Changing Base Address of Boot Flash

[Dietrich]

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Nov 4, 2005, 7:43 AM

Post #1 of 3 (29 views)
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 [ColdFire] Changing Base Address of Boot Flash  Can't Post 

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I'm working with the 5475EVB and the LinuxBSP provided by metrowerks. I
am trying to get colilo to boot without needing to use dBUG first.
However, the version of colilo that came with the BSP assumes that dBUG
has done a lot of the initialization already (flex bus, SDRAM, etc.), so
I am adding that initialization back into colilo.

I have a question about the boot process. When the coldfire boots, it
uses the reset values for CS0 and boots from the boot flash. At some
point in dBUG, the code changes the CS0 base address to 0xFFE00000. It
is my understanding that we're running from flash at that point, so
wouldn't that make the program counter invalid? The PC should contain a
value based on the original CS0 base address (0x00000000), which is no
longer valid. What am I missing?

Thanks,
Steve

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Nov 4, 2005, 8:31 AM

Post #2 of 3 (29 views)
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 Re: [ColdFire] Changing Base Address of Boot Flash [In reply to]  Can't Post 

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It is magic, during start up and until you set the CS0(i think) ffe00000
and 0 are the same. It has been a long time so i don't remember any
more.
Tom
On Fri, 2005-11-04 at 10:43 -0500, Steve Joiner wrote:
> I'm working with the 5475EVB and the LinuxBSP provided by metrowerks. I
> am trying to get colilo to boot without needing to use dBUG first.
> However, the version of colilo that came with the BSP assumes that dBUG
> has done a lot of the initialization already (flex bus, SDRAM, etc.), so
> I am adding that initialization back into colilo.
>
> I have a question about the boot process. When the coldfire boots, it
> uses the reset values for CS0 and boots from the boot flash. At some
> point in dBUG, the code changes the CS0 base address to 0xFFE00000. It
> is my understanding that we're running from flash at that point, so
> wouldn't that make the program counter invalid? The PC should contain a
> value based on the original CS0 base address (0x00000000), which is no
> longer valid. What am I missing?
>
> Thanks,
> Steve
>
>

Tom Burrell
Southwest Microwave

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Nov 6, 2005, 1:42 PM

Post #3 of 3 (26 views)
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 Re: [ColdFire] Changing Base Address of Boot Flash [In reply to]  Can't Post 

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Hi Steve,

Steve Joiner wrote:
> Wow! Matt, thanks so much for this info, this is a huge help. This is
> a very nicely packaged BSP.
>

Great. LTIB is still pretty new and we're working on it. I'm glad
it's helped you.

> This is my first exposure to LTIB. How easy is it to modify the BSP for
> a custom board (based on the 5472?). Are there any docs about
> customizing it? I found the savannah site, but there are no docs there.
>

The best place to look for information like this would be in
./ltib/doc/LtibFaq document.

However, I think most of the issues you'd encounter would be in
the kernel software. Since the 5472 is a V4e ColdFire core it
shouldn't be that difficult. The LtibFaq section "How can I
re-configure the kernel under LTIB" gives directions for
kernel development and rebuilding. The kernel name used for
the -p option in this case is "kernel-2.6.10-rig".

The package names for all the source code can be found in
the ./ltib/dist/lfs-5.1/ directory. Be aware that all the
packages listed there have *not* been tested on all the
platforms.

Regards,
Matt

> Thanks,
> Steve
>
> On Fri, 2005-11-04 at 14:56 -0700, Matt Waddel wrote:
>
>>Hi Steve,
>>
>>This work has already been done. You can download the LTIB BSP at:
>>
>>http://www.codewarrior.com/MW/Develop/Embedded/Linux/DownloadBSP.htm
>>
>>Go to the bottom of the page and find the BSP:
>>
>>Freescale MCF547x & MCF548x 2.6 kernel - BSP Information - LTIB
>>
>>The colilo included with this BSP can be run from RAM, Flash + dBUG,
>>or Flash solo. The users manual User_Manual_MCF54X5_20050822.doc
>>has the instructions. It's setup so you can use a colilo running
>>in RAM to replace dBUG.
>>
>>Hope this helps.
>>
>>--Matt
>>
 
 
 

Message Edited by Dietrich on 04-03-2006 11:01 AM

Message Edited by Dietrich on 04-04-2006 09:15 PM