[U-Boot] Question regarding FPGA firmware load in u-boot

[Dieter Kiermaier]

André,

> Dieter,
>
> On Mon, 2009-06-22 at 08:19 +0200, Dieter Kiermaier wrote:
> > André,
> >
> > > Dieter,
> > >
> > > On Fri, 2009-06-19 at 17:46 +0200, Dieter Kiermaier wrote:
> > > > Hello List,
> > > >
> > > > I want to boot a (Lattice) FPGA from u-boot by using Slave Serial
> > > > configuration on a Marvell Kirkwood device.
> > >
> > > Should be no problem as long as you'll have access to GPIO.
> >
> > I'm working on it :)
> > But more likely I would have the SPI controller to do the serializing of
> > the bitstream. But maybe this would be the second step.
>
> Bitbanging is not critical and works pretty fast.
> You definitely have to control maximum frequency and observe errors
> during load. If you'll use SPI make sure to disconnect the bus from the
> FPGA and keep the config pins in a sane state.
>
Do you have some time values how long your FPGA needs to boot by using 
bitbanging?

> > > > As seen there is an (Xilinx and Altera) FPGA loader driver allready
> > > > available in u-boot.
> > > > Please can somebody explain how I have to provide a FPGA bitstream
> > > > image to u-boot?
> > >
> > > The easiest way is to reserve some unused flash sectors and use the
> > > first sector's start adress as arg for "fpga load".
> >
> > I assume this will only work with NOR flash, right?
>
> I'm using NOR flash, but it will work with any adressable memory.
>
> > If I'm using NAND flash I have to copy the image to ram first?
>
> yes.
>
> > > > It seems I have to create a image with mkimage?
>
> you can store e.g. fpga.bin as a single file inside jffs, read it and
> load your fpga.
>
> > > no - Lattice specififc bitstream can be stored in raw format.
> > > mkimage may be useful for update, but personally I prefer update via
> > > dedicated linux mtd partition.
> > >
> > > > This image have to be loaded into ram and the address has to be
> > > > provided to the load command?
> > >
> > > Usually an FPGA is *very* board specific. I'd suggest to use flash and
> > > create a corresponding mtd partition for linux, i.e. make it
> > > maintainable.
> >
> > Seems to be a good way.
>
> yes - but not for jffs2 on NAND. You can use a plain binary file
> instead.
>
> > Is there a cmd in u-boot to read a file from a jffs2 filesystem inside a
> > nand flash partition?
>
> Have a look at the end of common/cmd_jffs2.c : fsload is the one for
> you.
>
Thanks for that link :)

> > > > Is there a maintainer for the FPGA code inside u-boot?
> > > > I'm willing to contribute some extensions for Lattice FPGAs if I'm
> > > > successful!
> > >
> > > excellent - all you'll need is the Lattice specific bit toggle
> > > sequence.
> > >
> > > submitting a proper patch will surely do.
> >
> > I'm trying to get an idea what place is the best to integrate the lattice
> > architecture in to the fpga framework.
> > If I have any further questions - can I ask you again?
>
> of course, but since I'm a PowerPC user I can't tell anything specific
> to ARM ...
>
Thanks again!

So I would try to bring it up and see what happens :)

Dieter

>
> Cheers,
>
> André
>
> > > Regards,
> > >
> > > André
> >
> > Many thanks for helping,
> > Dieter
> >
> > > > Thanks to all,
> > > > Dieter
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> MATRIX VISION GmbH, Talstraße 16, DE-71570 Oppenweiler
> Registergericht: Amtsgericht Stuttgart, HRB 271090
> Geschäftsführer: Gerhard Thullner, Werner Armingeon, Uwe Furtner,
> Hans-Joachim Reich