dc
- DEC/Intel 21143 and clone 10/100 Ethernet driver
SYNOPSIS
To compile this driver into the kernel,
place the following lines in your
kernel configuration file:
device miibusdevice dc
Alternatively, to load the driver as a
module at boot time, place the following line in
loader.conf5:
if_dc_load="YES"
DESCRIPTION
The
driver provides support for several PCI Fast Ethernet adapters and
embedded controllers based on the the DEC/Intel 21143 chipset and clones.
All of supported chipsets have the same general register layout, DMA
descriptor format and method of operation.
All of the clone chips
are based on the 21143 design with various modifications.
The
21143 itself has support for 10baseT, BNC, AUI, MII and symbol
media attachments, 10 and 100Mbps speeds in full or half duplex,
built in NWAY autonegotiation and wake on LAN.
The 21143 also
offers several receive filter programming options including
perfect filtering, inverse perfect filtering and hash table
filtering.
Some clone chips duplicate the 21143 fairly closely while others
only maintain superficial similarities.
Some support only MII
media attachments.
Others use different receiver filter programming
mechanisms.
At least one supports only chained DMA descriptors
(most support both chained descriptors and contiguously allocated
fixed size rings).
Some chips (especially the PNIC) also have
peculiar bugs.
The
driver does its best to provide generalized support for all
of these chipsets in order to keep special case code to a minimum.
These chips are used by many vendors which makes it
difficult to provide a complete list of all supported cards.
The
driver supports the following media types:
autoselect
Enable autoselection of the media type and options.
The user can manually override
the autoselected mode by adding media options to the
/etc/rc.conf
file.
Note: the built-in NWAY autonegotiation on the original PNIC 82c168
chip is horribly broken and is not supported by the
driver at this time (see the
Sx BUGS
section for details).
The original 82c168 appears
on very early revisions of the LinkSys LNE100TX and Matrox FastNIC.
10baseT/UTP
Set 10Mbps operation.
The
mediaopt
option can also be used to enable
full-duplex
operation.
Not specifying
full-duplex
implies
half-duplex
mode.
100baseTX
Set 100Mbps (Fast Ethernet) operation.
The
mediaopt
option can also be used to enable
full-duplex
operation.
Not specifying
full-duplex
implies
half-duplex
mode.
The
driver supports the following media options:
full-duplex
Force full duplex operation.
The interface will operate in
half duplex mode if this media option is not specified.
Note that the 100baseTX media type may not be available on certain
Intel 21143 adapters which support 10Mbps media attachments only.
For more information on configuring this device, see
ifconfig(8).
HARDWARE
The
driver provides support for the following chipsets:
DEC/Intel 21143
ADMtek AL981 Comet, AN985 Centaur, ADM9511 Centaur II and ADM9513
Centaur II
ASIX Electronics AX88140A and AX88141
Conexant LANfinity RS7112 (miniPCI)
Davicom DM9009, DM9100, DM9102 and DM9102A
Lite-On 82c168 and 82c169 PNIC
Lite-On/Macronix 82c115 PNIC II
Macronix 98713, 98713A, 98715, 98715A, 98715AEC-C, 98725, 98727 and 98732
Xircom X3201 (cardbus only)
The
following NICs are known to work with the
driver at this time:
Microsoft MN-120 10/100 CardBus (ADMTek Centaur-C)
Microsoft MN-130 10/100 PCI (ADMTek Centaur-P)
NDC SOHOware SFA110A (98713A)
NDC SOHOware SFA110A Rev B4 (98715AEC-C)
NetGear FA310-TX Rev. D1, D2 or D3 (PNIC 82c169)
Netgear FA511
PlaneX FNW-3602-T (ADMtek AN985)
SMC EZ Card 10/100 1233A-TX (ADMtek AN985)
SVEC PN102-TX (98713)
Xircom Cardbus Realport
Xircom Cardbus Ethernet 10/100
Xircom Cardbus Ethernet II 10/100
NOTES
On sparc64 the
driver respects the
local-mac-address?
system configuration variable for the built in Sun DMFE 10/100 Mbps Ethernet
interfaces on Sun Netra X1 and Sun Fire V100.
This system configuration variable can be set in the Open Firmware boot
monitor using the
setenv
command or by
eeprom(8).
If set to
``false
''
(the default), the
driver will use the system's default MAC address for both of the built in
devices.
