[U-Boot-Users] Please pull u-boot-83xx.git

Wolfgang Denk wd at denx.de
Mon Nov 27 22:36:19 CET 2006

In message <456B57F9.9070405 at freescale.com> you wrote:
> > The problem is that I don't want to see any  such  hard-coded  sizes.
> > What  I want is documented in the (very old!) "System Initialization"
> > section in the README: we may have to configure for a  maximum  size,
> > but  except  from that, U-Boot should auto-adjust to different seizes
> > of RAM and flash memory.
> If I knew how to auto-adjust, I would have coded it that way.  To my knowledge, 
> there is no generic way to query to amount of flash on the system when the code 
> in start.S is being run.  The flash configuration code (e.g. flash_init()) is 
> executed much later in the boot process.

Right. that's why  we  start  with  preliminary  mappings  which  get
adjusted  later,  when the memory sizes are known. Please see section
"System Initialization" in the README.

> So one suggested to me a while back that I should just program LBLAWAR1 to 16MB 
> for everyone.  But then what do I do if a new system comes out with 32MB of 
> flash?  Or more?  LBLAWAR1 supports up to 2GB of flash.

I think it is a good idea to have the maximum size configurable.

>  > If
> > the  board  comes  with  a different flash size, what will the U-Boot
> > start messages report, and what size will  be  actually  mapped  once
> > U-Boot enters interactive mode?
> U-Boot will report whatever flash_init() says, which is typically calculated by 
> querying the hardware.

Will the mapping be adjusted as well?

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
The first 90% of a project takes 90% of the time, the last 10%  takes
the other 90% of the time.

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