[U-Boot-Users] set up stack before board_init_f() on ppc440 core?

[Shawn Jin <shawnxjin@gmail.com>]

Dear Wolfgang,

> Which part of section "Initial Stack,  Global  Data"  in  the  README
> don't you understand?

Thanks for pointing out the section. I didn't read it through before. :(

> > stack in DCACHE (Walnut 405 is an example). But the CFG_INIT_RAM_ADDR
> > is 0x40000000, which is inside SDRAM. Why was it commented that the
> 
> No, this is not inside SDRAM. There is no board (yet) with  1  GB  of
> RAM.

Well, "inside SDRAM" is what is commented on WALNUT.h. Now I
understand the value of CFG_INIT_RAM_ADDR is better not to interfere
with the system design.

> In short: cache is like normal memory, just very fast (which does not
> play a role here). We just have to make sure that no cache  fills  or
> cache  flushes  will  be done (at least not for that part of the data
> cache which is being used for the initial stack).

I don't see any caches are in a system memory mapping. Then I thought
it could be only accessed by those cache specific instructions, like
dcread. That's my misunderstanding.

Thanks,
-Shawn.