[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
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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