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

[Bedia, Vaibhav]

On Tuesday, February 01, 2011 1:48 PM, Aneesh V wrote:
> Dear Wolfgang,
> 
> On Tuesday 01 February 2011 01:25 PM, Wolfgang Denk wrote:
>> Dear Aneesh V,
>> 
>> In message<4D4798E2.3050500 at ti.com>  you wrote:
>>> 
>>> I had been working on creating an MMC SPL for OMAP4. OMAP boards
>>> typically support booting from the FAT partition of a removable
>>> SD/MMC card. So, we need to have FAT support in the SPL. But I am
>>> having some difficulties in adding FAT support to SPL.
>>> 
>>> BSS footprint of fat.c is very high. It has three buffers each of
>>> size 64KB. To workaround this problem I have done something like
>>> below(The way x-loader works around this problem today).
>>> CONFIG_SYS_SPL_FAT_BUFFER_BASE is in SDRAM.Is this ok?
>> 
>> 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
> rest of the bss in internal RAM so that it's available as soon as
> we enter C code.   
> 

This approach looks very messy to me. I would rather revisit the init sequence to see if things can be fixed there.

Regards,
Vaibhav