Date: Fri, 9 Jan 2009 10:07:25 -0500
From: Hugo Villeneuve <hugo@hugovil.com>
To: "Thiago Galesi" <thiagogalesi@gmail.com>
Cc: "Florian Fainelli" <florian@openwrt.org>, linux-kernel@vger.kernel.org,
       linux-embedded@vger.kernel.org
Subject: Re: FPGA programming driver architecture
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On Thu, 8 Jan 2009 20:14:36 -0200
"Thiago Galesi" <thiagogalesi@gmail.com> wrote:

> > > > Hi,
> > > > I have written some code to program a FPGA in Linux, for two
> > > > different types of boards: one uses a serial interface (SPI) and
> > > > the second a parallel interface. I have been able to sucessfully
> > > > program both boards. I'm now trying to clean my code and make it
> > > > more generic, as well as better in line with the Linux driver
> > > > model.
> 
> Considering the several FPGA models available and ways to program it,
> I guess the important thing to consider is what can be made generic.
> (that is what will become fpgaload)

I have a pretty good idea of what goes into the core and
what goes into the specific interface modules (spi, parallel, etc).

> Also, there may be cases where after FPGA is programmed it "becomes a
> device" (PCI or whatever)

This is exactly the case for my board, but it doesn?t change anything
to the programming side of things, apart for the fact that the FPGA
must be configured before using any in-FPGA PCI bus for example.

> > > - fpgaload-core which contains all the code that can be shared
> > > between the drivers like requesting firmware, providing sysfs
> > > attributes,
> > > - fpgaload-spi would handle the low-level SPI connection
> > > - fpgaload-par would handle the low-level parallel connection
> 
> I think this maybe split into three layers (maybe)
> 
> 1 - low level connection: paralell / spi / i2c / whatever
> 2 - vendor: xylinx, altera, etc
> 3 - generic stuff
> 
> Take a look at the MTD and SPI drivers and how they split things

I think that for the moment, I will focus on implementing the core
module and the parallel/SPI interfaces only. Later we may want to add
more fonctionality (vendors, JTAG, etc).

But for now, my main problem is that I need to have some insight on how
I actually implement the different modules:

Bus driver?
class driver?
platform driver?

Can anybody give some advice on that?

Thank-you, Hugo.

---------------
Hugo Villeneuve
www.hugovil.com
---------------
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