hme - SUNW,hme Fast-Ethernet device driver




The SUNW,hme Fast-Ethernet driver is a multi-threaded, loadable,
clonable, STREAMS hardware driver supporting the connectionless Data Link
Provider Interface, dlpi(4P), over a SUNW,hme Fast-Ethernet controller.
The motherboard and add-in SBus SUNW,hme controllers of several varieties
are supported. Multiple SUNW,hme controllers installed within the system
are supported by the driver.

The hme driver provides basic support for the SUNW,hme hardware. It is
used to handle the SUNW,hme device. Functions include chip
initialization, frame transit and receive, multicast and promiscuous
support, and error recovery and reporting. SUNW,hme The SUNW,hme device
provides 100Base-TX networking interfaces using SUN's FEPS ASIC and an
Internal Transceiver. The FEPS ASIC provides the Sbus interface and MAC
functions and the Physical layer functions are provided by the Internal
Transceiver which connects to a RJ-45 connector. In addition to the RJ-45
connector, an MII (Media Independent Interface) connector is also
provided on all SUNW,hme devices except the SunSwith SBus adapter
board. The MII interface is used to connect to an External Transceiver
which may use any physical media (copper or fiber) specified in the
100Base-TX standard. When an External Transceiver is connected to the
MII, the driver selects the External Transceiver and disables the
Internal Transceiver.

The 100Base-TX standard specifies an "auto-negotiation" protocol to
automatically select the mode and speed of operation. The Internal
transceiver is capable of doing "auto-negotiation" with the remote-end of
the link (Link Partner) and receives the capabilities of the remote end.
It selects the Highest Common Denominator mode of operation based on the
priorities. It also supports forced-mode of operation where the driver
can select the mode of operation.


The cloning character-special device /dev/hme is used to access all
SUNW,hme controllers installed within the system.

hme and DLPI
The hme driver is a "style 2" Data Link Service provider. All M_PROTO
and M_PCPROTO type messages are interpreted as DLPI primitives. Valid
DLPI primitives are defined in <sys/dlpi.h>. Refer to dlpi(4P) for more
information. An explicit DL_ATTACH_REQ message by the user is required to
associate the opened stream with a particular device (ppa). The ppa ID is
interpreted as an unsigned long data type and indicates the corresponding
device instance (unit) number. An error (DL_ERROR_ACK) is returned by the
driver if the ppa field value does not correspond to a valid device
instance number for this system. The device is initialized on first
attach and de-initialized (stopped) at last detach.

The values returned by the driver in the DL_INFO_ACK primitive in
response to the DL_INFO_REQ from the user are as follows:

o The maximum SDU is 1500 (ETHERMTU - defined in
<sys/ethernet.h> ).

o The minimum SDU is 0.

o The dlsap address length is 8.

o The MAC type is DL_ETHER.

o The sap length values is -2 meaning the physical address
component is followed immediately by a 2 byte sap component
within the DLSAP address.

o The service mode is DL_CLDLS.

o No optional quality of service (QOS) support is included at
present so the QOS fields are 0.

o The provider style is DL_STYLE2.

o The version is DL_VERSION_2.

o The broadcast address value is Ethernet/IEEE broadcast address

Once in the DL_ATTACHED state, the user must send a DL_BIND_REQ to
associate a particular SAP (Service Access Pointer) with the stream. The
hme driver interprets the sap field within the DL_BIND_REQ as an Ethernet
"type" therefore valid values for the sap field are in the [0-0xFFFF]
range. Only one Ethernet type can be bound to the stream at any time.

If the user selects a sap with a value of 0, the receiver will be in
"802.3 mode". All frames received from the media having a "type" field in
the range [0-1500] are assumed to be 802.3 frames and are routed up all
open Streams which are bound to sap value 0. If more than one Stream is
in "802.3 mode" then the frame will be duplicated and routed up multiple
Streams as DL_UNITDATA_IND messages.

In transmission, the driver checks the sap field of the DL_BIND_REQ if
the sap value is 0, and if the destination type field is in the range
[0-1500]. If either is true, the driver computes the length of the
message, not including initial M_PROTO mblk (message block), of all
subsequent DL_UNITDATA_REQ messages and transmits 802.3 frames that have
this value in the MAC frame header length field.

The hme driver DLSAP address format consists of the 6 byte physical
(Ethernet) address component followed immediately by the 2 byte sap
(type) component producing an 8 byte DLSAP address. Applications should
not hardcode to this particular implementation-specific DLSAP address
format but use information returned in the DL_INFO_ACK primitive to
compose and decompose DLSAP addresses. The sap length, full DLSAP length,
and sap/physical ordering are included within the DL_INFO_ACK. The
physical address length can be computed by subtracting the sap length
from the full DLSAP address length or by issuing the DL_PHYS_ADDR_REQ to
obtain the current physical address associated with the stream.

