[U-Boot-Users] AT91RM9200 boot.bin interaction with u-boot and SDRAM

[Ulf Samuelsson]

fre 2007-10-12 klockan 13:32 +0100 skrev Craig Robinson:
> Dear Ulf, 
> 
> A while back
> (http://www.nabble.com/at91rm9200---silent-console-tf4418118.html#a12631849)
> you pointed me at the atmel patched source for u-boot 1.2.0. I have compiled
> and run this on the EK with out problems. Thank-you. 
> 
> However, I now come to getting u-boot to function on our EK based hardware.
> Our new board has AT49BV642D flash and I have added support to the code for
> this part (still compiles and runs on the EK). Aside from a total lack of
> Ethernet support, the main difference between our board and the EK is the
> size of the SDRAM. We use half that on the EK (16Meg rather than 32Meg). So,
> reading the source code for both u-boot and boot.bin, I'm thinking that we
> need to change some things to take into account the change in SDRAM. What I
> think I need to alter is: 
> 
> boot.bin - 
> 
> main.c 
> #define DST 0x21f00000 to 0x20f00000
> entry.S
> redefine STACK to be 0x21000000 not 0x22000000
> 
> u-boot - 
> 
> change TEXT_BASE to 0x20f00000
> redefine PHYS_SDRAM_SIZE to 0x1000000 in <board>.h
> 
> Is this correct and have I missed anything? 
> 
This looks OK to me. I do not know if this is everything needed.
YOu might have a look at where you store your environment.

> Also, is it broadly correct to say that boot.bin does the following: 
> 
> 1. low level init
> 2. uncompress a gzipped file from SRC in parallel flash and put it in SDRAM
> at DST
> 3. jump to unzipped file at DST.
> 
> If this is the case, then do we need to also ensure that
> CONFIG_SKIP_RELOCATE_UBOOT is defined? Is there a point to this aside from
> saving space in flash? 

I think You need to relocate to SDRAM, 
if you have linked the U-boot as you mention above.

> 
> Many thanks in advance.
> Craig Robinson.
> 
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> 15:09
>  
> 
-- 
Best Regards
Ulf Samuelsson