bit wary going there as this would mean to rework the
> 32-bit code as well, which affects a lot of boards, which I can barely
> test here.

The path flow here on 32bit, both with and without SPL is what makes
this area a good bit of a pain to make changes in.

-- 
Tom
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