[U-Boot-Users] TEXT_BASE

Wolfgang Denk wd at denx.de
Tue Feb 4 22:57:03 CET 2003

In message <722E4866-3888-11D7-8C12-00039390D626 at pepper.com> you wrote:
> I am confused about the TEXT_BASE define in the config.mk file.
> Should this be the address of where the loader is in flash or where it 
> should go in SDRAM?

It is the physical start address of the code (not the  entry  point!)
in flash memory _after_ the final address mapping has been set up.

The start address in RAM usually cannot be determined at compile time
as it depends on a couple of parameters like:

- RAM size (U-Boot should always automagically adjust to different
  RAM sizes and install itself always at the very end of available

- Use of "protected RAM", which will "shift down" the location where
  U-Boot gets installed in RAM by an amount which may depend on
  environment variable settings

- Use of a common syslog buffer within U-Boot and Linux, which also
  shifts down the location where U-Boot gets installed in RAM

[I know that there are some boards that  don't  bother  to  implement
this  intelligence;  they will break when trying to use some of these
more advanced features.]

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
Quote from a recent meeting:   "We are going to continue having these
meetings everyday until I find out why no work is getting done."

More information about the U-Boot mailing list