[U-Boot] how can i change u-boot load address?

Wolfgang Denk wd at denx.de
Tue Oct 7 16:02:23 CEST 2008


Dear Roman,

In message <40a670230810070536w5ab3251cm39b1a4ebd199e14a at mail.gmail.com> you wrote:
> 
> > On ARM it's being done wrong  -  no  real  relocation  is  preformed;
> 
> What do you mean by "real relocation"? As per start.S bootcode is
> copied from ROM to RAM.

Copied to a fixed address where it is actiually already  linked  for.
See my previous message with a lenghty explanation why this is a poor
design when dealing with variable sized memory.

> > The problem with the ARM implementation is that the link  address  is
> > fixed,  i. e. it cannot be adjusted to varying RAM sizes.
> Usually one ports U-Boot on a board with predefined hardware layout,
> i.e. flash, SDRAM and peripherals are fixed. If hardware changes, say
> SDRAM size, no big deal to make two/three distinct u-boot images --
> after all it ends up by changing TEXT_BASE only, as I understand.

This may be your opinion, but it is an isolated one and not shared by
*many* board vendors who offer  different  configurations  of  boards
with  smaller and bigger amounts of RAM etc. For these, having only a
single binary image of U-Boot for all board configurations is a MAJOR
win. Also consider systems which use memory modules.

Just try to imagine you have to install a new version of the BIOS  on
your PC just because you add or remove a memory module. Would you buy
such a PC?

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
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Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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