1.\" 2.\" Copyright (c) 2016-2019 Alexander Motin <mav@FreeBSD.org> 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd August 29, 2019 29.Dt NTB_TRANSPORT 4 30.Os 31.Sh NAME 32.Nm ntb_transport 33.Nd Packet-oriented transport for Non-Transparent Bridges 34.Sh SYNOPSIS 35To compile this driver into your kernel, 36place the following lines in your kernel configuration file: 37.Bd -ragged -offset indent 38.Cd "device ntb" 39.Cd "device ntb_transport" 40.Ed 41.Pp 42Or, to load the driver as a module at boot, place the following line in 43.Xr loader.conf 5 : 44.Bd -literal -offset indent 45ntb_transport_load="YES" 46.Ed 47.Pp 48The following tunables are settable from the 49.Xr loader 8 : 50.Bl -ohang 51.It Va hw.ntb_transport.debug_level 52Driver debug level. 53The default value is 0, higher means more verbose. 54.It Va hw.ntb_transport.max_mw_size 55Limits maximum memory window usage. 56Allocation of big physically contiguous memory buffer may be a problem, 57while too big buffers makes no much sense for low latency network interface. 58.It Va hint.ntb_transport. Ns Ar X Ns Va .config 59Configures a set of the transport consumers, separated by commas. 60Each consumer can be configured as: "[<name>][:<queues>]", where: 61.Va name 62is a name of the driver to attach (empty means any), 63.Va queues 64is a number of queues to allocate (empty means automatic). 65The default configuration is empty string, which means single consumer 66with one queue per memory window, allowing any driver to attach. 67.El 68.Sh DESCRIPTION 69The 70.Nm 71driver attaches on top of the 72.Nm ntb 73driver to utilize its resources to create a set of bidirectional queues, 74delivering packets between the systems. 75The primary purpose of this driver is to be used by 76.Nm if_ntb 77network interface, but other consumers may also be developed using KPI. 78.Pp 79Each 80.Nm 81require from underlying 82.Nm ntb 83instance: 84.Bl -bullet -compact 85.It 861 or more memory windows; 87.It 886 scratchpads, plus 2 more for each additional memory window; 89.It 901 doorbell for each memory window or configured queue. 91.El 92.Sh SEE ALSO 93.Xr if_ntb 4 , 94.Xr ntb 4 , 95.Xr ntb_hw_amd 4 , 96.Xr ntb_hw_intel 4 , 97.Xr ntb_hw_plx 4 98.Sh AUTHORS 99.An -nosplit 100The 101.Nm 102driver was developed by Intel and originally written by 103.An Carl Delsey Aq Mt carl@FreeBSD.org . 104Later improvements were done by 105.An Conrad E. Meyer Aq Mt cem@FreeBSD.org 106and 107.An Alexander Motin Aq Mt mav@FreeBSD.org . 108