[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

    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...

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