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

[Mark Jackson]

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 !?!

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.

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 ?

Mark J.