[U-Boot] AT91RM9200 boots from NOR Flash or not

[Pink Boy]

Martin Hejnfelt sez,

> Message from Jens Scharsig,
>> I am a little bit confused. We have designed a new AT91RM9200 
>> based board. It should boot from 16-bit NOR Flash. I have read 
>> many relevant article in the forum, but I don't know , which 
>> board should I use as a base. I have look at the actual source 
>> (2008.10 and> git), and I think, u-boot can't boot without a 
>> preloader as long> CONFIG_AT91RM9200 is defined. Is there an 
>> open patch to resolve this? Can you get an example for a working
>> implementation?

I built u-boot 1.3.4 for the AT91RM9200DK and was able to hack in
support for the flash chip I'm using.  You might try the same.

The setup I'm using is to store boot.bin from atmel in flash
at .  And a copy of u-boot.gz at 10010000.

The way I did was to enable the AT91RM9200's boot serial port boot
loader and download Atmels loader.bin via XMODEM.  Then download
uboot.bin via XMODEM.  Once that it downloaded you should get a
prompt.

For auto booting I have Atmels boot program boot.bin stored in
flash at 10000000-10005fff.  And gzipped u-boot stored at 
10010000-1001ffff.

> It's true that it won't boot when CONFIG_AT91RM9200
> is defined. I don't know why it is like this since older 
> versions of U-boot didn't have this problem (it changed 
> around 1.3.0 if I remember correctly).

Hmmm...

> It's almost like even if you do not define CONFIG_SKIP_LOWLEVEL_INIT
> and/or CONFIG_SKIP_RELOCATE_UBOOT, it still works like they were.
> Maybe it's because Atmel usually supplies their own Boot.bin 
> along with the Development Kit (the configuration I would say 
> you should use as example for your own) You can resolve this by 
> editing two lines in the start.S file of the ARM920T cpu specific
> directory. In version 2008.10 its line 181 you can delete this, or
> change to ifdef, and again in line 264 you can either delete the if
> statement, or just make it branch to the lowlevel_init no matter 
> what.
> 
> I know its what someone would call a hack, but it works :)

This is the second place I've seen this.  I've been using atmels
boot.bin loader to uncompress u-boot and it seems to work okay.

Matt Harper
Tehama-Wireless.