1.\" Copyright (c) 2016 Ruslan Bukin <br@bsdpad.com> 2.\" All rights reserved. 3.\" 4.\" This software was developed by SRI International and the University of 5.\" Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237 6.\" ("CTSRD"), as part of the DARPA CRASH research programme. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 17.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27.\" SUCH DAMAGE. 28.\" 29.\" $FreeBSD$ 30.\" 31.Dd December 12, 2016 32.Dt XDMA 4 33.Os 34.Sh NAME 35.Nm xdma 36.Nd DMA abstraction layer 37.Sh SYNOPSIS 38To compile xDMA device support into the kernel, place the following line 39in your kernel configuration file: 40.Bd -ragged -offset indent 41.Cd "device xdma" 42.Ed 43.Pp 44To compile xDMA FDT-based test driver, place the following line as well: 45.Bd -literal -offset indent 46.Cd "device xdma_test" 47.Ed 48.Sh DESCRIPTION 49xDMA is a DMA framework designed to abstract the interaction between device 50drivers and DMA engines. 51.Pp 52xDMA defines an interface for efficient interaction between the device driver 53and DMA controller. 54The 55.Nm 56device provides a virtual DMA controller and virtual channels called xchans. 57The controller provides virtual channels management (allocation, deallocation, 58configuration) and interrupt notification esteblishment needed to receive 59events from the hardware DMA controller. 60.Nm 61supports the following transfer types: 62.Bl -hang -offset indent -width xxxxxxxx 63.It Nm Cyclic 64A non-stop periodic transfer designed for applications like audio. 65.It Nm Memcpy 66A memory-to-memory transfer. 67.El 68.Sh SEE ALSO 69.Xr bus_dma 9 70.Sh HISTORY 71Support for xDMA first appeared in 72.Fx 12.0 . 73.Sh AUTHORS 74.An -nosplit 75.Fx 76xDMA framework was first added by 77.An Ruslan Bukin Aq Mt br@FreeBSD.org . 78