[ECOS] Re: Limit region of flash used by RedBoot for FIS?

Grant Edwards grante@visi.com
Tue Nov 7 22:33:00 GMT 2006


In gmane.os.ecos.general, you wrote:

>> That's the exact same situation I'm in: the top 1MB contains
>> that's loaded into an FPGA by hardware on startup (before the
>> CPU starts).
>
> Our setup was different. The CPU downloaded the bitstream in the
> FPGA. So erasing the flash did not brick the system. It just mean the
> FPGA did not "boot".
>  
>> However, I don't want "fis init -f" to erase that block, and it
>> appears that it would do so as the code exists now.  Is that
>> correct?
>  
> It looks like that.
>
>> I'd like to be able to do that as well, so perhaps my proposed
>> solution isn't the best.  
>> 
>> What I really want is:
>> 
>>  * A reserved block in the top of flash for the CPLD data.
>> 
>>    That block must be left untouched by "fis init -f".
>> 
>>    It would be cool if that block showed up in fis list and
>>    could be updated using RedBoot as long as it can't be
>>    deleted by "fis del" and re-used for something else.
>
> It sounds like you need to add your own entries to the table,
> in the same way cfg/fis is added to the table and fis init
> known not to touch them.

I think it already works that way for the reserved space at
the bottom of flash.  There's an option called
CYGOPT_REDBOOT_FIS_RESERVED_BASE with this description:

    If an area of FLASH is reserved, it is informative to have
    a fis entry describing it.  This option controls creation
    of such an entry by default in the fis init command.

> I don't think this is going to be a generic solution which you
> can contribute back. It seems to be too specific to your
> platform.

I'm going to have to test it a bit, but I think the
FIS_RESERVED_BASE option does almost exactly what I want. What
I'm not positive there's a RedBoot command that will allow the
user to write a block of data into the reserved space.  I think
that "fis create -f <addr>" will do that, but I'm not sure yet.

I just need the same thing at the top of flash as well. :)

-- 
Grant Edwards                   grante             Yow!  ... Um...Um...
                                  at               
                               visi.com            

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