[U-Boot] AM335x : failure to boot SPL from NAND

[Tom Rini]

On Mon, Feb 18, 2013 at 02:43:47PM +0000, Mark Jackson wrote:
> On 15/02/13 21:13, Tom Rini wrote:
> > On Thu, Feb 14, 2013 at 03:54:23PM +0000, Mark Jackson wrote:
> > 
> >> I'm trying to diagnose why our AM335x based CPU board (based on the
> >> AM335x Starter Kit) can boot SPL and U-Boot from an MMC card, but is
> >> unable to boot from NAND (connected to CS0).
> >>
> >> Following the TI wiki
> >> (http://processors.wiki.ti.com/index.php/AM335x_U-Boot_User%27s_Guide#Flashing_images_to_NAND_in_SD_boot)
> >> I:-
> >>
> >> (1) boot from MMC
> >> (2) erase the nand
> >> (3) copy MLO from MMC into NAND
> >> (4) verified it copied correctly (using crc32)
> >>
> >> When I reboot the board in NAND mode, I get nothing on UART0.
> >>
> >> If I reboot in MMC mode, SPL and U-Boot load correctly.
> >>
> >> Can anyone give me some pointers on the boot sequence, and where I
> >> might look to help debug the problem ?
> > 
> > Assuming you're using mainline U-Boot and can rule out "vendor
> > problems", if you can access the SYSBOOT pins, set it up for a mode that
> > does NAND and UART.  If you never see the 'CCC' on console (or only see
> > it the first time if you do UART then NAND), then you are starting SPL
> > and dying in there.  If you just see a stream of C then your file is not
> > written to NAND correctly.
> 
> Interesting ... I don't get any 'CCC' on the console.
> 
> However, I then tested this by booting via MMC, erasing the NAND chip and
> then trying to reboot via NAND again.
> 
> I still get no 'CCC' on the console !?!

How did you wire the SYSBOOT pins, and which UART is connected to
console?  If you have UART0 as the one hooked up to console and have
SYSBOOT[4:0] as 00100, the order is UART0,XIP (NOR),MMC0,NAND.  So you
should see 'CCCCCCCC' (UART0 trying to initiate X-Modem), then it will
try MMC0 and then NAND..

> This is using boot mode 10011 (NAND, NANDI2C, MMC0, UART0), so I would expect
> to either boot via MMC (if I left it in) or get some 'CCC' output on the
> console.

Correct.  If you have an empty NAND and nothing inserted in MMC, it
should be an endless cycle of 'C'.

> I can see that the NAND signals always have a burst of activity every 10ms.
> That must be a timeout of some sort ... do you know if that's a hardware or
> software timeout ?

Moving beyond what I can easily help with, sorry.  Hit up the TI forums
at http://e2e.ti.com/ as this is getting a bit off-topic for the U-Boot
list as well :)  Thanks!

-- 
Tom
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