[U-Boot-Users] Re: after a sw reset, u-boot hangs in relocate_code

[U-Boot-Users] Re: after a sw reset, u-boot hangs in relocate_code

[Jaka Močnik]

> Given that it is a problem on restart, I would speculate you have a 
> peripheral (ethernet is your #1 suspect) that isn"t being shut down 
> before you reset/reboot.  As a result, a packet comes in after you 
> reboot and your peripheral (ethernet) DMAs the packet into memory in the 
> middle of somewhere it doesn"t belong.
it's certainly an interesting thought - I will look into it, but I do
not think that this is the cause of my problems: if it were, I would
expect the CPU to throw an exception and go down the hard way. it
doesn't: it just hangs (or so it seems - I am currently JTAG-less, so I
can't really tell what's going on inside). also, in that case the board
would probably not behave as deterministically as it does (as the
problem would be caused by an unpredictable external event). besides,
eth is really the only possible culprit since the problem occurs even
when rebooting from u-boot, where eth is the only thing that can mess
with memory asynchronously. serial console I/O is polling-based...

regards,
	jaKa

-- 
e-mail: jaka at activetools.si
w3:     http://fish.homeunix.org/people/jaka/

[U-Boot-Users] Re: after a sw reset, u-boot hangs in relocate_code

[Wolfgang Denk]

In message <1109963987.4094.11.camel@pink> you wrote:
>
> it's certainly an interesting thought - I will look into it, but I do
> not think that this is the cause of my problems: if it were, I would
> expect the CPU to throw an exception and go down the hard way. it
> doesn't: it just hangs (or so it seems - I am currently JTAG-less, so I
> can't really tell what's going on inside). also, in that case the board

There is a likelyhood of some 99.5% that you are asking a FAQ.
Like this one:
http://www.denx.de/twiki/bin/view/DULG/UBootCrashAfterRelocation

I bet your SDRAM init sequence is broken.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Brain fried - Core dumped

[U-Boot-Users] Re: after a sw reset, u-boot hangs in relocate_code

[Jaka Močnik]

On Sat, 2005-03-05 at 11:58 +0100, Wolfgang Denk wrote:
> In message <1110013168.3977.2.camel@pink> you wrote:
> >
> > > I bet your SDRAM init sequence is broken.
> > ...as mentioned before, the crash only happens after a sw reset; after a
> > hard reset, both u-boot and linux kernel work like a charm, therefore I
> > believe that this is not the case.
> 
> I am prtty certain about this.
you were right to be certain;) and I should never doubt the advice of
the Wise(tm).

it seems that the DDR controller on PQ3 (at least on my board) hates
being initialized twice, so I put in some (rather hackish) code that
detects if it is already initialized (which is the case after a warm
boot) and skips the initialization. it seems to Just Work(tm) and I'm a
happy person once again: now I can reboot the linux kernel without
having to unplug the board, which will prevent some healthy walks during
work;)

regards,
	jaKa

-- 

w3: http://fish.homeunix.org/people/jaka
email: jaka at activetools.si