Re: [Qemu-devel] [PATCH v10 4/5] arm: SoC model for Calxeda Highbank

[Mark Langsdorf <mark.langsdorf@calxeda.com>]

On 01/18/2012 08:53 AM, Peter Maydell wrote:
> On 18 January 2012 14:35, Mark Langsdorf <mark.langsdorf@calxeda.com> wrote:

>> Is there a good example of how to write secondary smp boot
>> code other than arm_boot.c? Should I just expect to pull
>> most of arm_boot.c into highbank and adjust from there? I
>> don't want to duplicate code like that, but I need more
>> flexibility than I can easily add to arm_boot.c.
> 
> Nope, I'm afraid you're the first one to run into this.
> arm_boot.c started off as just implementing the realview
> secondary boot protocol, and exynos4 and vexpress have
> been close enough to piggyback on it. So highbank is the
> first board that's different enough to need its own code.
> 
> A big chunk of arm_boot.c is the primary CPU boot code,
> which should be standard for all arm platforms, so that
> shouldn't need to change. So we just need a reasonably
> clean solution for a platform to provide its own secondary
> boot code. I'm vaguely thinking about providing a hook
> function for 'write secondary boot code' and one for
> 'post-cpu-reset hook for secondary cpus', which would go
> in the "if (info->nb_cpus > 1) {...}" condition in
> arm_load_kernel() and in the else-clause of "if (env ==
> first_cpu) in do_cpu_reset().
> 
> Can you try something along those lines?

I think so. I was worried about accessing some of the
arm_boot static variables but it doesn't look like
I'll need to do that.

I'll do a quick refactor RFC of arm_boot.c and then
get into the gory bits of getting something to work
for Highbank.

--Mark Langsdorf
Calxeda, Inc.