[U-Boot] commit "powerpc: Remove warm reset entry point" does not work on mpc83xx

[Peter Tyser]

> > > It seems like my board uses the warm start vector at all times.
> > > Padding with 4 nop's after the _start symbol fixes the problem.
> > > It might be due to a somewhat peculiar reset design but I cannot 
> > > understand
> > > why. Does this work for everyone else using 83xx?
> > 
> > Odd...  I don't have an 83xx board to test on unfortunately.  Nothing
> > jumps out as being obviously wrong in the assembly:
> 
> The difference is that I suspect execution starts at 0xXXXXXX110 rather
> than 0xXXXXXX100. BTW, I have my reset vector at 0x0
> 
> What causes a warm reset?

My understanding is that a warm reset on the 8xxx CPUs isn't really a
hardware reset - its just when code explicitly jumps to the warm reset
entry point.  For example, this board used to jump to _start_warm when
"reset" was ran in U-Boot: 
http://git.denx.de/?p=u-boot.git;a=commitdiff;h=3792d7436e2bf881b6abdede5a481a62b5dedd55

During normal use I thought that the reset entry point was always
0xXXXXX100 and a warm reset would never occur.

What is the power on reset process like on your board?

Best,
Peter