If set to
``true
''
the unique MAC address of each interface is used rather than the system's
default MAC address.
DIAGNOSTICS
"dc%d: couldn't map ports/memory"
A fatal initialization error has occurred.
"dc%d: couldn't map interrupt"
A fatal initialization error has occurred.
"dc%d: watchdog timeout"
A packet was queued for transmission and a transmit command was
issued, but the device failed to acknowledge the transmission
before a timeout expired.
This can happen if the device is unable
to deliver interrupts for some reason, of if there is a problem with
the network connection (cable or network equipment) that results in a loss
of link.
"dc%d: no memory for rx list"
The driver failed to allocate an mbuf for the receiver ring.
"dc%d: TX underrun -- increasing TX threshold"
The device generated a transmit underrun error while attempting to
DMA and transmit a packet.
This happens if the host is not able to
DMA the packet data into the NIC's FIFO fast enough.
The driver
will dynamically increase the transmit start threshold so that
more data must be DMAed into the FIFO before the NIC will start
transmitting it onto the wire.
"dc%d: TX underrun -- using store and forward mode"
The device continued to generate transmit underruns even after all
possible transmit start threshold settings had been tried, so the
driver programmed the chip for store and forward mode.
In this mode,
the NIC will not begin transmission until the entire packet has been
transfered into its FIFO memory.
"dc%d: chip is in D3 power state -- setting to D0"
This message applies only to adapters which support power
management.
Some operating systems place the controller in low power
mode when shutting down, and some PCI BIOSes fail to bring the chip
out of this state before configuring it.
The controller loses all of
its PCI configuration in the D3 state, so if the BIOS does not set
it back to full power mode in time, it will not be able to configure it
correctly.
The driver tries to detect this condition and bring
the adapter back to the D0 (full power) state, but this may not be
enough to return the driver to a fully operational condition.
If
you see this message at boot time and the driver fails to attach
the device as a network interface, you will have to perform a second
warm boot to have the device properly configured.
Note that this condition only occurs when warm booting from another
operating system.
If you power down your system prior to booting
Fx ,
the card should be configured correctly.
The Macronix application notes claim that in order to put the
chips in normal operation, the driver must write a certain magic
number into the CSR16 register.
The numbers are documented in
the app notes, but the exact meaning of the bits is not.
The 98713A seems to have a problem with 10Mbps full duplex mode.
The transmitter works but the receiver tends to produce many
unexplained errors leading to very poor overall performance.
The
98715A does not exhibit this problem.
All other modes on the
98713A seem to work correctly.
The original 82c168 PNIC chip has built in NWAY support which is
used on certain early LinkSys LNE100TX and Matrox FastNIC cards,
however it is horribly broken and difficult to use reliably.
Consequently, autonegotiation is not currently supported for this
chipset: the driver defaults the NIC to 10baseT half duplex, and it is
up to the operator to manually select a different mode if necessary.
(Later cards use an external MII transceiver to implement NWAY
autonegotiation and work correctly.)
The
driver programs 82c168 and 82c169 PNIC chips to use the store and
forward setting for the transmit start threshold by default.
This
is to work around problems with some NIC/PCI bus combinations where
the PNIC can transmit corrupt frames when operating at 100Mbps,
probably due to PCI DMA burst transfer errors.
The 82c168 and 82c169 PNIC chips also have a receiver bug that
sometimes manifests during periods of heavy receive and transmit
activity, where the chip will improperly DMA received frames to
the host.
The chips appear to upload several kilobytes of garbage
data along with the received frame data, dirtying several RX buffers
instead of just the expected one.
The
driver detects this condition and will salvage the frame; however,
it incurs a serious performance penalty in the process.
The PNIC chips also sometimes generate a transmit underrun error when
the driver attempts to download the receiver filter setup frame, which
can result in the receive filter being incorrectly programmed.
The
driver will watch for this condition and requeue the setup frame until
it is transfered successfully.
The ADMtek AL981 chip (and possibly the AN985 as well) has been observed
to sometimes wedge on transmit: this appears to happen when the driver
queues a sequence of frames which cause it to wrap from the end of the
transmit descriptor ring back to the beginning.
The
driver attempts to avoid this condition by not queuing any frames past
the end of the transmit ring during a single invocation of the
dc_start ();
routine.
This workaround has a negligible impact on transmit performance.
