[U-Boot-Users] RFC: Xilinx Spartan3 relocation code

[Matthias Fuchs <matthias.fuchs@esd-electronics.com>]

Bruce,

what kind of bitstream file do you download to your FPGA?
A .bit File? In this case we should put the bit mirroring into the
wdata() callback or the *_sp_load() function, because the serial slave
download is fine without mirroring. Any way there is not need to malloc
a very huge amount of memory an do the mirroring on a buffer. This 
can be done on-the-fly during download.

Matthias

On Monday 20 August 2007 19:46, Bruce_Leonard at selinc.com wrote:
> Stefan,
> 
> > > > I fixed and added some things for the generic FPGA boot. Patches 
> will be
> > > > posted with the new board patch.
> 
> Sorry for the late reply, had a big BBQ this weekend for my anniversary 
> and haven't checked my e-mail in three or four days.  Could you please let 
> me know what your patches are going to look like?  I don't want to push up 
> any patches that will cover/conflict things you've got in your queue.
> 
> > > trouble getting the FPGA to program.  We're currently assuming that 
> our
> > > interface to the FPGA is broken, but if there's known issues in the
> > > generic code that would be nice to know :).
> 
> I finally figured out what stupid thing I was doing.  Both the FPGA and 
> the PPC are big endian, however if the processor is little endian the data 
> needs to be bit-swapped before going to the FPGA over SelectMap.  When I 
> was commenting out the code to do the bit-swapping (which we don't need to 
> do) I got over zealous by one line and wasn't initializing a pointer.  So 
> I was sending nothing but 0x24 to the FPGA.  Wonder why it didn't program? 
> :0
> 
> I'm going to try and come up with a clean way (probably a config option) 
> of doing or not doing the bit-swap thing in code.  If you're running a bit 
> endian system you really don't need or want to do it.  Little endian 
> systems, unless you're very carefull with your HW design, you want to do 
> it.  I'll have a patch for it in a couple of days.  I was thinking 
> something along the lines of "#define CFG_NO_SELECTMAP_BITSWAP".  If it's 
> not defined the code does the bit-swap, which is the way everything 
> currently works.  Or should it be a CONFIG instead?
> 
> Bruce
> 
>