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.Dd December 12, 2016 30.Dt XDMA 4 31.Os 32.Sh NAME 33.Nm xdma 34.Nd DMA abstraction layer 35.Sh SYNOPSIS 36To compile xDMA device support into the kernel, place the following line 37in your kernel configuration file: 38.Bd -ragged -offset indent 39.Cd "device xdma" 40.Ed 41.Pp 42To compile xDMA FDT-based test driver, place the following line as well: 43.Bd -literal -offset indent 44.Cd "device xdma_test" 45.Ed 46.Sh DESCRIPTION 47xDMA is a DMA framework designed to abstract the interaction between device 48drivers and DMA engines. 49.Pp 50xDMA defines an interface for efficient interaction between the device driver 51and DMA controller. 52The 53.Nm 54device provides a virtual DMA controller and virtual channels called xchans. 55The controller provides virtual channels management (allocation, deallocation, 56configuration) and interrupt notification esteblishment needed to receive 57events from the hardware DMA controller. 58.Nm 59supports the following transfer types: 60.Bl -hang -offset indent -width xxxxxxxx 61.It Nm Cyclic 62A non-stop periodic transfer designed for applications like audio. 63.It Nm Memcpy 64A memory-to-memory transfer. 65.El 66.Sh SEE ALSO 67.Xr bus_dma 9 68.Sh HISTORY 69Support for xDMA first appeared in 70.Fx 12.0 . 71.Sh AUTHORS 72.An -nosplit 73.Fx 74xDMA framework was first added by 75.An Ruslan Bukin Aq Mt br@FreeBSD.org . 76