[U-Boot-Users] Dynamic U-Boot configuration via FDT

Jerry Van Baren gerald.vanbaren at smiths-aerospace.com
Fri Sep 21 13:47:41 CEST 2007

Wolfgang Grandegger wrote:
> Hello,
> it want to report on my experience with using FDT to configure
> U-Boot dynamically for a custom board based on the MPC823. The customer
> wanted _one_ U-Boot and Linux image for various variants of that board
> mainly to simplify software maintenance. The following devices required
> configuration via FDT blob:


> The central question is to what extend we want to use the FDT to 
> configure U-Boot. I already regard the extensive use of the FDT in Linux 
> 2.6 as kind of overkill.

Beauty is in the eye of the beholder. :-)

In the kernel's defense, they are working in a vastly more diverse 
(hardware-wise) environment than us embedded guys and many of their 
users (probably overwhelmingly most of their users by a simple head 
count) have no desire to configure and build a custom kernel for their 

Personally, it has been a looong time since I built an x86 kernel for 
one of my workstations.  Since my workstation hardware is probeable, I 
don't need to do it.  The FDT brings that configuration to non-probeable 
hardware by having wizards (that's us, kindly deposit your money at the 
door ;-) generate the hardware description that the kernel can use to 
auto-configure itself.

I look at the FDT as a kernel "make menuconfig" done once by the wizards 
rather than having to repeat it every time you want to upgrade your kernel.

"The Navy is a master plan designed by geniuses for execution by idiots."
     - Wouk, Herman: The Caine Mutiny : a novel of World War II


> Please comment.
> Thanks.
> Wolfgang.

Thanks for the update, Wolfgang, and I'm pleased that it went so well.


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