[ECOS] ROMRAM start for ARM

[ECOS] ROMRAM start for ARM

[Andrew Lunn]

Hi Folks

Im trying to figure out how to make the ARM family ROMRAM start. In
particular im interested in the EBSA285.

I have to modify PLATFORM_SETUP1 so that after its setup the DRAM it
copies the image from ROM into RAM. My question is, what exactly do i
have to copy from where to where?

I need to copy the text, rodata sections. What about the rom_vectors
and fixed_vectors section? I assume these also need copying. It looks
like i just have to copy the image to address 0x0. 

I assume a ROMRAM application is linked using the RAM memory layout?
So all symbols will have the RAM values. How do i get the address the
code is currently in ROM? Does the linker know this or do i just have
to hard code it? It looks like the MIPs has the FLASH address
hardcoded into it. Is there is symbol i can use the find out how much
i have to copy? __rom_data_end?

At the moment it looks like i need to do the equivelent of
        memcpy(0,FLASH_START,__rom_data_end);
        goto ram
ram: nop;

Does this seem right?

       Thanks
                Andrew

Re: [ECOS] ROMRAM start for ARM

[David Airlie]

Hi Andrew,

I have this done I submitted patches to the list ...

I've done it for the PID platform and my own internal platform ...

Look back in the lists... I don't know why my patches were never merged,
I think Jonathan said something about it working on other ARM
platforms.. well it works on two of mine fairly handly.... 

 http://sources.redhat.com/ml/ecos-discuss/2001-03/msg00016.html

is the last patch I submitted.. you also need some mlt files..
 http://sources.redhat.com/ml/ecos-discuss/2001-02/msg00261.html

See if it works for you..
Dave.

On Tue, 5 Jun 2001, Andrew Lunn wrote:

> Hi Folks
> 
> Im trying to figure out how to make the ARM family ROMRAM start. In
> particular im interested in the EBSA285.
> 
> I have to modify PLATFORM_SETUP1 so that after its setup the DRAM it
> copies the image from ROM into RAM. My question is, what exactly do i
> have to copy from where to where?
> 
> I need to copy the text, rodata sections. What about the rom_vectors
> and fixed_vectors section? I assume these also need copying. It looks
> like i just have to copy the image to address 0x0. 
> 
> I assume a ROMRAM application is linked using the RAM memory layout?
> So all symbols will have the RAM values. How do i get the address the
> code is currently in ROM? Does the linker know this or do i just have
> to hard code it? It looks like the MIPs has the FLASH address
> hardcoded into it. Is there is symbol i can use the find out how much
> i have to copy? __rom_data_end?
> 
> At the moment it looks like i need to do the equivelent of
>         memcpy(0,FLASH_START,__rom_data_end);
>         goto ram
> ram: nop;
> 
> Does this seem right?
> 
>        Thanks
>                 Andrew
> 

-- 
      David Airlie, Software Engineer, Parthus Technologies plc.,
       Mary Rosse Centre, National Tech Park, Limerick, Ireland.
   t: +353-61-508116 / f: +353-61-508101 / David.Airlie@parthus.com