[U-Boot] u-boot fails to read from nand flash in omap3

[Nick Thompson]

On 19/01/10 08:21, fgd wrote:
> 
>  Hi everyone,
> I've recently been playing with an omap3 beagle board and I've found a
> problem that I think involves the reading of nand memory...
> I have recompiled u-boot for the beagle board (I just changed its prompt, as
> a simple test to check that it's my u-boot and not the one that was there
> before, and I used the default configs for the beagle), then I have loaded
> u-boot and the x-loader into flash, and I have succesfully rebooted and seen
> 'my' u-boot prompt...
> after that, I wanted to load a linux kernel and a file system into nand
> flash, instead of using the external memory card (if I boot a kernel stored
> there, it works), so I go and load an uImage into flash, then read it back
> to RAM, and boot from there, and it still works, BUT, as soon as I reset the

Maybe you do this after running Linux and Linux has configured the SoC
to access the NAND? Can you use u-boot to write to NAND after a reset, but
before Linux boots?

> OMAP, when it tries to copy the kernel data stored in flash into RAM to boot
> from it, the nand reading operation will fail, and if I try to boot that
> kernel it will complain about a CRC checksum error...

After a reset, I guess your UBL (and u-boot) is not enabling NAND accesses?
I added some code to the Davinci nand driver to fix a similar issue on that
arch.

> the exact error looks like this:
> #  nand read ${loadaddr} 280000 400000

u-boot's nboot command can read the uImage header and copy from NAND only the
required amount of data. It only copies to RAM, so you still need to bootm...

> 
> NAND read: device 0 offset 0x280000, size 0x400000
> NAND read from offset 280000 failed -74
> 
> note that this just happens after I reset the board... I thought it could be
> a hardware problem with my board, but I've tried in a different board (an
> omap3 evm) and I'm getting the same thing, so I think I might be missing
> something...
> has anyone of you tried something like this or has encountered any similar
> problem? any help will be greatly appreciated, if you need any extra info
> about what I have done just tell me...
> thanks a lot in advance, regards
> 
> Fernando

Nick