Re: [coreboot] CBFS bullfart (forked from GSoC-2014 Project for Coreboot)

[mrnuke]

On Friday, March 14, 2014 12:03:01 PM you wrote:
> Just to step back here.
>
> The flash is 8M. The system has 4G. What do I care if I leak memory? What's
> the issue you are solving?

Thank you! You have pointed out the number one issue with this bullfart: that 
CBFS design is x86-centric.

When you're in the bootblock on ARM, before ram is up, and you're leaking 20+ 
KiB of SRAM, when you only have 40 KiB left for stack + CBFS cache + romstage 
destination...

See where, I'm going?

Alex

CBFS bullfart (forked from GSoC-2014 Project for Coreboot)

[ron minnich]

You're going where we were in 2000. Many of us have been here before. We'd
have killed to have the 40K of space you have on the ARM. We were doing
this with either just the register set or a 16-register scratchpad.

And we solved it with a streaming abstraction. So the argument that we're
somehow x86 centric because we don't deal with small memory in the
bootblock is baloney. If you want to argue that we got sloppy for other
reasons, point taken. But in the case of DoC at least, we had very small
memory window and that was it. It was NOT directly addressable.

I think the real issue is that when cbfs came along (2007) we had hit a
point where all flash was addressable on the platforms we had. The idea
that flash would not be memory addressable is, well, so brain dead that I
guess we thought it would never happen. So of course it happened.

But there's several ways to deal with that problem, and I'm not convinced
you're there yet. Don't have time to look but the original cbfs design
could function with all the headers at the front, data following. Maybe we
need to get back to that.

ron

On Fri, Mar 14, 2014 at 12:11 PM, mrnuke  wrote:
> On Friday, March 14, 2014 12:03:01 PM you wrote:
> > Just to step back here.
> >
> > The flash is 8M. The system has 4G. What do I care if I leak memory?
>
> What's
> > the issue you are solving?
>
> Thank you! You have pointed out the number one issue with this bullfart:
> that
> CBFS design is x86-centric.
>
> When you're in the bootblock on ARM, before ram is up, and you're leaking
> 20+
> KiB of SRAM, when you only have 40 KiB left for stack + CBFS cache +
> romstage
> destination...
>
> See where, I'm going?
>
> Alex