Re: [RFC PATCH v2 0/1] FPGA subsystem core

[Greg Kroah-Hartman]

On Tue, Oct 08, 2013 at 11:49:46AM -0500, Alan Tull wrote:
> On Tue, 2013-10-08 at 15:00 +0200, Michal Simek wrote:
> > On 10/07/2013 05:07 PM, H. Peter Anvin wrote:
> > > Special soft IP presenting a PCI device to the host.
> > 
> > ok. It means that you should need just different backend for this device
> > which is able to communicate over PCI.
> > 
> > I still can't see why this case should be problematic for this fpga
> > manager.
> > As Jason pointed if this is just about JTAG emulation and your
> > data is in different format then you have to create your backend
> > which will support this configuration.
> > I will want to look at gpio jtag emulation to be able to program
> > different board. We have this support for u-boot and doing in Linux
> > should be also possible.
> > 
> > I think the question is if we can live with 2/3 user interfaces.
> > I tend to keep firmware one because it is covering a lot of common
> > use cases and it can be easily to use.
> > And then I don't have any preference if sysfs or char device
> 
> The sysfs and char device interface are equal, except I don't think it
> is right to write binary data to a sysfs attribute.

That's exactly what binary sysfs files are for :)

> The difference between these 3 options is that firmware will work for
> some fixed use cases, but either the sysfs or char interface will work
> for all the use cases.

I don't understand how one will work but the other will not, please
explain.

thanks,

greg k-h
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