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

[Jason Gunthorpe]

On Wed, Oct 09, 2013 at 01:37:05PM -0700, H. Peter Anvin wrote:

> A very common use case would be where a device contains an FPGA but is
> presented to the user as a product, often having its own device driver
> to drive the programmed device and/or additional logic.  From *that*
> point of view it would be nice if the FPGA subsystem had the capability
> for the *device driver* to trigger a firmware load request which is then
> fed to the FPGA subsystem for programming.  This would be an in-kernel
> interface, in other words.

That is sort of backwards though, how does the driver know it should
load and start fpga progamming?

The way we are working driver attach today is to program the FPGA,
under control of user space, and then do a PCI rescan, which discovers
the FPGA device and triggers driver binding of the PCI FPGA driver.

Please keep in mind that loading the wrong FPGA could permanently
destroy the system. This is why we have meta-data encoded with the
bitstream. The user space loader does some sanity checks :)

Jason
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/