1.\" 2.\" Copyright (c) 2017-2019 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 November 9, 2019 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.It Va hint.ntb_hw. Ns Ar X Ns Va .split 58Being set above zero splits BAR2 into 2^x memory windows using Address 59Lookup Table (A-LUT). 60.El 61.Sh DESCRIPTION 62The 63.Nm 64driver provides support for the Non-Transparent Bridge (NTB) hardware in 65PLX PCIe bridge chips, which allow up to two of their PCIe ports to be 66switched from transparent to non-transparent bridge mode. 67In this mode bridge looks not as a PCI bridge, but as PCI endpoint device. 68The driver hides hardware details, exposing memory windows, scratchpads 69and doorbells of the other side via hardware independent KPI to 70.Xr ntb 4 71subsystem. 72.Pp 73Each PLX NTB provides up to 2 64-bit or 4 32-bit memory windows to the 74other system's memory, 6 or 12 scratchpad registers and 16 doorbells to 75interrupt the other system. 76If Address Lookup Table (A-LUT) is enabled, BAR2 can be split into several 77(up to 128) memory windows. 78In NTB-to-NTB mode one of memory windows (or half of it, if bigger then 1MB) 79is consumed by the driver itself to access scratchpad and doorbell registers 80of the other side. 81.Sh HARDWARE 82The following PLX/Avago/Broadcom chips are supported by the 83.Nm 84driver: 85.Pp 86.Bl -bullet -compact 87.It 88PEX 8713 89.It 90PEX 8717 91.It 92PEX 8725 93.It 94PEX 8733 95.It 96PEX 8749 97.El 98.Pp 99, but it may also work with other compatible ones. 100.Sh CONFIGURATION 101The basic chip configuration should be done by serial EEPROM or via i2c. 102It includes enabling NTB on one or both sides (choosing between NTB-to-NTB 103(back-to-back) and NTB-to-Root Port modes) and configuring BARs sizes. 104.Pp 105The recommended mode is NTB-to-NTB mode, since while NTB-to-Root Port is 106generally supported by the driver, it require PCI hotplug handling on the 107Root Port, that may be difficult or cause different kinds of problems. 108.Sh SEE ALSO 109.Xr if_ntb 4 , 110.Xr ntb 4 , 111.Xr ntb_transport 4 112.Sh AUTHORS 113.An -nosplit 114The 115.Nm 116driver was written by 117.An Alexander Motin Aq Mt mav@FreeBSD.org . 118.Sh BUGS 119There is no way to protect your system from malicious behavior on the other 120system once the link is brought up. 121Anyone with root or kernel access on the other system can read or write to 122any location on your system. 123In other words, only connect two systems that completely trust each other. 124