From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162979AbdD0Oua (ORCPT ); Thu, 27 Apr 2017 10:50:30 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:51458 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S968732AbdD0OuO (ORCPT ); Thu, 27 Apr 2017 10:50:14 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 5232C61475 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=okaya@codeaurora.org Subject: Re: Generic DMA-capable streaming device driver looking for home To: Jon Masters , Alex Williams , linux-kernel@vger.kernel.org Cc: Moritz Fischer , dmaengine References: <1492726231.2029.36.camel@ni.com> From: Sinan Kaya Message-ID: <93a062e2-09ef-bb1e-5818-c0b9cc7745c9@codeaurora.org> Date: Thu, 27 Apr 2017 10:50:11 -0400 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.0.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/27/2017 10:00 AM, Jon Masters wrote: > 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? > I added dmaengine group to CC above. I have recently experimented with a similar concept by hacking the rapidio code. http://lxr.free-electrons.com/source/drivers/rapidio/devices/rio_mport_cdev.c It sounds like your code belongs to dmaengine. > > -- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.