[U-Boot-Users] Support for softcore ethernet chips

Robert Schwebel r.schwebel at pengutronix.de
Tue Nov 15 22:32:21 CET 2005

On Tue, Nov 15, 2005 at 10:12:17PM +0100, Wolfgang Denk wrote:
> See for example the FPGA support code which does something similar  -
> load some images into a FPGA.

Ah, ok. 

> I'm not sure if this is really the best solution; it may  be  a  good
> thing  to have the firmware image separated and be able to replace it
> without needing to replace U-boot.

Generally yes, but in this case replace most probably means that you
need to get a replacement, which would be difficult without a working
network card, taken that we won't fall back to the stonage where we
morsed firmware images over a serial line ;)

> My opinion is that linking is linking, and code is code. But I am not
> a lawyer (Thank goodness!). There  are  nearly  twenty  boards  which
> include  some binary firmware images (search for "fpgadata.c" files),
> but  in  my  (limited(  understanding  this  is   just   a   hardware
> description,  not  code.  Now  "binary  firmware"  may  be  something
> different. It sounds very much like code to me.

Well, it is some kind of generic communication hardware engine; not
really microcode, not really vhdl. Something inbetween and very, very
weird. I've no idea what exactly, but you can make it behave like
ethernet, like CAN, profinet, interbus, sercos or whatever...

> Which license is used for this firmware?

For the ethernet firmware: free beer. I suppose it's the only one
relevant for U-Boot, because when Linux is running the rest can be
separated in a clean way using the firmware interface. 

> Unless somebody with a better understanding of the legal aspects  ex-
> plains to me that I'm wrong (and why), then I will not complain about
> hardware definitions like FPGA images; but code (even for a different
> CPU) should be GPLed.
> Just providing a loader that  loads  the  image  from  some  external
> storage is IMHO the better approach anyway.

Ok, that's also my understanding. Let's see it like a hardware device
where the developers forgot to make the functionality persistent ;) 

> This depends on your sector size ;-) Also, you can locate  the  image
> in one of your file system images und use U-Boot to laod it - we have
> support  for  FAT/VFAT,  ext2, JFFS2, cramfs, and reiser - you should
> find something that matches your setup.

Seen from a functionality point of view I would like to load it from
jffs2, but if you have crashed your flash image you would not be able to
load a new one via ethernet. The firmware works; so I see no reason to
exchange it later, or at least no reason which wouldn't also justify
exchanging the U-Boot image as well. 

 Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de
 Pengutronix - Linux Solutions for Science and Industry
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