[U-Boot] [PATCH v2 7/7] am335x_evm: Add support to boot from NOR.

[Mark Jackson <mpfj-list@newflow.co.uk>]

On 13/05/13 19:28, Tom Rini wrote:
> From: Steve Kipisz <s-kipisz2@ti.com>
> 
> NOR requires that s_init be within the first 4KiB of the image so that
> we can perform the rest of the required pinmuxing to talk with the rest
> of NOR that we are found on.  When NOR_BOOT is set we save our
> environment in NOR at 512KiB and a redundant copy at 768KiB.  We avoid
> using SPL for this case and u-boot.bin is written directly to the start
> of NOR.

I'm trying to get this up and running our NanoBone platform, but I'm having
no success.

Using a non "NOR_BOOT" version, I can boot u-boot and read / write to the
NOR device (located at 0x08000000).

So I've compiled my "NOR_BOOT" version and stored it at the start of the
flash device.

But when I switch to booting from NOR (rather than SD) I get no output on
the serial console.

Using an oscilloscope, I can see the NOR chip select is active for a while
(approx 350us), so *something* is trying to boot.

How can I debug such an early part of the boot process ?

Thanks for any help you can give me.

Regards
Mark J.