On Tue, Dec 04, 2012 at 08:43:18PM +0000, Arnd Bergmann wrote: > On Tuesday 04 December 2012, Eli Billauer wrote: > > I'm currently writing some documentation which will cover the API and > > also help reading the code, I hope. It takes some time... > > > > Until it's done, let's look at a usage example: Suppose that the FPGA's > > application is to receive a high-speed bitstream with time multiplexed > > data, demultiplex the bitstream into individual channel streams, and > > send each channel's data to the host. And let's say that there are 64 > > channels in original bitstream. So the FPGA has now 64 independent > > sources of data. > > > > For that purpose, the Xillybus IP core (on the FPGA) is configured to > > create 64 pipes for FPGA to host communication. The names of these pipes > > (say, "chan00", "chan01", ...) are also stored in the FPGA. > > > > When the driver starts, it queries the FPGA for its Xillybus > > configuration, and creates 64 device nodes: /dev/xillybus_chan00, > > /dev/xillybus_chan01, ... /dev/xillybus_chan63. > > > > If the user wants to dump the data in channel 43 into a file, it's just: > > > > $ cat /dev/xillybus_chan43 > mydump.dat > > > > I hope this clarified things a bit. > > > > I can't see how the firmware interface would help here. > > I think a lot of us (including Greg and me) were confused about > the purpose of the driver, since you did not include much documentation. > > The request_firmware interface would be useful for loading a model > into the FPGA, but that doesn't seem to be what your driver is > concerned with. It's also a bit confusing because it doesn't appear > to be a "bus" in the Linux sense of being something that provides > an abstract interface between hardware and kernel device drivers.
Yes, that's what I was confused about as well. I'll wait for a new patch with new documentation, before commenting further. greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
