Imx51 processor hangs when we do an md 0xf0000000 (memory display) in u-boot

Greg Topmiller Greg.Topmiller at
Mon Apr 18 05:44:16 EDT 2011

Thank you for your response.

Is there any way we can put code in u-boot to handle the abort?



From: Sascha Hauer [s.hauer at]
Sent: Monday, April 18, 2011 3:29 AM
To: Greg Topmiller
Cc: barebox at
Subject: Re: Imx51 processor hangs when we do an md 0xf0000000 (memory display) in u-boot

On Sat, Apr 16, 2011 at 11:14:13AM -0700, Greg Topmiller wrote:
> We're are using the Freescale release L2.6.31_MX51_SDK_0912_Image and
> it will do this on a Freescale Babbage board and our design.  It also
> does the same thing in Linux when we mmap the address 0xf0000000 and
> try to read from it.  It does not hang on the Redboot.bin image
> supplied with the Freescale SDK.  The Redboot dump command displays
> some data.  On the Freescale 3Stack board we get an illegal address
> error in Redboot, but it will hang in u-boot.  We realize this is a
> reserved physical address but would hope that an error of some kind
> would occur rather than locking up the CPU.  Could it be some sort of
> MMU initialization difference between Redboot and u-boot?

I have no idea how redboot maps the memory in the mmu, but barebox and
u-boot use a 1:1 mapping which results in the behaviour you see.
Accessing reserved memory can result in a abort.


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