Once in the DL_BOUND state, the user may transmit frames on the Ethernet
by sending DL_UNITDATA_REQ messages to the hme driver. The hme driver
will route received Ethernet frames up all those open and bound streams
having a sap which matches the Ethernet type as DL_UNITDATA_IND messages.
Received Ethernet frames are duplicated and routed up multiple open
streams if necessary. The DLSAP address contained within the
DL_UNITDATA_REQ and DL_UNITDATA_IND messages consists of both the sap
(type) and physical (Ethernet) components.

In addition to the mandatory connectionless DLPI message set the driver
additionally supports the following primitives.

hme Primitives
The DL_ENABMULTI_REQ and DL_DISABMULTI_REQ primitives enable/disable
reception of individual multicast group addresses. A set of multicast
addresses may be iteratively created and modified on a per-stream basis
using these primitives. These primitives are accepted by the driver in
any state following DL_ATTACHED.

The DL_PROMISCON_REQ and DL_PROMISCOFF_REQ primitives with the
DL_PROMISC_PHYS flag set in the dl_level field enables/disables reception
of all ("promiscuous mode") frames on the media including frames
generated by the local host. When used with the DL_PROMISC_SAP flag set
this enables/disables reception of all sap (Ethernet type) values. When
used with the DL_PROMISC_MULTI flag set this enables/disables reception
of all multicast group addresses. The effect of each is always on a per-
stream basis and independent of the other sap and physical level
configurations on this stream or other streams.

The DL_PHYS_ADDR_REQ primitive returns the 6 octet Ethernet address
currently associated (attached) to the stream in the DL_PHYS_ADDR_ACK
primitive. This primitive is valid only in states following a successful

The DL_SET_PHYS_ADDR_REQ primitive changes the 6 octet Ethernet address
currently associated (attached) to this stream. The credentials of the
process which originally opened this stream must be superuser. Otherwise
EPERM is returned in the DL_ERROR_ACK. This primitive is destructive in
that it affects all other current and future streams attached to this
device. An M_ERROR is sent up all other streams attached to this device
when this primitive is successful on this stream. Once changed, all
streams subsequently opened and attached to this device will obtain this
new physical address. Once changed, the physical address will remain
until this primitive is used to change the physical address again or the
system is rebooted, whichever comes first.

By default, the hme driver performs "auto-negotiation" to select the
mode and speed of the link, when the Internal Transceiver is used.

When an External Transceiver is connected to the MII interface, the
driver selects the External Transceiver for networking operations. If
the External Transceiver supports "auto-negotiation", the driver uses the
auto-negotiation procedure to select the link speed and mode. If the
External Transceiver does not support auto-negotiation, it will select
the highest priority mode supported by the transceiver.

o 100 Mbps, full-duplex

o 100 Mbps, half-duplex

o 10 Mbps, full-duplex

o 10 Mbps, half-duplex

The link can be in one of the 4 following modes:

These speeds and modes are described in the 100Base-TX standard.

The auto-negotiation protocol automatically selects:

o Operation mode (half-duplex or full-duplex)

o Speed (100 Mbps or 10 Mbps)

The auto-negotiation protocol does the following:

o Gets all the modes of operation supported by the Link Partner

o Advertises its capabilities to the Link Partner

o Selects the highest common denominator mode of operation based
on the priorities

The internal transceiver is capable of all of the operating speeds and
modes listed above. When the internal transceiver is used, by default,
auto-negotiation is used to select the speed and the mode of the link and
the common mode of operation with the Link Partner.

When an external transceiver is connected to the MII interface, the
driver selects the external transceiver for networking operations. If the
external transceiver supports auto-negotiation:

o The driver uses the auto-negotiation procedure to select the
link speed and mode.

If the external transceiver does not support auto-negotiation

o The driver selects the highest priority mode supported by the

Sometimes, the user may want to select the speed and mode of the link.
The SUNW,hme device supports programmable "IPG" (Inter-Packet Gap)
parameters ipg1 and ipg2. By default, the driver sets ipg1 to 8 byte-
times and ipg2 to 4 byte-times (which are the standard values).
Sometimes, the user may want to alter these values depending on whether
the driver supports 10 Mbps or 100 Mbps and accordingly, IPG will be set
to 9.6 or 0.96 microseconds.

hme Parameter List
The hme driver provides for setting and getting various parameters for
the SUNW,hme device. The parameter list includes:
current transceiver status
current link status
inter-packet gap
local transceiver capabilities
link partner capabilities

The local transceiver has two set of capabilities: one set reflects the
capabilities of the hardware, which are read-only (RO) parameters and
the second set reflects the values chosen by the user and is used in
speed selection. There are read/write (RW) capabilities. At boot time,
these two sets of capabilities will be the same. The Link Partner
capabilities are also read only parameters because the current default
value of these parameters can only be read and cannot be modified.


hme special character device

System-wide default device driver properties


dlpi(4P), driver.conf(5), ndd(8), netstat(8)

September 5, 1995 HME(4D)