[U-Boot] BSS footprint of FAT very high - SPL issues

[Aneesh V]

Hello Wolfgang, Albert,

On Tuesday 01 February 2011 03:33 PM, Wolfgang Denk wrote:
> Dear Aneesh V,
>
> In message<4D47C1C9.1020002 at ti.com>  you wrote:
>>
>>> Why would that be necessary?  Just put the BSS segment in SDRAM, and
>>> everything is fine, isn't it?
>>
>> SDRAM is initialized by the SPL. So, bss can not be initialized and
>> used until SDRAM initialization is complete. I would prefer to have
>
> Yes, this is normal.
>
>> rest of the bss in internal RAM so that it's available as soon as we
>> enter C code.
>
> Well, you probably have to decide if you want an easy solution with
> the restictions of the internal RAM size, or a somewhat more complex
> solution with much more powerful resources.

I tried putting bss in SDRAM and it works for me. I just had to put a
couple of variables explicitly in .data section. However, there is one
minor issue that I would like to report.

Making .bss disjoint from the rest of the image may break the
relocation code in start.S. Currently the assumption is that
'__bss_start' indicates the end of .data and hence the image.
That will not be the case when .text and .data are in IRAM and .bss in
SDRAM. I am not affected because our SPL doesn't need relocation.

Best regards,
Aneesh