[U-Boot-Users] IVT on 405GP

Jerry Walden jwalden at digitalatlantic.com
Wed Apr 16 23:05:35 CEST 2003

No -- that is not what I did - I did not start u-boot from RAM
what I meant to say is that in the debugger the base address

r3 = 0x03fcf000 = not used
r7 = 0x03fcf100 = _start
r8 = 0x03fd1090 = _end_of_vectors
r9 = 0x3100 =  - this is incorrect

what I should have said is I need to place a number in CONFIG_MONITOR_LEN
that makes the calculation for the address of _start in relocate_code
to be something like 0x3fc0000 - right now I have it set to (196 * 1024)
which is used to calculate _start - that is what I need to change.

Jerry Walden

-----Original Message-----
From: wd at denx.de [mailto:wd at denx.de]
Sent: Wednesday, April 16, 2003 4:47 PM
To: jwalden at digitalatlantic.com
Cc: u-boot-users at lists.sourceforge.net
Subject: Re: [U-Boot-Users] IVT on 405GP

In message <EGEGIJHKDKJGAJMGIDPNOEPICKAA.jwalden at digitalatlantic.com> you
> Thanks for the response. I think my problem may be the base uboot address.
> The
> address is 0x3fcf000. The mask is 3fff. If my uboot started on a nice 16
> address then the result would be 0(3fc0000 & 3fff) but I was getting
> 0xf000(3fcf000 & 3fff). So I think that the fix is to move uboot down to
> 0x3fc0000 or 0x3fc8000.

I have warned often enough NOT to try to start U-Boot from RAM unless
you know _EXACTLY_ what you are doing.

You tried, and you failed. You kind of got what you deserved ;-)

Put U-Boot in flash, and start it from the reset entry point like  it
was designed for, and everything will be fine.

Actually I have to admit that I don't remember why the target address
was computed using "& 3fff" instead of a hard-wired  0x100.  I  don't
even remember where I got this code fragment from.

A similar assumption is buried in the code  relocation  stuff  -  see
llandre's  problem  when setting CFG_MONITOR_BASE to a value that was
not a multiple of 16 k.

We probably should get rid of this ASAP.

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
How does a project get to be a year late?      ... One day at a time.

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