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

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

[Robert Schwebel]

Hi, 

I have a board which uses a softcore ethernet chip, so before for
example U-Boot is able to do networking some binary firmware has to be
loaded into the device. 

What's the preferred method to do this? I didn't find other boards in
the U-Boot code but maybe missed something. 

Seen from a technical point of view it would be the best solution to
just link the firmware somewhere into the U-Boot image, but I would be
interested how this is generally seen wrt. GPL issues. I don't think
that this creates a derivative work, taken that it is just being
bit-banged into the hardware by some GPL code, which is not different
from what the Linux firmware interface does, but anyway. It has to be
located somehow, and spending another flash sector just for some 40KiB
would be uggly.  

Robert
-- 
 Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de
 Pengutronix - Linux Solutions for Science and Industry
   Handelsregister:  Amtsgericht Hildesheim, HRA 2686
     Hannoversche Str. 2, 31134 Hildesheim, Germany
   Phone: +49-5121-206917-0 |  Fax: +49-5121-206917-9

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

[Wolfgang Denk]

Hello Robert,

in message <20051115183458.GX1099@pengutronix.de> you wrote:
> 
> I have a board which uses a softcore ethernet chip, so before for
> example U-Boot is able to do networking some binary firmware has to be
> loaded into the device. 
> 
> What's the preferred method to do this? I didn't find other boards in
> the U-Boot code but maybe missed something. 

See for example the FPGA support code which does something similar  -
load some images into a FPGA.

> Seen from a technical point of view it would be the best solution to
> just link the firmware somewhere into the U-Boot image, but I would be

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.

> interested how this is generally seen wrt. GPL issues. I don't think

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.

Which license is used for this firmware?

> that this creates a derivative work, taken that it is just being
> bit-banged into the hardware by some GPL code, which is not different

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.

> from what the Linux firmware interface does, but anyway. It has to be
> located somehow, and spending another flash sector just for some 40KiB
> would be uggly.  

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.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Imitation is the sincerest form of plagarism.

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

[Robert Schwebel]

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. 

Thanks, 
Robert
-- 
 Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de
 Pengutronix - Linux Solutions for Science and Industry
   Handelsregister:  Amtsgericht Hildesheim, HRA 2686
     Hannoversche Str. 2, 31134 Hildesheim, Germany
   Phone: +49-5121-206917-0 |  Fax: +49-5121-206917-9