[U-Boot-Users] mpc824x/start.S

Chris Hallinan clh at net1plus.com
Wed May 28 16:03:54 CEST 2003


Matthew,

First, you will get much more response on this list if you *do not*
post HTML or other formats to this list.  Please use plain text
only.  It takes more time that I have to reformat a proper reply :)

There are a number of issues with the code snippet you pointed out.

> #ifdef DEBUG
>     lis   r4, CFG_SDRAM_BASE at h   /* Source      Address     */
>     ori   r4, r4, CFG_SDRAM_BASE at l
> #else
<snip>

First, if one really wants to do this, the label DEBUG is mis-named.
It should be

#ifdef BOOT_IMAGE_FROM_RAM or something like that.  This is simply
the address where the ppcboot image is located before it is copied
to RAM.

Second, this is *very* old code and broken.  As others have pointed
out repeatedly on this list, if you have a flash burning tool such
as the BDI-2000 and it is properly configured to use a workspace to
speed up the flash burning process, it is just as fast to burn a new
image into flash and test it, rather than to do all the detail work
to get a U-Boot image to boot from RAM.  I've used both methods, but
I am now convinced that booting from RAM isn't worth the trouble.

My suggestion: submit a patch with these four lines deleted from the
file.  It's broken code anyway.

-Chris Hallinan
DS4.COM, Inc.

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