[U-Boot] memory display question

[U-Boot] memory display question

[Steve Iribarne]

Hello List.

I have a Freescale iMX25.  Seems to work fine and I'm trying to get some 
of the security features working.

I'm currently getting an error when I try to do a secure boot (internal 
to the processor). So the next step is to verify that my u-boot image is 
loaded where I think it should be loaded (at TEXT_BASE (0x83F0_0000)).

When I do a md.w 0x83F00000 0x20 it display's all zero's which is wrong. 
  It should have my reset vector and some other things there.  The image 
header is really at offset 0x400.

So I tried md.w 0x83F00400 0x20 and still all 0's.

This makes no sense because the darn thing boots!

When I hook my Lauterbach to it and do a view memory through the JTAG 
the memory looks as I expect.  This makes complete sense because if this 
wasn't the case I wasn't sure how my system was going to boot.

Has anyone else seen something like this?  If so, could you shed some 
light on what you did to remedy the issue.

thanks.
-- 
Steve Iribarne
Sr. Software Engineer
Embedded Devices

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[U-Boot] memory display question

[Detlev Zundel]

Hi Steve,

>
> I'm currently getting an error when I try to do a secure boot (internal 
> to the processor). So the next step is to verify that my u-boot image is 
> loaded where I think it should be loaded (at TEXT_BASE (0x83F0_0000)).
>
> When I do a md.w 0x83F00000 0x20 it display's all zero's which is wrong. 
>   It should have my reset vector and some other things there.  The image 
> header is really at offset 0x400.
>
> So I tried md.w 0x83F00400 0x20 and still all 0's.

Why do you do a "md.w" to explicitely select 16-bit entities?  Did you
try without (i.e. correpsonding to .l) and .b?  Maybe your system has
problems with different access widths.

> This makes no sense because the darn thing boots!
>
> When I hook my Lauterbach to it and do a view memory through the JTAG 
> the memory looks as I expect.  This makes complete sense because if this 
> wasn't the case I wasn't sure how my system was going to boot.

What accesses do you perform in this setup to read the memory?

Cheers
  Detlev

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[U-Boot] memory display question

[Steve Iribarne]

Detlev Zundel wrote:
> Hi Steve,
> 
>> I'm currently getting an error when I try to do a secure boot (internal 
>> to the processor). So the next step is to verify that my u-boot image is 
>> loaded where I think it should be loaded (at TEXT_BASE (0x83F0_0000)).
>>
>> When I do a md.w 0x83F00000 0x20 it display's all zero's which is wrong. 
>>   It should have my reset vector and some other things there.  The image 
>> header is really at offset 0x400.
>>
>> So I tried md.w 0x83F00400 0x20 and still all 0's.
> 
> Why do you do a "md.w" to explicitely select 16-bit entities?  Did you
> try without (i.e. correpsonding to .l) and .b?  Maybe your system has
> problems with different access widths.
> 

Yes I've tried both md.b and md.l, same deal.


>> This makes no sense because the darn thing boots!
>>
>> When I hook my Lauterbach to it and do a view memory through the JTAG 
>> the memory looks as I expect.  This makes complete sense because if this 
>> wasn't the case I wasn't sure how my system was going to boot.
> 
> What accesses do you perform in this setup to read the memory?
> 

Oh good question.. I'll look at that...

Thanks.


-- 
Steve Iribarne
Sr. Software Engineer
Embedded Devices

This e-mail and any of its attachments may contain proprietary 
information, which is privileged, confidential or subject to copyright 
belonging to Grid Net, Inc. This e-mail is intended solely for the use 
of the individual or entity to which it is addressed. If you are not the 
intended recipient, you are hereby notified that any dissemination, 
distribution, copying or action taken in relation to the contents of 
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permanently delete.