[U-Boot-Users] Running test code from RAM while having GOT po inting to flash

[atul.sabharwal at exgate.tek.com]

I am using DDR2 memory abstracted from me by a FPGA based memory controller.
Hopefully, the hardware engineer is configuring it correctly. All register
accesses are GPCM based.  I build a version of u-boot with I-Cache turned
off and it still failed. The Burst inhibit flag is turned on.  I am able 
To do block copies with the assembly routines (memcpy, strcpy) which are
faster than a C based for loop.

I am thinking of using the JTAG and copy some PPC code into RAM in a
Infinite loop and run it manually.  

Basically, some test to run some code from flash without relocation.

--
Atul

-----Original Message-----
From: wd at denx.de [mailto:wd at denx.de] 
Sent: Monday, October 24, 2005 11:51 PM
To: Sabharwal, Atul
Cc: u-boot-users at lists.sourceforge.net
Subject: Re: [U-Boot-Users] Running test code from RAM while having GOT
pointing to flash 

In message
<4A062D477D842B4C8FC48EA5AF2D41F20152806A at us-bv-m23.global.tektronix.net>
you wrote:
> My code seems to be crashing in the relocate_code routine while switching
> from flash to RAM.  There was an address_probe fixup which was not enabled
> And I enabled it. So, the relocation table (GOT) gets copied successfully
> From flash to RAM but the code dies seomewhere between coping the fixups

I think you misunderstand the function of the GOT.

> And the in_ram label.  Somehow, on my BDI, it sees an exception and goes
> to the reset vector i.e 0x100.

See the FAQ at http://www.denx.de/wiki/view/DULG/UBootCrashAfterRelocation

> My approach is to avoid the GOT stuff and write a test routine which is

The "GOT stuff" is known to work just fine. I suggest  you  focus  on
the  remaining  stuff, i. e. your SDRAM init sequence. Again, see the
FAQ.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
I often quote myself; it adds spice to my conversation.  - G. B. Shaw