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

[w.wegner at astro-kom.de]

Hi,

On 11 Nov 2007 at 17:45, Matthias Fuchs wrote:

> Hi,
> 
> we had some discussions about the FPGA subsystem some days (and also 
> a couple of months) before on this list. I have also some local improvements 
> for the FPGA subsystem.
> 
> Before posting a couple of clean patches I dare to post a single patch just to
> get an ok for the different topics. When all points are clear, I will split my patch
> into one patch per per topic.

I have one wish on my list:

Would it be possible to have an optional "block write" function for the FPGA?

While I appreciate the current approach of single bit functions for the FPGA
to be very convenient for board bring-up, it is somewhat slow on the larger
FPGAs (with something like 1.5 MByte bitstream size).

An additional block write function that - if present - replaces the internal
(generic) programming algorithm would give a clean way to use the existing
FPGA infrastructure (commands, image handling, pre- and post-configuration)
and switch to a fast load for production use.

Only then, you could take advantage of buses like SPI for FPGA load, too.

(I hacked something like this in my local u-boot, and the speed-up for
FPGA loading was significant, at least 3 times. And I still did not
implement the SPI path because I did not have the time yet...)

Best regards,
Wolfgang