kernel startup

[Kumar Gala]

On Fri, 10 Feb 2006 atul.sabharwal at exgate.tek.com wrote:

> >>I'm not that familiar with 8xx, but can't you move IMMR?
> 
> Not much choice with IMMR as it can be 0x0 or 0x00f00000 or 0xFF000000
> Or 0xFFF00000.  
> 
> Flash is from 0xfe000000 thru 0xffffffff.  Now on POR,
> Processor goes to offset 0x100 on CS0.  So, if IMMR is overlapping with
> flash, it might not boot.
> 
> On 870, it seems that reset value for BR0/OR0 is undefined.
> Data fetch goes on CS0 and then in cpu_init_f BR0 & OR0
> Are remapped.  So, I could put flash at a non-standard address like
> 0xDE000000 and move IMMR to 0xFF000000.
> 
> The problem this creates is that I can set IIP to 0 or 1. So, exception
> Vector prefix can be 0 or 0xfff.  Since no flash at 0xfff00000 base 
> Address I cannot have any exceptions in my code till the u-boot code
> has relocated to RAM.  Which should be acceptable as what can I do
> if there is exception so early in the system. 
> 
> Unless there is a better design ?

It sounds like you should move this discussion to the u-boot list since it 
has very little to do with the kernel.

- k