From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162588AbdD0OAU (ORCPT ); Thu, 27 Apr 2017 10:00:20 -0400 Received: from edison.jonmasters.org ([173.255.233.168]:43470 "EHLO edison.jonmasters.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1162548AbdD0OAI (ORCPT ); Thu, 27 Apr 2017 10:00:08 -0400 To: Alex Williams , linux-kernel@vger.kernel.org References: <1492726231.2029.36.camel@ni.com> Cc: Moritz Fischer , Sinan Kaya From: Jon Masters Organization: World Organi{s,z}ation Of Broken Dreams Message-ID: Date: Thu, 27 Apr 2017 10:00:04 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.0 MIME-Version: 1.0 In-Reply-To: <1492726231.2029.36.camel@ni.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 74.92.29.237 X-SA-Exim-Mail-From: jcm@jonmasters.org Subject: Re: Generic DMA-capable streaming device driver looking for home X-SA-Exim-Version: 4.2.1 (built Sun, 08 Nov 2009 07:31:22 +0000) X-SA-Exim-Scanned: Yes (on edison.jonmasters.org) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/20/2017 06:10 PM, Alex Williams wrote: > Hi all, > > We're writing a device driver and having some difficulty matching a > subsystem to the driver/device properties. Can anyone help with > direction? > > These are some basic properties: > 1) Device is used to carry generic data to/from userspace. It's a pair > of dumb streams with one sink and one source for each direction (no > addressable endpoints for the other side). > 2) Data goes to/from a DMA engine in an FPGA at high throughput. > 3) The driver enables userspace to queue multiple DMA-able buffers for > asynchronous, pipelined data transfer. We currently use the > videobuf2 API to provide the feature. We're not carrying video data > in general, though. > > It's a piece of a software-defined radio system, and while it can carry > data from DACs/ADCs, the device is only a generic transport. It doesn't > know what data it's carrying, so neither would the driver. > > Some guidance would be greatly appreciated. Thanks! This might be close enough to hidma that Sinan would have suggestions?