[ECOS] IXDP425 SDRAM CONFIG & Linux ATAGS

Dave dave@cc0.net
Wed Oct 5 18:27:00 GMT 2005


Hello all,

Following up on the issue I originally reported. I dug into the issue more 
and I just cannot see anything that I am missing. The memory looks correct 
between a working 64mb configuration and a 32mb configuration...however 
ATAGS are still not usable on the 32mb configuration.

The issue as originally reported is that I have a 64mb IXDP425 board with 
RedBoot 2.01 which works fine with a 2.4.27 kernel. ATAGS work correctly, I 
can override the kernel command line just fine via exec -c "". I have a 32mb 
IXDP425 board with the same RedBoot 2.01 except that changes have been made 
to reflect the SDRAM memory layout and size. Also adjusted are the mlt files 
in pkgconf/. The ATAGS on the 32mb board look fine in memory after calling 
exec -c "" however the 2.4.27 kernel thinks they are somewhere else than on 
the 64mb board. The kernel being used is identical for both the 32mb and 
64mb boards.

I placed a memory dump in redboot after exec but before kernel exec and the 
ATAGS can be seen just fine on both 32 and 64. I also placed some printks in 
the kernel to show ATAG stuff and it is different between the 64/32.

The changes made to the RedBoot source as well as the memory dump and kernel 
printks I placed at:

http://ixp.cc0.net/

To save forwarding all this info to the mailing list.

Anyone have an idea what I am missing that needs to be changed?


Thanks!

-Dave



> On Wednesday 28 September 2005 02:54 am, Dave wrote:
>> I just dug into this today...I put a dump in redboot_linux_exec.c after
>> filling up the ATAGs and before executing kernel and looked at memory at
>> 0x100. It looks perfect to me...ATAGs present are ATAG_CORE, ATAG_MEM and
>> ATAG_CMDLINE.
>
> Dump the value of
> CYGARC_PHYSICAL_ADDRESS(CYGHWR_REDBOOT_ARM_LINUX_TAGS_ADDRESS)
>
> This is the value that should be in your linux's machine_desc.boot_params
>
> Jon
>
> -- 
> Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
> and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
>
> 


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