Re: FW: Barebox on Karo TX25

[Sascha Hauer <s.hauer@pengutronix.de>]

On Tue, Dec 03, 2013 at 08:01:26PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 10:26 Tue 03 Dec     , Sascha Hauer wrote:
> > BTW Please don't top-post.
> > 
> > On Mon, Dec 02, 2013 at 09:13:31AM +0000, John Parker wrote:
> > > Hi again
> > > 
> > > So now my problem is that I really could do with the LED and UBIFS stuff that happened since February.
> > > 
> > > Should I try to fix mx25 in the latest code, or undo the problematic commit?
> > 
> > Well preferably you should fix the latest code and send a patch to make
> > it work again ;) However, that could become tricky. For doing so the
> > patch to enable the debug UART early may become useful. With this you
> > can use putc_ll and puthex_ll in early code.
> > 
> > I did some investigation. What happens here is really strange. First I
> > added a missing instruction cache invalidation. That alone doesn't fix
> > the problem. Inserting a nop fixes booting for me, see the attached
> > patch. If I move the nop up in the code it still works. If I move it
> > down, then the board does not work. I have no idea what's happening here
> > :(
> 
> could be that the sdram controler need times to stabelized and that you miss a
> delay for this

I thought about this aswell, but I don't believe that a single nop could
make such a reproducable difference. I tried all this with JTAG
debugging aswell which should make all timing issues vanish.

Sascha

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