[ECOS] IXDP425 SDRAM CONFIG & Linux ATAGS

[ECOS] IXDP425 SDRAM CONFIG & Linux ATAGS

[Dave]

Hello all,

I am working on a custom IXP425 board which is wired identical to an IXDP425 
except using different flash and SDRAM sizes/configs.

I am running into an interesting problem regarding passing of ATAG values 
from RedBoot to a Linux kernel (2.4.27) and was hoping someone might have 
some insight and pointers on where to look. I have reviewed the several 
similar messages on the ecos-discuss mailing list regarding SDRAM config on 
IXP boards but nothing that helped with my issue. I have also been googling 
a bit to no avail.

One of our boards is a 64MB SDRAM board and when using RedBoot 2.01 and 
setting SDRAM size appropriately and SDRAM_CONFIG_2x16Mx16, etc all seems 
well. ATAGs are passed correctly from RB to the kernel, in particular 
ATAG_CMDLINE gets passed correctly via exec -c ""...and the kernel picks it 
up just fine.

A new board is a 32MB SDRAM board and using same RB 2.01 except changing 
SDRAM size and SDRAM_CONFIG_2x8Mx16, etc to reflect the 32MB layout. This 
board boots fine and most all seems ok however ATAGs are not being passed 
down to the kernel. Specifically ATAG_CMDLINE is not being recognized and I 
would presume the others are not as well.

I suspect I am missing something that needs to be modified in RB with regard 
to the SDRAM changes between boards however I cannot locate anything that I 
may be missing. I have read that hal_platform_extras. needs to be fixed up 
for SDRAM changes however it has apparently been replaced with 
hal_platform_setup.h and it seems it uses all macros from ixdp425.h thus 
leading me to believe no change is needed.

Anyone have any ideas on what I may be missing?


Thanks!

-Dave









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Re: [ECOS] IXDP425 SDRAM CONFIG & Linux ATAGS

[Peter Korsgaard]

>>>>> "Dave" == Dave  <dave@cc0.net> writes:

 Dave> The offset is in the dumps at http://ixp.cc0.net It is during
 Dave> the kernel boot there are a bunch of printk's and param_offset
 Dave> is one of them. It is at 0x100 which is same as RedBoot.

Yes, but could you dump the memory around 0x100 in the kernel as well?
It should be the same as the dump in RedBoot, but apparently it isn't.

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Re: [ECOS] IXDP425 SDRAM CONFIG & Linux ATAGS

[Dave]

The offset is in the dumps at http://ixp.cc0.net
It is during the kernel boot there are a bunch of printk's and param_offset 
is one of them. It is at 0x100 which is same as RedBoot.

I know that the command line is offering a different mem value..that is what 
I am using to test if ATAGs are working or not. I should see the command 
line in the kernel if they are working.



-Dave


>>>>>> "Dave" == Dave  <dave@cc0.net> writes:
>
> Dave> Anyone have an idea what I am missing that needs to be changed?
>
> Your cmdline tells your kernel that you have 64MB on the 32MB
> board. The mem= line shouldn't be needed as the kernel gets it from
> ATAG_MEM (if it works atleast).
>
> Could you dump the mdesc->param_offset memory in the kernel to see if
> it's the same as in RedBoot?
>
> -- 
> Bye, Peter Korsgaard
>
> -- 
> 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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Re: [ECOS] IXDP425 SDRAM CONFIG & Linux ATAGS

[Peter Korsgaard]

>>>>> "Dave" == Dave  <dave@cc0.net> writes:

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

Your cmdline tells your kernel that you have 64MB on the 32MB
board. The mem= line shouldn't be needed as the kernel gets it from
ATAG_MEM (if it works atleast).

Could you dump the mdesc->param_offset memory in the kernel to see if
it's the same as in RedBoot?

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Bye, Peter Korsgaard

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Re: [ECOS] IXDP425 SDRAM CONFIG & Linux ATAGS

[Dave]

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
>
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>
> 


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