Re: [PATCH] fpga: add simple userspace interface to trigger FPGA programming

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Hello,

On Sat, 9 Dec 2017 22:03:06 -0600, Alan Tull wrote:

> > We can actually use the Linux device driver model to do that though.
> > Assuming all peripherals behind the FPGA do have the FPGA manager's
> > struct device as a parent (which they should), when there is a bistream
> > load request, we ought to be able to teardown all of these child struct
> > device's and their corresponding drivers (unbind), load the bistream,
> > and then rebind the drivers accordingly.  
> 
> Hi Florain,
> 
> FPGA regions are a way of handling all that plus the bridges [1] or
> are you proposing something else?  An FPGA region knows what manager
> to use and what bridges (if any) needs to be disabled while
> programming is happening.  Applying a DT overlay targeting a FPGA
> region is used to program the FPGA.

I thought my initial patch made it clear: DT overlays are not an
applicable solution for my use case, for two reasons:

 1. My platform doesn't use Device Tree at all.

 2. The device implemented in the FPGA is self-discoverable because it
    sits on a PCI bus, so there is no point in doing a static
    description of the device in a DT overlay.

So, solutions based on DT overlays are quite irrelevant for my use
case. Am I missing something here ?

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com