[U-Boot-Users] RFC: Some improvements for the FPGA subsystem

Matthias Fuchs matthias.fuchs at esd-electronics.com
Tue Dec 11 18:00:16 CET 2007

Hi Wolfgang,

On Monday 10 December 2007 13:04, you wrote:
> Hi,
> The observation is that using callbacks for every single data/clock
> line change takes very long, doing this in a monolithic function is
> much faster; additionally, you could take advantage of some
> hardware (e.g. SPI, although I did not get this to work yet) to
> do the actual load.

The new fwr callback makes sense to me. I agree that using the callbacks for every signal
change might be very slow. I used the the slave parallel code to load an fpga in slave serial
mode some time before. This reduces the callbacks a lot and booting was about 4 times faster.
I used the byte write callback to shift out 8 bits in this case.

I hope that my FPGA patches will get it into U-Boot when the next merge windows opens.
Perhaps you can provide a patch on top of that afterwards.


More information about the U-Boot mailing list