.\" Copyright (c) 2008 Pyun YongHyeon
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
.\" are met:
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.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" $FreeBSD$
.\"
.Dd December 20, 2010
.Dt JME 4
.Os
.Sh NAME
.Nm jme
.Nd JMicron Gigabit/Fast Ethernet driver
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following lines in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device miibus"
.Cd "device jme"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
if_jme_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
device driver provides support for JMicron JMC25x PCI Express
Gigabit Ethernet controllers and JMicron JMC26x PCI Express Fast
Ethernet controllers.
.Pp
All LOMs supported by the
.Nm
driver have TCP/UDP/IP checksum offload for both transmit and receive,
TCP segmentation offload (TSO), hardware VLAN tag stripping/insertion
features, Wake On Lan (WOL) and an interrupt coalescing/moderation
mechanism as well as a 64-bit multicast hash filter.
.Pp
The JMC25x also supports Jumbo Frames (up to 9216 bytes), which can be
configured via the interface MTU setting.
Selecting an MTU larger than 1500 bytes with the
.Xr ifconfig 8
utility configures the adapter to receive and transmit Jumbo Frames.
.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.
.It Cm 100baseTX
Set 100Mbps (Fast Ethernet) operation.
.It Cm 1000baseTX
Set 1000baseTX operation over twisted pair.
.El
.Pp
The
.Nm
driver supports the following media options:
.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
device driver provides support for the following Ethernet controllers:
.Pp
.Bl -bullet -compact
.It
JMicron JMC250 PCI Express Gigabit Ethernet controller
.It
JMicron JMC251 PCI Express Gigabit Ethernet with Card Read Host controller
.It
JMicron JMC260 PCI Express Fast Ethernet controller
.It
JMicron JMC261 PCI Express Gigabit Ethernet with Card Read Host controller
.El
.Sh LOADER TUNABLES
Tunables can be set at the
.Xr loader 8
prompt before booting the kernel or stored in
.Xr loader.conf 5 .
.Bl -tag -width "xxxxxx"
.It Va hw.jme.msi_disable
This tunable disables MSI support on the Ethernet hardware.
The default value is 0.
.It Va hw.jme.msix_disable
This tunable disables MSI-X support on the Ethernet hardware.
The default value is 0.
.El
.Sh SYSCTL VARIABLES
The following variables are available as both
.Xr sysctl 8
variables and
.Xr loader 8
tunables:
.Bl -tag -width "xxxxxx"
.It Va dev.jme.%d.tx_coal_to
Maximum amount of time to delay for Tx completion interrupt in
units of 1us.
The accepted range is 1 to 65535, the default is 100 (100us).
.It Va dev.jme.%d.tx_coal_pkt
Maximum number of packets to fire Tx completion interrupt.
The accepted range is 1 to 255, the default is 8.
.It Va dev.jme.%d.rx_coal_to
Maximum amount of time to delay for Rx completion interrupt in
units of 1us.
The accepted range is 1 to 65535, the default is 100 (100us).
.It Va dev.jme.%d.rx_coal_pkt
Maximum number of packets to fire Rx completion interrupt.
The accepted range is 1 to 255, the default is 2.
.It Va dev.jme.%d.process_limit
Maximum amount of Rx events to be processed in the event loop before
rescheduling a taskqueue.
The accepted range is 10 to 255, the default value is 128 events.
The interface does not need to be brought down and up again before
a change takes effect.
.El
.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
driver was written by
.An Pyun YongHyeon
.Aq yongari@FreeBSD.org .
It first appeared in
.Fx 7.1 .
.Sh CAVEATS
The
.Nm
driver tries to avoid unnecessary station address reprogramming for
controllers that use eFuse to store station address.
The number of times that eFuse can be safely reprogrammed is 16 at
most.
In addition, there is no way to restore factory default station
address once station address is reprogrammed via eFuse.
It is highly recommended not to reprogram station address and
it is responsibility of administrator to store original station
address into a safe place when station address should be changed.