1.\" 2.\" Copyright (c) 2017 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 30, 2017 29.Dt NTB_HW_PLX 4 30.Os 31.Sh NAME 32.Nm ntb_hw_plx 33.Nd PLX/Avago/Broadcom Non-Transparent Bridge driver 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_hw_plx" 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_hw_plx_load="YES" 46.Ed 47.Pp 48The following tunables are settable from the 49.Xr loader 8 : 50.Bl -ohang 51.It Va hint.ntb_hw. Ns Ar X Ns Va .b2b 52Being set to 1 (default) tells the driver attached to Virtual Interface of the 53NTB that it works in NTB-to-NTB (back-to-back) mode, 0 -- NTB-to-Root Port. 54Driver attached to Link Interface (visible from Root Port side) switches to 55NTB-to-Root Port mode automatically, but one attached to Virtual Interface 56can't detect what is on the other side and require external knowledge. 57.El 58.Sh DESCRIPTION 59The 60.Nm 61driver provides support for the Non-Transparent Bridge (NTB) hardware in 62PLX PCIe bridge chips, which allow up to two of their PCIe ports to be 63switched from transparent to non-transparent bridge mode. 64In this mode bridge looks not as a PCI bridge, but as PCI endpoint device. 65The driver hides hardware details, exposing memory windows, scratchpads 66and doorbells of the other side via hardware independent KPI to 67.Xr ntb 4 68subsystem. 69.Pp 70Each PLX NTB provides up to 2 64-bit or 4 32-bit memory windows to the 71other system's memory, 6 or 12 scratchpad registers and 16 doorbells to 72interrupt the other system. 73In NTB-to-NTB mode one of memory windows (or half of it, if bigger then 1MB) 74is consumed by the driver itself to access scratchpad and doorbell registers 75of the other side. 76.Sh HARDWARE 77The following PLX/Avago/Broadcom chips are supported by the 78.Nm 79driver: 80.Pp 81.Bl -bullet -compact 82.It 83PEX 8713 84.It 85PEX 8717 86.It 87PEX 8725 88.It 89PEX 8733 90.It 91PEX 8749 92.El 93.Pp 94, but it may also work with other compatible ones. 95.Sh CONFIGURATION 96The basic chip configuration should be done by serial EEPROM or via i2c. 97It includes enabling NTB on one or both sides (choosing between NTB-to-NTB 98(back-to-back) and NTB-to-Root Port modes) and configuring BARs sizes. 99.Pp 100The recommended mode is NTB-to-NTB mode, since while NTB-to-Root Port is 101generally supported by the driver, it require PCI hotplug handling on the 102Root Port, that may be difficult or cause different kinds of problems. 103.Sh SEE ALSO 104.Xr if_ntb 4 , 105.Xr ntb_transport 4 , 106.Xr ntb 4 , 107.Sh AUTHORS 108.An -nosplit 109The 110.Nm 111driver was written by 112.An Alexander Motin Aq Mt mav@FreeBSD.org . 113.Sh BUGS 114There is no way to protect your system from malicious behavior on the other 115system once the link is brought up. 116Anyone with root or kernel access on the other system can read or write to 117any location on your system. 118In other words, only connect two systems that completely trust each other. 119