LE(4) | Device Drivers Manual | LE(4) |
le
—
nele0 at isa? port 0x320 irq 9 drq 7 # NE2100
le* at nele?
bicc0 at isa? port 0x320 irq 10 drq 7 # BICC Isolan
le* at bicc?
depca0 at isa? port 0x300 iomem 0xc8000 iosiz 0x8000 irq 5 #
DEC DEPCA
le* at depca?
le* at isapnp? # ISA Plug-and-Play adapters
depca* at eisa? slot ? # DEC DE422
le* at depca?
le* at mca? slot ? # SKNET Personal/MC2+
le* at pci? dev? function ?
le* at tc? slot ? offset ?
le* at ioasic? offset ?
le* at zbus0
le0 at vme0 irq 4 # BVME410
le0 at vme0 irq 5 # Riebl/PAM
le* at dio? scode ?
le0 at pcc? ipl 3 # MVME147
le0 at hb0 addr 0xe0f00000 ipl 4
le0 at hb0 addr 0xbff80000 level 1
le* at ioasic? offset ?
le* at ibus0 addr ?
le* at sbus? slot ? offset ?
le* at ledma0 slot ? offset ?
le* at lebuffer? slot ? offset ?
le0 at obio0 addr 0x120000 ipl 3
options LANCE_REVC_BUG
le0 at vsbus0 csr 0x200e0000
le
interface provides access to a Ethernet network
via the AMD Am7990 and Am79C90 (CMOS, pin-compatible) LANCE (Local Area
Network Controller - Ethernet) chip set.
The le
driver also supports PCnet-PCI
cards based on the AMD 79c970 chipset, which is a single-chip implementation
of a LANCE chip and PCI bus interface.
Each of the host's network addresses is specified at boot time
with an SIOCSIFADDR
ioctl(2). The
le
interface employs the Address Resolution Protocol
(ARP) described in arp(4) to
dynamically map between Internet and Ethernet addresses on the local
network.
Selective reception of multicast Ethernet frames is provided by a 64-bit mask; multicast destination addresses are hashed to a bit entry using the Ethernet CRC function.
The use of “trailer” encapsulation to minimize copying data on input and output is supported by the interface but offers no advantage on systems with large page sizes. The use of trailers is automatically negotiated with ARP. This negotiation may be disabled, on a per-interface basis, with ifconfig(8).
le
interface supports the following Zorro II
expansion cards:
The A2065 and Ameristar Ethernet cards support only manual media selection.
The Ariadne card supports a software media selection for its two different connectors:
The Ariadne card uses an autoselect between UTP and BNC, so it uses UTP when an active UTP line is connected or otherwise BNC. See ifmedia(4) for media selection options for ifconfig(8).
le
interface
are:
le
interface are:
le
interface
are:
No support is provided for switching between media ports. The DECstation 3100 provides both AUI and BNC (thinwire or 10BASE2) connectors. Port selection is via a manual switch and is not software configurable.
The DECstation model 5000/200 PMAD-AA baseboard device provides only a BNC connector.
The ioasic
baseboard devices and the
PMAD-AA TURBOchannel option card provide only an AUI port.
le
interface
include:
Interfaces attached to an ledma0 on SPARC systems typically have two types of connectors:
The appropriate connector can be selected by supplying a
media
parameter to
ifconfig(8). The supported
arguments for media
are:
If a media
parameter is not specified, a
default connector is selected for use by examining all media types for
carrier. The first connector on which a carrier is detected will be
selected. Additionally, if carrier is dropped on a port, the driver will
switch between the possible ports until one with carrier is found.
TDR is “Time Domain Reflectometry”. The LANCE TDR value is an internal counter of the interval between the start of a transmission and the occurrence of a collision. This value can be used to determine the distance from the Ethernet tap to the point on the Ethernet cable that is shorted or open (unterminated).
le
driver allocates buffers large enough to
receive the maximum size Ethernet packet, this means some other station on
the LAN transmitted a packet larger than allowed by the Ethernet
standard.Am79C90 - CMOS Local Area Network Controller for Ethernet, 17881, May 1994, Advanced Micro Devices.
le
driver is derived from a
le
driver that first appeared in
4.4BSD. Support for multiple bus attachments first
appeared in NetBSD 1.2.
The Amiga le
interface first appeared in
NetBSD 1.0
The Ariadne Ethernet card first appeared with the Amiga ae
interface in NetBSD 1.1 and was converted to the
Amiga le
interface in NetBSD
1.3
LANCE_REVC_BUG
kernel
option.
When LANCE_REVC_BUG
is enabled, the
le
driver executes one or two calls to an inline
Ethernet address comparison function for every received packet. On the
mc68000 it is exactly eight instructions of 16 bits each. There is one
comparison for each unicast packet, and two comparisons for each broadcast
packet.
In summary, the cost of the LANCE_REVC_BUG option is:
All sun3 systems are presumed to have this bad revision of the Am7990, until proven otherwise. Alas, the only way to prove what revision of the chip is in a particular system is inspection of the date code on the chip package, to compare against a list of what chip revisions were fabricated between which dates.
Alas, the Am7990 chip is so old that AMD has “de-archived” the production information about it; pending a search elsewhere, we don't know how to identify the revision C chip from the date codes.
On all pmax front-ends, performance is impaired by hardware which
forces a software copy of packets to and from DMA buffers. The
ioasic
machines and the DECstation 3100 must copy
packets to and from non-contiguous DMA buffers. The DECstation 5000/200 and
the PMAD-AA must copy to and from an onboard SRAM DMA buffer. The CPU
overhead is noticeable, but all machines can sustain full 10 Mb/s media
speed.
April 27, 2001 | NetBSD 9.4 |