git: 93a95ebbf7c8 - stable/13 - Add genet.4 for RPi 4 Ethernet

The branch stable/13 has been updated by karels:

URL: https://cgit.FreeBSD.org/src/commit/?id=93a95ebbf7c8eb85aeb53a9fde329348992333e7

commit 93a95ebbf7c8eb85aeb53a9fde329348992333e7
Author:     Mike Karels <karels@FreeBSD.org>
AuthorDate: 2021-12-09 14:06:15 +0000
Commit:     Mike Karels <karels@FreeBSD.org>
CommitDate: 2021-12-17 16:02:47 +0000

    Add genet.4 for RPi 4 Ethernet
    
    Add new man page for genet(4) Ethernet on Raspberry Pi 4B, based on
    several other Ethernet man pages.  Hook into build.
    
    Note, this could potentially be added as an aarch64 man page; not
    sure if that matters now.  Include if_genet(4) link as for other
    network devices.
    
    Copyright notice cloned from a recent FreeBSD Foundation copyright.
    
    Reviewed by:    imp bcr #manpages
    Differential Revision: https://reviews.freebsd.org/D33360
    
    (cherry picked from commit 61eaac599ce157b36796dcdac5fb2f420f4bfd8d)
---
 share/man/man4/Makefile |   2 +
 share/man/man4/genet.4  | 183 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 185 insertions(+)

diff --git a/share/man/man4/Makefile b/share/man/man4/Makefile
index be66bf02e9f7..665ecb6b3237 100644
--- a/share/man/man4/Makefile
+++ b/share/man/man4/Makefile
@@ -167,6 +167,7 @@ MAN=	aac.4 \
 	gbde.4 \
 	gdb.4 \
 	gem.4 \
+	genet.4 \
 	geom.4 \
 	geom_linux_lvm.4 \
 	geom_map.4 \
@@ -677,6 +678,7 @@ MLINKS+=fwe.4 if_fwe.4
 MLINKS+=fwip.4 if_fwip.4
 MLINKS+=fxp.4 if_fxp.4
 MLINKS+=gem.4 if_gem.4
+MLINKS+=genet.4 if_genet.4
 MLINKS+=geom.4 GEOM.4
 MLINKS+=gif.4 if_gif.4
 MLINKS+=gpio.4 gpiobus.4
diff --git a/share/man/man4/genet.4 b/share/man/man4/genet.4
new file mode 100644
index 000000000000..bd6e2589d3f5
--- /dev/null
+++ b/share/man/man4/genet.4
@@ -0,0 +1,183 @@
+.\" Copyright (c) 2021 Michael J. Karels
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd December 8, 2021
+.Dt GENET 4
+.Os
+.Sh NAME
+.Nm genet
+.Nd "Raspberry Pi 4 / BCM2711 Gigabit Ethernet controller driver"
+.Sh SYNOPSIS
+To compile this driver into the kernel,
+place the following lines in the
+kernel configuration file:
+.Bd -ragged -offset indent
+.Cd "device miibus"
+.Cd "device genet"
+.Ed
+.Sh DESCRIPTION
+The
+.Nm
+driver supports the BCM2711 Ethernet controller
+as found on the Raspberry Pi 4.
+.Pp
+The following features are supported in the
+.Nm
+driver in
+.Fx :
+.Pp
+.Bl -item -offset indent -compact
+.It
+IP/TCP/UDP checksum offload for IPv4 and IPv6
+.It
+10/100/1000Mbps operation in full-duplex mode
+.It
+10/100Mbps operation in half-duplex mode
+.El
+.Pp
+Note that the operation of transmit checksum offload is coupled
+for IPv4 and IPv6; to disable it, both must be disabled even if both
+address families are not in use.
+.Pp
+The
+.Nm
+driver supports the following media types:
+.Bl -tag -width ".Cm 10baseT/UTP"
+.It Cm autoselect
+Enable autoselection of the media type and options.
+The user can manually override
+the autoselected mode by adding media options to
+.Xr rc.conf 5 .
+.It Cm 10baseT/UTP
+Set 10Mbps operation.
+The
+.Xr ifconfig 8
+.Cm mediaopt
+option can also be used to select either
+.Cm full-duplex
+or
+.Cm half-duplex
+modes.
+.It Cm 100baseTX
+Set 100Mbps (Fast Ethernet) operation.
+The
+.Xr ifconfig 8
+.Cm mediaopt
+option can also be used to select either
+.Cm full-duplex
+or
+.Cm half-duplex
+modes.
+.It Cm 1000baseT
+Set 1000baseT operation over twisted pair.
+Only
+.Cm full-duplex
+mode is supported.
+.El
+.Pp
+The
+.Nm
+driver supports the following media options set with the
+.Cm mediaopt
+option to the
+.Xr ifconfig 8
+command:
+.Bl -tag -width ".Cm full-duplex"
+.It Cm full-duplex
+Force full duplex operation.
+.It Cm half-duplex
+Force half duplex operation.
+.El
+.Pp
+For more information on configuring this device, see
+.Xr ifconfig 8 .
+.Sh HARDWARE
+The
+.Nm
+driver supports the Ethernet controller portion of the Broadcom BCM2711
+on the Raspberry Pi 4 Model B and related systems.
+It utilizes the BCM54213PE PHY.
+.Sh LOADER TUNABLES
+Tunables can be set at the
+.Xr loader 8
+prompt before booting the kernel or stored in
+.Xr loader.conf 5 .
+The following loader tunable variable is available, and is also
+available as a read-only
+.Xr sysctl 8
+variable:
+.Bl -tag -width indent
+.It Va hw.genet.rx_batch
+The maximum number of packets to pass to the link-layer input routine
+at one time.
+The default is 16.
+.El
+.Sh SYSCTL VARIABLES
+The following variable is available as a
+.Xr sysctl 8
+variable:
+.Bl -tag -width indent
+.It Va hw.genet.tx_hdr_min
+When the driver is given an output packet in a buffer chain
+in which the first buffer contains only the Ethernet header,
+the number of bytes of the packet to add to the Ethernet header
+in the first buffer.
+Certain packets may be lost if this value is too small.
+The default value is 56, and is sufficient for the observed cases to date.
+.El
+.Sh DIAGNOSTICS
+The
+.Nm
+driver has no diagnostics that are likely in normal operation.
+However, when the
+.Cm debug
+option is set with
+.Xr ifconfig 8 ,
+most failures that cause packet loss in the transmit and receive paths
+cause a cryptic diagnostic message naming the failure.
+These messages generally make sense only when looking at the driver source.
+.Sh SEE ALSO
+.Xr altq 4 ,
+.Xr arp 4 ,
+.Xr miibus 4 ,
+.Xr netintro 4 ,
+.Xr ng_ether 4 ,
+.Xr vlan 4 ,
+.Xr ifconfig 8
+.Sh HISTORY
+The
+.Nm
+device driver first appeared in
+.Fx 13.0 .
+.Sh AUTHORS
+The
+.Nm
+driver was written by
+.An Mike Karels Aq Mt karels@freebsd.org .
+Portions are derived from the bcmgenet driver in
+.Nx
+by Jared McNeill,
+and parts of the structure and common code are from the awg driver
+for the Allwinner EMAC by Jared McNeill.